Patent Publication Number: US-2022218407-A1

Title: Surgical end effector jaw and electrode configurations

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 15/472,668, entitled SURGICAL END EFFECTOR JAW AND ELECTRODE CONFIGURATIONS, filed on Mar. 29, 2017, now U.S. Patent Application No. 2017/0296257, which is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 15/392,265, entitled SURGICAL END EFFECTOR JAW AND ELECTRODE CONFIGURATIONS, filed on Dec. 28, 2016, now U.S. Patent Application Publication No. 2017/0105785, which is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 13/536,393, entitled SURGICAL END EFFECTOR JAW AND ELECTRODE CONFIGURATIONS, filed on Jun. 28, 2012, now U.S. Patent Application Publication No. 2014/0005640, the entire disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Over the years a variety of minimally invasive robotic (or “telesurgical”) systems have been developed to increase surgical dexterity as well as to permit a surgeon to operate on a patient in an intuitive manner. Many of such systems are disclosed in the following U.S. patents which are each herein incorporated by reference in their respective entirety: U.S. Pat. No. 5,792,135, entitled ARTICULATED SURGICAL INSTRUMENT FOR PERFORMING MINIMALLY INVASIVE SURGERY WITH ENHANCED DEXTERITY AND SENSITIVITY, U.S. Pat. No. 6,231,565, entitled ROBOTIC ARM DLUS FOR PERFORMING SURGICAL TASKS, U.S. Pat. No. 6,783,524, entitled ROBOTIC SURGICAL TOOL WITH ULTRASOUND CAUTERIZING AND CUTTING INSTRUMENT, U.S. Pat. No. 6,364,888, entitled ALIGNMENT OF MASTER AND SLAVE IN A MINIMALLY INVASIVE SURGICAL APPARATUS, U.S. Pat. No. 7,524,320, entitled MECHANICAL ACTUATOR INTERFACE SYSTEM FOR ROBOTIC SURGICAL TOOLS, U.S. Pat. No. 7,691,098, entitled PLATFORM LINK WRIST MECHANISM, U.S. Pat. No. 7,806,891, entitled REPOSITIONING AND REORIENTATION OF MASTER/SLAVE RELATIONSHIP IN MINIMALLY INVASIVE TELESURGERY, and U.S. Pat. No. 7,824,401, entitled SURGICAL TOOL WITH WRITED MONOPOLAR ELECTROSURGICAL END EFFECTORS. Many of such systems, however, have in the past been unable to generate the magnitude of forces required to effectively cut and fasten tissue. In addition, existing robotic surgical systems are limited in the number of different types of surgical devices that they may operate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of example embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
       Various example embodiments are described herein by way of example in conjunction with the following FIGS. wherein: 
         FIG. 1  is a perspective view of one embodiment of a robotic controller. 
         FIG. 2  is a perspective view of a robotic surgical arm cart/manipulator of a robotic system operably supporting a plurality of surgical tool embodiments. 
         FIG. 3  is a side view of one embodiment of the robotic surgical arm cart/manipulator depicted in  FIG. 2 . 
         FIG. 4  is a perspective view of a cart structure with positioning linkages for operably supporting robotic manipulators that may be used with surgical tool embodiments. 
         FIG. 5  is a perspective view of a surgical tool embodiment and a surgical end effector embodiment. 
         FIG. 6  is a perspective view of one embodiment of an electrosurgical tool in electrical communication with a generator 
         FIG. 7  shows a perspective view of one embodiment of the end effector of the surgical tool of  FIG. 6  with the jaw members open and the distal end of an axially movable member in a retracted position. 
         FIG. 8  shows a perspective view of one embodiment of the end effector of the surgical tool of  FIG. 6  with the jaw members closed and the distal end of an axially movable member in a partially advanced position. 
         FIG. 9  is a perspective view of one embodiment of the axially moveable member of the surgical tool of  FIG. 6 . 
         FIG. 10  is a section view of one embodiment of the electrosurgical end effector of the surgical tool of  FIG. 6 . 
         FIG. 11  is an exploded assembly view of one embodiment of an adapter and tool holder arrangement for attaching various surgical tool embodiments to a robotic system. 
         FIG. 12  is a side view of one embodiment of the adapter shown in  FIG. 11 . 
         FIG. 13  is a bottom view of one embodiment of the adapter shown in  FIG. 11 . 
         FIG. 14  is a top view of one embodiment of the adapter of  FIGS. 11 and 12 . 
         FIG. 15  is a partial bottom perspective view of one embodiment of a surgical tool. 
         FIG. 16  is a front perspective view of one embodiment of a portion of a surgical tool with some elements thereof omitted for clarity. 
         FIG. 17  is a rear perspective view of one embodiment of the surgical tool of  FIG. 16 . 
         FIG. 18  is a top view of one embodiment of the surgical tool of  FIGS. 16 and 17 . 
         FIG. 19  is a partial top view of one embodiment of the surgical tool of  FIGS. 16-18  with the manually actuatable drive gear in an unactuated position. 
         FIG. 20  is another partial top view of one embodiment of the surgical tool of  FIGS. 16-19  with the manually actuatable drive gear in an initially actuated position. 
         FIG. 21  is another partial top view of one embodiment of the surgical tool of  FIGS. 16-20  with the manually actuatable drive gear in an actuated position. 
         FIG. 22  is a rear perspective view of another surgical tool embodiment. 
         FIG. 23  is a side elevational view of one embodiment of the surgical tool of  FIG. 22 . 
         FIG. 24  is a cross-sectional view of one embodiment of a portion of an articulation joint and end effector. 
         FIG. 24A  illustrates one embodiment of the shaft assembly and articulation joint of  FIG. 24  showing connections between distal cable sections and proximal cable portions. 
         FIG. 25  is an exploded assembly view of one embodiment of a portion of the articulation joint and end effector of  FIG. 24 . 
         FIG. 26  is a partial cross-sectional perspective view of one embodiment of the articulation joint and end effector portions depicted in  FIG. 25 . 
         FIG. 27  is a partial perspective view of an end effector and drive shaft assembly embodiment. 
         FIG. 28  is a partial side view of one embodiment of a drive shaft assembly. 
         FIG. 29  is a perspective view of one embodiment of a drive shaft assembly. 
         FIG. 30  is a side view of one embodiment of the drive shaft assembly of  FIG. 29 . 
         FIG. 31  is a perspective view of one embodiment of a composite drive shaft assembly. 
         FIG. 32  is a side view of one embodiment of the composite drive shaft assembly of  FIG. 31 . 
         FIG. 33  is another view of one embodiment of the drive shaft assembly of  FIGS. 29 and 30  assuming an arcuate or “flexed” configuration. 
         FIG. 33A  is a side view of one embodiment of a drive shaft assembly assuming an arcuate or “flexed” configuration. 
         FIG. 33B  is a side view of one embodiment of another drive shaft assembly assuming an arcuate or “flexed” configuration. 
         FIG. 34  is a perspective view of a portion of another drive shaft assembly embodiment. 
         FIG. 35  is a top view of the drive shaft assembly embodiment of  FIG. 34 . 
         FIG. 36  is another perspective view of the drive shaft assembly embodiment of  FIGS. 34 and 35  in an arcuate configuration. 
         FIG. 37  is a top view of the drive shaft assembly embodiment depicted in  FIG. 36 . 
         FIG. 38  is a perspective view of another drive shaft assembly embodiment. 
         FIG. 39  is another perspective view of the drive shaft assembly embodiment of  FIG. 38  in an arcuate configuration. 
         FIG. 40  is a top view of the drive shaft assembly embodiment of  FIGS. 38 and 39 . 
         FIG. 41  is a cross-sectional view of the drive shaft assembly embodiment of  FIG. 40 . 
         FIG. 42  is a partial cross-sectional view of another drive shaft assembly embodiment. 
         FIG. 43  is another cross-sectional view of the drive shaft assembly embodiment of  FIG. 42 . 
         FIG. 44  is another cross-sectional view of a portion of another drive shaft assembly embodiment. 
         FIG. 45  is another cross-sectional view of one embodiment of the drive shaft assembly of  FIG. 44 . 
         FIG. 46  is a perspective view of another surgical tool embodiment. 
         FIG. 47  is a cross-sectional perspective view of the surgical tool embodiment of FIG. 
         FIG. 48  is a cross-sectional perspective view of a portion of one embodiment of an articulation system. 
         FIG. 49  is a cross-sectional view of one embodiment of the articulation system of  FIG. 48  in a neutral position. 
         FIG. 50  is another cross-sectional view of one embodiment of the articulation system of  FIGS. 48 and 49  in an articulated position. 
         FIG. 51  is a side elevational view of a portion of one embodiment of the surgical tool of  FIGS. 46-47  with portions thereof omitted for clarity. 
         FIG. 52  is a rear perspective view of a portion of one embodiment of the surgical tool of  FIGS. 46-47  with portions thereof omitted for clarity. 
         FIG. 53  is a rear elevational view of a portion of one embodiment of the surgical tool of  FIGS. 46-47  with portions thereof omitted for clarity. 
         FIG. 54  is a front perspective view of a portion of one embodiment of the surgical tool of  FIGS. 46-47  with portions thereof omitted for clarity. 
         FIG. 55  is a side elevational view of a portion of the surgical tool embodiment of  FIGS. 46-47  with portions thereof omitted for clarity. 
         FIG. 56  is an exploded assembly view of an example reversing system embodiment of the surgical tool of  FIGS. 46-47 . 
         FIG. 57  is a perspective view of a lever arm embodiment of the reversing system of  FIG. 56 . 
         FIG. 58  is a perspective view of a knife retractor button of one embodiment of the reversing system of  FIG. 56 . 
         FIG. 59  is a perspective view of a portion of the surgical tool embodiment of  FIGS. 46-47  with portions thereof omitted for clarity and with the lever arm in actuatable engagement with the reversing gear. 
         FIG. 60  is a perspective view of a portion of the surgical tool embodiment of  FIGS. 46-47  with portions thereof omitted for clarity and with the lever arm in an unactuated position. 
         FIG. 61  is another perspective view of a portion of the surgical tool embodiment of  FIGS. 46-47  with portions thereof omitted for clarity and with the lever arm in actuatable engagement with the reversing gear. 
         FIG. 62  is a side elevational view of a portion of a handle assembly portion of the surgical tool embodiment of  FIGS. 46-47  with a shifter button assembly moved into a position which will result in the rotation of the end effector when the drive shaft assembly is actuated. 
         FIG. 63  is another side elevational view of a portion of a handle assembly portion of one embodiment of the surgical tool of  FIGS. 46-47  with the a shifter button assembly moved into another position which will result in the firing of the firing member in the end effector when the drive shaft assembly is actuated. 
         FIG. 64  is a perspective view of an embodiment of a multi-axis articulating and rotating surgical tool. 
         FIG. 65  is an exploded perspective view of various components of one embodiment of the surgical tool shown in  FIG. 64 . 
         FIG. 66  is a partial cross-sectional perspective view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating a rotary drive shaft engaging a rotary drive nut for actuating translation of an I-beam member and closure of a jaw assembly of an end effector. 
         FIG. 67  is a cross-sectional perspective view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating a rotary drive shaft engaging a rotary drive nut for actuating translation of an I-beam member and closure of a jaw assembly of an end effector. 
         FIG. 68  is a partial cross-sectional perspective view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating a rotary drive shaft engaging a shaft coupling for actuating rotation of an end effector. 
         FIG. 69  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the jaw assembly of an end effector in an open position, an I-beam member in a proximally retracted position, and a rotary drive shaft engaging a rotary drive nut for actuating translation of the I-beam member and closure of the jaw assembly of the end effector. 
         FIG. 70  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the jaw assembly of an end effector in a closed position, an I-beam member in a distally advanced position, and a rotary drive shaft engaging a rotary drive nut for actuating translation of the I-beam member and opening of the jaw assembly of the end effector. 
         FIG. 71  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the jaw assembly of an end effector in an open position, an I-beam member in a proximally retracted position, and a rotary drive shaft engaging a shaft coupling for actuating rotation of the end effector. 
         FIG. 72  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the jaw assembly of an end effector in a closed position, an I-beam member in a distally advanced position, and a rotary drive shaft engaging a shaft coupling for actuating rotation of the end effector. 
         FIGS. 73 and 74  are side cross-sectional detail views of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the engagement of cam surfaces of an I-beam member with anvil surfaces of a first jaw member to move the first jaw member relative to a second jaw member between an open position and a closed position. 
         FIG. 75  is an exploded view of the components comprising an embodiment of a multi-axis articulating and rotating surgical tool comprising a head locking mechanism. 
         FIG. 76  is an exploded view of spline lock components of one embodiment of the head locking mechanism of the surgical tool illustrated in  FIG. 75 . 
         FIG. 77  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 75 , illustrating the jaw assembly of an end effector in an open position, an I-beam member in a proximally retracted position, a rotary drive shaft engaging a rotary drive nut for actuating translation of the I-beam member and closure of the jaw assembly of the end effector, and an engaged spline lock preventing rotation of the end effector. 
         FIG. 78  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 75 , illustrating the jaw assembly of an end effector in a closed position, an I-beam member in a distally advanced position, a rotary drive shaft engaging a rotary drive nut for actuating translation of the I-beam member and opening of the jaw assembly of the end effector, and an engaged spline lock preventing rotation of the end effector. 
         FIG. 79  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 75 , illustrating the jaw assembly of an end effector in an open position, an I-beam member in a proximally retracted position, a rotary drive shaft engaging a shaft coupling for actuating rotation of the end effector, and a disengaged spline lock allowing rotation of the end effector. 
         FIG. 80  is a side cross-sectional view of one embodiment of the surgical tool shown in  FIG. 64 , illustrating the jaw assembly of an end effector in a closed position, an I-beam member in a distally advanced position, a rotary drive shaft engaging a shaft coupling for actuating rotation of the end effector, and a disengaged spline lock allowing rotation of the end effector. 
         FIG. 81  is a side cross-sectional detail view of one embodiment of the surgical tool shown in  FIG. 80 . 
         FIG. 82  is a side cross-sectional detail view of one embodiment of the surgical tool shown in  FIG. 78 . 
         FIG. 83  is a cross sectional perspective view of a surgical tool having first and second jaw members in accordance with certain embodiments described herein. 
         FIG. 84  is prospective view of a closure nut of one embodiment of the surgical tool of  FIG. 83 . 
         FIG. 85  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially open position, and wherein the rotary drive shaft is operably disengaged with the rotary drive nut. 
         FIG. 86  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially open position, and wherein the rotary drive shaft is operably engaged with the rotary drive nut. 
         FIG. 87  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially closed position, wherein the rotary drive shaft is operably engaged with the rotary drive nut, and wherein the closure nut is operably disengaged from the rotary drive nut. 
         FIG. 88  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially closed position, wherein the rotary drive shaft is operably engaged with the rotary drive nut, and wherein the I-beam member is at least partially extended. 
         FIG. 89  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially closed position, wherein the rotary drive shaft is operably engaged with the rotary drive nut, and wherein the I-beam member is at least partially retracted. 
         FIG. 90  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially closed position, wherein the rotary drive shaft is operably engaged with the rotary drive nut, and wherein the I-beam member is at least partially retracted. 
         FIG. 91  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 83  wherein the first jaw member and the second jaw member are in an at least partially open position, wherein the rotary drive shaft is operably engaged with the rotary drive nut, and wherein the closure nut is operably engaged from the rotary drive nut. 
         FIG. 92  is a cross sectional perspective view of a surgical tool having first and second jaw members in accordance with certain embodiments described herein. 
         FIG. 93  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 92  wherein the first jaw member and the second jaw member are in an at least partially open position, and wherein the rotary drive shaft is operably engaged with spline coupling portion of the end effector drive housing. 
         FIG. 94  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 92  wherein the first jaw member and the second jaw member are in an at least partially closed position, and wherein the rotary drive shaft is operably engaged with spline coupling portion of the barrel cam. 
         FIG. 95  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 92  wherein the first jaw member and the second jaw member are in an at least partially closed position, and wherein the rotary drive shaft is not operably engaged with any of the spline coupling portions. 
         FIG. 96  is a cross sectional elevation view of one embodiment of the surgical tool of  FIG. 92  wherein the first jaw member and the second jaw member are in an at least partially closed position, and wherein the rotary drive shaft is operably engaged with spline coupling portion of the rotary drive nut. 
         FIG. 97  illustrates a perspective view of an end effector and an articulation joint of a surgical instrument in accordance with at least one embodiment illustrated with portions removed for the purposes of illustration. 
         FIG. 98  illustrates a detail view of a drive shaft in accordance with at least one embodiment configured to be translated within the end effector and the articulation joint of  FIG. 97 . 
         FIG. 99  illustrates a perspective view of a drive shaft in accordance with at least one alternative embodiment. 
         FIG. 100  illustrates an elevational view of one embodiment of the drive shaft of  FIG. 99 . 
         FIG. 101  illustrates an elevational view of one embodiment of the drive shaft of  FIG. 99  illustrated in an articulated condition. 
         FIG. 102  illustrates a perspective view of a drive shaft assembly comprising a drive tube and a thread extending around the drive tube in accordance with at least one alternative embodiment. 
         FIG. 103  illustrates an elevational view of one embodiment of the drive shaft assembly of  FIG. 102 . 
         FIG. 104  illustrates a perspective view of a drive shaft assembly comprising a drive tube, a thread extending around the drive tube, and an inner core extending through the drive tube in accordance with at least one embodiment. 
         FIG. 105  illustrates an elevational view of one embodiment of the drive shaft assembly of  FIG. 104 . 
         FIG. 106  is a perspective view of a surgical tool having first and second jaw members in accordance with certain embodiments described herein. 
         FIG. 107  is cross sectional view of distal portions of one embodiment of the first and second jaw members of the surgical end tool shown in  FIG. 106 . 
         FIG. 108  is a perspective view of a surgical end effector and a shaft assembly in accordance with certain embodiments described herein. 
         FIG. 109  is a prospective view of a jaw member of a surgical end effector in accordance with certain embodiments described herein. 
         FIG. 110  is a cross-sectional view of a surgical effector detached from a shaft assembly in accordance with certain embodiments described herein. 
         FIG. 111  is a cross-sectional view of a surgical effector attached to a shaft assembly in accordance with certain embodiments described herein. 
         FIG. 112  is a perspective view of multiple interchangeable surgical end effectors in accordance with certain embodiments described herein. 
         FIG. 113  is a perspective view of a surgical end effector including a cross sectional view of a jaw member in accordance with certain embodiments described herein. 
         FIG. 114  is a cross-sectional view of a surgical effector detached from a shaft assembly in accordance with certain embodiments described herein. 
         FIG. 115  is a cross-sectional view of a surgical effector attached to a shaft assembly in accordance with certain embodiments described herein. 
         FIG. 116  is a perspective view of a surgical end effector having first and second jaws in accordance with certain embodiments described herein. 
         FIG. 117  is another perspective view of the surgical end effector shown in  FIG. 116  including a cross sectional perspective view of a jaw member in accordance with certain embodiments described herein. 
         FIG. 118  is cross sectional view of a first jaw member and a second jaw member of a surgical end effector in accordance with certain embodiments described herein. 
         FIG. 119  is cross sectional view of a first jaw member and a second jaw member of a surgical end effector in accordance with certain embodiments described herein 
         FIG. 120  is a perspective view of a first jaw member and a second jaw member of a surgical end effector in accordance with certain embodiments described herein. 
         FIG. 121  is a prospective view of a distal portion of a jaw member of a surgical end effector in accordance with certain embodiments described herein. 
         FIG. 122  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 123  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 124  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 125  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 126  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 127  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 128  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 129  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 130  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 131  is a top view of a gripping portion in accordance with certain embodiments described herein. 
         FIG. 132  is a perspective view of one embodiment of an end effector having first and second jaw members in an open position and angled tissue-contacting surfaces along substantially the entire length of the jaw members. 
         FIG. 133  is another perspective view of one embodiment of the end effector shown in  FIG. 132  with the first and second jaw members in a closed position. 
         FIG. 134  is a front view of one embodiment of the end effector shown in  FIG. 133 . 
         FIG. 135  is a cross-sectional view of one embodiment of the end effector shown in  FIG. 134 . 
         FIG. 136  is a side view of one embodiment of the end effector shown in  FIG. 132 . 
         FIG. 137  is a side view of one embodiment of the end effector shown in  FIG. 133 . 
         FIG. 138  is a schematic diagram showing a front view of one embodiment of an end effector having first and second jaw members, wherein each jaw member has two oppositely-angled tissue-contacting surfaces. 
         FIG. 139  is a perspective view of one embodiment of an end effector having first and second jaw members in an open position and angled tissue-contacting surfaces along a portion of the length of the jaw members. 
         FIG. 140  is another perspective view of one embodiment of the end effector shown in  FIG. 139 . 
         FIG. 141  is a perspective view of one embodiment of an end effector having first and second jaw members in an open position, angled tissue-contacting surfaces along a portion of the length of the jaw members, and electrodes positioned between the two angled tissue-contacting surfaces on the second jaw member. 
         FIG. 142  is a cross-sectional view of one embodiment of an end effector having first and second jaw members in a closed position clamping tissue between the jaw members, wherein the first and second jaw members have opposed angled tissue-contacting surfaces. 
         FIG. 143  is a cross-sectional view of one embodiment of the end effector and shaft assembly of  FIGS. 64-82  illustrating an example installation of a rotary electrode assembly. 
         FIG. 144  is an exploded view of one embodiment of the end effector and shaft assembly of  FIG. 143  showing the rotary electrode assembly both installed and exploded. 
         FIG. 145  is a cross-sectional view of one embodiment of the end effector and shaft assembly of  FIG. 143  showing the rotary electrode assembly with a rotary drive head in a proximal position. 
         FIG. 146  is a cross-sectional view of one embodiment of the end effector and shaft assembly of  FIG. 143  showing the rotary electrode assembly with the rotary drive head in a distal position. 
         FIGS. 147-148  are cross-sectional views of one embodiment of the end effector and shaft assembly of  FIG. 143  where a longitudinal length of the outer contact is selected such that the rotary connector assembly alternately creates and breaks an electrical connection limited by the longitudinal position of the brush assembly. 
         FIGS. 149-150  illustrate one embodiment of the end effector and shaft assembly of  FIG. 143  showing a configuration including lead portions and connector assembly between the end effector and the shaft assembly. 
         FIG. 151  illustrates a cross-sectional view one embodiment of an end effector and shaft assembly showing another context in which a rotary connector assembly may utilized. 
         FIG. 152  illustrates a cross-sectional view of one embodiment of the end effector and shaft assembly of  FIGS. 83-91  illustrating another example installation of a rotary electrode assembly. 
         FIG. 153  illustrates one embodiment of an end effector that may be utilized with various surgical tools, including those described herein. 
         FIG. 154  illustrates one embodiment of the end effector of  FIG. 153  showing a tissue contacting portion adjacent a longitudinal channel of the second jaw member of the end effector. 
         FIG. 155  illustrates one embodiment of the end effector of  FIG. 153  showing an axial cross-section along a midline of the first jaw member showing a tissue-contacting portion disposed adjacent to a longitudinal channel of the first jaw member. 
         FIG. 156  illustrates a perspective view of one embodiment of the end effector of  FIG. 153  in an open position. 
         FIG. 157  illustrates a top view of one embodiment of a second jaw member suitable for use with the end effector of  FIG. 153 . 
         FIG. 158  illustrates a bottom view of one embodiment of a first jaw member suitable for use with the end effector of  FIG. 153 . 
         FIG. 159  illustrates a front cross-sectional view of another embodiment of the end effector of  FIG. 153  in a closed position. 
         FIGS. 160-165  illustrates side cross-sectional views of various embodiments of the end effector of  FIG. 153   
         FIG. 166  illustrates another embodiment of the second jaw member suitable for use with the end effector of  FIG. 153 . in a closed position holding a surgical implement. 
         FIG. 167  illustrates one embodiment of the second jaw member suitable for use with the end effector of  FIG. 153 . 
         FIG. 168  illustrates another embodiment of the second jaw member suitable for use with the end effector of  FIG. 153 . 
     
    
    
     DETAILED DESCRIPTION 
     Applicant of the present application also owns the following patent applications that have been filed on Jun. 28, 2012 and which are each herein incorporated by reference in their respective entireties:
     1. U.S. patent application Ser. No. 13/536,271, entitled FLEXIBLE DRIVE MEMBER, now U.S. Pat. No. 9,204,879.   2. U.S. patent application Ser. No. 13/536,288, entitled MULTI-FUNCTIONAL POWERED SURGICAL DEVICE WITH EXTERNAL DISSECTION FEATURES, now U.S. Patent Application Publication No. 2014/0005718 A1.   3. U.S. patent application Ser. No. 13/536,277, entitled COUPLING ARRANGEMENTS FOR ATTACHING SURGICAL END EFFECTORS TO DRIVE SYSTEMS THEREFOR, now U.S. Patent Application Publication No. 2014/0001234 A1.   4. U.S. patent application Ser. No. 13/536,295, entitled ROTARY ACTUATABLE CLOSURE ARRANGEMENT FOR SURGICAL END EFFECTOR, now U.S. Pat. No. 9,119,657.   5. U.S. patent application Ser. No. 13/536,326, entitled SURGICAL END EFFECTORS HAVING ANGLED TISSUE-CONTACTING SURFACES, now U.S. Pat. No. 9,289,256.   6. U.S. patent application Ser. No. 13/536,303, entitled INTERCHANGEABLE END EFFECTOR COUPLING ARRANGEMENT, now U.S. Pat. No. 9,028,494.   7. U.S. patent application Ser. No. 13/536,362, entitled MULTI-AXIS ARTICULATING AND ROTATING SURGICAL TOOLS, now U.S. Pat. No. 9,125,662.   8. U.S. patent application Ser. No. 13/536,284, entitled DIFFERENTIAL LOCKING ARRANGEMENTS FOR ROTARY POWERED SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,072,536.   9. U.S. patent application Ser. No. 13/536,374, entitled INTERCHANGEABLE CLIP APPLIER, now U.S. Pat. No. 9,561,038.   10. U.S. patent application Ser. No. 13/536,292, entitled FIRING SYSTEM LOCKOUT ARRANGEMENTS FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2014/0001231 A1.   11. U.S. patent application Ser. No. 13/536,301, entitled ROTARY DRIVE SHAFT ASSEMBLIES FOR SURGICAL INSTRUMENTS WITH ARTICULATABLE END EFFECTORS, now U.S. Pat. No. 8,747,238.   12. U.S. patent application Ser. No. 13/536,313, entitled ROTARY DRIVE ARRANGEMENTS FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2014/0005678 A1.   13. U.S. patent application Ser. No. 13/536,323, entitled ROBOTICALLY POWERED SURGICAL DEVICE WITH MANUALLY-ACTUATABLE REVERSING SYSTEM, now U.S. Pat. No. 9,408,606.   14. U.S. patent application Ser. No. 13/536,379, entitled REPLACEABLE CLIP CARTRIDGE FOR A CLIP APPLIER, now U.S. Patent Application Publication No. 2014/0005694 A1.   15. U.S. patent application Ser. No. 13/536,386, entitled EMPTY CLIP CARTRIDGE LOCKOUT, now U.S. Pat. No. 9,282,974.   16. U.S. patent application Ser. No. 13/536,360, entitled SURGICAL INSTRUMENT SYSTEM INCLUDING REPLACEABLE END EFFECTORS, now U.S. Pat. No. 9,226,751.   17. U.S. patent application Ser. No. 13/536,335, entitled ROTARY SUPPORT JOINT ASSEMBLIES FOR COUPLING A FIRST PORTION OF A SURGICAL INSTRUMENT TO A SECOND PORTION OF A SURGICAL INSTRUMENT, now U.S. Pat. No. 9,364,230.   18. U.S. patent application Ser. No. 13/536,417, entitled ELECTRODE CONNECTIONS FOR ROTARY DRIVEN SURGICAL TOOLS, now U.S. Pat. No. 9,101,385.   

     Applicant also owns the following patent applications that are each incorporated by reference in their respective entireties:
     U.S. patent application Ser. No. 13/118,259, entitled SURGICAL INSTRUMENT WITH WIRELESS COMMUNICATION BETWEEN A CONTROL UNIT OF A ROBOTIC SYSTEM AND REMOTE SENSOR, now U.S. Pat. No. 8,684,253;   U.S. patent application Ser. No. 13/118,210, entitled ROBOTICALLY-CONTROLLED DISPOSABLE MOTOR DRIVEN LOADING UNIT, now U.S. Pat. No. 8,752,749;   U.S. patent application Ser. No. 13/118,194, entitled ROBOTICALLY-CONTROLLED ENDOSCOPIC ACCESSORY CHANNEL, now U.S. Pat. No. 8,992,422;   U.S. patent application Ser. No. 13/118,253, entitled ROBOTICALLY-CONTROLLED MOTORIZED SURGICAL INSTRUMENT, now U.S. Pat. No. 9,386,983;   U.S. patent application Ser. No. 13/118,278, entitled ROBOTICALLY-CONTROLLED SURGICAL STAPLING DEVICES THAT PRODUCE FORMED STAPLES HAVING DIFFERENT LENGTHS, now U.S. Pat. No. 9,237,891;   U.S. patent application Ser. No. 13/118,190, entitled ROBOTICALLY-CONTROLLED MOTORIZED CUTTING AND FASTENING INSTRUMENT, now U.S. Pat. No. 9,179,912;   U.S. patent application Ser. No. 13/118,223, entitled ROBOTICALLY-CONTROLLED SHAFT BASED ROTARY DRIVE SYSTEMS FOR SURGICAL INSTRUMENTS, now U.S. Pat. No. 8,931,682;   U.S. patent application Ser. No. 13/118,263, entitled ROBOTICALLY-CONTROLLED SURGICAL INSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Patent Application Publication No. 2011/0295295 A1;   U.S. patent application Ser. No. 13/118,272, entitled ROBOTICALLY-CONTROLLED SURGICAL INSTRUMENT WITH FORCE FEEDBACK CAPABILITIES, U.S. Patent Application Publication No. 2011/0290856 A1;   U.S. patent application Ser. No. 13/118,246, entitled ROBOTICALLY-DRIVEN SURGICAL INSTRUMENT WITH E-BEAM DRIVER, Now U.S. Pat. No. 9,060,770; and   U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535.   

     Certain example embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these example embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting example embodiments and that the scope of the various example embodiments of the present invention is defined solely by the claims. The features illustrated or described in connection with one example embodiment may be combined with the features of other example embodiments. Such modifications and variations are intended to be included within the scope of the present invention. 
       FIG. 1  depicts a master controller  12  that is used in connection with a robotic arm slave cart  20  of the type depicted in  FIG. 2 . Master controller  12  and robotic arm slave cart  20 , as well as their respective components and control systems are collectively referred to herein as a robotic system  10 . Examples of such systems and devices are disclosed in U.S. Pat. No. 7,524,320 which has been herein incorporated by reference. Thus, various details of such devices will not be described in detail herein beyond that which may be necessary to understand various example embodiments disclosed herein. As is known, the master controller  12  generally includes master controllers (generally represented as  14  in  FIG. 1 ) which are grasped by the surgeon and manipulated in space while the surgeon views the procedure via a stereo display  16 . The master controllers  12  generally comprise manual input devices which preferably move with multiple degrees of freedom, and which often further have an actuatable handle for actuating tools (for example, for closing grasping jaws, applying an electrical potential to an electrode, or the like). 
     As can be seen in  FIG. 2 , the robotic arm cart  20  is configured to actuate a plurality of surgical tools, generally designated as  30 . Various robotic surgery systems and methods employing master controller and robotic arm cart arrangements are disclosed in U.S. Pat. No. 6,132,368, entitled MULTI-COMPONENT TELEPRESENCE SYSTEM AND METHOD, the full disclosure of which is incorporated herein by reference. As shown, the robotic arm cart  20  includes a base  22  from which, in the illustrated embodiment, three surgical tools  30  are supported. The surgical tools  30  are each supported by a series of manually articulatable linkages, generally referred to as set-up joints  32 , and a robotic manipulator  34 . These structures are herein illustrated with protective covers extending over much of the robotic linkage. These protective covers may be optional, and may be limited in size or entirely eliminated to minimize the inertia that is encountered by the servo mechanisms used to manipulate such devices, to limit the volume of moving components so as to avoid collisions, and to limit the overall weight of the cart  20 . The cart  20  generally has dimensions suitable for transporting the cart  20  between operating rooms. The cart  20  is configured to typically fit through standard operating room doors and onto standard hospital elevators. The cart  20  would preferably have a weight and include a wheel (or other transportation) system that allows the cart  20  to be positioned adjacent an operating table by a single attendant. 
     Referring now to  FIG. 3 , robotic manipulators  34  as shown include a linkage  38  that constrains movement of the surgical tool  30 . Linkage  38  includes rigid links coupled together by rotational joints in a parallelogram arrangement so that the surgical tool  30  rotates around a point in space  40 , as more fully described in U.S. Pat. No. 5,817,084, the full disclosure of which is herein incorporated by reference. The parallelogram arrangement constrains rotation to pivoting about an axis  40   a , sometimes called the pitch axis. The links supporting the parallelogram linkage are pivotally mounted to set-up joints  32  ( FIG. 2 ) so that the surgical tool  30  further rotates about an axis  40   b , sometimes called the yaw axis. The pitch and yaw axes  40   a ,  40   b  intersect at the remote center  42 , which is aligned along a shaft  44  of the surgical tool  30 . The surgical tool  30  may have further degrees of driven freedom as supported by manipulator  50 , including sliding motion of the surgical tool  30  along the longitudinal tool axis “LT-LT”. As the surgical tool  30  slides along the tool axis LT-LT relative to manipulator  50  (arrow  40   c ), remote center  42  remains fixed relative to base  52  of manipulator  50 . Hence, the entire manipulator is generally moved to re-position remote center  42 . Linkage  54  of manipulator  50  is driven by a series of motors  56 . These motors actively move linkage  54  in response to commands from a processor of a control system. Motors  56  are also employed to manipulate the surgical tool  30 . An alternative set-up joint structure is illustrated in  FIG. 4 . In this embodiment, a surgical tool  30  is supported by an alternative manipulator structure  50 ′ between two tissue manipulation tools. 
     Other embodiments may incorporate a wide variety of alternative robotic structures, including those described in U.S. Pat. No. 5,878,193, entitled AUTOMATED ENDOSCOPE SYSTEM FOR OPTIMAL POSITIONING, the full disclosure of which is incorporated herein by reference. Additionally, while the data communication between a robotic component and the processor of the robotic surgical system is described with reference to communication between the surgical tool  30  and the master controller  12 , similar communication may take place between circuitry of a manipulator, a set-up joint, an endoscope or other image capture device, or the like, and the processor of the robotic surgical system for component compatibility verification, component-type identification, component calibration (such as off-set or the like) communication, confirmation of coupling of the component to the robotic surgical system, or the like. 
     A surgical tool  100  that is well-adapted for use with a robotic system  10  is depicted in  FIGS. 5-6 .  FIG. 5  illustrates an additional embodiment of the surgical tool  100  and electrosurgical end effector  3000 . As can be seen in  FIG. 5 , the surgical tool  100  includes an electrosurgical end effector  3000 . The electrosurgical end effector  3000  may utilize electrical energy to treat and/or destroy tissue. The electrosurgical end effector  3000  generally comprises first and second jaw members  3008 A,  3008 B which may be straight, as shown in  FIGS. 6-10 , or curved as shown in various other figures described herein. One or both of the jaw members  3008 A,  3008 B generally comprise various electrodes for providing electrosurgical energy to tissue. The surgical tool  100  generally includes an elongate shaft assembly  200  that is operably coupled to the manipulator  50  by a tool mounting portion, generally designated as  300 . Electrosurgical tools (e.g., surgical tools that include an electrosurgical end effector, such at the tool  100  and end effector  3000 ) may be used in any suitable type of surgical environment including, for example, open, laparoscopic, endoscopic, etc. 
     Generally, electrosurgical tools comprise one or more electrodes for providing electric current. The electrodes may be positioned against and/or positioned relative to tissue such that electrical current can flow through the tissue. The electrical current may generate heat in the tissue that, in turn, causes one or more hemostatic seals to form within the tissue and/or between tissues. For example, tissue heating caused by the electrical current may at least partially denature proteins within the tissue. Such proteins, such as collagen, for example, may be denatured into a proteinaceous amalgam that intermixes and fuses, or “welds”, together as the proteins renature. As the treated region heals over time, this biological “weld” may be reabsorbed by the body&#39;s wound healing process. 
     Electrical energy provided by electrosurgical tools may be of any suitable form including, for example, direct or alternating current. For example, the electrical energy may include high frequency alternating current such as radio frequency or “RF” energy. RF energy may include energy in the range of 300 kilohertz (kHz) to 1 megahertz (MHz). When applied to tissue, RF energy may cause ionic agitation or friction, increasing the temperature of the tissue. Also, RF energy may provide a sharp boundary between affected tissue and other tissue surrounding it, allowing surgeons to operate with a high level of precision and control. The low operating temperatures of RF energy enables surgeons to remove, shrink or sculpt soft tissue while simultaneously sealing blood vessels. RF energy works particularly well on connective tissue, which is primarily comprised of collagen and shrinks when contacted by heat. 
     In certain arrangements, some bi-polar (e.g., two-electrode) electrosurgical tools can comprise opposing first and second jaw members, where the face of each jaw can comprise a current path and/or electrode. In use, the tissue can be captured between the jaw faces such that electrical current can flow between the electrodes in the opposing jaw members and through the tissue positioned therebetween. Such tools may have to coagulate, seal or “weld” many types of tissues, such as anatomic structures having walls with irregular or thick fibrous content, bundles of disparate anatomic structures, substantially thick anatomic structures, and/or tissues with thick fascia layers such as large diameter blood vessels, for example. Some embodiments may include a knife or cutting edge to transect the tissue, for example, during or after the application of electrosurgical energy. With particular regard to cutting and sealing large diameter blood vessels, for example, such applications may require a high strength tissue weld immediately post-treatment. 
       FIG. 6  is a perspective view of one embodiment of the electrosurgical tool  100  in electrical communication with a generator  3002 . The electrosurgical tool  100  in conjunction with the generator  3002  can be configured to supply energy, such as electrical energy, ultrasonic energy, and/or heat energy, for example, to the tissue of a patient. In the illustrated embodiment and in functionally similar embodiments, the generator  3002  is connected to electrosurgical tool  100  via a suitable transmission medium such as a cable  3010 . In one embodiment, the generator  3002  is coupled to a controller, such as a control unit  3004 , for example. In various embodiments, the control unit  3004  may be formed integrally with the generator  3002  or may be provided as a separate circuit module or device electrically coupled to the generator  3002  (shown in phantom to illustrate this option). Although in the presently disclosed embodiment, the generator  3002  is shown separate from the electrosurgical tool  100 , in one embodiment, the generator  3002  (and/or the control unit  3004 ) may be formed integrally with the electrosurgical tool  100  to form a unitary electrosurgical system. For example, in some embodiments a generator or equivalent circuit may be present within the tool mounting portion  300  and/or within a handle in suitable manual embodiments (as described herein). 
     The generator  3002  may comprise an input device  3006  located on a front panel of the generator  3002  console. The input device  3006  may comprise any suitable device that generates signals suitable for programming the operation of the generator  3002 , such as a keyboard, or input port, for example. In one embodiment, various electrodes in the first jaw member  3008 A and the second jaw member  3008 B may be coupled to the generator  3002 . A cable  3010  connecting the tool mounting portion  300  to the generator  3002  may comprise multiple electrical conductors for the application of electrical energy to positive (+) and negative (−) electrodes of the electrosurgical tool  100 . The control unit  3004  may be used to activate the generator  3002 , which may serve as an electrical source. In various embodiments, the generator  3002  may comprise an RF source, an ultrasonic source, a direct current source, and/or any other suitable type of electrical energy source, for example. 
     In various embodiments, surgical tool  100  may comprise at least one supply conductor  3012  and at least one return conductor  3014 , wherein current can be supplied to electrosurgical tool  100  via the supply conductor  3012  and wherein the current can flow back to the generator  3002  via return conductor  3014 . In various embodiments, the supply conductor  3012  and the return conductor  3014  may comprise insulated wires and/or any other suitable type of conductor. In certain embodiments, as described below, the supply conductor  3012  and the return conductor  3014  may be contained within and/or may comprise the cable  3010  extending between, or at least partially between, the generator  3002  and the end effector  3000  of the electrosurgical tool  100 . In any event, the generator  3002  can be configured to apply a sufficient voltage differential between the supply conductor  3012  and the return conductor  3014  such that sufficient current can be supplied to the end effector  3000 . 
     The electrosurgical end effector  3000  may be adapted for capturing and transecting tissue and for the contemporaneously welding the captured tissue with controlled application of energy (e.g., RF energy).  FIG. 7  illustrates one embodiment of the electrosurgical end effector  3000  with the jaw members  3008 A,  3008 B open and an axially movable member  3016  in a proximally retracted position.  FIG. 8  illustrates one embodiment of the electrosurgical end effector  3000  with the jaw members  3008 A,  3008 B closed and the axially movable member  3016  in a partially advanced position. 
     In use, the jaw members  3008 A,  3008 B close to thereby capture or engage tissue about a longitudinal tool axis LT-LT defined by the axially moveable member  3016  (or a distal portion thereof). The first jaw member  3008 A and second jaw member  3008 B may also apply compression to the tissue. In some embodiments, the elongate shaft  200 , along with first jaw member  3008 A and second jaw member  3008 B, can be rotated a full 360° degrees, as shown by arrow  3018  (see  FIG. 8 ), relative to tool mounting portion  300 . 
     The first jaw member  3008 A and the second jaw member  3008 B may each comprise an elongate slot or channel  3020 A and  3020 B ( FIG. 7 ), respectively, disposed outwardly along their respective middle portions. Further, the first jaw member  3008 A and second jaw member  3008 B may each have tissue-gripping elements, such as teeth  3022 , disposed on the inner portions of first jaw member  3008 A and second jaw member  3008 B. The lower jaw member  3008 B may define a jaw body with an energy delivery surface or electrode  3024 B. For example, the electrode  3024 B may be in electrical communication with the generator  3002  via the supply conductor  3012 . An energy delivery surface  3024 A on the upper first jaw member  3008  may provide a return path for electrosurgical energy. For example, the energy delivery surface  3024 A may be in electrical communication with the return conductor  3014 . In the illustrated embodiment and in functionally similar embodiments, other conductive parts of the surgical tool  100  including, for example the jaw members  3008 A,  3008 B, the shaft  200 , etc. may form all or a part of the return path. Various configurations of electrodes and various configurations for coupling the energy delivery surfaces  3024 A,  3024 B to the conductors  3012 ,  3014  are described herein. Also, it will be appreciated that the supply electrode  3024 B may be provided on the lower jaw member  3008 B as shown or on the upper jaw member  3008 A. 
     Distal and proximal translation of the axially moveable member  3016  may serve to open and close the jaw members  3008 A,  3008 B and to sever tissue held therebetween.  FIG. 9  is a perspective view of one embodiment of the axially moveable member  3016  of the surgical tool  100 . The axially moveable member  3016  may comprise one or several pieces, but in any event, may be movable or translatable with respect to the elongate shaft  200  and/or the jaw members  3008 A,  3008 B. Also, in at least one embodiment, the axially moveable member  3016  may be made of 17-4 precipitation hardened stainless steel. The distal end of axially moveable member  3016  may comprise a flanged “I”-beam configured to slide within the channels  3020 A and  3020 B in jaw members  3008 A and  3008 B. The axially moveable member  3016  may slide within the channels  3020 A,  3020 B to open and close first jaw member  3008 A and second jaw member  3008 B. The distal end of the axially moveable member  3016  may also comprise an upper flange or “c”-shaped portion  3016 A and a lower flange or “c”-shaped portion  3016 B. The flanges  3016 A and  3016 B respectively define inner cam surfaces  3026 A and  3026 B for engaging outward facing surfaces of first jaw member  3008 A and second jaw member  3008 B. The opening-closing of jaw members  3008 A and  3008 B can apply very high compressive forces on tissue using cam mechanisms which may include movable “I-beam” axially moveable member  3016  and the outward facing surfaces  3028 A,  3028 B of jaw members  3008 A,  3008 B. 
     More specifically, referring now to  FIGS. 7-9 , collectively, the inner cam surfaces  3026 A and  3026 B of the distal end of axially moveable member  3016  may be adapted to slidably engage the first outward-facing surface  3028 A and the second outward-facing surface  3028 B of the first jaw member  3008 A and the second jaw member  3008 B, respectively. The channel  3020 A within first jaw member  3008 A and the channel  3020 B within the second jaw member  3008 B may be sized and configured to accommodate the movement of the axially moveable member  3016 , which may comprise a tissue-cutting element  3030 , for example, comprising a sharp distal edge.  FIG. 8 , for example, shows the distal end of the axially moveable member  3016  advanced at least partially through channels  3020 A and  3020 B ( FIG. 7 ). The advancement of the axially moveable member  3016  may close the end effector  3000  from the open configuration shown in  FIG. 7 . In the closed position shown by  FIG. 8 , the upper first jaw member  3008 A and lower second jaw member  3008 B define a gap or dimension D between the first energy delivery surface  3024 A and second energy delivery surface  3024 B of first jaw member  3008 A and second jaw member  3008 B, respectively. In various embodiments, dimension D can equal from about 0.0005″ to about 0.040″, for example, and in some embodiments, between about 0.001″ to about 0.010″, for example. Also, the edges of the first energy delivery surface  3024 A and the second energy delivery surface  3024 B may be rounded to prevent the dissection of tissue. 
       FIG. 10  is a section view of one embodiment of the end effector  3000  of the surgical tool  100 . The engagement, or tissue-contacting, surface  3024 B of the lower jaw member  3008 B is adapted to deliver energy to tissue, at least in part, through a conductive-resistive matrix, such as a variable resistive positive temperature coefficient (PTC) body, as discussed in more detail below. At least one of the upper and lower jaw members  3008 A,  3008 B may carry at least one electrode  3032  configured to deliver the energy from the generator  3002  to the captured tissue. The engagement, or tissue-contacting, surface  3024 A of upper jaw member  3008 A may carry a similar conductive-resistive matrix (i.e., a PTC material), or in some embodiments the surface may be a conductive electrode or an insulative layer, for example. Alternatively, the engagement surfaces of the jaw members can carry any of the energy delivery components disclosed in U.S. Pat. No. 6,773,409, filed Oct. 22, 2001, entitled ELECTROSURGICAL JAW STRUCTURE FOR CONTROLLED ENERGY DELIVERY, the entire disclosure of which is incorporated herein by reference. 
     The first energy delivery surface  3024 A and the second energy delivery surface  3024 B may each be in electrical communication with the generator  3002 . The first energy delivery surface  3024 A and the second energy delivery surface  3024 B may be configured to contact tissue and deliver electrosurgical energy to captured tissue which are adapted to seal or weld the tissue. The control unit  3004  regulates the electrical energy delivered by electrical generator  3002  which in turn delivers electrosurgical energy to the first energy delivery surface  3024 A and the second energy delivery surface  3024 B. The energy delivery may be initiated in any suitable manner (e.g., upon actuation of the robot system  10 . In one embodiment, the electrosurgical tool  100  may be energized by the generator  3002  by way of a foot switch  3034  ( FIG. 6 ). When actuated, the foot switch  3034  triggers the generator  3002  to deliver electrical energy to the end effector  3000 , for example. The control unit  3004  may regulate the power generated by the generator  3002  during activation. Although the foot switch  3034  may be suitable in many circumstances, other suitable types of switches can be used. 
     As mentioned above, the electrosurgical energy delivered by electrical generator  3002  and regulated, or otherwise controlled, by the control unit  3004  may comprise radio frequency (RF) energy, or other suitable forms of electrical energy. Further, one or both of the opposing first and second energy delivery surfaces  3024 A and  3024 B may carry variable resistive positive temperature coefficient (PTC) bodies that are in electrical communication with the generator  3002  and the control unit  3004 . Additional details regarding electrosurgical end effectors, jaw closing mechanisms, and electrosurgical energy-delivery surfaces are described in the following U.S. patents and published patent applications: U.S. Pat. Nos. 7,087,054; 7,083,619; 7,070,597; 7,041,102; 7,011,657; 6,929,644; 6,926,716; 6,913,579; 6,905,497; 6,802,843; 6,770,072; 6,656,177; 6,533,784; and 6,500,176; and U.S. Patent Application Publication Nos. 2010/0036370 and 2009/0076506, all of which are incorporated herein in their entirety by reference and made a part of this specification. 
     In one embodiment, the generator  3002  may be implemented as an electrosurgery unit (ESU) capable of supplying power sufficient to perform bipolar electrosurgery using radio frequency (RF) energy. In one embodiment, the ESU can be a bipolar ERBE ICC  350  sold by ERBE USA, Inc. of Marietta, Ga. In some embodiments, such as for bipolar electrosurgery applications, a surgical tool having an active electrode and a return electrode can be utilized, wherein the active electrode and the return electrode can be positioned against, adjacent to and/or in electrical communication with, the tissue to be treated such that current can flow from the active electrode, through the positive temperature coefficient (PTC) bodies and to the return electrode through the tissue. Thus, in various embodiments, the electrosurgical system  150  may comprise a supply path and a return path, wherein the captured tissue being treated completes, or closes, the circuit. In one embodiment, the generator  3002  may be a monopolar RF ESU and the electrosurgical tool  100  may comprise a monopolar end effector  3000  in which one or more active electrodes are integrated. For such a system, the generator  3002  may require a return pad in intimate contact with the patient at a location remote from the operative site and/or other suitable return path. The return pad may be connected via a cable to the generator  3002 . 
     During operation of electrosurgical tool  100 , the clinician generally grasps tissue, supplies energy to the captured tissue to form a weld or a seal (e.g., by actuating button  214  and/or pedal  216 ), and then drives the tissue-cutting element  3030  at the distal end of the axially moveable member  3016  through the captured tissue. According to various embodiments, the translation of the axial movement of the axially moveable member  3016  may be paced, or otherwise controlled, to aid in driving the axially moveable member  3016  at a suitable rate of travel. By controlling the rate of the travel, the likelihood that the captured tissue has been properly and functionally sealed prior to transection with the cutting element  3030  is increased. 
     Referring now to the embodiment depicted in  FIGS. 11-15 , the tool mounting portion  300  includes a tool mounting plate  304  that operably supports a plurality of (four are shown in  FIG. 15 ) rotatable body portions, driven discs or elements  306 , that each include a pair of pins  308  that extend from a surface of the driven element  306 . One pin  308  is closer to an axis of rotation of each driven elements  306  than the other pin  308  on the same driven element  306 , which helps to ensure positive angular alignment of the driven element  306 . Interface  302  may include an adaptor portion  310  that is configured to mountingly engage a mounting plate  304  as will be further discussed below. The illustrated adaptor portion  310  includes an array of electrical connecting pins  312  ( FIG. 13 ) which may be coupled to a memory structure by a circuit board within the tool mounting portion  300 . While interface  302  is described herein with reference to mechanical, electrical, and magnetic coupling elements, it should be understood that a wide variety of telemetry modalities might be used, including infrared, inductive coupling, or the like in other embodiments. 
     As can be seen in  FIGS. 11-14 , the adapter portion  310  generally includes a tool side  314  and a holder side  316 . A plurality of rotatable bodies  320  are mounted to a floating plate  318  which has a limited range of movement relative to the surrounding adaptor structure normal to the major surfaces of the adaptor  310 . Axial movement of the floating plate  318  helps decouple the rotatable bodies  320  from the tool mounting portion  300  when levers or other latch formations along the sides of the tool mounting portion housing (not shown) are actuated. Other embodiments may employ other mechanisms/arrangements for releasably coupling the tool mounting portion  300  to the adaptor  310 . In the embodiment of  FIGS. 11-15 , rotatable bodies  320  are resiliently mounted to floating plate  318  by resilient radial members which extend into a circumferential indentation about the rotatable bodies  320 . The rotatable bodies  320  can move axially relative to plate  318  by deflection of these resilient structures. When disposed in a first axial position (toward tool side  314 ) the rotatable bodies  320  are free to rotate without angular limitation. However, as the rotatable bodies  320  move axially toward tool side  314 , tabs  322  (extending radially from the rotatable bodies  320 ) laterally engage detents on the floating plates so as to limit angular rotation of the rotatable bodies  320  about their axes. This limited rotation can be used to help drivingly engage the rotatable bodies  320  with drive pins  332  of a corresponding tool holder portion  330  of the robotic system  10 , as the drive pins  332  will push the rotatable bodies  320  into the limited rotation position until the pins  332  are aligned with (and slide into) openings  334 ′. Openings  334  on the tool side  314  and openings  334 ′ on the holder side  316  of rotatable bodies  320  are configured to accurately align the driven elements  306  ( FIG. 15 ) of the tool mounting portion  300  with the drive elements  336  of the tool holder  330 . As described above regarding inner and outer pins  308  of driven elements  306 , the openings  304 ,  304 ′ are at differing distances from the axis of rotation on their respective rotatable bodies  306  so as to ensure that the alignment is not 180 degrees from its intended position. Additionally, each of the openings  304  may be slightly radially elongate so as to fittingly receive the pins  308  in the circumferential orientation. This allows the pins  308  to slide radially within the openings  334 ,  334 ′ and accommodate some axial misalignment between the tool  100  and tool holder  330 , while minimizing any angular misalignment and backlash between the drive and driven elements. Openings  334  on the tool side  314  may be offset by about 90 degrees from the openings  334 ′ (shown in broken lines) on the holder side  316 , as can be seen most clearly in  FIG. 14 . 
     In the embodiment of  FIGS. 11-15 , an array of electrical connector pins  340  are located on holder side  316  of adaptor  310  and the tool side  314  of the adaptor  310  includes slots  342  ( FIG. 14 ) for receiving a pin array (not shown) from the tool mounting portion  300 . In addition to transmitting electrical signals between the surgical tool  100  and the tool holder  330 , at least some of these electrical connections may be coupled to an adaptor memory device  344  ( FIG. 13 ) by a circuit board of the adaptor  310 . 
     In the embodiment of  FIGS. 11-15 , a detachable latch arrangement  346  is employed to releasably affix the adaptor  310  to the tool holder  330 . As used herein, the term “tool drive assembly” when used in the context of the robotic system  10 , at least encompasses the adapter  310  and tool holder  330  and which have been collectively generally designated as  110  in  FIG. 11 . As can be seen in  FIG. 11 , the tool holder  330  includes a first latch pin arrangement  337  that is sized to be received in corresponding clevis slots  311  provided in the adaptor  310 . In addition, the tool holder  330  further has second latch pins  338  that are sized to be retained in corresponding latch clevises  313  in the adaptor  310 . See  FIG. 11 . A latch assembly  315  is movably supported on the adapter  310  and has a pair of latch devises  317  formed therein that is biasable from a first latched position wherein the latch pins  338  are retained within their respective latch clevis  313  and an unlatched position wherein the devises  317  are aligned with devises  313  to enable the second latch pins  338  may be inserted into or removed from the latch devises  313 . A spring or springs (not shown) are employed to bias the latch assembly into the latched position. A lip on the tool side  314  of adaptor  310  slidably receives laterally extending tabs of the tool mounting housing (not shown). 
     Referring now to  FIGS. 5 and 16-21 , the tool mounting portion  300  operably supports a plurality of drive systems for generating various forms of control motions necessary to operate a particular type of end effector that is coupled to the distal end of the elongate shaft assembly  200 . As shown in  FIGS. 5 and 16-21 , the tool mounting portion  300  includes a first drive system generally designated as  350  that is configured to receive a corresponding “first” rotary output motion from the tool drive assembly  110  of the robotic system  10  and convert that first rotary output motion to a first rotary control motion to be applied to the surgical end effector. In the illustrated embodiment, the first rotary control motion is employed to rotate the elongate shaft assembly  200  (and surgical end effector  3000 ) about a longitudinal tool axis LT-LT. 
     In the embodiment of  FIGS. 5 and 16-18 , the first drive system  350  includes a tube gear segment  354  that is formed on (or attached to) the proximal end  208  of a proximal tube segment  202  of the elongate shaft assembly  200 . The proximal end  208  of the proximal tube segment  202  is rotatably supported on the tool mounting plate  304  of the tool mounting portion  300  by a forward support cradle  352  that is mounted on the tool mounting plate  304 . See  FIG. 16 . The tube gear segment  354  is supported in meshing engagement with a first rotational gear assembly  360  that is operably supported on the tool mounting plate  304 . As can be seen in  FIG. 16 , the rotational gear assembly  360  comprises a first rotation drive gear  362  that is coupled to a corresponding first one of the driven discs or elements  306  on the holder side  316  of the tool mounting plate  304  when the tool mounting portion  300  is coupled to the tool drive assembly  110 . See  FIG. 15 . The rotational gear assembly  360  further comprises a first rotary driven gear  364  that is rotatably supported on the tool mounting plate  304 . The first rotary driven gear  364  is in meshing engagement with a second rotary driven gear  366  which, in turn, is in meshing engagement with the tube gear segment  354 . Application of a first rotary output motion from the tool drive assembly  110  of the robotic system  10  to the corresponding driven element  306  will thereby cause rotation of the rotation drive gear  362 . Rotation of the rotation drive gear  362  ultimately results in the rotation of the elongate shaft assembly  200  (and the surgical end effector  3000 ) about the longitudinal tool axis LT-LT (represented by arrow “R” in  FIG. 5 ). It will be appreciated that the application of a rotary output motion from the tool drive assembly  110  in one direction will result in the rotation of the elongate shaft assembly  200  and surgical end effector  3000  about the longitudinal tool axis LT-LT in a first rotary direction and an application of the rotary output motion in an opposite direction will result in the rotation of the elongate shaft assembly  200  and surgical end effector  3000  in a second rotary direction that is opposite to the first rotary direction. 
     In embodiment of  FIGS. 5 and 16-21 , the tool mounting portion  300  further includes a second drive system generally designated as  370  that is configured to receive a corresponding “second” rotary output motion from the tool drive assembly  110  of the robotic system  10  and convert that second rotary output motion to a second rotary control motion for application to the surgical end effector. The second drive system  370  includes a second rotation drive gear  372  that is coupled to a corresponding second one of the driven discs or elements  306  on the holder side  316  of the tool mounting plate  304  when the tool mounting portion  300  is coupled to the tool drive assembly  110 . See  FIG. 15 . The second drive system  370  further comprises a first rotary driven gear  374  that is rotatably supported on the tool mounting plate  304 . The first rotary driven gear  374  is in meshing engagement with a shaft gear  376  that is movably and non-rotatably mounted onto a proximal drive shaft segment  380 . In this illustrated embodiment, the shaft gear  376  is non-rotatably mounted onto the proximal drive shaft segment  380  by a series of axial keyways  384  that enable the shaft gear  376  to axially move on the proximal drive shaft segment  380  while being non-rotatably affixed thereto. Rotation of the proximal drive shaft segment  380  results in the transmission of a second rotary control motion to the surgical end effector  3000 . 
     The second drive system  370  in the embodiment of  FIGS. 5 and 16-21  includes a shifting system  390  for selectively axially shifting the proximal drive shaft segment  380  which moves the shaft gear  376  into and out of meshing engagement with the first rotary driven gear  374 . For example, as can be seen in  FIGS. 16-18 , the proximal drive shaft segment  380  is supported within a second support cradle  382  that is attached to the tool mounting plate  304  such that the proximal drive shaft segment  380  may move axially and rotate relative to the second support cradle  382 . In at least one form, the shifting system  390  further includes a shifter yoke  392  that is slidably supported on the tool mounting plate  304 . The proximal drive shaft segment  380  is supported in the shifter yoke  392  and has a pair of collars  386  thereon such that shifting of the shifter yoke  392  on the tool mounting plate  304  results in the axial movement of the proximal drive shaft segment  380 . In at least one form, the shifting system  390  further includes a shifter solenoid  394  that operably interfaces with the shifter yoke  392 . The shifter solenoid  394  receives control power from the robotic controller  12  such that when the shifter solenoid  394  is activated, the shifter yoke  392  is moved in the distal direction “DD”. 
     In this illustrated embodiment, a shaft spring  396  is journaled on the proximal drive shaft segment  380  between the shaft gear  376  and the second support cradle  382  to bias the shaft gear  376  in the proximal direction “PD” and into meshing engagement with the first rotary driven gear  374 . See  FIGS. 16, 18 and 19 . Rotation of the second rotation drive gear  372  in response to rotary output motions generated by the robotic system  10  ultimately results in the rotation of the proximal drive shaft segment  380  and other drive shaft components coupled thereto (drive shaft assembly  388 ) about the longitudinal tool axis LT-LT. It will be appreciated that the application of a rotary output motion from the tool drive assembly  110  in one direction will result in the rotation of the proximal drive shaft segment  380  and ultimately of the other drive shaft components attached thereto in a first direction and an application of the rotary output motion in an opposite direction will result in the rotation of the proximal drive shaft segment  380  in a second direction that is opposite to the first direction. When it is desirable to shift the proximal drive shaft segment  380  in the distal direction “DD” as will be discussed in further detail below, the robotic controller  12  activates the shifter solenoid  390  to shift the shifter yoke  392  in the distal direction “DD”. IN some embodiments, the shifter solenoid  390  may be capable of shifting the proximal drive shaft segment  380  between more than two longitudinal positions. For example, some embodiments, such as those described herein with respect to  FIGS. 83-96 , may utilize the rotary drive shaft (e.g., coupled to the proximal drive shaft segment  380 ) in more than two longitudinal positions. 
       FIGS. 22-23  illustrate another embodiment that employs the same components of the embodiment depicted in  FIGS. 5 and 16-21  except that this embodiment employs a battery-powered drive motor  400  for supplying rotary drive motions to the proximal drive shaft segment  380 . Such arrangement enables the tool mounting portion to generate higher rotary output motions and torque which may be advantageous when different forms of end effectors are employed. As can be seen in those Figures, the motor  400  is attached to the tool mounting plate  304  by a support structure  402  such that a driver gear  404  that is coupled to the motor  400  is retained in meshing engagement with the shaft gear  376 . In the embodiment of  FIGS. 22-23 , the support structure  402  is configured to removably engage latch notches  303  formed in the tool mounting plate  304  that are designed to facilitate attachment of a housing member (not shown) to the mounting plate  304  when the motor  400  is not employed. Thus, to employ the motor  400 , the clinician removes the housing from the tool mounting plate  304  and then inserts the legs  403  of the support structure into the latch notches  303  in the tool mounting plate  304 . The proximal drive shaft segment  380  and the other drive shaft components attached thereto are rotated about the longitudinal tool axis LT-LT by powering the motor  400 . As illustrated, the motor  400  is battery powered. In such arrangement, however, the motor  400  interface with the robotic controller  12  such that the robotic system  10  controls the activation of the motor  400 . In alternative embodiments, the motor  400  is manually actuatable by an on/off switch (not shown) mounted on the motor  400  itself or on the tool mounting portion  300 . In still other embodiments, the motor  400  may receive power and control signals from the robotic system. 
     The embodiment illustrated in  FIGS. 5 and 16-21  includes a manually-actuatable reversing system, generally designated as  410 , for manually applying a reverse rotary motion to the proximal drive shaft segment  380  in the event that the motor fails or power to the robotic system is lost or interrupted. Such manually-actuatable reversing system  410  may also be particularly useful, for example, when the drive shaft assembly  388  becomes jammed or otherwise bound in such a way that would prevent reverse rotation of the drive shaft components under the motor power alone. In the illustrated embodiment, the mechanically-actuatable reversing system  410  includes a drive gear assembly  412  that is selectively engagable with the second rotary driven gear  376  and is manually actuatable to apply a reversing rotary motion to the proximal drive shaft segment  380 . The drive gear assembly  412  includes a reversing gear  414  that is movably mounted to the tool mounting plate  304 . The reversing gear  414  is rotatably journaled on a pivot shaft  416  that is movably mounted to the tool mounting plate  304  through a slot  418 . See  FIG. 17 . In the embodiment of  FIGS. 5 and 16-21 , the manually-actuatable reversing system  410  further includes a manually actuatable drive gear  420  that includes a body portion  422  that has an arcuate gear segment  424  formed thereon. The body portion  422  is pivotally coupled to the tool mounting plate  304  for selective pivotal travel about an actuator axis A-A ( FIG. 16 ) that is substantially normal to the tool mounting plate  304 . 
       FIGS. 16-19  depict the manually-actuatable reversing system  410  in a first unactuated position. In one example form, an actuator handle portion  426  is formed on or otherwise attached to the body portion  422 . The actuator handle portion  426  is sized relative to the tool mounting plate  304  such that a small amount of interference is established between the handle portion  426  and the tool mounting plate  304  to retain the handle portion  426  in the first unactuated position. However, when the clinician desires to manually actuate the drive gear assembly  412 , the clinician can easily overcome the interference fit by applying a pivoting motion to the handle portion  426 . As can also be seen in  FIGS. 16-19 , when the drive gear assembly  412  is in the first unactuated position, the arcuate gear segment  424  is out of meshing engagement with the reversing gear  414 . When the clinician desires to apply a reverse rotary drive motion to the proximal drive shaft segment  380 , the clinician begins to apply a pivotal ratcheting motion to drive gear  420 . As the drive gear  420  begins to pivot about the actuation axis A-A, a portion of the body  422  contacts a portion of the reversing gear  414  and axially moves the reversing gear  414  in the distal direction DD taking the drive shaft gear  376  out of meshing engagement with the first rotary driven gear  374  of the second drive system  370 . See  FIG. 20 . As the drive gear  420  is pivoted, the arcuate gear segment  424  is brought into meshing engagement with the reversing gear  414 . Continued ratcheting of the drive gear  420  results in the application of a reverse rotary drive motion to the drive shaft gear  376  and ultimately to the proximal drive shaft segment  380 . The clinician may continue to ratchet the drive gear assembly  412  for as many times as are necessary to fully release or reverse the associated end effector component(s). Once a desired amount of reverse rotary motion has been applied to the proximal drive shaft segment  380 , the clinician returns the drive gear  420  to the starting or unactuated position wherein the arcuate gear segment  416  is out of meshing engagement with the drive shaft gear  376 . When in that position, the shaft spring  396  once again biases the shaft gear  376  into meshing engagement with first rotary driven gear  374  of the second drive system  370 . 
     In use, the clinician may input control commands to the controller or control unit of the robotic system  10  which “robotically-generates” output motions that are ultimately transferred to the various components of the second drive system  370 . As used herein, the terms “robotically-generates” or “robotically-generated” refer to motions that are created by powering and controlling the robotic system motors and other powered drive components. These terms are distinguishable from the terms “manually-actuatable” or “manually generated” which refer to actions taken by the clinician which result in control motions that are generated independent from those motions that are generated by powering the robotic system motors. Application of robotically-generated control motions to the second drive system in a first direction results in the application of a first rotary drive motion to the drive shaft assembly  388 . When the drive shaft assembly  388  is rotated in a first rotary direction, the axially movable member  3016  is driven in the distal direction “DD” from its starting position toward its ending position in the end effector  3000 , for example, as described herein with respect to  FIGS. 64-96 . Application of robotically-generated control motions to the second drive system in a second direction results in the application of a second rotary drive motion to the drive shaft assembly  388 . When the drive shaft assembly  388  is rotated in a second rotary direction, the axially movable member  3016  is driven in the proximal direction “PD” from its ending position toward its starting position in the end effector  3000 . When the clinician desires to manually-apply rotary control motion to the drive shaft assembly  388 , the drive shaft assembly  388  is rotated in the second rotary direction which causes a firing member (e.g., axially translatable member  3016 ) to move in the proximal direction “PD” in the end effector. Other embodiments containing the same components are configured such that the manual-application of a rotary control motion to the drive shaft assembly could cause the drive shaft assembly to rotate in the first rotary direction which could be used to assist the robotically-generated control motions to drive the axially movable member  3016  in the distal direction. 
     The drive shaft assembly that is used to fire, close and rotate the end effector can be actuated and shifted manually allowing the end effector to release and be extracted from the surgical site as well as the abdomen even in the event that the motor(s) fail, the robotic system loses power or other electronic failure occurs. Actuation of the handle portion  426  results in the manual generation of actuation or control forces that are applied to the drive shaft assembly  388 ′ by the various components of the manually-actuatable reversing system  410 . If the handle portion  426  is in its unactuated state, it is biased out of actuatable engagement with the reversing gear  414 . The beginning of the actuation of the handle portion  426  shifts the bias. The handle  426  is configured for repeated actuation for as many times as are necessary to fully release the axially movable member  3016  and the end effector  3000 . 
     As illustrated in  FIGS. 5 and 16-21 , the tool mounting portion  300  includes a third drive system  430  that is configured to receive a corresponding “third” rotary output motion from the tool drive assembly  110  of the robotic system  10  and convert that third rotary output motion to a third rotary control motion. The third drive system  430  includes a third drive pulley  432  that is coupled to a corresponding third one of the driven discs or elements  306  on the holder side  316  of the tool mounting plate  304  when the tool mounting portion  300  is coupled to the tool drive assembly  110 . See  FIG. 15 . The third drive pulley  432  is configured to apply a third rotary control motion (in response to corresponding rotary output motions applied thereto by the robotic system  10 ) to a corresponding third drive cable  434  that may be used to apply various control or manipulation motions to the end effector that is operably coupled to the shaft assembly  200 . As can be most particularly seen in  FIGS. 16-17 , the third drive cable  434  extends around a third drive spindle assembly  436 . The third drive spindle assembly  436  is pivotally mounted to the tool mounting plate  304  and a third tension spring  438  is attached between the third drive spindle assembly  436  and the tool mounting plate  304  to maintain a desired amount of tension in the third drive cable  434 . As can be seen in the Figures, cable end portion  434 A of the third drive cable  434  extends around an upper portion of a pulley block  440  that is attached to the tool mounting plate  304  and cable end portion  434 B extends around a sheave pulley or standoff on the pulley block  440 . It will be appreciated that the application of a third rotary output motion from the tool drive assembly  110  in one direction will result in the rotation of the third drive pulley  432  in a first direction and cause the cable end portions  434 A and  434 B to move in opposite directions to apply control motions to the end effector  3000  or elongate shaft assembly  200  as will be discussed in further detail below. That is, when the third drive pulley  432  is rotated in a first rotary direction, the cable end portion  434 A moves in a distal direction “DD” and cable end portion  434 B moves in a proximal direction “PD”. Rotation of the third drive pulley  432  in an opposite rotary direction result in the cable end portion  434 A moving in a proximal direction “PD” and cable end portion  434 B moving in a distal direction “DD”. 
     The tool mounting portion  300  illustrated in  FIGS. 5 and 16-21  includes a fourth drive system  450  that is configured to receive a corresponding “fourth” rotary output motion from the tool drive assembly  110  of the robotic system  10  and convert that fourth rotary output motion to a fourth rotary control motion. The fourth drive system  450  includes a fourth drive pulley  452  that is coupled to a corresponding fourth one of the driven discs or elements  306  on the holder side  316  of the tool mounting plate  304  when the tool mounting portion  300  is coupled to the tool drive assembly  110 . See  FIG. 15 . The fourth drive pulley  452  is configured to apply a fourth rotary control motion (in response to corresponding rotary output motions applied thereto by the robotic system  10 ) to a corresponding fourth drive cable  454  that may be used to apply various control or manipulation motions to the end effector that is operably coupled to the shaft assembly  200 . As can be most particularly seen in  FIGS. 16-17 , the fourth drive cable  454  extends around a fourth drive spindle assembly  456 . The fourth drive spindle assembly  456  is pivotally mounted to the tool mounting plate  304  and a fourth tension spring  458  is attached between the fourth drive spindle assembly  456  and the tool mounting plate  304  to maintain a desired amount of tension in the fourth drive cable  454 . Cable end portion  454 A of the fourth drive cable  454  extends around a bottom portion of the pulley block  440  that is attached to the tool mounting plate  304  and cable end portion  454 B extends around a sheave pulley or fourth standoff  462  on the pulley block  440 . It will be appreciated that the application of a rotary output motion from the tool drive assembly  110  in one direction will result in the rotation of the fourth drive pulley  452  in a first direction and cause the cable end portions  454 A and  454 B to move in opposite directions to apply control motions to the end effector or elongate shaft assembly  200  as will be discussed in further detail below. That is, when the fourth drive pulley  434  is rotated in a first rotary direction, the cable end portion  454 A moves in a distal direction “DD” and cable end portion  454 B moves in a proximal direction “PD”. Rotation of the fourth drive pulley  452  in an opposite rotary direction result in the cable end portion  454 A moving in a proximal direction “PD” and cable end portion  454 B to move in a distal direction “DD”. 
     The surgical tool  100  as depicted in  FIGS. 5-6  includes an articulation joint  3500 . In such embodiment, the third drive system  430  may also be referred to as a “first articulation drive system” and the fourth drive system  450  may be referred to herein as a “second articulation drive system”. Likewise, the third drive cable  434  may be referred to as a “first proximal articulation cable” and the fourth drive cable  454  may be referred to herein as a “second proximal articulation cable”. 
     The tool mounting portion  300  of the embodiment illustrated in  FIGS. 5 and 16-21  includes a fifth drive system generally designated as  470  that is configured to axially displace a drive rod assembly  490 . The drive rod assembly  490  includes a proximal drive rod segment  492  that extends through the proximal drive shaft segment  380  and the drive shaft assembly  388 . See  FIG. 18 . The fifth drive system  470  includes a movable drive yoke  472  that is slidably supported on the tool mounting plate  304 . The proximal drive rod segment  492  is supported in the drive yoke  372  and has a pair of retainer balls  394  thereon such that shifting of the drive yoke  372  on the tool mounting plate  304  results in the axial movement of the proximal drive rod segment  492 . In at least one example form, the fifth drive system  370  further includes a drive solenoid  474  that operably interfaces with the drive yoke  472 . The drive solenoid  474  receives control power from the robotic controller  12 . Actuation of the drive solenoid  474  in a first direction will cause the drive rod assembly  490  to move in the distal direction “DD” and actuation of the drive solenoid  474  in a second direction will cause the drive rod assembly  490  to move in the proximal direction “PD”. As can be seen in  FIG. 5 , the end effector  3000  includes a jaw members that are movable between open and closed positions upon application of axial closure motions to a closure system. In the illustrated embodiment of  FIGS. 5 and 16-21 , the fifth drive system  470  is employed to generate such closure motions. Thus, the fifth drive system  470  may also be referred to as a “closure drive”. 
     The surgical tool  100  depicted in  FIGS. 5 and 16-21  includes an articulation joint  3500  that cooperates with the third and fourth drive systems  430 ,  450 , respectively for articulating the end effector  3000  about the longitudinal tool axis “LT”. The articulation joint  3500  includes a proximal socket tube  3502  that is attached to the distal end  233  of the distal outer tube portion  231  and defines a proximal ball socket  3504  therein. See  FIG. 24 . A proximal ball member  3506  is movably seated within the proximal ball socket  3504 . As can be seen in  FIG. 24 , the proximal ball member  3506  has a central drive passage  3508  that enables the distal drive shaft segment  3740  to extend therethrough. In addition, the proximal ball member  3506  has four articulation passages  3510  therein which facilitate the passage of distal cable segments  444 ,  445 ,  446 ,  447  therethrough. In various embodiments, distal cable segments  444 ,  445 ,  446 ,  447  may be directly or indirectly coupled to proximal cable end portions  434 A,  434 B,  454 A,  454 B, respectively, for example, as illustrated by  FIG. 24A . As can be further seen in  FIG. 24 , the articulation joint  3500  further includes an intermediate articulation tube segment  3512  that has an intermediate ball socket  3514  formed therein. The intermediate ball socket  3514  is configured to movably support therein an end effector ball  3522  formed on an end effector connector tube  3520 . The distal cable segments  444 ,  445 ,  446 ,  447  extend through cable passages  3524  formed in the end effector ball  3522  and are attached thereto by lugs  3526  received within corresponding passages  3528  in the end effector ball  3522 . Other attachment arrangements may be employed for attaching distal cable segments  444 ,  445 ,  446 ,  447  to the end effector ball  3522 . 
     A unique and novel rotary support joint assembly, generally designated as  3540 , is depicted in  FIGS. 25 and 26 . The illustrated rotary support joint assembly  3540  includes a connector portion  4012  of the end effector drive housing  4010  that is substantially cylindrical in shape. A first annular race  4014  is formed in the perimeter of the cylindrically-shaped connector portion  4012 . The rotary support joint assembly  3540  further comprises a distal socket portion  3530  that is formed in the end effector connector tube  3520  as shown in  FIGS. 25 and 26 . The distal socket portion  3530  is sized relative to the cylindrical connector portion  4012  such that the connector portion  4012  can freely rotate within the socket portion  3530 . A second annular race  3532  is formed in an inner wall  3531  of the distal socket portion  3530 . A window  3533  is provided through the distal socket  3530  that communicates with the second annular race  3532  therein. As can also be seen in  FIGS. 25 and 26 , the rotary support joint assembly  3540  further includes a ring-like bearing  3534 . In various example embodiments, the ring-like bearing  3534  comprises a plastic deformable substantially-circular ring that has a cut  3535  therein. The cut forms free ends  3536 ,  3537  in the ring-like bearing  3534 . As can be seen in  FIG. 25 , the ring-like bearing  3534  has a substantially annular shape in its natural unbiased state. 
     To couple a surgical end effector  3000  (e.g., a first portion of a surgical tool) to the articulation joint  3500  (e.g., a second portion of a surgical tool), the cylindrically shaped connector position  4012  is inserted into the distal socket portion  3530  to bring the second annular race  3532  into substantial registry with the first annular race  4014 . One of the free ends  3536 ,  3537  of the ring-like bearing is then inserted into the registered annular races  4014 ,  3532  through the window  3533  in the distal socket portion  3530  of the end effector connector tube  3520 . To facilitate easy insertion, the window or opening  3533  has a tapered surface  3538  formed thereon. See  FIG. 25 . The ring-like bearing  3534  is essentially rotated into place and, because it tends to form a circle or ring, it does not tend to back out through the window  3533  once installed. Once the ring-like bearing  3534  has been inserted into the registered annular races  4014 ,  3532 , the end effector connector tube  3520  will be rotatably affixed to the connector portion  4012  of the end effector drive housing  4010 . Such arrangement enables the end effector drive housing  4010  to rotate about the longitudinal tool axis LT-LT relative to the end effector connector tube  3520 . The ring-like bearing  3534  becomes the bearing surface that the end effector drive housing  4010  then rotates on. Any side loading tries to deform the ring-like bearing  3534  which is supported and contained by the two interlocking races  4014 ,  3532  preventing damage to the ring-like bearing  3534 . It will be understood that such simple and effective joint assembly employing the ring-like bearing  3534  forms a highly lubricious interface between the rotatable portions  4010 ,  3530 . If during assembly, one of the free ends  3536 ,  3537  is permitted to protrude out through the window  3533  (see e.g.,  FIG. 26 ), the rotary support joint assembly  3540  may be disassembled by withdrawing the ring-like bearing member  3532  out through the window  3533 . The rotary support joint assembly  3540  allows for easy assembly and manufacturing while also providing for good end effector support while facilitating rotary manipulation thereof. 
     The articulation joint  3500  facilitates articulation of the end effector  3000  about the longitudinal tool axis LT. For example, when it is desirable to articulate the end effector  3000  in a first direction “FD” as shown in  FIG. 5 , the robotic system  10  may power the third drive system  430  such that the third drive spindle assembly  436  ( FIGS. 16-18 ) is rotated in a first direction thereby drawing the proximal cable end portion  434 A and ultimately distal cable segment  444  in the proximal direction “PD” and releasing the proximal cable end portion  434 B and distal cable segment  445  to thereby cause the end effector ball  3522  to rotate within the socket  3514 . Likewise, to articulate the end effector  3000  in a second direction “SD” opposite to the first direction FD, the robotic system  10  may power the third drive system  430  such that the third drive spindle assembly  436  is rotated in a second direction thereby drawing the proximal cable end portion  434 B and ultimately distal cable segment  445  in the proximal direction “PD” and releasing the proximal cable end portion  434 A and distal cable segment  444  to thereby cause the end effector ball  3522  to rotate within the socket  3514 . When it is desirable to articulate the end effector  3000  in a third direction “TD” as shown in  FIG. 5 , the robotic system  10  may power the fourth drive system  450  such that the fourth drive spindle assembly  456  is rotated in a third direction thereby drawing the proximal cable end portion  454 A and ultimately distal cable segment  446  in the proximal direction “PD” and releasing the proximal cable end portion  454 B and distal cable segment  447  to thereby cause the end effector ball  3522  to rotate within the socket  3514 . Likewise, to articulate the end effector  3000  in a fourth direction “FTH” opposite to the third direction TD, the robotic system  10  may power the fourth drive system  450  such that the fourth drive spindle assembly  456  is rotated in a fourth direction thereby drawing the proximal cable end portion  454 B and ultimately distal cable segment  447  in the proximal direction “PD” and releasing the proximal cable end portion  454 A and distal cable segment  446  to thereby cause the end effector ball  3522  to rotate within the socket  3514 . 
     The end effector embodiment depicted in  FIGS. 5 and 16-21  employs rotary and longitudinal motions that are transmitted from the tool mounting portion  300  through the elongate shaft assembly for actuation. The drive shaft assembly employed to transmit such rotary and longitudinal motions (e.g., torsion, tension and compression motions) to the end effector is relatively flexible to facilitate articulation of the end effector about the articulation joint.  FIGS. 27-28  illustrate an alternative drive shaft assembly  3600  that may be employed in connection with the embodiment illustrated in  FIGS. 5 and 16-21  or in other embodiments. In the embodiment depicted in  FIG. 5  the proximal drive shaft segment  380  comprises a segment of drive shaft assembly  3600  and the distal drive shaft segment  3740  similarly comprises another segment of drive shaft assembly  3600 . The drive shaft assembly  3600  includes a drive tube  3602  that has a series of annular joint segments  3604  cut therein. In that illustrated embodiment, the drive tube  3602  comprises a distal portion of the proximal drive shaft segment  380 . For example, the shaft assembly  3600 , as well as the shaft assemblies  3600 ′,  3600 ″ described herein with respect to  FIGS. 27-45  may be components of and/or mechanically coupled to various rotary drive shafts described herein including, for example, rotary drive shafts  680 ,  1270 ,  1382 , etc. 
     The drive tube  3602  comprises a hollow metal tube (stainless steel, titanium, etc.) that has a series of annular joint segments  3604  formed therein. The annular joint segments  3604  comprise a plurality of loosely interlocking dovetail shapes  3606  that are, for example, cut into the drive tube  3602  by a laser and serve to facilitate flexible movement between the adjoining joint segments  3604 . See  FIG. 28 . Such laser cutting of a tube stock creates a flexible hollow drive tube that can be used in compression, tension and torsion. Such arrangement employs a full diametric cut that is interlocked with the adjacent part via a “puzzle piece” configuration. These cuts are then duplicated along the length of the hollow drive tube in an array and are sometimes “clocked” or rotated to change the tension or torsion performance. 
       FIGS. 29-33  illustrate alternative example micro-annular joint segments  3604 ′ that comprise plurality of laser cut shapes  3606 ′ that roughly resemble loosely interlocking, opposed “T” shapes and T-shapes with a notched portion therein. The annular joint segments  3604 ,  3604 ′ essentially comprise multiple micro-articulating torsion joints. That is, each joint segment  3604 ,  3604 ′ can transmit torque while facilitating relative articulation between each annular joint segment. As shown in  FIGS. 29-30 , the joint segment  3604 D′ on the distal end  3603  of the drive tube  3602  has a distal mounting collar portion  3608 D′ that facilitates attachment to other drive components for actuating the end effector or portions of the quick disconnect joint, etc. and the joint segment  3604 P′ on the proximal end  3605  of the drive tube  3602  has a proximal mounting collar portion  3608 P′ that facilitates attachment to other proximal drive components or portions of the quick disconnect joint. 
     The joint-to-joint range of motion for each particular drive shaft assembly  3600  can be increased by increasing the spacing in the laser cuts. For example, to ensure that the joint segments  3604 ′ remain coupled together without significantly diminishing the drive tube&#39;s ability to articulate through desired ranges of motion, a secondary constraining member  3610  is employed. In the embodiment depicted in  FIGS. 31-32 , the secondary constraining member  3610  comprises a spring  3612  or other helically-wound member. In various example embodiments, the distal end  3614  of the spring  3612  corresponds to the distal mounting collar portion  3608 D′ and is wound tighter than the central portion  3616  of the spring  3612 . Similarly, the proximal end  3618  of the spring  3612  is wound tighter than the central portion  3616  of the spring  3612 . In other embodiments, the constraining member  3610  is installed on the drive tube  3602  with a desired pitch such that the constraining member also functions, for example, as a flexible drive thread for threadably engaging other threaded control components on the end effector and/or the control system. It will also be appreciated that the constraining member may be installed in such a manner as to have a variable pitch to accomplish the transmission of the desired rotary control motions as the drive shaft assembly is rotated. For example, the variable pitch arrangement of the constraining member may be used to enhance open/close and firing motions which would benefit from differing linear strokes from the same rotation motion. In other embodiments, for example, the drive shaft assembly comprises a variable pitch thread on a hollow flexible drive shaft that can be pushed and pulled around a ninety degree bend. In still other embodiments, the secondary constraining member comprises an elastomeric tube or coating  3611  applied around the exterior or perimeter of the drive tube  3602  as illustrated in  FIG. 33A . In still another embodiment, for example, the elastomeric tube or coating  3611 ′ is installed in the hollow passageway  3613  formed within the drive tube  3602  as shown in  FIG. 33B . 
     Such drive shaft arrangements comprise a composite torsional drive axle which allows superior load transmission while facilitating a desirable axial range of articulation. See, e.g.,  FIGS. 33 and 33A-33B . That is, these composite drive shaft assemblies allow a large range of motion while maintaining the ability to transmit torsion in both directions as well as facilitating the transmission of tension and compression control motions therethrough. In addition, the hollow nature of such drive shaft arrangements facilitate passage of other control components therethrough while affording improved tension loading. For example, some other embodiments include a flexible internal cable that extends through the drive shaft assembly which can assist in the alignment of the joint segments while facilitating the ability to apply tension motions through the drive shaft assembly. Moreover, such drive shaft arrangements are relatively easily to manufacture and assemble. 
       FIGS. 34-37  depict a segment  3620  of a drive shaft assembly  3600 ′. This embodiment includes joint segments  3622 ,  3624  that are laser cut out of tube stock material (e.g., stainless steel, titanium, polymer, etc.). The joint segments  3622 ,  3624  remain loosely attached together because the cuts  3626  are radial and are somewhat tapered. For example, each of the lug portions  3628  has a tapered outer perimeter portion  3629  that is received within a socket  3630  that has a tapered inner wall portion. See, e.g.,  FIGS. 35 and 37 . Thus, there is no assembly required to attach the joint segments  3622 ,  3624  together. As can be seen in the Figures, joint segment  3622  has opposing pivot lug portions  3628  cut on each end thereof that are pivotally received in corresponding sockets  3630  formed in adjacent joint segments  3624 . 
       FIGS. 34-37  illustrate a small segment of the drive shaft assembly  3600 ′. Those of ordinary skill in the art will appreciate that the lugs/sockets may be cut throughout the entire length of the drive shaft assembly. That is, the joint segments  3624  may have opposing sockets  3630  cut therein to facilitate linkage with adjoining joint segments  3622  to complete the length of the drive shaft assembly  3600 ′. In addition, the joint segments  3624  have an angled end portion  3632  cut therein to facilitate articulation of the joint segments  3624  relative to the joint segments  3622  as illustrated in  FIGS. 36-37 . In the illustrated embodiment, each lug  3628  has an articulation stop portion  3634  that is adapted to contact a corresponding articulation stop  3636  formed in the joint segment  3622 . See  FIGS. 36-37 . Other embodiments, which may otherwise be identical to the segment  3620 , are not provided with the articulation stop portions  3634  and stops  3636 . 
     As indicated above, the joint-to-joint range of motion for each particular drive shaft assembly can be increased by increasing the spacing in the laser cuts. In such embodiments, to ensure that the joint segments  3622 ,  3624  remain coupled together without significantly diminishing the drive tube&#39;s ability to articulate through desired ranges of motion, a secondary constraining member in the form of an elastomeric sleeve or coating  3640  is employed. Other embodiments employ other forms of constraining members disclosed herein and their equivalent structures. As can be seen in  FIG. 34 , the joint segments  3622 ,  3624  are capable of pivoting about pivot axes “PA-PA” defined by the pivot lugs  3628  and corresponding sockets  3630 . To obtain an expanded range of articulation, the drive shaft assembly  3600 ′ may be rotated about the tool axis TL-TL while pivoting about the pivot axes PA-PA. 
       FIGS. 38-43  depict a segment  3640  of another drive shaft assembly  3600 ″. The drive shaft assembly  3600 ″ comprises a multi-segment drive system that includes a plurality of interconnected joint segments  3642  that form a flexible hollow drive tube  3602 ″. A joint segment  3642  includes a ball connector portion  3644  and a socket portion  3648 . Each joint segment  3642  may be fabricated by, for example, metal injection molding “MIM” and be fabricated from 17-4, 17-7, 420 stainless steel. Other embodiments may be machined from 300 or 400 series stainless steel, 6065 or 7071 aluminum or titanium. Still other embodiments could be molded out of plastic infilled or unfilled Nylon, Ultem, ABS, Polycarbonate or Polyethylene, for example. As can be seen in the Figures, the ball connector  3644  is hexagonal in shape. That is, the ball connector  3644  has six arcuate surfaces  3646  formed thereon and is adapted to be rotatably received in like-shaped sockets  3650 . Each socket  3650  has a hexagonally-shaped outer portion  3652  formed from six flat surfaces  3654  and a radially-shaped inner portion  3656 . See  FIG. 41 . Each joint segment  3642  is identical in construction, except that the socket portions of the last joint segments forming the distal and proximal ends of the drive shaft assembly  3600  may be configured to operably mate with corresponding control components. Each ball connector  3644  has a hollow passage  3645  therein that cooperate to form a hollow passageway  3603  through the hollow flexible drive tube  3602 ″. 
     As can be seen in  FIGS. 42 and 43 , the interconnected joint segments  3642  are contained within a constraining member  3660  which comprises a tube or sleeve fabricated from a flexible polymer material, for example.  FIG. 44  illustrates a flexible inner core member  3662  extending through the interconnected joint segments  3642 . The inner core member  3662  comprises a solid member fabricated from a polymer material or a hollow tube or sleeve fabricated from a flexible polymer material.  FIG. 45  illustrates another embodiment wherein a constraining member  3660  and an inner core member  3662  are both employed. 
     Drive shaft assembly  3600 ″ facilitates transmission of rotational and translational motion through a variable radius articulation joint. The hollow nature of the drive shaft assembly  3600 ″ provides room for additional control components or a tensile element (e.g., a flexible cable) to facilitate tensile and compressive load transmission. In other embodiments, however, the joint segments  3624  do not afford a hollow passage through the drive shaft assembly. In such embodiments, for example, the ball connector portion is solid. Rotary motion is translated via the edges of the hexagonal surfaces. Tighter tolerances may allow greater load capacity. Using a cable or other tensile element through the centerline of the drive shaft assembly  3600 ″, the entire drive shaft assembly  3600 ″ can be rotated bent, pushed and pulled without limiting range of motion. For example, the drive shaft assembly  3600 ″ may form an arcuate drive path, a straight drive path, a serpentine drive path, etc. 
     While the various example embodiments described herein are configured to operably interface with and be at least partially actuated by a robotic system, the various end effector and elongate shaft components described herein, may be effectively employed in connection with handheld tools. For example,  FIGS. 46-47  depict a handheld surgical tool  2400  that may employ various components and systems described above to operably actuate an electrosurgical end effector  3000  coupled thereto. It will be appreciated that the handheld surgical tool  2400  may contain and/or be electrically connected to a generator, such as the generator  3002 , for generating an electrosurgical drive signal to drive the end effector  3000 . In the example embodiment depicted in  FIGS. 46-47 , a quick disconnect joint  2210  is employed to couple the end effector  3000  to an elongate shaft assembly  2402 . For example, the quick disconnect joint  2210  may operate to remove the end effector  3000  in the manner described herein with reference to  FIGS. 106-115 . To facilitate articulation of the end effector  3000  about the articulation joint  3500 , the proximal portion of the elongate shaft assembly  2402  includes an example manually actuatable articulation drive  2410 . 
     Referring now to  FIGS. 48-50 , in at least one example form, the articulation drive  2410  includes four axially movable articulation slides that are movably journaled on the proximal drive shaft segment  380 ′ between the proximal outer tube segment  2214  and the proximal drive shaft segment  380 ′. For example, the articulation cable segment  434 A′ is attached to a first articulation slide  2420  that has a first articulation actuator rod  2422  protruding therefrom. Articulation cable segment  434 B′ is attached to a second articulation slide  2430  that is diametrically opposite from the first articulation slide  2420 . The second articulation slide  2430  has a second articulation actuator rod  2432  protruding therefrom. Articulation cable segment  454 A′ is attached to a third articulation slide  2440  that has a third articulation actuator rod  2442  protruding therefrom. Articulation cable segment  454 B′ is attached to a fourth articulation slide  2450  that is diametrically opposite to the third articulation slide  2440 . A fourth articulation actuator rod  2452  protrudes from the fourth articulation slide  2450 . Articulation actuator rods  2422 ,  2432 ,  2442 ,  2452  facilitate the application of articulation control motions to the articulation slides  2420 ,  2430 ,  2440 ,  2450 , respectively by an articulation ring assembly  2460 . 
     As can be seen in  FIG. 48 , the articulation actuator rods  2422 ,  2432 ,  2442 ,  2452  movably pass through a mounting ball  2470  that is journaled on a proximal outer tube segment  2404 . In at least one embodiment, the mounting ball  2470  may be manufactured in segments that are attached together by appropriate fastener arrangements (e.g., welding, adhesive, screws, etc.). As shown in  FIG. 50 , the articulation actuator rods  2422  and  2432  extend through slots  2472  in the proximal outer tube segment  2404  and slots  2474  in the mounting ball  2470  to enable the articulation slides  2420 ,  2430  to axially move relative thereto. Although not shown, the articulation actuator rods  2442 ,  2452  extend through similar slots  2472 ,  2474  in the proximal outer tube segment  2404  and the mounting ball  2470 . Each of the articulation actuator rods  2422 ,  2432 ,  2442 ,  2452  protrude out of the corresponding slots  2474  in the mounting ball  2470  to be operably received within corresponding mounting sockets  2466  in the articulation ring assembly  2460 . See  FIG. 49 . 
     In at least one example form, the articulation ring assembly  2460  is fabricated from a pair of ring segments  2480 ,  2490  that are joined together by, for example, welding, adhesive, snap features, screws, etc. to form the articulation ring assembly  2460 . The ring segments  2480 ,  2490  cooperate to form the mounting sockets  2466 . Each of the articulation actuator rods has a mounting ball  2468  formed thereon that are each adapted to be movably received within a corresponding mounting socket  2466  in the articulation ring assembly  2460 . 
     Various example embodiments of the articulation drive  2410  may further include an example locking system  2486  configured to retain the articulation ring assembly  2460  in an actuated position. In at least one example form, the locking system  2486  comprises a plurality of locking flaps formed on the articulation ring assembly  2460 . For example, the ring segments  2480 ,  2490  may be fabricated from a somewhat flexible polymer or rubber material. Ring segment  2480  has a series of flexible proximal locking flaps  2488  formed therein and ring segment  2490  has a series of flexible distal locking flaps  2498  formed therein. Each locking flap  2488  has at least one locking detent  2389  formed thereon and each locking flap  2498  has at least one locking detent  2399  thereon. Locking detents  2389 ,  2399  may serve to establish a desired amount of locking friction with the articulation ball so as to retain the articulation ball in position. In other example embodiments, the locking detents  2389 ,  2399  are configured to matingly engage various locking dimples formed in the outer perimeter of the mounting ball  2470 . 
     Operation of the articulation drive  2410  can be understood from reference to  FIGS. 49 and 50 .  FIG. 49  illustrates the articulation drive  2410  in an unarticulated position. In  FIG. 50 , the clinician has manually tilted the articulation ring assembly  2460  to cause the articulation slide  2420  to move axially in the distal direction “DD” thereby advancing the articulation cable segment  434 A′ distally. Such movement of the articulation ring assembly  2460  also results in the axial movement of the articulation slide  2430  in the proximal direction which ultimately pulls the articulation cable  434 B in the proximal direction. Such pushing and pulling of the articulation cable segments  434 A′,  434 B′ will result in articulation of the end effector  3000  relative to the longitudinal tool axis “LT-LT” in the manner described above. To reverse the direction of articulation, the clinician simply reverses the orientation of the articulation ring assembly  2460  to thereby cause the articulation slide  2430  to move in the distal direction “DD” and the articulation slide  2420  to move in the proximal direction “PD”. The articulation ring assembly  2460  may be similarly actuated to apply desired pushing and pulling motions to the articulation cable segments  454 A′,  454 B′. The friction created between the locking detents  2389 ,  2399  and the outer perimeter of the mounting ball serves to retain the articulation drive  2410  in position after the end effector  3000  has been articulated to the desired position. In alternative example embodiments, when the locking detents  2389 ,  2399  are positioned so as to be received in corresponding locking dimples in the mounting ball, the mounting ball will be retained in position. 
     In the illustrated example embodiments and others, the elongate shaft assembly  2402  operably interfaces with a handle assembly  2500 . An example embodiment of handle assembly  2500  comprises a pair of handle housing segments  2502 ,  2504  that are coupled together to form a housing for various drive components and systems as will be discussed in further detail below. See, e.g.,  FIG. 46 . The handle housing segments  2502 ,  2504  may be coupled together by screws, snap features, adhesive, etc. When coupled together, the handle segments  2502 ,  2504  may form a handle assembly  2500  that includes a pistol grip portion  2506 . 
     To facilitate selective rotation of the end effector  3000  about the longitudinal tool axis “LT=LT”, the elongate shaft assembly  2402  may interface with a first drive system, generally designated as  2510 . The drive system  2510  includes a manually-actuatable rotation nozzle  2512  that is rotatably supported on the handle assembly  2500  such that it can be rotated relative thereto as well as be axially moved between a locked position and an unlocked position. 
     The surgical tool  2400  may include a closure system  3670 . The closure system  3670  may be used in some embodiments to bring about distal and proximal motion in the elongate shaft assembly  2402  and end effector  3000 . For example, in some embodiments, the closure system  3670  may drive an axially movable member such as  3016 . For example, the closure system  3670  may be used to translate the axially movable member  3016  instead of the various rotary drive shafts described herein with respect to  FIGS. 64-82, 83-91 and 92-96 . In this example embodiment, the closure system  3670  is actuated by a closure trigger  2530  that is pivotally mounted to the handle frame assembly  2520  that is supported within the handle housing segments  2502 ,  2504 . The closure trigger  2530  includes an actuation portion  2532  that is pivotally mounted on a pivot pin  2531  that is supported within the handle frame assembly  2520 . See  FIG. 51 . Such example arrangement facilitates pivotal travel toward and away from the pistol grip portion  2506  of the handle assembly  2500 . As can be seen in  FIG. 51 , the closure trigger  2530  includes a closure link  2534  that is linked to the first pivot link and gear assembly  3695  by a closure wire  2535 . Thus, by pivoting the closure trigger  2530  toward the pistol grip portion  2506  of the handle assembly  2500  into an actuated position, the closure link  2534  and closure wire  2535  causes the first pivot link and gear assembly  3695  to move in the distal direction “DD” to cause distal motion through the shaft and, in some embodiments, to the end effector. 
     The surgical tool  2400  may further include a closure trigger locking system  2536  to retain the closure trigger in the actuated position. In at least one example form, the closure trigger locking system  2536  includes a closure lock member  2538  that is pivotally coupled to the handle frame assembly  2520 . As can be seen in  FIGS. 52 and 53 , the closure lock member  2538  has a lock arm  2539  formed thereon that is configured to ride upon an arcuate portion  2537  of the closure link  2534  as the closure trigger  2530  is actuated toward the pistol grip portion  2506 . When the closure trigger  2530  has been pivoted to the fully actuated position, the lock arm  2539  drops behind the end of the closure link  2534  and prevents the closure trigger  2530  from returning to its unactuated position. Thus, the distal motion translated through the shaft assembly to the end effector may be locked. To enable the closure trigger  2530  to return to its unactuated position, the clinician simply pivots the closure lock member  2538  until the lock arm  2539  thereof disengages the end of the closure link  2534  to thereby permit the closure link  2534  to move to the unactuated position. 
     The closure trigger  2530  is returned to the unactuated position by a closure return system  2540 . For example, as can be seen in  FIG. 51 , one example form of the closure trigger return system  2540  includes a closure trigger slide member  2542  that is linked to the closure link  2534  by a closure trigger yoke  2544 . The closure trigger slide member  2542  is slidably supported within a slide cavity  2522  in the handle frame assembly  2520 . A closure trigger return spring  2546  is positioned within the slide cavity  2520  to apply a biasing force to the closure trigger slide member  2542 . Thus, when the clinician actuates the closure trigger  2530 , the closure trigger yoke  2544  moves the closure trigger slide member  2542  in the distal direction “DD” compressing the closure trigger return spring  2546 . When the closure trigger locking system  2536  is disengaged and the closure trigger  2530  is released, the closure trigger return spring  2546  moves the closure trigger slide member  2542  in the proximal direction “PD” to thereby pivot the closure trigger  2530  into the starting unactuated position. 
     The surgical tool  2400  can also employ any of the various example drive shaft assemblies described above. In at least one example form, the surgical tool  2400  employs a second drive system  2550  for applying rotary control motions to a proximal drive shaft assembly  380 ′. See  FIG. 55 . The second drive system  2550  may include a motor assembly  2552  that is operably supported in the pistol grip portion  2506 . The motor assembly  2552  may be powered by a battery pack  2554  that is removably attached to the handle assembly  2500  or it may be powered by a source of alternating current. A second drive gear  2556  is operably coupled to the drive shaft  2555  of the motor assembly  2552 . The second drive gear  2556  is supported for meshing engagement with a second rotary driven gear  2558  that is attached to the proximal drive shaft segment  380 ′ of the drive shaft assembly. In at least one form, for example, the second drive gear  2556  is also axially movable on the motor drive shaft  2555  relative to the motor assembly  2552  in the directions represented by arrow “U” in  FIG. 55 . A biasing member, e.g., a coil spring  2560  or similar member, is positioned between the second drive gear  2556  and the motor housing  2553  and serves to bias the second drive gear  2556  on the motor drive shaft  2555  into meshing engagement with a first gear segment  2559  on the second driven gear  2558 . 
     The second drive system  2550  may further include a firing trigger assembly  2570  that is movably, e.g., pivotally attached to the handle frame assembly  2520 . In at least one example form, for example, the firing trigger assembly  2570  includes a first rotary drive trigger  2572  that cooperates with a corresponding switch/contact (not shown) that electrically communicates with the motor assembly  2552  and which, upon activation, causes the motor assembly  2552  to apply a first rotary drive motion to the second driven gear  2558 . In addition, the firing trigger assembly  2570  further includes a retraction drive trigger  2574  that is pivotal relative to the first rotary drive trigger. The retraction drive trigger  2574  operably interfaces with a switch/contact (not shown) that is in electrical communication with the motor assembly  2552  and which, upon activation, causes the motor assembly  2552  to apply a second rotary drive motion to the second driven gear  2558 . The first rotary drive motion results in the rotation of the drive shaft assembly and the implement drive shaft in the end effector to cause the firing member to move distally in the end effector  3000 . Conversely, the second rotary drive motion is opposite to the first rotary drive motion and will ultimately result in rotation of the drive shaft assembly and the implement drive shaft in a rotary direction which results in the proximal movement or retraction of the firing member in the end effector  3000 . 
     The illustrated embodiment also includes a manually actuatable safety member  2580  that is pivotally attached to the closure trigger actuation portion  2532  and is selectively pivotable between a first “safe” position wherein the safety member  2580  physically prevents pivotal travel of the firing trigger assembly  2570  and a second “off” position, wherein the clinician can freely pivot the firing trigger assembly  2570 . As can be seen in  FIG. 51 , a first dimple  2582  is provided in the closure trigger actuation portion  2532  that corresponds to the first position of the safety member  2580 . When the safety member  2580  is in the first position, a detent (not shown) on the safety member  2580  is received within the first dimple  2582 . A second dimple  2584  is also provided in the closure trigger actuation portion  2532  that corresponds to the second position of the safety member  2580 . When the safety member  2580  is in the second position, the detent on the safety member  2580  is received within the second dimple  2582 . 
     In at least some example forms, the surgical tool  2400  may include a mechanically actuatable reversing system, generally designated as  2590 , for mechanically applying a reverse rotary motion to the proximal drive shaft segment  380 ′ in the event that the motor assembly  2552  fails or battery power is lost or interrupted. Such mechanical reversing system  2590  may also be particularly useful, for example, when the drive shaft system components operably coupled to the proximal drive shaft segment  380 ′ become jammed or otherwise bound in such a way that would prevent reverse rotation of the drive shaft components under the motor power alone. In at least one example form, the mechanically actuatable reversing system  2590  includes a reversing gear  2592  that is rotatably mounted on a shaft  2524 A formed on the handle frame assembly  2520  in meshing engagement with a second gear segment  2562  on the second driven gear  2558 . See  FIG. 53 . Thus, the reversing gear  2592  freely rotates on shaft  2524 A when the second driven gear  2558  rotates the proximal drive shaft segment  380 ′ of the drive shaft assembly. 
     In various example forms, the mechanical reversing system  2590  further includes a manually actuatable driver  2594  in the form of a lever arm  2596 . As can be seen in  FIGS. 56 and 57 , the lever arm  2596  includes a yoke portion  2597  that has elongate slots  2598  therethrough. The shaft  2524 A extends through slot  2598 A and a second opposing shaft  2598 B formed on the handle housing assembly  2520  extends through the other elongate slot to movably affix the lever arm  2596  thereto. In addition, the lever arm  2596  has an actuator fin  2597  formed thereon that can meshingly engage the reversing gear  2592 . There is a detent or interference that keeps the lever arm  2596  in the unactuated state until the clinician exerts a substantial force to actuate it. This keeps it from accidentally initiating if inverted. Other embodiments may employ a spring to bias the lever arm into the unactuated state. Various example embodiments of the mechanical reversing system  2590  further includes a knife retractor button  2600  that is movably journaled in the handle frame assembly  2520 . As can be seen in  FIGS. 56 and 57 , the knife retractor button  2600  includes a disengagement flap  2602  that is configured to engage the top of the second drive gear  2556 . The knife retractor button  2600  is biased to a disengaged position by a knife retractor spring  2604 . When in the disengaged position, the disengagement flap  2602  is biased out of engagement with the second drive gear  2556 . Thus, until the clinician desires to activate the mechanical reversing system  2590  by depressing the knife retractor button  2600 , the second drive gear  2556  is in meshing engagement with the first gear segment  2559  of the second driven gear  2558 . 
     When the clinician desires to apply a reverse rotary drive motion to the proximal drive shaft segment  380 ′, the clinician depresses the knife retractor button  2600  to disengage the first gear segment  2559  on the second driven gear  2558  from the second drive gear  2556 . Thereafter, the clinician begins to apply a pivotal ratcheting motion to the manually actuatable driver  2594  which causes the gear fin  2597  thereon to drive the reversing gear  2592 . The reversing gear  2592  is in meshing engagement with the second gear segment  2562  on the second driven gear  2558 . Continued ratcheting of the manually actuatable driver  2594  results in the application of a reverse rotary drive motion to the second gear segment  2562  and ultimately to the proximal drive shaft segment  380 ′. The clinician may continue to ratchet the driver  2594  for as many times as are necessary to fully release or reverse the associated end effector component(s). Once a desired amount of reverse rotary motion has been applied to the proximal drive shaft segment  380 ′, the clinician releases the knife retractor button  2600  and the driver  2594  to their respective starting or unactuated positions wherein the fin  2597  is out of engagement with the reversing gear  2592  and the second drive gear  2556  is once again in meshing engagement with the first gear segment  2559  on the second driven gear  2558 . 
     The surgical tool  2400  can also be employed with an electrosurgical end effector comprising various rotary drive components that are driven differently with a rotary drive shaft at different axial positions. Examples of such end effectors and drive mechanisms are described herein with respect to  FIGS. 64-82, 83-91 and 92-96 . The surgical tool  2400  may employ a shifting system  2610  for selectively axially shifting the proximal drive shaft segment  380 ′ which moves the shaft gear  376  into and out of meshing engagement with the first rotary driven gear  374 . For example, the proximal drive shaft segment  380 ′ is movably supported within the handle frame assembly  2520  such that the proximal drive shaft segment  380 ′ may move axially and rotate therein. In at least one example form, the shifting system  2610  further includes a shifter yoke  2612  that is slidably supported by the handle frame assembly  2520 . See  FIGS. 51 and 54 . The proximal drive shaft segment  380 ′ has a pair of collars  386  (shown in  FIGS. 51 and 55 ) thereon such that shifting of the shifter yoke  2612  on the handle frame assembly  2520  results in the axial movement of the proximal drive shaft segment  380 ′. In at least one form, the shifting system  2610  further includes a shifter button assembly  2614  operably interfaces with the shifter yoke  2612  and extends through a slot  2505  in the handle housing segment  2504  of the handle assembly  2500 . See  FIGS. 62 and 63 . A shifter spring  2616  is mounted with the handle frame assembly  2520  such that it engages the proximal drive shaft segment  380 ′. See  FIGS. 54 and 61 . The spring  2616  serves to provide the clinician with an audible click and tactile feedback as the shifter button assembly  2614  is slidably positioned between the first axial position depicted in  FIG. 62  wherein rotation of the drive shaft assembly results in rotation of the end effector  3000  about the longitudinal tool axis “LT-LT” relative to the articulation joint  3500  (illustrated in  FIG. 67 ) and the second axial position depicted in  FIG. 63  wherein rotation of the drive shaft assembly results in the axial movement of the firing member in the end effector (illustrated in  FIG. 66 ). Thus, such arrangement enables the clinician to easily slidably position the shifter button assembly  2614  while holding the handle assembly  2500 . In some embodiments, the shifter button assembly  2500  may have more than two axial positions, corresponding to more than two desired axial positions of the rotary drive shaft. Examples of such surgical tools are provided herein in conjunction with  FIGS. 83-91 and 92-96 . 
     Referring to  FIGS. 64-72 , a multi-axis articulating and rotating surgical tool  600  comprises an end effector  550  comprising a first jaw member  602 A and a second jaw member  602 B. The first jaw member  602 A is movable relative to the second jaw member  602 B between an open position ( FIGS. 64, 66-69, 71 ) and a closed position ( FIGS. 70 and 72 ) to clamp tissue between the first jaw member  602 A and the second jaw member  602 B. The surgical tool  600  is configured to independently articulate about an articulation joint  640  in a vertical direction (labeled direction V in  FIGS. 64 and 66-72 ) and a horizontal direction (labeled direction H in  FIGS. 64 and 65-68 ). Actuation of the articulation joint  640  may be brought about in a manner similar to that described above with respect to  FIGS. 24-26 . The surgical tool  600  is configured to independently rotate about a head rotation joint  645  in a longitudinal direction (labeled direction H in  FIGS. 64 and 66-72 ). The end effector  550  comprises an I-beam member  620  and a jaw assembly  555  comprising the first jaw member  602 A, the second jaw member  602 B, a proximal portion  603  of the second jaw member  602 B, and a rotary drive nut  606  seated in the proximal portion  603 . The I-beam member  620  and jaw assembly  555  may operate in a manner described herein and similar to that described above with respect to the axially movable member  3016  and jaw members  3008 A,  3008 B described herein above. 
     The end effector  550  is coupled to a shaft assembly  560  comprising an end effector drive housing  608 , an end effector connector tube  610 , an intermediate articulation tube segment  616 , and a distal outer tube portion  642 . The end effector  550  and the shaft assembly  560  together comprise the surgical tool  600 . The end effector  550  may be removably coupled to the end effector drive housing  608  using a mechanism as described, for example, in connection with  FIGS. 106-115 . The end effector connector tube  610  comprises a cylindrical portion  612  and a ball member  614 . The end effector drive housing  608  is coupled to the cylindrical portion  612  of the end effector connector tube  610  through the head rotation joint  645 . The end effector  550  and the end effector drive housing  608  together comprise a head portion  556  of the surgical tool  600 . The head portion  556  of the surgical tool  600  is independently rotatable about the head rotation joint  645 , as described in greater detail below. 
     The intermediate articulation tube segment  616  comprises a ball member  618  and a ball socket  619 . The end effector connector tube  610  is coupled to the intermediate articulation tube segment  616  through a ball-and-socket joint formed by the mutual engagement of the ball member  614  of the end effector connector tube  610  and the ball socket  619  of the intermediate articulation tube segment  616 . The intermediate articulation tube segment  616  is coupled to the distal outer tube portion  642  through a ball-and-socket joint formed by the mutual engagement of the ball member  618  of the intermediate articulation tube segment  616  and a ball socket of the distal outer tube portion  642 . The articulation joint  640  comprises the end effector connector tube  610 , the intermediate articulation tube segment  616 , and the distal outer tube portion  642 . The independent vertical articulation and/or horizontal articulation of the surgical tool  600  about the articulation joint  640  may be actuated, for example, using independently actuatable cable segments, such as  444 ,  445 ,  446 ,  447  described herein above, connected to the ball member  614  of the end effector connector tube  610 . This independent articulation functionality is described, for example, in connection with  FIGS. 24, 24A and 25 . Robotic and hand-held apparatuses for allowing a clinician to initiate articulation functionality are described, for example, in connection with  FIGS. 6, 16-21 and 46-50 . 
     The movement of the first jaw member  602 A relative to the second jaw member  602 B between an open position ( FIGS. 64, 66-69, and 71 ) and a closed position ( FIGS. 70 and 72 ) may be actuated with a suitable closure actuation mechanism. Referring to  FIGS. 73 and 74 , closure of the jaw assembly  555  may be actuated by translation of the I-beam member  620 . The I-beam member  620  comprises a first I-beam flange  622 A and a second I-beam flange  622 B. The first I-beam flange  622 A and the second I-beam flange  622 B are connected with an intermediate portion  624 . The intermediate portion  624  of the I-beam member  620  comprises a cutting member  625 , which is configured to transect tissue clamped between the first jaw member  602 A and the second jaw member  602 B when the jaw assembly  555  is in a closed position. The I-beam member  620  is configured to translate within a first channel  601 A in the first jaw member  602 A and within a second channel  601 B in the second jaw member  602 B. The first channel  601 A comprises a first channel flange  605 A, and the second channel  601 B comprises a second channel flange  605 B. The first I-beam flange  622 A can define a first cam surface  626 A, and the second I-beam flange  622 B can define a second cam surface  626 B. The first and second cam surfaces  626 A and  626 B can slidably engage outwardly-facing opposed surfaces of the first and second channel flanges  605 A and  605 B, respectively. More particularly, the first cam surface  626 A can comprise a suitable profile configured to slidably engage the opposed surface of the first channel flange  605 A of the first jaw member  602 A and, similarly, the second cam surface  626 B can comprise a suitable profile configured to slidably engage the opposed surface of the second channel flange  605 B of the second jaw member  602 B, such that, as the I-beam member  620  is advanced distally, the cam surfaces  626 A and  626 B can co-operate to cam first jaw member  602 A toward second jaw member  602 B and move the jaw assembly  555  from an open position to a closed position as indicated by arrow  629  in  FIG. 74 . 
       FIG. 73  shows the I-beam member  620  in a fully proximal position and the jaw assembly  555  in an open position. In the position shown in  FIG. 73 , the first cam surface  626 A is engaging a proximal portion of an arcuate-shaped anvil surface  628 , which mechanically holds the first jaw member  602 A open relative to the second jaw member  602 B ( FIGS. 69 and 71 ). Translation of the I-beam member  620  distally in a longitudinal direction (labeled direction L in  FIGS. 64 and 66-74 ) results in sliding engagement of the first cam surface  626 A with the length of the arcuate-shaped anvil surface  628 , which cams first jaw member  602 A toward second jaw member  602 B until the first cam surface  626 A is engaging a distal portion of the arcuate-shaped anvil surface  628 . After the distal translation of the I-beam member  620  for a predetermined distance, the first cam surface  626 A engages a distal portion of the arcuate-shaped anvil surface  628  and the jaw assembly is in the closed position ( FIG. 74 ). Thereafter, the I-beam member  620  can be further translated distally in order to transect tissue clamped between the first jaw member  602 A and the second jaw member  602 B when in the closed position. 
     During distal translation of the I-beam member  620  after closure of the jaw assembly, the first and second cam surfaces  626 A and  626 B of the first and second I-beam flanges  622 A and  622 B slidably engage the opposed surfaces of the first and second channel flanges  605 A and  605 B, respectively. In this manner, the I-beam member is advanced distally through the first and second channels  601 A and  601 B of the first and second jaw members  602 A and  602 B. 
     The distal, or leading, end of the I-beam member  620  comprises a cutting member  625 , which may be a sharp edge or blade configured to cut through clamped tissue during a distal translation stroke of the I-beam member, thereby transecting the tissue.  FIGS. 72 and 70  show the I-beam member  620  in a fully distal position after a distal translation stroke. After a distal translation stroke, the I-beam member  620  may be proximally retracted back to the longitudinal position shown in  FIG. 74  in which the jaw assembly remains closed, clamping any transected tissue between the first jaw member  602 A and the second jaw member  602 B. Further retraction of the I-beam member to the fully proximal position ( FIGS. 69, 71, and 73 ) will result in engagement of the first cam surface  626 A and the proximal portion of the anvil surface  628 , which cams the first jaw member  602 A away from the second jaw member  602 B, opening the jaw assembly  555 . 
     Before, during, and/or after the I-beam member  620  is advanced through tissue clamped between the first jaw member  602 A and the second jaw member  602 B, electrical current can be supplied to electrodes located in the first and/or second jaw members  602 A and  602 B in order to weld/fuse the tissue, as described in greater detail in this specification. For example, electrodes may be configured to deliver RF energy to tissue clamped between the first jaw member  602 A and the second jaw member  602 B when in a closed position to weld/fuse the tissue. 
     Distal and proximal translation of the I-beam member  620  between a proximally retracted position ( FIGS. 64, 66-69, 71, and 73 ), an intermediate position ( FIG. 74 ), and a distally advanced position ( FIGS. 70 and 72 ) may be accomplished with a suitable translation actuation mechanism. Referring to  FIGS. 65-72 , the I-beam member  620  is connected to a threaded rotary drive member  604 . A threaded rotary drive nut  606  is threaded onto the threaded rotary drive member  604 . The threaded rotary drive nut  606  is seated in the proximal portion  603  of the second jaw member  602 B. The threaded rotary drive nut  606  is mechanically constrained from translation in any direction, but the threaded rotary drive nut  606  is rotatable within the proximal portion  603  of the second jaw member  602 B. Therefore, given the threaded engagement of the rotary drive nut  606  and the threaded rotary drive member  604 , rotational motion of the rotary drive nut  606  is transformed into translational motion of the threaded rotary drive member  604  in the longitudinal direction and, in turn, into translational motion of the I-beam member  620  in the longitudinal direction. 
     The threaded rotary drive member  604  is threaded through the rotary drive nut  606  and is located inside a lumen of a rotary drive shaft  630 . The threaded rotary drive member  604  is not attached or connected to the rotary drive shaft  630 . The threaded rotary drive member  604  is freely movable within the lumen of the rotary drive shaft  630  and will translate within the lumen of the rotary drive shaft  630  when driven by rotation of the rotary drive nut  606 . The rotary drive shaft  630  comprising the threaded rotary drive member  604  located within the lumen of the rotary drive shaft  630  forms a concentric rotary drive shaft/screw assembly that is located in the lumen of the shaft assembly  560 . 
     As shown in  FIG. 65 , the end effector drive housing  608 , the end effector connector tube  610 , and the intermediate articulation tube segment  616 , which together comprise the shaft assembly  560 , have open lumens and, therefore, the shaft assembly has a lumen, as shown in  FIGS. 66-68 . Referring again to  FIGS. 66-68 , the concentric rotary drive shaft/threaded rotary drive member assembly is located within the lumen of the shaft assembly  560  and passes through the end effector drive housing  608 , the end effector connector tube  610 , and the intermediate articulation tube segment  616 . Although not shown in  FIGS. 66-68 , at least the rotary drive shaft  630  passes through a lumen of the distal outer tube portion  642  and is operably coupled to a driving mechanism that provides rotational and axial translational motion to the rotary drive shaft  630 . For example, in some embodiments, the surgical tool  600  may be operably coupled through the shaft assembly  560  to a robotic surgical system that provides rotational motion and axial translational motion to the rotary drive shaft  630 , such as, for example, the robotic surgical systems described in connection with  FIGS. 5 and 16-21 . For example, the rotary drive shaft  630  may be operably coupled, through the shaft assembly  560 , to the proximal drive shaft segment  380  described herein above. Also, in some embodiments, the surgical tool  600  may be utilized in conjunction with a hand-held surgical device, such as the device described herein above with respect to  FIGS. 46-63 . For example, the rotary drive shaft  630  may be operably coupled, though the shaft assembly  560 , to the proximal drive shaft segment  380 ′ described herein above. 
     The rotary drive shaft  630  comprises a rotary drive head  632 . The rotary drive head  632  comprises a female hex coupling portion  634  on the distal side of the rotary drive head  632 , and the rotary drive head  632  comprises a male hex coupling portion  636  on the proximal side of the rotary drive head  632 . The distal female hex coupling portion  634  of the rotary drive head  632  is configured to mechanically engage with a male hex coupling portion  607  of the rotary drive nut  606  located on the proximal side of the rotary drive nut  606 . The proximal male hex coupling portion  636  of the rotary drive head  632  is configured to mechanically engage with a female hex shaft coupling portion  609  of the end effector drive housing  608 . 
     Referring to  FIGS. 66, 67, 69, and 70 , the rotary drive shaft  630  is shown in a fully distal axial position in which the female hex coupling portion  634  of the rotary drive head  632  is mechanically engaged with the male hex coupling portion  607  of the rotary drive nut  606 . In this configuration, rotation of the rotary drive shaft  630  actuates rotation of the rotary drive nut  606 , which actuates translation of the threaded rotary drive member  604 , which actuates translation of the I-beam member  620 . The orientation of the threading of the threaded rotary drive member  604  and the rotary drive nut  606  may be established so that either clockwise or counterclockwise rotation of the rotary drive shaft  630  will actuate distal or proximal translation of the threaded rotary drive member  604  and I-beam member  620 . In this manner, the direction, speed, and duration of rotation of the rotary drive shaft  630  can be controlled in order to control the direction, speed, and magnitude of the longitudinal translation of the I-beam member  620  and, therefore, the closing and opening of the jaw assembly and the transection stroke of the I-beam member along the first and second channels  601 A and  601 B, as described above. 
     Referring to  FIG. 69 , for example, rotation of the rotary drive shaft  630  in a clockwise direction (as viewed from a proximal-to-distal vantage point) actuates clockwise rotation of the rotary drive nut  606 , which actuates distal translation of the threaded rotary drive member  604 , which actuates distal translation of the I-beam member  620 , which actuates closure of the jaw assembly and a distal transection stroke of the I-beam member  620 /cutting member  625 . Referring to  FIG. 70 , for example, rotation of the rotary drive shaft  630  in a counterclockwise direction (as viewed from a proximal-to-distal vantage point) actuates counterclockwise rotation of the rotary drive nut  606 , which actuates proximal translation of the threaded rotary drive member  604 , which actuates proximal translation of the I-beam member  620 , which actuates a proximal return stroke of the I-beam member  620 /cutting member  625  and opening of the jaw assembly. In this manner, the rotary drive shaft  630  may be used to independently actuate the opening and closing of the jaw assembly and the proximal-distal transection stroke of the I-beam  620 /cutting member  625 . 
     Referring to  FIGS. 68, 71, and 72 , the rotary drive shaft  630  is shown in a fully proximal axial position in which the male hex coupling portion  636  of the rotary drive head  632  is mechanically engaged with the female hex shaft coupling portion  609  of the end effector drive housing  608 . In this configuration, rotation of the rotary drive shaft  630  actuates rotation of the head portion  556  of the surgical tool  600  about rotation joint  645 , including rotation of the end effector  550  and the end effector drive housing  608 . In this configuration, the portion of the surgical tool  600  that is distal to the head rotation joint  645  (i.e., the head portion  556  of the surgical tool  600 , comprising the end effector  550  and the end effector drive housing  608 ) rotates with rotation of the rotary drive shaft  630 , and the portion of the surgical tool that is proximal to the head rotation joint  645  (e.g., the end effector connector tube  610 , the intermediate articulation tube segment  616 , and the distal outer tube portion  642 ) does not rotate with rotation of the rotary drive shaft  630 . It will be appreciated that a desired rotation speed of the rotary drive shaft  630  to drive the rotary drive nut  606  may be greater than a desired rotational speed for rotating the head portion  556 . For example, the rotary drive shaft  630  may be driven by a motor (not shown) that is operable at different rotary speeds. 
     Referring to  FIG. 71 , for example, rotation of the rotary drive shaft  630  in a clockwise direction (as viewed from a proximal-to-distal vantage point) actuates clockwise rotation of the end effector  550  and the end effector drive housing  608  (i.e., the head portion  556  of the surgical tool  600 ) with the jaw assembly  555  in an open position. Rotation of the rotary drive shaft  630  in a counterclockwise direction (as viewed from a proximal-to-distal vantage point) actuates counterclockwise rotation of the end effector  550  and the end effector drive housing  608  with the jaw assembly  555  in an open position. Referring to  FIG. 72 , for example, rotation of the rotary drive shaft  630  in a clockwise direction (as viewed from a proximal-to-distal vantage point) actuates clockwise rotation of the end effector  550  and the end effector drive housing  608  with the jaw assembly  555  in a closed position. Rotation of the rotary drive shaft  630  in a counterclockwise direction (as viewed from a proximal-to-distal vantage point) actuates counterclockwise rotation of the end effector  550  and the end effector drive housing  608  with the jaw assembly  555  in a closed position. Although not shown, it is understood that the I-beam member  620  may be located in an intermediate position where the jaw assembly is closed but the I-beam is not fully distally advanced (see, e.g.,  FIG. 74 ) when the rotary drive shaft  630  is in a fully proximal axial position and the male hex coupling portion  636  of the rotary drive head  632  is mechanically engaged with the female hex shaft coupling portion  609  of the end effector drive housing  608  to actuate rotation of the head portion of the surgical tool. 
     Thus, the rotary drive shaft  630  may be used to independently actuate the opening and closing of the jaw assembly, the proximal-distal transection stroke of the I-beam  620 /cutting member  625 , and the rotation of the head portion  556  of the surgical tool  600   d.    
     In various embodiments, a surgical tool may comprise an end effector, a first actuation mechanism, and a second actuation mechanism. The surgical tool may also comprise a clutch member configured to selectively engage and transmit rotary motion to either the first actuation mechanism or the second actuation mechanism. For example, in various embodiments, a clutch member may comprise a rotary drive shaft comprising a rotary drive head as described, for example, in connection with  FIGS. 64-72 . In various embodiments, a first actuation mechanism may comprise an I-beam member connected to a threaded rotary drive member threaded through a rotary drive nut, as described, for example, in connection with  FIGS. 64-74 , wherein the I-beam, the threaded rotary drive member, and the rotary drive nut are configured to actuate the closing and opening of a jaw assembly and/or the translation of a cutting member. In various embodiments, a second actuation mechanism may comprise a shaft coupling portion, as described, for example, in connection with  FIGS. 64-72 , wherein the shaft coupling portion is configured to actuate rotation of a head portion of a surgical tool. 
     In various embodiments, a surgical tool may comprise an end effector comprising a first jaw member, a second jaw member, and a first actuation mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The surgical tool may also comprise a shaft assembly proximal to the surgical end effector. The surgical tool may also comprise a rotary drive shaft. The rotary drive shaft may be configured to transmit rotary motions and may also be selectively moveable between a first position and a second position relative to the shaft assembly. The rotary drive shaft may be configured to engage and selectively transmit the rotary motions to the first actuation mechanism when in the first position and the rotary drive shaft may be configured to disengage from the actuation mechanism when in the second position. For example, in various embodiments, the first actuation mechanism may comprise an I-beam member connected to a threaded rotary drive member threaded through a rotary drive nut, as described, for example, in connection with  FIGS. 64-74 , wherein the I-beam, the threaded rotary drive member, and the rotary drive nut are configured to actuate the closing and opening of a jaw assembly when the rotary drive shaft engages and selectively transmits rotary motion to the drive nut. 
     In various embodiments, a surgical tool may comprise a surgical end effector comprising a first jaw member, a second jaw member, and a closure mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The surgical tool may also comprise a shaft assembly proximal to the surgical end effector, wherein the surgical end effector is configured to rotate relative to the shaft assembly. The surgical tool may also comprise a rotary drive shaft configured to transmit rotary motions, the rotary drive shaft selectively movable axially between a first position and a second position relative to the shaft assembly, wherein the rotary drive shaft is configured to apply the rotary motions to the closure mechanism when in the first axial position, and wherein the rotary drive shaft is configured to apply the rotary motions to the surgical end effector when in the second axial position. For example, in various embodiments, the first axial position may correspond to the rotary drive shaft being in a fully distal axial position in which a rotary drive head is mechanically engaged with a rotary drive nut as described, for example, in connection with  FIGS. 64-72 . In various embodiments, the second axial position may correspond to the rotary drive shaft being in a fully proximal axial position in which a rotary drive head is mechanically engaged with a shaft coupling portion of a shaft member as described, for example, in connection with  FIGS. 64-72 . 
     In various embodiments, a surgical tool comprising an end effector, a first actuation mechanism, and a second actuation mechanism, may further comprise a head locking mechanism. For example, referring to  FIGS. 75-82 , a multi-axis articulating and rotating surgical tool  650  comprises an end effector  570 , a shaft assembly  580 , and a head locking mechanism  590 . The end effector  570  comprises a first jaw member  652 A and a second jaw member  652 B. The first jaw member  602 A is movable relative to the second jaw member  602 B between an open position ( FIGS. 77 and 79 ) and a closed position ( FIGS. 78 and 80 ) to clamp tissue between the first jaw member  652 A and the second jaw member  652 B. The surgical tool  650  is configured to independently articulate about an articulation joint in a vertical direction and a horizontal direction like the surgical tool  600  shown in  FIGS. 64-72 . The surgical tool  650  is also configured to independently rotate about a head rotation joint like the surgical tool  600  shown in  FIGS. 64-72 . The end effector  570  comprises an I-beam member  670  and a jaw assembly  575  comprising the first jaw member  652 A, the second jaw member  652 B, a proximal portion  653  of the second jaw member  652 B, and a rotary drive nut  656  seated in the proximal portion  653 . 
     The end effector  570  is coupled to a shaft assembly  580  comprising an end effector drive housing  658 , an end effector connector tube  660 , an intermediate articulation tube segment  666 , and a surgical tool shaft member (not shown). The end effector  570  and the shaft assembly  580  together comprise the surgical tool  650 . The end effector  570  may be removably coupled to the end effector drive housing  658  using a mechanism as described, for example, in connection with  FIGS. 106-115 . The end effector drive housing  608  is coupled to the end effector connector tube  660  through the head rotation joint. The end effector  570  and the end effector drive housing  658  together comprise a head portion  578  of the surgical tool  650 . The head portion  578  of the surgical tool  650  is independently rotatable about the head rotation joint, as described in greater detail above in connection  FIGS. 64-72  showing the surgical tool  600 . 
     The end effector connector tube  660  is coupled to the intermediate articulation tube segment  666  through a ball-and-socket joint formed by the mutual engagement of the ball member of the end effector connector tube  660  and the ball socket of the intermediate articulation tube segment  666 . The intermediate articulation tube segment  666  is coupled to a surgical tool shaft member through a ball-and-socket joint formed by the mutual engagement of the ball member of the intermediate articulation tube segment  616  and a ball socket of the surgical tool shaft member. The articulation joint comprises the end effector connector tube  660 , the intermediate articulation tube segment  666 , and the surgical tool shaft member. The independent vertical articulation and/or horizontal articulation of the surgical tool  650  about the articulation joint may be actuated, for example, using independently actuatable drive cables connected to the ball member of the end effector connector tube  660 . This independent articulation functionality is described, for example, in connection with  FIGS. 24-25 . Robotic and hand-held apparatuses for allowing a clinician to initiate articulation functionality are described, for example, in connection with  FIGS. 6, 16-21 and 46-50 . 
     The movement of the first jaw member  652 A relative to the second jaw member  652 B is actuated using the same actuation mechanism described above in connection with  FIGS. 73 and 74 . Distal and proximal translation of the I-beam member  670  between a proximally retracted position ( FIGS. 77 and 79 ), an intermediate position (see  FIG. 74 ), and a distally advanced position ( FIGS. 78 and 80 ) may be accomplished with a suitable translation actuation mechanism. Referring to  FIGS. 75-80 , the I-beam member  670  is connected to a threaded rotary drive member  654 . A threaded rotary drive nut  656  is threaded onto the threaded rotary drive member  654 . The threaded rotary drive nut  656  is seated in the proximal portion  653  of the second jaw member  652 B. The threaded rotary drive nut  656  is mechanically constrained from translation in any direction, but is rotatable within the proximal portion  653  of the second jaw member  652 B. Therefore, given the threaded engagement of the rotary drive nut  656  and the threaded rotary drive member  654 , rotational motion of the rotary drive nut  656  is transformed into translational motion of the threaded rotary drive member  654  in the longitudinal direction and, in turn, into translational motion of the I-beam member  670  in the longitudinal direction. 
     The threaded rotary drive member  654  is threaded through the rotary drive nut  656  and is located inside a lumen of a rotary drive shaft  680 . The threaded rotary drive member  654  is not attached or connected to the rotary drive shaft  680 . The threaded rotary drive member  654  is freely movable within the lumen of the rotary drive shaft  680  and will translate within the lumen of the rotary drive shaft  680  when driven by rotation of the rotary drive nut  656 . The rotary drive shaft  680  comprising the threaded rotary drive member  654  located within the lumen of the rotary drive shaft  680  forms a concentric rotary drive shaft/screw assembly that is located in the lumen of the shaft assembly  580 . 
     Referring to  FIGS. 77-80 , the concentric rotary drive shaft/screw assembly is located within the lumen of the shaft assembly  560  and passes through the end effector drive housing  658 , the end effector connector tube  660 , and the intermediate articulation tube segment  666 . Although not shown in  FIGS. 77-80 , at least the rotary drive shaft  680  passes through a lumen of the surgical tool shaft member and is operably coupled to a driving mechanism that provides rotary motion and axial translational motion to the rotary drive shaft  680 . For example, in some embodiments, the surgical tool  650  may be operably coupled through the shaft assembly  580  to a robotic surgical system that provides rotary motion and axial translational motion to the rotary drive shaft  680 , such as, for example, the robotic surgical systems described in connection with  FIGS. 5 and 16-21 . In some embodiments, for example, the surgical tool  650  may be operably coupled through the shaft assembly  580  to a hand-held surgical device that provides rotary motion and axial translational motion to the rotary drive shaft  680 , such as, for example, the hand-held surgical devices described in connection with  FIGS. 46-63 . In some embodiments, the threaded rotary drive member  654  has a length that is less than the length of the rotary drive shaft  680  and, therefore, lies within only a distal portion of the rotary drive shaft  680 . 
     The threaded rotary drive member  654  and the rotary drive shaft  680  are flexible so that the portions of the threaded rotary drive member  654  and the rotary drive shaft  680  that are located in the articulation joint can bend without damage or loss of operability during independent articulation of the surgical tool  650  about the articulation joint. Example configurations of the rotary drive shaft  680  are provided herein with reference to  FIGS. 28-45 . 
     The rotary drive shaft  680  comprises a rotary drive head  682 . The rotary drive head  682  comprises a female hex coupling portion  684  on the distal side of the rotary drive head  682 , and the rotary drive head  682  comprises a male hex coupling portion  686  on the proximal side of the rotary drive head  682 . The distal female hex coupling portion  684  of the rotary drive head  682  is configured to mechanically engage with a male hex coupling portion  657  of the rotary drive nut  656  located on the proximal side of the rotary drive nut  656 . The proximal male hex coupling portion  686  of the rotary drive head  682  is configured to mechanically engage with a female hex shaft coupling portion  659  of the end effector drive housing  658 . 
     Referring to  FIGS. 77 and 78 , the rotary drive shaft  680  is shown in a fully distal axial position in which the female hex coupling portion  684  of the rotary drive head  682  is mechanically engaged with the male hex coupling portion  657  of the rotary drive nut  656 . In this configuration, rotation of the rotary drive shaft  680  actuates rotation of the rotary drive nut  656 , which actuates translation of the threaded rotary drive member  654 , which actuates translation of the I-beam member  670 . Referring to  FIGS. 79 and 80 , the rotary drive shaft  680  is shown in a fully proximal axial position in which the male hex coupling portion  686  of the rotary drive head  682  is mechanically engaged with the female hex shaft coupling portion  659  of the end effector drive housing  658 . In this configuration, rotation of the rotary drive shaft  680  actuates rotation of the head portion  578  of the surgical tool  650  about rotation joint, including rotation of the end effector  570  and the end effector drive housing  658 . 
     The rotary drive shaft  680  also comprises a spline lock  690 . The spline lock  690  is coupled to the rotary drive shaft  680  using shaft flanges  685 . The spline lock  690  is mechanically constrained from translation in any direction by the rotary drive shaft  680  and the shaft flanges  685 , but the spline lock  690  is freely rotatable about the rotary drive shaft  680 . The spline lock  690  comprises spline members  692  disposed circumferentially around the external surface of the spline lock  690  and oriented co-axially with the shaft assembly  580 . As shown in  FIGS. 75 and 76 , the spline lock  690  is located at the rotational joint formed by the coupling of the end effector drive housing  658  and the end effector connector tube  660 . The end effector drive housing  658  comprises a spline coupling portion  694  comprising spline members  696  disposed circumferentially around the internal surface of the end effector drive housing  658  and oriented co-axially with the shaft assembly  580 . The end effector connector tube  660  comprises a spline coupling portion  662  comprising spline members  664  disposed circumferentially around the internal surface of the end effector connector tube  660  and oriented co-axially with the shaft assembly  580 . 
     The spline members  692 ,  696 , and  664  of the spline lock  690 , the end effector drive housing  658 , and the end effector connector tube  660 , respectively, are configured to mechanically engage with each other when the rotary drive shaft  680  is in a fully distal axial position in which the female hex coupling portion  684  of the rotary drive head  682  is mechanically engaged with the male hex coupling portion  657  of the rotary drive nut  656  to drive rotation of the rotary drive nut  656  and translation of the threaded rotary drive member  654  and the I-beam member  670  ( FIGS. 77, 78, and 82 ). The mechanical engagement of the respective spline members  692 ,  696 , and  664  locks the end effector drive housing  658  into position with the end effector connector tube  660 , thereby locking the rotational joint and preventing rotation of the head portion  578  of the surgical tool  650 . Because the spline lock  690  is freely rotatable about the rotary drive shaft  680 , the mechanical engagement of the respective spline members  692 ,  696 , and  664  does not prevent the rotary drive shaft  680  from actuating the rotary drive nut  656 , the threaded rotary drive member  654 , and the I-beam member  670 . 
     When the rotary drive shaft  680  is in a fully proximal axial position in which the male hex coupling portion  686  of the rotary drive head  682  is mechanically engaged with the female hex shaft coupling portion  659  of the end effector drive housing  658  to drive rotation of the head portion  578  of the surgical tool  650 , the spline lock  690  is completely retracted into the lumen of the end effector connector tube  660  and the spline lock  690  is completely disengaged from the spline coupling portion  694  of the end effector drive housing  658 . ( FIGS. 79, 80, and 81 ). In this configuration, the spline members  692  of the spline lock  690  and the spline members  664  of the end effector connector tube  660  are completely engaged, and the spline members  692  of the spline lock  690  and the spline members  696  of the end effector drive housing  658  are completely disengaged. The mechanical disengagement of the spline members  692  of the spline lock  690  and the spline members  696  of the end effector drive housing  658  when the rotary drive shaft  680  is in a fully proximal axial position unlocks the end effector drive housing  658  from the end effector connector tube  660 , thereby unlocking the rotational joint and permitting rotation of the head portion  578  of the surgical tool  650 . Because the spline lock  690  is freely rotatable about the rotary drive shaft  680 , the mechanical engagement of spline members  692  of the spline lock  690  and the spline members  664  of the end effector connector tube  660  does not prevent the rotary drive shaft  680  from actuating the rotation of the head portion  578  of the surgical tool  650 . 
     The head locking mechanism  590  ensures that the head portion  578  of the surgical tool  650  does not rotate when the rotary drive shaft  680  is in a fully distal axial position engaging the rotary drive nut  656  to drive actuation of the jaw closure mechanism and/or the I-beam translation mechanism as described above ( FIGS. 77, 78, and 82 ). The head locking mechanism  590  ensures that the head portion  578  of the surgical tool  650  is freely rotatable when the rotary drive shaft  680  is in a fully proximal axial position engaging the shaft coupling portion  659  of the end effector drive housing  658  to drive actuation of head rotation as described above ( FIGS. 79, 80, and 81 ). 
     Referring to  FIGS. 77 and 78 , for example, rotation of the rotary drive shaft  680  actuates rotation of the rotary drive nut  656 , which actuates distal or proximal translation of the threaded rotary drive member  654  (depending on the direction of rotary motion of the rotary drive shaft  680 ), which actuates distal or proximal translation of the I-beam member  670 , which actuates the closing and opening of the jaw assembly  575 , and distal and proximal transection strokes of the I-beam member  670 /cutting member  675 . Simultaneously, the spline lock  690  engages both the end effector drive housing  658  and the end effector connector tube  660  to prevent unintended head rotation. 
     Referring to  FIGS. 79 and 80 , for example, rotation of the rotary drive shaft  680  actuates rotation of the end effector drive housing  658 , which actuates rotation of the end effector  570 . Simultaneously, the spline lock  690  is disengaged both the end effector drive housing  658  and does not prevent head rotation. Thus, the rotary drive shaft  680  may be used to independently actuate the opening and closing of the jaw assembly  575 , the proximal-distal transection stroke of the I-beam  670 /cutting member  675 , and the rotation of the head portion  578  of the surgical tool  650 . 
     In various embodiments, an end effector, such as the end effectors  550  and  570  shown in  FIGS. 64-82 , may comprise first and second jaw members comprising a first and second distal textured portions, respectively. The first and second distal textured portions of the first and second jaw members of an end effector may be opposed and may allow the end effector to grip, pass, and/or manipulate surgical implements such as needles for suturing tissue, in addition to gripping tissue, for example, during dissection operations. In some embodiments, the distal textured portions may also be electrodes configured, for example, to deliver RF energy to tissue during dissection operations. This gripping, passing, manipulating, and/or dissecting functionality is described, for example, in connection with  FIGS. 153-168 . 
     In various embodiments, an end effector, such as the end effectors  550  and  570  shown in  FIGS. 64-82 , may comprise first and second jaw members comprising first and second gripping portions disposed on outwardly facing surfaces of the first and second jaw members. The first and second gripping portions of the first and second jaw members of an end effector may function to aid in tissue dissection as described, for example, in connection with  FIGS. 116-131 . 
     In various embodiments, an end effector, such as the end effectors  550  and  570  shown in  FIGS. 64-82 , may comprise at least one electrode disposed on at least one tissue-contacting surface of at least one jaw member. The electrodes may be configured, for example, to deliver RF energy to tissue clamped between the jaw members when in a closed position to weld/fuse the tissue, which in some embodiments, may also be transected by translating an I-beam member comprising a cutting member. In some embodiments, a second jaw member may also comprise an offset electrode located at the distal tip of the jaw member, the electrode configured to deliver RF energy to tissue during dissection operations, for example. This electrode functionality is described, for example, in connection with  153 - 168 . 
     In various embodiments, an end effector, such as the end effectors  550  and  570  shown in  FIGS. 64-82 , may comprise jaw members comprising angled tissue-contacting surfaces as described, for example, in connection with  FIGS. 132-142 . 
     Referring to  FIGS. 83-91 , a multi-axis articulating and rotating surgical tool  1200  comprises an end effector  1202  including a jaw assembly  1211  comprising a first jaw member  1204  and a second jaw member  1206 . The first jaw member  1204  is movable relative to the second jaw member  1206  between an open position and a closed position to clamp tissue between the first jaw member  1204  and the second jaw member  1206 . The surgical tool  1200  is configured to independently articulate about an articulation joint  1208 . As described above, the surgical tool  1200  is also configured to independently rotate about a head rotation joint  1210 . Referring primarily to  FIG. 83 , the end effector  1202  further comprises a proximal shaft portion  1212 . 
     The end effector  1202  is coupled to a shaft assembly  1214  comprising an end effector drive housing  1216 , an end effector connector tube  1218 , an intermediate articulation tube segment  1220 , and a distal outer tube portion (not shown in  FIGS. 83-91 ). The end effector  1202  and the shaft assembly  1214  together can comprise the surgical tool  1200 . The end effector  1202  may be removably coupled to the end effector drive housing  1216  using a mechanism as described, for example, in connection with  FIGS. 106-115 . The end effector connector tube  1218  comprises a cylindrical portion  1222  and a ball portion  1224 . The end effector drive housing  1216  is coupled to the cylindrical portion  1222  of the end effector connector tube  1218  through the head rotation joint  1210 . The end effector  1202  and the end effector drive housing  1216  together comprise a head portion of the surgical tool  1200 . The head portion of the surgical tool  1200  is independently rotatable about the head rotation joint  1210 . 
     Referring primarily to  FIGS. 85-87 , the surgical tool  1200  may include a closure mechanism  1226  for moving the first jaw member  1204  relative to the second jaw member  1206  between an open position ( FIG. 86 ) and a closed position ( FIG. 87 ). As illustrated in  FIG. 83 , the first jaw member  1204  may include first mounting holes  1228 , and the second jaw member  1206  may include second mounting holes (not shown in  FIGS. 83-91 ). The first jaw member  1204  can be arranged relative to the second jaw member  1206  such that a pivot or trunnion pin (not shown in  FIGS. 83-91 ) extends through the first mounting holes  1228  of the first jaw member  1204  and the second mounting holes of the second jaw member  1206  to pivotally couple the first jaw member  1204  to the second jaw member  1206 . Other suitable means for coupling the first jaw member  1204  and the second jaw member  1206  are within the scope of this disclosure. 
     Referring to  FIGS. 83-91 , the closure mechanism  1226  may comprise a linkage arrangement which may comprise a first link  1230  and a second link (not shown in  FIGS. 83-91 ). The closure mechanism  1226  may also comprise a closure driver in the form of a closure nut  1232  for example. The closure nut  1232  ( FIG. 84 ) may be at least partially positioned within the end effector drive housing  1216 . In use, the closure nut  1232  may translate axially between a first position ( FIG. 86 ) and a second position ( FIG. 87 ) relative to the end effector drive housing  1216  and may include a first arm  1234  and a second arm  1236 . Referring primarily to  FIG. 84 , the first arm  1234  and the second arm  1236  may extend distally from a distal portion  1238  of the closure nut  1232 , wherein the first arm  1234  may comprise a first opening  1240  and the first arm  1234  may be pivotally connected to the first link  1230  by a first pin (not shown in  FIGS. 83-91 ) through the first opening  1240 . Similarly, the second arm  1236  may comprise a second opening  1244 , wherein the second arm  1236  may be pivotally connected to the second link by a second pin (not shown in  FIGS. 83-91 ) through the second opening  1244 . The first link  1230  and the second link (not shown in  FIGS. 83-91 ) are also pivotally connected to the first jaw member  1204  such that when the closure nut  1232  is advanced distally from the first position ( FIG. 86 ) to the second position ( FIG. 87 ), the first jaw member  1204  is pivoted relative to the second jaw member  1206  towards a closed position. Correspondingly, when the closure nut  1232  is retracted proximally from the second position ( FIG. 89 ) to the first position ( FIG. 91 ), the first jaw member  1204  is pivoted relative to the second jaw member  1206  towards the open position.  FIG. 85  illustrates the closure nut  1232  in a first position and the jaw assembly  1211  in an open position.  FIG. 87  shows the closure nut  1232  in a second position and the jaw assembly  1211  in a closed position. The closure nut  1232 , however, may be constrained from rotation relative to the end effector drive housing  1316  by an indexing feature, for example, abutting against the end effector drive housing  11316 . 
     Referring to  FIGS. 83-91 , the surgical tool  1200  may include a firing mechanism  1246  having a suitable firing driver. The firing mechanism  1246  may include an I-beam member  1247 , a threaded drive member  1248 , and a threaded rotary drive nut  1250 . The I-beam member  1247  may comprise a first I-beam flange  1252  and a second I-beam flange  1254 . The I-beam member  1247  may operate in a manner similar to that described above with respect to the axially movable member  3016  described herein above. For example, the first I-beam flange  1252  and the second I-beam flange  1254  are connected with an intermediate portion  1256 . The intermediate portion  1256  of the I-beam member  1247  may comprise a cutting member  1258  on a distal or a leading end thereof. The I-beam member  1247  is configured to translate within a first channel  1260  in the first jaw member  1204  and within a second channel  1262  in the second jaw member  1206 .  FIG. 84  shows the I-beam member  1247  in a fully proximal position and the jaw assembly  1211  in an open position. The I-beam member  1247  may be translated distally in order for the cutting member  1258  to transect tissue clamped between the first jaw member  1204  and the second jaw member  1206  when in the closed position. The cutting member  1258 , which may comprise a sharp edge or blade for example, is configured to cut through clamped tissue during a distal translation (firing) stroke of the I-beam member  1247 , thereby transecting the tissue.  FIG. 88  shows the I-beam member  1247  in a fully distal position after a firing stroke. 
     Before, during, and/or after the I-beam member  1247  is advanced through tissue clamped between the first jaw member  1204  and the second jaw member  1206 , electrical current can be supplied to electrodes located in the first jaw member  1204  and/or second jaw member  1206  in order to weld/fuse the tissue, as described in greater detail in this specification. For example, electrodes may be configured to deliver RF energy to tissue clamped between the first jaw member  1204  and the second jaw member  1206  when in a closed position to weld/fuse the tissue. 
     Distal and proximal translation of the I-beam member  1247  between a proximally retracted position and a distally advanced position may be accomplished with a suitable firing mechanism  1246 . Referring to  FIGS. 83-91 , the I-beam member  1247  is connected to the threaded drive member  1248 , wherein the threaded rotary drive nut  1250  is in a threaded engagement with the threaded drive member  1248 . Referring primarily to  FIG. 83 , the threaded rotary drive nut  1250  is positioned within in the end effector drive housing  1216  proximal to the closure nut  1232  between a proximal annular flange  1264  and a distal annular flange  1266 . The threaded rotary drive nut  1250  is mechanically constrained from translation in any direction, but is rotatable within the end effector drive housing  1216  around a central axis A. Therefore, given the threaded engagement of the rotary drive nut  1250  and the threaded drive member  1248 , rotational motion of the rotary drive nut  1250  is transformed into translational motion of the threaded drive member  1248  along the central axis A and, in turn, into translational motion of the I-beam member  1247  along the central axis A. 
     The threaded drive member  1248  is threaded through the rotary drive nut  1250  and is located at least partially inside a lumen  1268  of a rotary drive shaft  1270 . The threaded drive member  1248  is not attached or connected to the rotary drive shaft  1270 . In use, the threaded drive member  1248  is freely movable within the lumen of the rotary drive shaft  1270  and will translate within the lumen of the rotary drive shaft  1270  when driven by rotation of the rotary drive nut  1250 . The rotary drive shaft  1270  and the threaded drive member  1248  form a concentric rotary drive shaft/screw assembly that is located in the shaft assembly  1214 . In addition, the threaded drive member  1248  extends distally through a lumen  1272  of the closure nut  1232 . Similar to the above, the threaded drive member  1248  is freely movable within the lumen  1272  of the closure nut  1232 , and, as a result, the threaded drive member  1248  will translate within the lumen  1272  of the closure nut  1232  when driven by rotation of the rotary drive nut  1250 . 
     Referring to  FIGS. 83-91 , the rotary drive nut  1250  may comprise a threaded distal portion  1274 . The closure nut  1232  may comprise a threaded proximal portion  1276 . The threaded distal portion  1274  of the rotary drive nut  1250  and the threaded proximal portion  1276  of the closure nut  1232  are in a threaded engagement. As described above, the threaded rotary drive nut  1250  is mechanically constrained from translation in any direction, but is rotatable within the end effector drive housing  1216  around a central axis A. Therefore, given the threaded engagement of the rotary drive nut  1250  and the closure nut  1232 , the rotational motion of the rotary drive nut  1250  is transformed into translational motion of the closure nut  1232  along the central axis A and, in turn, into pivotal motion in the jaw assembly  1211 . 
     As shown in  FIG. 83 , the end effector drive housing  1216 , the end effector connector tube  1218 , and the intermediate articulation tube segment  1220 , which together comprise the shaft assembly  1214 , have open lumens and, therefore, the shaft assembly  1214  comprises a lumen extending longitudinally therethrough, as shown in  FIGS. 83 and 85-91 . Referring again to  FIGS. 83 and 85-91 , the concentric rotary drive shaft/threaded drive member assembly is located within the lumen of the shaft assembly  1214  and passes through the end effector drive housing  1216 , the end effector connector tube  1218 , and the intermediate articulation tube segment  1220 . Although not shown in  FIGS. 83-91 , at least the rotary drive shaft  1270  passes through a lumen of the shaft assembly  1214  and is operably coupled to a driving mechanism that provides rotational motion and axial translational motion to the rotary drive shaft  1270 . For example, in some embodiments, the surgical tool  1200  may be operably coupled through the shaft assembly  1214  to a robotic surgical system that provides rotational motion and axial translational motion to the rotary drive shaft  1270 , such as, for example, the robotic surgical systems described in connection with  FIGS. 5 and 16-21 . For example, the rotary drive shaft  1270  may be coupled, through the shaft assembly, to the proximal drive shaft segment  380  described herein above. In some embodiments, for example, the surgical tool  1200  may be operably coupled through the shaft assembly  1214  to a hand-held surgical device, such as the device described herein above with respect to  FIGS. 46-63 . For example, the rotary drive shaft  1270  may be operably coupled, though the shaft assembly  560 , to the proximal drive shaft segment  380 ′ described herein above. 
     In some embodiments, the threaded drive member  1248  has a length that is less than the length of the rotary drive shaft  1270  and, therefore, lies within only a distal portion of the rotary drive shaft  1270 , for example. The threaded drive member  1248  and the rotary drive shaft  1270  may be flexible so that the threaded drive member  1248  and the rotary drive shaft  1270  can bend without damage or loss of operability during articulation of the surgical tool  1200  about the articulation joint  1208 . 
     Described in greater detail elsewhere in the specification, the rotary drive shaft  1270  may comprise a rotary drive head  1278 . The rotary drive head  1278  comprises a female hex coupling portion  1280  on the distal side of the rotary drive head  1278  and the rotary drive head  1278  comprises a male hex coupling portion  1282  on the proximal side of the rotary drive head  1278 . The distal female hex coupling portion  1280  of the rotary drive head  1278  is configured to mechanically engage with a male hex coupling portion  1284  of the rotary drive nut  1250  located on the proximal side of the rotary drive nut  1250 . As described elsewhere, the proximal male hex coupling portion  1282  of the rotary drive head  1278  is configured to mechanically engage with a female hex coupling portion  1286  of the end effector drive housing  1216  in order to rotate the end effector  1202  around the central axis A. 
     Referring to  FIG. 85 , the rotary drive shaft  1270  is shown in a fully proximal axial position in which the hex coupling portion  1282  of the rotary drive head  1278  is mechanically engaged with the female hex shaft coupling portion of the end effector drive housing  1216 . In this configuration, rotation of the rotary drive shaft  1270  causes rotation of the head portion of the surgical tool  1200  about the head rotation joint  1210 , including rotation of the end effector  1202  and the end effector drive housing  1216 . In this configuration, the portion of the surgical tool  1200  that is distal to the head rotation joint  1210  (e.g., a head portion) rotates with rotation of the rotary drive shaft  1270 , and the portion of the surgical tool  1200  that is proximal to the head rotation joint  1210  does not rotate with rotation of the rotary drive shaft  1270 . An example of a head rotation joint  1210  is described in connection with  FIGS. 64-82, 83-91 and 92-96 . Other suitable techniques and rotation means for rotating the end effector  1202  relative to the shaft assembly  1214  are within the scope of the current disclosure. It will be appreciated that a desired rotation speed of the rotary drive shaft  1270  to drive the rotary drive nut  1250  may be greater than a desired rotational speed for rotating the head portion. For example, the rotary drive shaft  1270  may be driven by a motor (not shown) that is operable at different rotary speeds. 
     The orientation of the threading of the threaded drive member  1248  and the rotary drive nut  1250  may be established so that either clockwise or counterclockwise rotation of the rotary drive shaft  1270  will cause distal or proximal translation of the threaded drive member  1248  and I-beam member  1247 . Stated another way, the rotary drive shaft  1270 , and the rotary drive nut  1250  can be rotated in a first direction to advance the threaded drive member  1248  distally and correspondingly, rotated in a second opposite direction to retract the threaded drive member  1248  proximally. The pitch and/or number of starts of the threading of the threaded drive member  1248  and the threading of the rotary drive nut  1250  may be selected to control the speed and/or duration of the rotation of the rotary drive nut  1250  and, in turn, the translation of the threaded drive member  1248 . In this manner, the direction, speed, and/or duration of rotation of the rotary drive shaft  1270  can be controlled in order to control the direction, speed, and magnitude of the longitudinal translation of the I-beam member  1247  along the first channel  1260  and second channel  1262 , as described above. 
     Similar to the above, the orientation of the threading of the threaded distal portion  1274  of the rotary drive nut  1250  and the threading of the threaded proximal portion  1276  of the closure nut  1232  may be established so that either clockwise or counterclockwise rotation of the rotary drive shaft  1270  will cause distal or proximal translation of the closure nut  1232  and in turn closure or opening of the jaw assembly  1211 . Stated another way, threaded distal portion  1274  can be rotated in a first direction to advance the threaded proximal portion  1276  distally and correspondingly, rotated in a second opposite direction to retract the threaded proximal portion  1276  proximally. The pitch and/or number of starts of the threading of the threaded distal portion  1274  of the threaded drive member  1248  and the threading of threaded proximal portion  1276  of the closure nut  1232  may be selected to control speed and/or duration of the rotation of the rotary drive nut  1250  and translation of the closure nut  1232 . In this manner, the direction, speed, and/or duration of rotation of the rotary drive shaft  1270  can be controlled in order to control the direction, speed, and magnitude of the pivoting of the of the jaw assembly  1211 . 
     Referring to  FIGS. 86-88 , the rotary drive shaft  1270  is shown in a fully extended distal axial position in which the female hex coupling portion  1280  of the rotary drive head  1278  is mechanically engaged with the male hex coupling portion  1284  of the rotary drive nut  1250 . In this configuration, rotation of the rotary drive shaft  1270  in a first direction (for example a clockwise direction) around the central axis A begins a firing stroke by causing rotation of the rotary drive nut  1250  in the first direction. The rotation of the rotary drive nut advances the threaded drive member  1248 , which, in turn, advances the I-beam member  1247  distally. Simultaneously, the rotation of the rotary drive nut  1250  advances the closure nut  1232  distally, which closes the jaw assembly  1211 . The closure nut  1232  and the threaded drive member  1248  are advanced distally until the closure nut  1232  is disengaged from threaded engagement with the rotary drive nut  1250  as illustrated in  FIG. 88 . Stated another way, the closure nut  1232  can be advanced distally until the threads of the threaded distal portion  1274  of the rotary drive nut  1250  are no longer threadedly engaged with the threads of the threaded proximal portion  1276  of the closure nut  1232 . Thus, as a result, further rotation of the rotary drive nut  1250  in the first direction will not advance the closure nut  1232  distally. The closure nut  1232  will sit idle during the remainder of a firing stroke. Additional rotation of the rotary drive nut  1250 , in the same direction, continues the distal advancement of the threaded drive member  1248 , which continues the distal advancement of the I-beam member  1247  for the remainder of the firing stroke. 
     The surgical tool  1200  may comprise a biasing member  1288 , a helical spring, and/or a washer spring for example, situated at least partially around the threaded distal portion  1274  of the rotary drive nut  1250 . As illustrated in  FIG. 86 , the biasing member  1288  may include a proximal end abutted against the distal annular flange  1266  of the end effector drive housing  1216 , and a distal end abutted against a proximal end  1290  of the closure nut  1232 . Once the closure nut  1232  is released from threaded engagement with the rotary drive nut  1250 , the biasing member  1288  can keep the closure nut  1232  from reengaging the rotary drive nut  1250  by pushing the closure nut  1232  axially in a distal direction along the central axis A until the distal portion  1238  of the closure nut  1232  abuts against a terminal wall  1294  of the proximal shaft portion  1212  of the end effector  1202 . The biasing member  1288  also ensures that the jaw assembly  1211  remains under positive closure pressure by biasing the closure nut  1232  abutted against the terminal wall  1294  of the proximal shaft portion  1212  of the end effector  1202  as the I-beam member  1247  is being advanced distally through the closed jaw assembly  1211 . 
     Referring primarily to  FIG. 84 , the closure nut  1232  may comprise a cam member  1296  extending distally from the closure nut  1232 . Referring primarily to  FIG. 87 , the cam member  1296  may extend through an opening  1298  of the terminal wall  1294  of the proximal shaft portion  1212  of the end effector  1202  when the distal portion  1238  of the closure nut  1232  is abutted against the terminal wall  1294  of the proximal shaft portion  1212  of the end effector  1202  under positive pressure from the biasing member  1288 . 
     Referring to  FIG. 88 , the rotary drive shaft  1270  is shown in a fully extended distal axial position in which the female hex coupling portion  1280  of the rotary drive head  1278  is mechanically engaged with the make hex coupling portion  1284  of the rotary drive nut  1250 . In this configuration, rotation of the rotary drive shaft  1270  in a second direction opposite the first direction (for example a counter clockwise direction) begins a reverse stroke by causing an opposite rotation of the rotary drive nut  1250 , which retracts the threaded drive member  1248 , which in turn retracts the I-beam member  1247 . At least during the initial phase of the reverse stroke, the closure nut  1232  remains disengaged from the rotary drive nut  1250 . However, when the I-beam member  1247  is being retracted, the I-beam member  1247  can engage the cam member  1296  of the closure nut  1232 . Any further retraction of the I-beam member  1247  can simultaneously open the jaw assembly  1211  by pushing the closure nut  1232  axially in a proximal direction along the central axis A toward the rotary drive nut  1250 . In order for the I-beam member  1247  to push the closure nut  1232  proximally, the I-beam member  1247  must compress the biasing member  1288 . As the I-beam member  1247  is retracted, the I-beam member  1247  can push the closure nut  1232  proximally until the closure nut is returned into threaded engagement with the rotary drive nut  1250 . At such point, the rotary drive nut  1250  can pull the closure nut  1232  proximally owing to the threaded engagement therebetween. As the closure nut  1232  is retracted proximally, the first link  1230 , and the second link will cause the jaw assembly  1211  to open. The retraction of the I-beam member  1247  and the opening of the jaw assembly  1211  continue simultaneously during the remainder of the reverse stroke. 
     The sequence of events causing the closure of the jaw assembly  1211 , the full extension of the I-beam member  1247 , the full retraction of the I-beam member  1247 , and the reopening of the jaw assembly  1211  is illustrated in  FIGS. 85-91  in a chronological order.  FIG. 85  shows the jaw assembly  1211  in a fully open position, the I-beam member  1247  in a fully retracted position, and the rotary drive shaft  1270  in a fully retracted axial position, wherein the female hex coupling portion  1280  of the rotary drive head  1278  is mechanically disengaged from the male hex coupling portion  1284  of the rotary drive nut  1250 . In a first phase of operation, returning to  FIG. 86 , the rotary drive shaft  1270  is advanced axially to mechanically engage the female hex coupling portion  1280  of the rotary drive head  1278  with the male hex coupling portion  1284  of the rotary drive nut  1250 . Referring again to  FIG. 86 , the rotation of the rotary drive shaft  1270  in a first direction (for example a clockwise direction) around the central axis A causes the rotation of the rotary drive nut  1250  in the first direction. The closure nut  1232  and the threaded drive member  1248  are simultaneously advanced distally by rotation of the rotary drive nut  1250  in the first direction. In turn, the closure of the jaw assembly  1211  and the initial advancement of the I-beam member  1247  occur simultaneously during the first phase of operation. In a second phase of operation, referring now to  FIG. 87 , the closure nut  1232  is disengaged from threaded engagement with the rotary drive nut  1250 . During the remainder of the second phase of operation, the rotary drive nut  1250  continues to advance the threaded drive member  1248  independently of the closure nut  1232 . As a result, referring primarily to  FIG. 88 , the jaw assembly  1211  remains closed and the I-beam member  1247  continues to advance until the end of the second phase of operation. 
     In a third phase of operation, as illustrated in  FIG. 89 , the rotary drive shaft  1270  is rotated in a second direction opposite the first direction, which causes the rotation of the rotary drive nut  1250  in the second direction. In the third phase of operation, the closure nut  1232  remains disengaged from rotary drive nut  1250 . The rotation of the rotary drive nut  1250  retracts the threaded drive member  1248  independent of the closure nut  1232 . In result, the jaw assembly  1211  remains closed, and the I-beam member  1247  is retracted in response to the rotation of the rotary drive. In a fourth phase of operation, referring primarily to  FIG. 90 , the rotary drive nut  1250  continues its rotation in the second direction thereby retracting the threaded drive member  1248  which retracts I-beam member  1247  until the I-beam member  1247  engages the cam member  1296  of closure nut  1232 . Any further retraction of the I-beam member  1247  simultaneously opens the jaw assembly  1211  by pushing the closure nut  1232  axially in a proximal direction along the central axis A towards the rotary drive nut  1250  compressing the biasing member  1288 . Referring primarily to  FIG. 91 , the I-beam member  1247  can continue to push the closure nut  1232  proximally until it is returned into threaded engagement with the rotary drive nut  1250 . The retraction of the I-beam member  1247  and the opening of the jaw assembly  1211  continue simultaneously during the remainder of the fourth phase of operation. 
     Referring to  FIGS. 92-96 , a multi-axis articulating and rotating surgical tool  1300  comprises an end effector  1302  including a jaw assembly  1311  comprising a first jaw member  1304  and a second jaw member  1306 . The first jaw member  1304  is movable relative to the second jaw member  1306  between an open position and a closed position to clamp tissue between the first jaw member  1304  and the second jaw member  1306 . The surgical tool  1300  is configured to independently articulate about an articulation joint  1308 . As described above, the surgical tool  1300  is also configured to independently rotate about a head rotation joint  1310 . 
     The end effector  1302  is coupled to a shaft assembly  1314  comprising an end effector drive housing  1316 , an end effector connector tube  1318 , an intermediate articulation tube segment  1320 , and a distal outer tube portion (not shown in  FIGS. 92-96 ). The end effector  1302  and the shaft assembly  1314  together can comprise the surgical tool  1300 . The end effector  1302  may be removably coupled to the end effector drive housing  1316  using a mechanism as described, for example, in connection with  FIGS. 106-115 . The end effector connector tube  1318  comprises a cylindrical portion  1322  and a ball portion  1324 . The end effector drive housing  1316  is coupled to the cylindrical portion  1322  of the end effector connector tube  1318  through the head rotation joint  1310 . The end effector  1302  and the end effector drive housing  1316  together comprise a head portion of the surgical tool  1300 . The head portion of the surgical tool  1300  is independently rotatable about the head rotation joint  1310 . 
     Referring primarily to  FIG. 92 , the surgical tool  1300  may include a closure mechanism  1326  for moving the first jaw member  1304  relative to the second jaw member  1306  between an open position ( FIG. 93 ) and a closed position ( FIG. 94 ). As illustrated in  FIG. 83 , the first jaw member  1304  may include first mounting holes  1328 , and the second jaw member  1306  may include second mounting holes (not shown in  FIGS. 92-96 ). The first jaw member  1304  can be arranged relative to the second jaw member  1306  such that a pivot or trunnion pin (not shown in  FIGS. 92-96 ) extends through the first mounting holes  1328  of the first jaw member  1304  and the second mounting holes of the second jaw member  1306  to pivotally couple the first jaw member  1304  to the second jaw member  1306 . Other suitable means for coupling the first jaw member  1304  and the second jaw member  1306  are within the scope of this disclosure. 
     Referring to  FIGS. 92-96 , the closure mechanism may comprise a closure link  1330  which translates axially relative to the end effector drive housing  1316  between a first position and a second position. The closure link  1330  may comprise a distal end  1332  and a proximal end  1334 . The distal end  1332  may be pivotally connected to a proximal portion  1336  of the first jaw member  1304  such that when the closure link  1330  is translated between the first position and the second position, the first jaw member  1304  is moved relative to the second jaw member  1306  between an open and a closed position. 
     Referring to  FIGS. 92-96 , the closure mechanism  1328  may also comprise a closure driver in the form of a barrel cam  1338  for example. The barrel cam  1338  may be positioned within the end effector drive housing  1316 . The barrel cam  1338  may comprise a generally cylindrical shape having a lumen  1340  therethrough. The barrel cam  1338  may include a first arcuate groove  1346 , and a second arcuate groove  1348  defined in a peripheral surface thereof. The first arcuate groove  1346  may receive a first pin  1352  extending from the end effector drive housing  1316 . The second arcuate groove  1348  may receive a second pin (not shown in  FIGS. 92-96 ) extending from the end effector drive housing  1316 . The first pin  1352  and the second pin (not shown in  FIGS. 92-96 ) may extend from circumferentially opposite sides of an inner wall of the end effector drive housing  1316 . The barrel cam  1338  may rotate around central axis A, wherein, as the barrel cam  1338  is rotated around central axis A, the first pin  1352  travels along the first arcuate groove  1346 , and the second pin travels along the second arcuate groove  1348  thereby translating the barrel cam  1338  axially along central axis A. The result is a conversion of the rotational motion of the barrel cam  1338  into an axial motion of the closure link  1330 . Stated another way, the rotation of the barrel cam  1338  in a first direction (for example a clockwise direction) around the central axis A may result in advancing the barrel cam  1338  axially in a distal direction. Correspondingly, the rotation of the barrel cam  1338  in a second direction (for example a counter clockwise direction) opposite the first direction may result in retracting the barrel cam  1338  axially in a proximal direction along the central axis A. 
     Referring to  FIGS. 92-96 , the proximal end  1334  of the closure link  1330  may be operatively engaged with the barrel cam  1338  such that the axially advancement of the barrel cam  1338  may cause the closure link  1330  to be advanced axially, and, in turn close the jaw assembly  1311 . Similarly, the proximal retraction of the barrel cam  1338  may retract the closure link  1330 , which may open the jaw assembly  1311 . As illustrated in  FIGS. 92-96 , the barrel cam  1338  may include a circumferential recess  1354  on the external wall of the barrel cam  1338  at a distal portion thereof. The proximal end of the closure link  1330  may comprise a connector member  1356 . The connector member  1356  may be operably engaged with the barrel cam  1338  along the recess  1354 . As a result, the barrel cam  1338  may translate axial motions to the closure link  1330  through the connector member  1356 . 
     Referring primarily to  FIG. 92 , the surgical tool  1300  may include a firing mechanism  1358 . The firing mechanism  1358  may include an I-beam member  1360 , a threaded drive member  1362 , and a threaded rotary drive nut  1364 . The I-beam member  1360  may operate in a manner similar to that of the axially movable member  3016  described herein above and may comprise a first I-beam flange  1367  and a second I-beam flange  1368 . The first I-beam flange  1367  and the second I-beam flange  1368  are connected with an intermediate portion  1370 . The intermediate portion  1370  of the I-beam member  1360  may comprise a cutting member  1372 , which may comprise a sharp edge or blade for example, to transect tissue clamped between the first jaw member  1304  and the second jaw member  1306  when the jaw assembly  1311  is closed. The I-beam member  1360  may translate distally within a first channel (not shown in  FIGS. 92-96 ) defined in the first jaw member  1304  and within a second channel  1376  defined in the second jaw member  1306  to cut through clamped tissue during a distal translation (firing) stroke.  FIG. 96  illustrates the I-beam member  1360  after a firing stroke. 
     Before, during, and/or after the I-beam member  1360  is advanced through tissue clamped between the first jaw member  1304  and the second jaw member  1306 , electrical current can be supplied to electrodes  1378  located in the first jaw member  1304  and/or second jaw member  1306  in order to weld/fuse the tissue, as described in greater detail in this specification. For example, electrodes  1378  may be configured to deliver RF energy to tissue clamped between the first jaw member  1304  and the second jaw member  1306  when in a closed position to weld/fuse the tissue. 
     Distal and proximal translation of the I-beam member  1360  between a proximally retracted position and a distally advanced position may be accomplished with a suitable firing mechanism  1358 . Referring to  FIGS. 92-96 , the I-beam member  1360  is connected to the threaded drive member  1362 , wherein the threaded drive member  1362  is threadedly engaged with the rotary drive nut  1364 . The threaded rotary drive nut  1364  is positioned within the end effector drive housing  1316  distal to the barrel cam  1338  between a proximal annular flange  1339 A and a distal annular flange  1339 B. The threaded rotary drive nut  1364  is mechanically constrained from translation in any direction, but is rotatable within the end effector drive housing  1316 . Therefore, given the threaded engagement of the rotary drive nut  1364  and the threaded drive member  1362 , rotational motion of the rotary drive nut  1364  is transformed into translational motion of the threaded drive member  1362  along the central axis A and, in turn, into translational motion of the I-beam member  1360  along the central axis A. 
     The threaded drive member  1362  is threaded through the rotary drive nut  1364  and is located at least partially inside a lumen  1381  of a rotary drive shaft  1382 . The threaded drive member  1362  is not attached or connected to the rotary drive shaft  1382 . The threaded drive member  1362  is freely movable within the lumen  1381  of the rotary drive shaft  1382  and will translate within the lumen  1381  of the rotary drive shaft  1382  when driven by rotation of the rotary drive nut  1364 . The rotary drive shaft  1382  and the threaded drive member  1362  form a concentric rotary drive shaft/threaded drive member assembly that is located in the shaft assembly  1314 . In addition, the threaded drive member  1362  extends distally through a lumen  1384  of the barrel cam  1338  wherein the threaded drive member  1362  is freely movable within the lumen  1384  of the barrel cam  1338  and will translate within the lumen  1384  of the barrel cam  1338  when the threaded drive member is driven by rotation of the rotary drive nut  1364 . 
     As shown in  FIG. 92 , the end effector drive housing  1316 , the end effector connector tube  1318 , and the intermediate articulation tube segment  1320 , which together comprise the shaft assembly  1314 , have lumens extending therethrough. As a result, the shaft assembly  1314  can comprise a lumen extending therethrough, as illustrated in  FIGS. 92-96 . Referring again to  FIGS. 92-96 , the concentric rotary drive shaft/threaded drive member assembly is located within the lumen of the shaft assembly  1314  and passes through the end effector drive housing  1316 , the end effector connector tube  1318 , and the intermediate articulation tube segment  1320 . Although not shown in  FIGS. 92-96 , at least the rotary drive shaft  1382  passes through a lumen of the shaft assembly  1314  and is operably coupled to a driving mechanism that provides rotational and/or axial translational motion to the rotary drive shaft  1382 . For example, in some embodiments, the surgical tool  1300  may be operably coupled through the shaft assembly  1314  to a robotic surgical system that provides rotational motion and/or axial translational motion to the rotary drive shaft  1382 , such as, for example, the robotic surgical systems described in connection with  FIGS. 5 and 16-21 . For example, the rotary drive shaft  1382  may be operably coupled, though the shaft assembly  1314 , to the proximal drive shaft segment  380  described herein above. Also, in some embodiments, the surgical tool  1300  may be utilized in conjunction with a hand-held surgical device, such as the device described herein above with respect to  FIGS. 46-63 . For example, the rotary drive shaft  1382  may be operably coupled, through the shaft assembly  1314 , to the proximal drive shaft segment  380 ′ described herein above. 
     In some embodiments, the threaded drive member  1362  has a length that is less than the length of the rotary drive shaft  1382  and, therefore, lies within only a distal portion of the rotary drive shaft  1382 , for example. The threaded drive member  1362  and the rotary drive shaft  1382  may be flexible so that the threaded drive member  1362  and the rotary drive shaft  1382  can bend without damage or loss of operability during articulation of the surgical tool  1300  about the articulation joint  1308 . 
     The rotary drive shaft  1382  may comprise a rotary drive head  1386 . The rotary drive head  1386  may comprise spline members  1388  disposed circumferentially around an external surface of the rotary drive head  1386  and oriented co-axially with the shaft assembly  1314 . The end effector drive housing  1316  may comprise a spline coupling portion  1390  comprising spline members  1392  disposed circumferentially around an internal wall of the end effector drive housing  1316  and oriented co-axially with the shaft assembly  1314 . The barrel cam  1338  may comprise a spline coupling portion  1394  comprising spline members  1396  disposed circumferentially around an internal wall of barrel cam  1338  and oriented co-axially with the shaft assembly  1314 . The rotary drive nut  1364  may also comprise a spline coupling portion  1397  comprising spline members  1398  disposed circumferentially around an internal wall of rotary drive nut  1364  and oriented co-axially with the shaft assembly  1314 . As illustrated in  FIG. 93 , the rotary drive shaft  1382  may be selectively retracted proximally to bring the rotary drive head  1386  into operable engagement with the spline coupling portion  1390  of the end effector drive housing  1316 . In this configuration, rotation of the rotary drive shaft  1382  causes rotation of the head portion of the surgical tool  1300  about the head rotation joint  1310 , including rotation of the end effector  1302  and the end effector drive housing  1316 . In this configuration, the portion of the surgical tool  1300  that is distal to the head rotation joint  1310  rotates with rotation of the rotary drive shaft  1382 , and the portion of the surgical tool  1300  that is proximal to the head rotation joint  1310  does not rotate with rotation of the rotary drive shaft  1382 . An example of a head rotation joint  1310  is described in connection with  FIGS. 64-82, 83-91 and 92-96 . Other suitable techniques and rotation means for rotating the end effector  1302  relative to the shaft assembly  1314  are within the scope of the current disclosure. It will be appreciated that a desired rotation speed of the rotary drive shaft  1382  to drive the rotary drive nut  1364  may be greater than a desired rotational speed for rotating the head portion. For example, the rotary drive shaft  1270  may be driven by a motor (not shown) that is operable at different rotary speeds. 
     As illustrated in  FIG. 94 , the rotary drive shaft  1382  may be selectively advanced distally to bring the rotary drive head  1386  into operable engagement with the spline coupling portion  1394  of the barrel cam  1338 . In this configuration, rotation of the rotary drive shaft  1382  causes rotation of the barrel cam  1338 . As described above, the rotation of the barrel cam  1338  causes axial motions in the closure link  1330 . In result, the rotation of the rotary drive shaft  1382  in a first direction (for example a clockwise direction) around the central axis A may cause the closure link  1330  to be advanced distally along the central axis A, which may close the jaw assembly  1311 . Alternatively, the rotation of the rotary drive shaft  1382  in a second direction (for example a clockwise direction) opposite the first direction may cause the closure link  1330  to be retracted proximally along the central axis A, which in turn may open the jaw assembly  1311 . 
     As illustrated in  FIG. 95 , the rotary drive shaft  1382  may be selectively advanced distally to pass the rotary drive head  1386  through the lumen of the barrel cam  1338  into a space  1399  in the end effector drive housing  1316  between the barrel cam  1338  and the rotary drive nut  1364  wherein the rotary drive head  1386  is not in operable engagement with any of the spline coupling portions. The rotary drive shaft  1382  may then be further advanced distally to bring rotary drive head  1386  into operable engagement with the spline coupling portion  1397  of the rotary drive nut  1364  as illustrated in  FIG. 96 . In this configuration, rotation of the rotary drive shaft  1382  causes rotation of the rotary drive nut  1364 . As described above, the rotation of the rotary drive nut  1364  causes axial motions in the threaded drive member  1362 . In result, rotation of the rotary drive shaft  1382  in a first direction (for example a clockwise direction) around the central axis A, may cause the threaded drive member  1362  to be advanced distally, which in turn may advance the I-beam member  1360  distally. Alternatively, rotation of the rotary drive shaft  1382  in a second direction (for example a clockwise direction) opposite the first direction may cause the threaded drive member  1362  to be retracted proximally, which may retract the I-beam member  1360  proximally. 
     The sequence of events causing the closure of the jaw assembly  1311 , the full extension of the I-beam member  1360 , the full retraction of the I-beam member  1360 , and the reopening of the jaw assembly  1311  is illustrated in  FIGS. 93-96  in a chronological order.  FIG. 93  shows the jaw assembly  1311  in a fully open position, the I-beam member  1360  in a fully retracted position, and the rotary drive shaft  1382  in a retracted axial position, wherein the rotary drive head  1386  is operably engaged with the spline coupling portion  1390  of the end effector drive housing  1316 . In a first phase of operation, the rotary drive shaft  1382  is rotated to rotate the end effector  1302  into an appropriate orientation, for example relative to a blood vessel. In a second phase of operation, the rotary drive shaft  1382  is advanced axially to bring the rotary drive head  1386  into operable engagement with the spline coupling portion  1394  of the barrel cam  1338 . In this configuration, the rotary drive shaft  1382  may be rotated in a first direction (for example a clockwise direction) around the central axis A to close the jaw assembly  1311  around the blood vessel. The electrodes  1378  in the first jaw member  1304  and the second jaw member  1306  may be activated to seal the blood vessel. In a third phase of operation, the rotary drive shaft  1382  may then be advanced axially to bring the rotary drive head  1386  into operable engagement with the spline coupling portion  1397  of the rotary drive nut  1364 . In this configuration, the rotary drive shaft  1382  may be rotated in a first direction around the central axis A (for example a clockwise direction) to advance the I-beam member  1360  thereby transecting the sealed blood vessel. In a fourth phase of operation, the rotary drive shaft  1382  may be rotated in a second direction (for example a counter clockwise direction) opposite the first direction to retract the I-beam member  1360 . 
     In a fifth phase of operation, the rotary drive shaft  1382  is retracted axially to bring the rotary drive head  1386  into operable engagement with the spline coupling portion  1394  of the barrel cam  1338 . In this configuration, the rotary drive shaft  1382  may be rotated in a second direction (for example a counter clockwise direction) opposite the first direction to reopen the jaw assembly  1311  thereby releasing the sealed cut blood vessel. 
     As described above, a surgical tool can utilize a drive system for translating a drive member distally within an end effector of the surgical tool, to advance a cutting member within the end effector, for example, and for translating the drive tube proximally to retract the drive tube and/or cutting member.  FIGS. 97 and 98  illustrate an example drive shaft assembly  1400  that may be employed in connection with an end effector  1420  and/or any of the end effectors described herein. For example, the drive shaft assembly  1400  (as well as the assembly  1400 ′) may correspond to various threaded rotary drive members described herein including, for example, the threaded rotary drive members  604 ,  654 ,  1040 ,  1248 ,  1364 , etc. Further to the above, the drive shaft assembly  1400  can be advanced distally in order to rotate a jaw member  1422  of the end effector  1420  between a closed position and an open position, as illustrated in  FIG. 97 , and advance a cutting member between the jaw member  1422  and a jaw member  1424  positioned opposite the jaw member  1422 . In one example form, the drive shaft assembly  1400  includes a drive member, or tube,  1402  that can comprise a series of annular joint segments  1404  cut therein. 
     In various example embodiments, the drive member  1402  can comprise a hollow metal tube comprised of stainless steel, titanium, and/or any other suitable material, for example, that has a series of annular joint segments  1404  formed therein. In at least one embodiment, the annular joint segments  1404  can comprise a plurality of loosely interlocking dovetail shapes  1406  that are, for example, cut into the drive member  1402  by a laser and serve to facilitate flexible movement between the adjoining joint segments  1404 . Such laser cutting of a tube stock can create a flexible hollow drive tube that can be used in compression, tension and/or torsion. Such an arrangement can employ a full diametric cut that is interlocked with the adjacent part via a “puzzle piece” configuration. These cuts are then duplicated along the length of the hollow drive tube in an array and are sometimes “clocked” or rotated to change the tension or torsion performance. Further to the above, the interlocking dovetails shapes  1406  are but one example embodiment and, in various circumstances, the drive member  1402  can comprise any suitable array of articulation joints comprising interlocking drive projections and drive recesses. In various circumstances, the drive member  1402  can comprise an articulation joint lattice comprising operably engaged projections and recesses which can be interlocked to transmit linear and/or rotary motions therebetween. In a sense, in various embodiments, the drive member  1402  can comprise a plurality or a multitude of articulation joints defined within the body of the drive member  1402 . The drive member  1402  can include a plurality of articulation joints which are intrinsic to the body of the drive member  1402 . 
     Further to the above, the drive member  1402  can be pushed distally such that a longitudinal force is transmitted through the drive member  1402  and to a cutting member, for example, operably coupled with a distal end of the drive member  1402 . Correspondingly, the drive member  1402  can be pulled proximally such that a longitudinal force is transmitted through the drive member  1402  and to the cutting member. The interlocking dovetail shapes  1406  can be configured to transmit the longitudinal pushing and pulling forces between the joint segments  1404  regardless of whether the joint segments  1404  are longitudinally aligned, as illustrated in  FIG. 98 , and/or articulated relative to each other to accommodate the articulation of the articulation joint  1430  which rotatably connects the end effector  1420  to the shaft of the surgical instrument. More particularly, further to the above, the articulation joint  1430  can comprise one or more articulation segments  1434  which can move relative to one another to permit the end effector  1420  to rotate wherein, in order to accommodate the relative movement of the articulation joint segments  1434 , the joint segments  1404  of the drive member  1402  can rotate or shift relative to each other. In at least the illustrated embodiment of  FIG. 97 , the articulation joint segments  1434  can define a passage  1435  extending therethrough which can be configured to closely receive the drive tube  1402  and constrain large transverse movements between the joint segments  1404  while concurrently permitting sufficient relative movement between the joint segments  1404  when the articulation joint  1430  has been articulated.  FIGS. 99-101  illustrate alternative example micro-annular joint segments  1404 ′ of a drive member  1402 ′ that can comprise a plurality of laser cut shapes  1406 ′ that roughly resemble loosely interlocking, opposed “T” shapes and T-shapes with a notched portion therein, for example. The laser cut shapes  1406 ′ can also roughly resemble loosely interlocking, opposed “L” shapes and L-shapes defining a notched portion, for example. The annular joint segments  1404 ,  1404 ′ can essentially comprise multiple micro-articulating torsion joints. That is, each joint segment  1404 ,  1404 ′ can transmit torque while facilitating at least some relative articulation between each annular joint segment. As shown in  FIGS. 99 and 100 , the joint segment  1404 D′ on the distal end  1403 ′ of the drive member  1402 ′ has a distal mounting collar portion  1408 D′ that facilitates attachment to other drive components for actuating the end effector. Similarly, the joint segment  1404 P′ on the proximal end  1405 ′ of the drive member  1402 ′ has a proximal mounting collar portion  1408 P′ that facilitates attachment to other proximal drive components or portions of a quick disconnect joint, for example. 
     The joint-to-joint range of motion for each particular joint segment  1404 ′ can be increased by increasing the spacing in the laser cuts. In various circumstances, however, the number and/or density of the laser cuts within any particular region of the drive member  1402 ′ can cause the drive member  1402 ′ to be particularly flexible in that region. To ensure that the joint segments  1404 ′ remain coupled together without significantly diminishing the drive tube&#39;s ability to articulate through desired ranges of motion, a secondary constraining member can be employed to limit or prevent the outward expansion of the joint segments  1404 ′. In the example embodiment depicted in  FIGS. 102 and 103 , a secondary constraining member  1410  comprises a spring  1412  or an otherwise helically-wound member. In various example embodiments, the distal end  1414  of the spring  1412  can correspond to and can be attached to the distal mounting collar portion  1408 D′ and can be wound tighter than the central portion  1416  of the spring  1412 . Similarly, the proximal end  1418  of the spring  1412  can correspond to and can be attached to the proximal collar portion  1408 P′ and can be wound tighter than the central portion  1416  of the spring  1412 . As a result of the tighter winding, the distal end  1414  and/or the proximal end  1418  can comprise coils which are positioned closer together than the coils of the central portion  1416 . Stated another way, the coils per unit distance of the distal end  1414  and/or the proximal end  1418  can be greater than the coils per unit distance of the central portion  1416 . In any event, the spring  1412  can define a longitudinal aperture  1413  within which the drive member  1402 ′, and/or the drive member  1402 , for example, can be positioned. The longitudinal aperture  1413  and the drive member  1402 ′ can be sized and configured such that the drive member  1402 ′ is closely received within the longitudinal aperture  1413  wherein, in various circumstances, the coils of the spring  1412  can limit the outward movement of the joint segments  1404 ′ such that the joint segments  1404 ′ do not become disconnected from one another when they are articulated relative to one other. As outlined above, the distal end  1414  of the spring  1412  can be fixedly mounted to the distal end  1403 ′ of the drive member  1402 ′ and the proximal end  1418  of the spring  1412  can be fixedly mounted to the proximal end  1405 ′ of the drive member  1402 ′ wherein the movement of the distal tube end  1403 ′ can move the distal spring end  1414  and, correspondingly, the movement of the proximal tube end  1405 ′ can move the proximal spring end  1418 . In various circumstances, the spring ends  1414  and  1418  can be welded, for example, to the tube ends  1403 ′ and  1405 ′, respectively. In at least the illustrated embodiment, the coils of the central portion  1416  may not be fixedly mounted to the drive member  1402 ′. In at least one such embodiment, the drive member  1402 ′ can be configured to at least partially articulate within the coils of the central portion  1416  until the drive member  1402 ′ contacts the coils wherein, at such point, the coils can be configured to at least partially expand or shift to accommodate the lateral movement of the drive member  1402 ′. In various other embodiments, at least portions of the coils of the central portion  1416  can be fixedly mounted, such as by welding, for example, to the drive member  1402 ′. 
     Further to the above, the constraining member  1410  may be installed on the drive member  1402 ′ with a desired pitch such that the constraining member  1410  also functions, for example, as a flexible drive thread  1440  which can be threadably engaged with other threaded drive components on the end effector and/or the drive system, as described above. The drive member  1402 ′ can be constrained from being revolved around its longitudinal axis wherein, when a threaded drive input is engaged with the thread  1440  and is rotated in a first direction by a motor, for example, the drive member  1402 ′ can be advanced distally within the end effector  1420 . Correspondingly, when the threaded drive input engaged with the thread  1440  is rotated in a second, or opposite, direction, the drive member  1402 ′ can be retracted proximally. It will be appreciated that the constraining member  1410  may be installed in such a manner that the thread  1440  includes a constant, or at least substantially constant, pitch along the length thereof. In such embodiments, the drive member  1402 ′ can be advanced and/or retracted at a constant, or an at least substantially constant, rate for a given rate in which the threaded drive input is rotated. It will also be appreciated that the constraining member  1410  can be installed in such a manner that the thread  1440  includes a variable pitch, or a pitch which changes along the length of the drive member  1402 ′. For example, the variable pitch arrangement of the constraining member  1410  may be used to slow the drive assembly  1400 ′ down or speed the drive assembly  1400 ′ up during certain portions of the firing stroke of the drive assembly  1400 ′. For instance a first portion of the thread  1440  can include a first pitch which is smaller than the pitch of a second portion of the thread  1440  wherein the first pitch can drive a closing member at a first rate and the second portion can drive a firing member at a second rate, for example. In at least some forms, for example, the drive shaft assembly comprises a variable pitch thread on a hollow flexible drive shaft that can be pushed and pulled around a ninety degree bend or greater, for example. 
     As discussed above, the drive member  1402 ′ can be constrained from revolving about its longitudinal axis. Moreover, the entire drive shaft assembly  1400 ′ can be constrained from rotating about its longitudinal axis. In various embodiments, the drive member  1402 ′ can comprise a longitudinal slot defined therein which can be engaged with one or more projections which can extend inwardly from the end effector  1420  and/or the articulation joint members  1434  into the longitudinal slot, for example. Such an arrangement of the longitudinal slot and the projections can be configured to prevent or at least limit the rotation of the drive shaft assembly  1400 ′ about its own longitudinal axis. As used herein, the longitudinal axis of the drive shaft assembly  1400 ′, and/or the drive member  1402 ′, can extend along the center of the drive shaft assembly  1400 ′ regardless of whether the drive shaft assembly  1400 ′ is in a straight configuration or a bent configuration. As a result, the path and direction of the longitudinal axis of the drive shaft assembly  1400 ′ may change when the end effector  1420  is articulated and the drive shaft assembly  1400 ′ articulates to accommodate the articulation of the end effector  1420 . Further to the above, the drive member  1402 ′ can be fixedly mounted to and extend proximally from a cutting member positioned within the end effector  1420 . As described herein, the cutting member can be closely received within various slots and/or channels defined in the end effector which can prevent the cutting member, and the drive shaft assembly  1400 ′ extending therefrom, from being rotated, or at least substantially rotated about its longitudinal axis. While the longitudinal axis of the drive shaft assembly  1400 ′ can be defined by the drive member  1402 ′, the longitudinal axis can be defined by the spring  1412 . In at least one such embodiment, the center path of the spring coils can define the longitudinal axis of the drive shaft assembly  1400 ′. In any event, the drive shaft assembly  1400 ′ can be constrained from revolving around its longitudinal axis. 
     Turning now to  FIGS. 104 and 105 , the drive shaft assembly  1400 ′ can comprise an internal constraining member, such as a flexible core  1417 , for example, which can be configured to limit or prevent the inward movement or collapse of the joint segments  1404 ′ of the drive member  1402 ′. The drive member  1402 ′ can define an internal longitudinal cavity  1415  which can be configured to closely receive the flexible core  1417 . In at least one such embodiment, the internal cavity  1415  defined in the drive member  1402 ′ can comprise a diameter or width which is equal to, or at least substantially equal to, the diameter or width of the flexible core  1417 . In various circumstances during the articulation of the end effector  1420 , for example, portions of the joint segments  1404 ′ can deflect or be displaced inwardly toward the flexible core  1417  wherein, when the joint segments  1404 ′ contact the flexible core  1417 , the core  1417  can inhibit the inward movement of the joint segments  1404 ′ and prevent the drive member  1402 ′ from collapsing inwardly. The flexible core  1417  can be mounted to at least portions of the drive member  1402 ′ such as the distal end  1408 D′ and/or the proximal end  1408 P′ thereof, for example. In certain embodiments, the flexible core  1417  may not be fixedly mounted to the drive member  1402 ′ wherein, in such embodiments, the flexible core  1417  can be held in place by the drive member  1402 ′. In any event, the flexible core  1417  can be sufficiently flexible so as to permit the drive shaft assembly  1400 ′ to bend or articulate as necessary to transmit the pushing and pulling motions applied thereto, as described above. 
     As outlined above, the shaft assembly  1400 ′, for example, can be configured to bend or flex to accommodate the articulation of the end effector  1420  about the articulation joint  1430 . The drive member  1402 ′, the flexible core  1417 , and/or the spring  1412  can be resilient such that the shaft assembly  1400 ′ can return to its original longitudinal configuration, for example. In various circumstances, the end effector  1420  can be rotated from its articulated position back to its longitudinal, or straight, position and, as such, the shaft assembly  1400 ′ can be configured to bend or flex in order to accommodate the return of the end effector  1420 . 
     Referring to  FIGS. 106-108 , a surgical tool  1000  may include a surgical end effector  1001  and a shaft assembly  1003 . Surgical end effector  1001  may be configured to perform surgical activities in response to drive motions applied thereto. Shaft assembly  1003  may be configured to transmit such drive motions to surgical end effector  1001 . The surgical end effector  1001  may include a first jaw member  1002 , and a second jaw member  1004 . The first jaw member  1002  may be movable relative to the second jaw member  1004  between a first position and a second position. Alternatively, the first jaw member  1002  and second jaw member  1004  may be moveable relative to each other between a first position and a second position. The first position may be an open position and the second position may be a closed position. 
     Referring to  FIGS. 106-108 , the first jaw member  1002  may be pivotally movable relative to the second jaw member  1004  between a first position and a second position. As illustrated in  FIG. 108 , the first jaw member  1002  may include mounting holes (not shown), and the second jaw member  1004  may include mounting holes  1008 . The first jaw member  1002  can be arranged relative to the second jaw member  1004  such that a pivot or trunnion pin (not shown) is inserted through the mounting holes of the first jaw member  1002  and the mounting holes  1008  of the second jaw member  1004  to pivotally couple the first jaw member  1002  to the second jaw member  1004 . Other suitable means for coupling the first jaw member  1002  and the second jaw member  1004  are contemplated within the scope of this disclosure. 
     Referring to  FIGS. 106-108 , surgical end effector  1001  may be adapted to perform multiple functions. For example, surgical end effector  1001  may include gripping portions  1010  disposed on exterior surfaces of the first jaw member  1002  and/or the second jaw member  1004 . Gripping portions  1010  may be adapted for contacting and bluntly dissecting tissue. Suitable gripping portions  1010  are described, for example, in connection with  FIGS. 116-131 . Surgical end effector  1001  may also include angled tissue engagement surfaces  1012  for transecting tissue. Suitable angled tissue engagement surfaces  1012  are described, for example, in connection with  FIGS. 132-142 . The first jaw member  1002  may include an interior surface  1014  and the second jaw member  1004  may include an interior surface  1016 . The first  1014  and second  1016  interior surfaces may be configured to grip, pass, and/or manipulate tissue and/or surgical implements such as needles  1015  for suturing tissue. This gripping, passing, and/or manipulating functionality is described, for example, in connection with  FIGS. 153-168 . Furthermore, surgical end effector  1001  may also include electrodes  1017  and/or another electrically active surface for sealing blood vessels during a surgical procedure. The electrodes  1017  may be configured to deliver radio frequency (RF) energy to tissue clamped between the first jaw member  1002  and the second jaw member  1004  when in a closed position to weld/fuse the tissue, which may be transected by translating a cutting member  1018 . Suitable electrodes are described, for example, in connection with  FIGS. 153-168 . 
     Referring to  FIGS. 108-111 , surgical end effector  1001  may be releasably attached to shaft assembly  1003 . An operator or a surgeon may attach surgical end effector  1001  to shaft assembly  1003  to perform a surgical procedure. In the embodiment depicted in  FIG. 108 , shaft assembly  1003  includes a coupling arrangement in the form of a quick disconnect arrangement or joint  1019  that facilitates quick attachment of a distal shaft portion  1020  of the shaft assembly  1003  to a proximal shaft portion  1022  of the surgical end effector  1001 . The quick disconnect joint  1019  may serve to facilitate the quick attachment and detachment of a plurality of drive train components used to provide control motions from a source of drive motions to an end effector that is operably coupled thereto. 
     As illustrated in  FIG. 112 , surgical end effector  1001  may be interchanged with other surgical end effectors suitable for use with shaft assembly  1003 . For example, surgical end effector  1001  may be detached from shaft assembly  1003  and a second surgical end effector  1024  may be attached to shaft assembly  1003 . In another example, the second surgical end effector  1024  may be replaced with a third surgical end effector  1026 . Surgical end effectors  1001 ,  1024 , and  1026  may include common drive train components that are operably engageable with their counter parts in the shaft assembly  1003 . Yet, surgical end effectors  1001 ,  1024 , and  1026  may each include unique operational features suitable for certain surgical tasks. 
     The surgical end effector  1001  may include an actuation mechanism. The actuation mechanism may comprise a closure mechanism for moving the first jaw member  1002  relative to the second jaw member  1004 . The actuation mechanism may comprise a firing mechanism for transecting tissue grasped between the first jaw member  1002  and the second jaw member  1004 . The closure and firing may be accomplished by separate mechanisms, which may be driven separately or contemporaneously. Alternatively, the closure and firing may be accomplished via a single mechanism. Suitable closure mechanisms and suitable firing mechanisms are described, for example, in connection with  FIGS. 64-82, 83-91 and 92-96 . 
     Referring to  FIG. 113 , an actuation mechanism  1028  is shown. The actuation mechanism may include a reciprocating member  1030 . The reciprocating member  1030  may define a cam slot  1032  configured to receive a cam pin  1034  coupled to the first jaw member  1002 . Distal and proximal movement of the reciprocating member  1030  may cause the cam pin  1032  to translate within the cam slot  1034 , which may, in turn, cause the first jaw member  1002  to pivot from an open position (e.g., proximal position of the reciprocating member  1030 ) to a closed (e.g., distal position of the reciprocating member  1030 ), In embodiments where the first  1002  and the second  1004  jaw members are movable, both jaw members  1002  and  1004  may comprise a cam pin and the reciprocating member  1030  may define a pair of cam slots or grooves. The reciprocating member  1030  may comprise an I-beam member adapted to slide over the jaw members  1002  and  1004  to close the jaw members  1002  and  1004 , and/or to provide a clamping force tending to force the jaw members  1002 , and  1004  together. The reciprocating member  1030  may include a cutting blade  1036 . The cutting blade  1036  may be attached to the reciprocating member  1030  and situated such that it can be extended and retracted with the reciprocating member  1030 . The cutting member may be extended to transect tissue or material present between the jaw members  1002 , and  1004 . 
     Referring to  FIGS. 108-111 , the actuation mechanism  1028  may include a rotary drive nut  1038  and a threaded rotary drive member  1040 . The rotary drive member  1040  may extend proximally from the reciprocating member  1030 . The reciprocating member  1030  and the rotary drive member  1040  may be formed together as one piece. Alternatively, the reciprocating member  1030  and the rotary drive member  1040  may be formed separately and welded together. Other techniques for joining the reciprocating member  1030  and the rotary drive member  1040  may be employed and are contemplated within the scope of this disclosure. The rotary drive nut  1038  may be operably supported within the proximal shaft portion  1022  of the surgical end effector  1001 , which extends proximally relative to the jaw members  1002 , and  1004 . The rotary drive nut  1038  may be rotated around a central axis extending through the proximal shaft portion  1022 , for example, as described herein above. The rotary drive member  1040  may extend proximally from the reciprocating member  1030  along the central axis through the rotary drive nut  1038 . The rotary drive nut  1038  and the rotary drive member  1040  may be arranged in a mating arrangement such that rotation of the rotary drive nut  1038  around the central axis in one direction (e.g. clockwise direction) may advance the rotary drive member  1040 , and rotation of the rotary drive nut  1038  around the central axis in the opposite direction (e.g. counter clockwise direction) may retract the rotary drive member  1040 . This actuation mechanism and other suitable actuations mechanisms are described, for example, in connection with  FIGS. 64-82, 83-91 and 92-96 . 
     Referring to  FIGS. 108-111 , the surgical tool  1000  may include a rotary drive shaft  1042  disposed longitudinally through shaft assembly  1003 . The rotary drive shaft  1042  may include a rotary drive head  1044  at a distal portion thereof. The rotary drive nut  1038  may comprise an actuation coupler  1046  for mating arrangement with the rotary drive head  1044  such that when coupled, the rotary drive head  1044  may transmit rotary motions to the actuation coupler  1046 . The rotary drive shaft  1042  may be selectively moved axially between multiple discrete positions. For example, the rotary drive shaft  1042  may be extended axially to bring the rotary drive head  1044  into operable engagement with the actuation coupler  1046  as depicted in  FIG. 111 . Alternatively, the rotary drive shaft  1042  may be retracted axially to disengage the rotary drive head  1044  from the actuation coupler  1046 . Such arrangement may allow for a quick and efficient attachment and detachment of a plurality of surgical end effectors to shaft assembly  1003 . 
     Referring to  FIGS. 108-110 , surgical end effector  1001  is shown detached from shaft assembly  1003 . The proximal shaft portion  1022  of surgical end effector  1001  is disengaged from the distal shaft portion  1020  of the shaft assembly  1003 . As depicted in  FIG. 108 , the proximal shaft portion  1022  of the surgical end effector  1001  may include a tapered end for mating arrangement with a funneling end on the distal shaft portion  1020  of the shaft assembly  1003 . The rotary drive shaft  1042  may include a hollow distal portion that extends distally along a central axis through the rotary drive head  1044  and terminates at a distal opening thereof. The hollow distal portion may receive a proximal portion of the rotary drive member  1040  when the surgical end effector  1001  is attached to the shaft assembly  1003 . The rotary drive member  1040  may rotate freely in the hollow distal portion of the rotary drive shaft  1042 . As depicted in  FIG. 110 , the surgical end effector  1001  is attached to shaft assembly  1003  simply by inserting the proximal portion of the rotary drive member  1040  into the hollow portion of the rotary drive shaft  1042  and guiding the tapered end of the proximal shaft portion  1022  of the surgical end effector  1001  into a mating arrangement with the funneling end of the distal shaft portion  1020  of the shaft assembly  1003 . As depicted in  FIG. 111 , once the surgical end effector  1001  is attached to shaft assembly  1003 , the rotary drive shaft  1042  may be advanced to bring the rotary drive head  1044  into operable engagement with the actuation coupler  1046  to transmit rotary motions to the rotary drive nut  1038 . Other attachment means and techniques for releasably attaching the surgical end effector  1001  to the shaft assembly  1003  are contemplated within the scope of this disclosure. 
     As illustrated in  FIGS. 108-110 , the proximal shaft portion  1022  of surgical end effector  1001  and the distal shaft portion  1020  of the shaft assembly  1003  may have aligning features to ensure that the surgical end effector  1001  and the shaft assembly  1003  are correctly aligned upon attachment. In an example embodiment, as illustrated in  FIG. 108 , the proximal shaft portion  1022  of surgical end effector  1001  includes a key feature  1048  and the distal shaft portion  1020  of the shaft assembly  1003  may include a slot  1050  for receiving the key feature. Other aligning means and techniques for aligning the surgical end effector  1001  to the shaft assembly  1003  are contemplated within the scope of this disclosure. 
     Referring to  FIG. 114 , the surgical end effector  1001  may include an actuation mechanism wherein the firing and closure are performed separately. This actuation mechanism and other suitable actuation mechanisms are described, for example, in connection with  FIGS. 83-91 and 92-96 . In an example embodiment, as illustrated in  FIG. 114 , the surgical end effector  1001  comprises a closure mechanism  1052  and a firing mechanism  1054  which are driven separately. The closure mechanism  1052  includes a closure driver  1056  and the firing mechanism  1054  includes a firing driver  1058 . As described above, surgical end effector  1001  may be releasably attached to shaft assembly  1003 . As depicted in  FIG. 114 , the proximal shaft portion  1022  of surgical end effector  1001  may be detached from the distal shaft portion  1020  of the shaft assembly  1003 . Once the proximal shaft portion  1022  of surgical end effector  1001  is attached to the distal shaft portion  1020  of the shaft assembly  1003 , the shaft drive  1042  may be extended distally to a first discrete position to be in operable engagement with the closure driver  1056 . Alternatively, the shaft drive may be extended distally to a second discrete position distal to the first discrete position to be in operable engagement with the firing driver  1058 . 
     As illustrated in  FIG. 115 , the surgical tool  1000  may include an articulation joint  1060  for articulating the surgical end effector  1001  about a longitudinal tool axis “LT”. In this example embodiment, the articulation joint  1060  is disposed proximal to the distal portion  1020  of the shaft assembly  1003 . The articulation joint  1060  articulates the distal portion  1020  of the shaft assembly  1003 . When the proximal portion  1022  of the surgical end effector  1001  is attached to the distal portion  1020  of the shaft assembly  1003 , articulation of the distal portion  1020  of shaft assembly  1003  will cause the surgical end effector  1003  to articulate. 
     In an example embodiment, as illustrated in  FIG. 115 , the articulation joint  1060  includes a proximal socket tube  1062  that is attached to the shaft assembly  1003  and defines a proximal ball socket therein. See  FIG. 115 . A proximal ball member  1064  is movably seated within the proximal ball socket. As can be seen in  FIG. 115 , the proximal ball member  1064  has a central drive passage that enables the rotary drive shaft  1042  to extend therethrough. In addition, the proximal ball member  1064  has four articulation passages therein which facilitate the passage of four distal cables  1066  therethrough. As can be further seen in  FIG. 115 , the articulation joint  1060  further includes an intermediate articulation tube segment  1068  that has an intermediate ball socket formed therein. The intermediate ball socket is configured to movably support therein a distal ball member  1070  formed on a distal connector tube  1072 . The cables  1066  extend through cable passages formed in the distal ball member  1070  and are attached thereto by lugs  1074 . Other attachment means suitable for attaching cables to the end effector ball  1070  are contemplated within the scope of this disclosure. 
     Referring to  FIGS. 116-120 , a surgical tool  900  may include a surgical end effector extending from a shaft assembly  903 . The surgical end effector  901  may be configured to perform surgical activities in response to drive motions applied thereto. The surgical end effector  901  may include a first jaw member  902 , and a second jaw member  904 . The first jaw member  902  may be movable relative to the second jaw member  904  between a first position and a second position. Alternatively, the first jaw member  902  and second jaw member  904  may be moveable relative to each other between a first position and a second position. The first position may be an open position and the second position may be a closed position. 
     Referring to  FIGS. 116-120 , the first jaw member  902  may be pivotally movable relative to the second jaw member  904  between an open position and a closed position. As illustrated in  FIG. 120 , the first jaw member  902  may include mounting holes  906 , and the second jaw member  904  may include mounting holes  908 . The first jaw member  902  can be arranged relative to the second jaw member  904  such that a pivot or trunnion pin (not shown) is inserted through the mounting holes  906  of the first jaw member  902  and the mounting holes  908  of the second jaw member  904  to pivotally couple the first jaw member  902  to the second jaw member  904 . Other suitable means for coupling the first jaw member  902  and the second jaw member  904  are contemplated within the scope of this disclosure. 
     Referring to  FIGS. 116-120 , surgical end effector  901  may be adapted to perform multiple functions. For example, surgical end effector  901  may include angled tissue engagement surfaces  910  for transecting tissue. Suitable tissue engagement surfaces  910  are described, for example, in connection with  FIGS. 132-142 . The first jaw member  902  may include an interior surface  912  and the second jaw member  904  may include an interior surface  914 . The first interior surface  912  and the second interior surface  914  may be configured to grip, pass, and/or manipulate tissue and/or surgical implements such as needles  915  for suturing tissue. This gripping, passing, and/or manipulating functionality is described, for example, in connection with  FIGS. 153-168 . 
     Referring to  FIGS. 116-120 , the surgical end effector  901  may also include electrodes  916  and/or another electrically active surface for sealing blood vessels during a surgical procedure. The electrodes  916  may be configured to deliver radio frequency (RF) energy to tissue clamped between the first jaw member  902  and the second jaw member  904  when in a closed position to weld/fuse the tissue, which may be transected by translating a cutting member. Suitable electrodes  916  are described, for example, in connection with  FIGS. 6-10  and  FIGS. 153-168 . The surgical end effector  901  may be releasably attached to a shaft assembly  903 . An operator or a surgeon may attach surgical end effector  901  to shaft assembly  903  to perform a surgical procedure. Suitable techniques and mechanisms for releasably attaching the surgical end effector  901  to the shaft assembly  903  are described, for example, in connection with  FIGS. 106-115 . 
     Referring to  FIGS. 116-120 , the surgical end effector  901  may include an actuation mechanism. The actuation mechanism may comprise a closure mechanism for moving the first jaw member relative to the second jaw member. The actuation mechanism may comprise a firing mechanism for transecting tissue grasped between the first jaw member and the second jaw member. The closure and firing may be accomplished by separate mechanisms, which may be driven separately or contemporaneously. Alternatively, the closure and firing may be accomplished by a single mechanism. Suitable closure mechanisms and suitable firing mechanisms are described, for example, in connection with  FIGS. 64-82, 83-91 and 92-96 . 
     As illustrated in  FIG. 117 , an example actuation mechanism  920  is shown. The actuation mechanism  920  may include a reciprocating member  918  similar to the axially movable member  3016  described herein above. The reciprocating member  918 , or a cam pin  924  thereof, may be received within a cam slot  922 . Distal and proximal movement of the reciprocating member  918  may cause the cam pin  924  to translate within the cam slot  922 , which may, in turn, cause the first jaw member  902  to pivot from an open position (e.g., proximal position of the reciprocating member  918 ) to a closed (e.g., distal position of the reciprocating member  918 ). In embodiments where the first  902  and the second  904  jaw members are movable, both jaw members may comprise cam slot  922  and the reciprocating member  918  may define a pair of cam pins. The reciprocating member  918  may comprise an I-beam member adapted to slide over the first jaw member  902  and the second jaw member  904  to close the first jaw member  902  and the second jaw member  904 , and/or to provide a clamping force tending to force the first jaw member  902  and the second jaw member  904  together. The reciprocating member  918  may include a cutting blade  926 . The cutting blade  926  may be attached to the reciprocating member  918  and situated such that it can be extended and retracted with the reciprocating member  918 . The cutting blade  926  may be extended to transect tissue or material present between the first jaw member  902  and the second jaw member  904 . 
     Referring to  FIGS. 116-120 , the first jaw member  902  may include an exterior surface  928 . The exterior surface of first jaw member  902  may include a first tissue gripping portion  930 . The second jaw member  904  may also include an exterior surface  932 . The exterior surface  932  of second jaw member  904  may include a second tissue gripping portion  934 . The first tissue gripping portion  930  and second tissue gripping portion  934  may grip tissue by contacting and temporarily adhering to tissue. The first gripping portion  930  and the second gripping portion  934  may contact and bluntly dissect tissue while the first jaw member  902  and the second jaw member  904  is moving relative to each other from the closed position to the open position. 
     In an example embodiment, the surgical end effector  901  may be utilized during a surgical procedure to dissect tissue. For example, the first gripping portion  930  and the second gripping portion  934  may contact and temporarily adhere to a first and second tissue portions (not shown) respectively such that when the first jaw member  902  is moved relative to the second jaw member  904  from a closed position to an open position, the first tissue portion is separated from the second tissue portion along facial planes while substantially preserving locoregional architecture and structural integrity of vessels and nerves. The first gripping portion  930  and the second gripping portion  934  may be configured to create operative space during a surgical procedure by bluntly separating (dissecting) tissue layers as the first jaw member  902  is moved relative to the second jaw member  904 . 
     As illustrated in  FIG. 121 , the first gripping portion  930  and the second gripping portion  934  may be formed onto distal sections of the exterior surfaces  928  and  932  of the first and second jaw members  902  and  904  by applying a coating. In one embodiment, the first and second gripping portions  930  and  934  are attached to the exterior surfaces  928  and  932  of their respective jaw members by an adhesive. In one embodiment, the first and second gripping portions  930  and  934  are press fitted onto distal portions of the exterior surfaces  928  and  932 . Other techniques and attachment means suitable for attaching or forming a gripping portion onto an exterior surface are contemplated by the current disclosure. 
     The first and second gripping portions  930  and  934  may include materials with high coefficient of friction to grip tissue as tissue slides relative to the first and second jaw members  902  and  904  upon moving the first and second jaw members  902  and  904  relative to each other to the open position thereby separating (dissecting) tissue layers along fascial planes while substantially preserving locoregional architecture and structural integrity of vessels and nerves. Examples of materials with high coefficient of friction that may be utilized to form the first and second gripping portions  930  and  934  include but are not limited to Silicone based elastomers, styrenic-based thermoplastic elastomers (TPE), polyisoprene, low density polyethylene, polypropylene, sanoprene, silicone, polyurethane, natural rubber, isoplast, liquid crystal polymer (LCP), etc. 
     The first and second gripping portions  930  and  934  may include a semi-rigid material sufficiently flexible to contour without shearing upon tissue contact. The first and second gripping portions  930  and  9 : 34  may include a non-allergenic biocompatible material. In one embodiment, the first and second gripping portions  930  and  934  may comprise a material with a low Young&#39;s modulus and high yield strain such as an elastomer. Examples of suitable elastomers include but are not limited to Silicone based elastomers, styrenic-based thermoplastic elastomers (TPE), polyisoprene, low density polyethylene, polypropylene, sanoprene, silicone, polyurethane, natural rubber, isoplast, liquid crystal polymer (LCP), etc. 
     Referring to  FIGS. 116-120 , the first and second gripping portions  930  and  934  may include gripping features  936 . The gripping features  936  may be sufficiently flexible to contour without shearing upon tissue contact. The gripping features  936  may be in the form of protrusions  938 . In at least one embodiment, the gripping features  936  may be in the form of depressions  940 . 
     Referring to  FIGS. 121-126 ., the gripping features  936  may be spatially arranged in a gripping pattern  942 . Gripping pattern  942  may include a plurality of protrusions  938 . The gripping pattern may include a plurality of depressions  940 . In at least one embodiment, as illustrated in  FIG. 127  the gripping pattern  942  may include a plurality of alternating protrusions  938  and depressions  940 . In one embodiment, as illustrated in  FIG. 123 , the gripping pattern  942  may include four protrusions  938 . 
     As illustrated in  FIG. 128 , gripping pattern  942  may include a plurality of protrusions  940  spatially arranged in a circle. Other arrangements are possible and within the scope of the present disclosure. As illustrated in  FIG. 122 , gripping pattern  942  may include a plurality of protrusions  938  spatially arranged in multiple rows wherein each row includes several protrusions  938  aligned along the length of the row. Each row may include alternating protrusions  938  and depressions  940 . 
     Referring to  FIG. 123-128 , the gripping pattern  942  may include vertical protrusions  938  that extend horizontally on gripping portion  930 . As illustrated in FIG., the vertical protrusions  938  may extend in opposing directions. In certain embodiments, as illustrated in  FIG. 124 , the protrusions  938  may extend in parallel rows. In at least one embodiment, as illustrated in  FIG. 125 , gripping pattern  942  includes a first plurality of parallel protrusions  938   a , and a second plurality of parallel protrusions  938   b , wherein the first plurality  938   a  is in a slanted arrangement with the second plurality  938   b . In at least one embodiment, as illustrated in  FIG. 125 , the gripping portion  930  may include a herringbone pattern. 
     Referring to  FIGS. 129-131 , the gripping pattern  942  may define vertical protrusions  938  that extend horizontally on gripping portion  930  in a non linear fashion. For example, as illustrated in  FIG. 129 , the non-linear protrusions  938  may extend in a in a zigzag fashion. In certain embodiments, as illustrated in  FIGS. 130 and 131 , the non-linear protrusions  938  may extend in parallel rows. In certain embodiments, as illustrated in  FIGS. 130, and 131 , the non-linear protrusions  938  may extend in opposing directions. 
     Referring to  FIGS. 132 through 137 , an end effector  500  comprises a first jaw member  502 A and a second jaw member  502 B. The first jaw member  502 A is movable relative to the second jaw member  502 B between an open position ( FIGS. 132 and 136 ) and a closed position ( FIGS. 133, 134, and 137 ) to clamp tissue between the first jaw member  502 A and the second jaw member  502 B. The first jaw member  502 A comprises angled tissue-contacting surfaces  504 A and  506 A. The second jaw member  502 B comprises angled tissue-contacting surfaces  504 B and  506 B. The first jaw member  502 A comprises a first positively-angled tissue-contacting surface  504 A and a first negatively-angled tissue-contacting surface  506 A. The second jaw member  502 B comprises a second positively-angled tissue-contacting surface  504 B and a second negatively-angled tissue-contacting surface  506 B. 
     As used herein, the terms “positively-angled” and “negatively-angled” refer to the direction in which a tissue-contacting surface is angled relative to the body of the jaw member comprising the tissue-contacting surface and a clamping plane of the jaw member. Referring to  FIG. 138 , a first jaw member  502 A′ and a second jaw member  502 B′ are shown in a closed position such as to clamp tissue between the opposed jaw members  502 A′ and  502 B′. This closed position is analogous to the closed position shown in  FIGS. 133, 134, 135, 137, and 142 . The first jaw member  502 A′ comprises a first jaw body  503 A′, a first tissue gripping element  507 A′, and a first clamping plane  505 A. The second jaw member  502 B′ comprises a second jaw body  503 B′, a second tissue gripping element  507 B′, and a second clamping plane  505 B. Generally, the tissue gripping elements and the clamping planes of the jaw members of an end effector are in an opposed orientation when the jaw members are in a closed position such as to clamp tissue between opposed jaw members. 
     The first jaw member  502 A′ comprises a first positively-angled tissue-contacting surface  504 A′ forming an angle (a) relative to the first clamping plane  505 A and away from the first jaw body  503 A′ at the periphery of the first tissue gripping element  507 A′ of the first jaw member  502 A′. The first jaw member  502 A′ comprises a first negatively-angled tissue-contacting surface  506 A′ forming an angle (a) relative to the first clamping plane  505 A and toward from the first jaw body  503 A′ at the periphery of the first tissue gripping element  507 A′ of the jaw member  502 A′. 
     Accordingly, as used herein, the term “positively-angled” is used to specify tissue-contacting surfaces that angle away from a clamping plane and that angle away from the jaw body at the periphery of the tissue gripping element of the jaw member comprising the positively-angled tissue-contacting surface. Likewise, as used herein, the term “negatively-angled” is used to specify tissue-contacting surfaces that angle away from a clamping plane and that angle toward the jaw body at the periphery of the tissue gripping element of the jaw member comprising the negatively-angled tissue-contacting surface. 
     Thus, the second jaw member  502 B′ comprises a second positively-angled tissue-contacting surface  504 B′ forming an angle (α) relative to the second clamping plane  505 B and away from the second jaw body  503 B′ at the periphery of the second tissue gripping element  507 B′ of the second jaw member  502 B′. The second jaw member  502 B′ comprises a second negatively-angled tissue-contacting surface  506 B′ forming an angle (α) relative to the second clamping plane  505 B and toward from the second jaw body  503 B′ at the periphery of the second tissue gripping element  507 B′ of the second jaw member  502 B′. 
     Referring again to  FIGS. 132-134 , the first jaw member  502 A comprises a first jaw body  503 A and a first tissue gripping element  507 A, and the second jaw member  502 B comprises a second jaw body  503 B and a second tissue gripping element  507 B. The first positively-angled tissue-contacting surface  504 A of the first jaw member  502 A is angled away from the first jaw body  503 A at the periphery of the first tissue gripping element  507 A. The first negatively-angled tissue-contacting surface  506 A of the first jaw member  502 A is angled toward the first jaw body  503 A at the periphery of the first tissue gripping element  507 A. The second positively-angled tissue-contacting surface  504 B of the second jaw member  502 B is angled away from the second jaw body  503 B at the periphery of the second tissue gripping element  507 B. The second negatively-angled tissue-contacting surface  506 B of the second jaw member  502 B is angled toward the second jaw body  503 B at the periphery of the second tissue gripping element  507 B. 
     When the first jaw member  502 A and the second jaw member  502 B are in a closed position, such as to clamp tissue between the first and second jaw members, the first positively-angled tissue-contacting surface  504 A opposes the second negatively-angled tissue-contacting surface  506 B. When the first jaw member  502 A and the second jaw member  502 B are in a closed position, such as to clamp tissue between the first and second jaw members, the first negatively-angled tissue-contacting surface  506 A opposes the second positively-angled tissue-contacting surface  504 B. 
     As shown in  FIGS. 132-133 and 136-137 , the first positively-angled tissue-contacting surface  504 A and the first negatively-angled tissue-contacting surface  506 A are disposed along substantially the entire length of the first jaw member  502 A. The second positively-angled tissue-contacting surface  504 B and the second negatively-angled tissue-contacting surface  506 B are disposed along substantially the entire length of the second jaw member  502 B. 
     The end effector  500  comprises an “I-beam” member  508 , which in some embodiments, may function as a closure member and/or a tissue-cutting member. The I-beam member  508  may operate in a manner similar to that described herein above with respect to the axially movable member  3016  described herein above. The I-beam member  508  may be sized and configured to fit at least partially within channels in the first jaw member  502 A and the second jaw member  502 B. The I-beam member  508  may operably translate along the channels in the first jaw member  502 A and the second jaw member  502 B, for example, between a first, proximally retracted position correlating with the jaw members  502 A and  502 B being at an open position, and a second, distally advanced position correlating with the jaw members  502 A and  502 B being at a closed position. In this manner, for example, the I-beam member  508  may be configured to operably translate within the channels in the first and second jaw members  502 A and  502 B to close the jaw members using a camming action and/or to advance a cutting member through the first and second tissue gripping elements  507 A and  507 B to transect tissue clamped between the first and second jaw members  502 A and  502 B. 
     The movement of the first jaw member  502 A relative to the second jaw member  502 B between an open position ( FIGS. 132 and 136 ) and a closed position ( FIGS. 133, 134, and 137 ) to clamp tissue between the first jaw member  502 A and the second jaw member  502 B may be actuated with a suitable closure actuation mechanism. Translation of the I-beam member between a retracted position and an advanced position may be actuated with a suitable translation actuation mechanism. Suitable closure actuation mechanisms and suitable translation actuation mechanisms are described, for example, in connection with  FIGS. 64-82, 83-91 and 92-96 . 
     Referring to  FIGS. 139 and 140 , an end effector  510  comprises a first jaw member  512 A and a second jaw member  512 B. The first jaw member  512 A is movable relative to the second jaw member  512 B between an open position ( FIGS. 139 and 140 ) and a closed position (no shown) to clamp tissue between the first jaw member  512 A and the second jaw member  512 B. The first jaw member  512 A comprises angled tissue-contacting surfaces  514 A and  516 A. The second jaw member  512 B comprises angled tissue-contacting surfaces  514 B and  516 B. The first jaw member  512 A comprises a first positively-angled tissue-contacting surface  514 A and a first negatively-angled tissue-contacting surface  516 A. The second jaw member  512 B comprises a second positively-angled tissue-contacting surface  514 B and a second negatively-angled tissue-contacting surface  516 B. 
     The first jaw member  512 A comprises a first jaw body  513 A and a first tissue gripping element  517 A, and the second jaw member  512 B comprises a second jaw body  513 B and a second tissue gripping element  517 B. The first positively-angled tissue-contacting surface  514 A of the first jaw member  512 A is angled away from a first jaw body  513 A at the periphery of the first tissue gripping element  517 A. The first negatively-angled tissue-contacting surface  516 A of the first jaw member  512 A is angled toward the first jaw body  513 A at the periphery of the first tissue gripping element  517 A. The second positively-angled tissue-contacting surface  514 B of the second jaw member  512 B is angled away from a second jaw body  513 B at the periphery of the second tissue gripping element  517 B. The second negatively-angled tissue-contacting surface  516 B of the second jaw member  512 B is angled toward the second jaw body  513 B at the periphery of the second tissue gripping element  517 B. 
     When the first jaw member  512 A and the second jaw member  512 B are in a closed position, such as to clamp tissue between the first and second jaw members, the first positively-angled tissue-contacting surface  514 A opposes the second negatively-angled tissue-contacting surface  516 B. When the first jaw member  512 A and the second jaw member  512 B are in a closed position, such as to clamp tissue between the first and second jaw members, the first negatively-angled tissue-contacting surface  516 A opposes the second positively-angled tissue-contacting surface  514 B. 
     The first positively-angled tissue-contacting surface  514 A is disposed along a proximal portion of the length of the first jaw member  512 A. The second positively-angled tissue-contacting surface  514 B is disposed along a proximal portion of the length of the second jaw member  512 B. The first negatively-angled tissue-contacting surface  516 A is disposed along substantially the entire length of the first jaw member  512 A. The second negatively-angled tissue-contacting surface  516 B is disposed along substantially the entire length of the second jaw member  502 B. 
     The end effector  510  comprises an “I-beam” member  518 , which in some embodiments, may function as a closure member and/or a tissue-cutting member. The I-beam member  518  may be sized and configured to fit at least partially within channels in the first jaw member  512 A and the second jaw member  512 B. The I-beam member  518  may translate along the channels in the first jaw member  512 A and the second jaw member  512 B, for example, between a first, proximally retracted position correlating with the jaw members  512 A and  512 B being at an open position, and a second, distally advanced position correlating with the jaw members  512 A and  512 B being at a closed position. In this manner, for example, the I-beam member  518  may be configured to operably translate within the channels in the first and second jaw members  512 A and  512 B to close the jaw members using a camming action and/or to advance a cutting member through the first and second tissue gripping elements  517 A and  517 B to transect tissue clamped between the first and second jaw members  512 A and  512 B. 
     The movement of the first jaw member  512 A relative to the second jaw member  512 B between an open position ( FIGS. 139 and 140 ) and a closed position (not shown) to clamp tissue between the first jaw member  512 A and the second jaw member  512 B may be actuated with a suitable closure actuation mechanism. Translation of the I-beam member between a retracted position and an advanced position may be actuated with a suitable translation actuation mechanism. Suitable closure actuation mechanisms and suitable translation actuation mechanisms are described, for example, in connection with  FIGS. 64-82, 83-91 and 92-96 . 
     The first jaw member  512 A and the second jaw member  512 B comprise a first distal textured portion  519 A and second distal textured portion  519 B, respectively. The first distal textured portion  519 A of the first jaw member  512 A is disposed distal and directly adjacent to the proximal tissue gripping element  517 A of the first jaw member  512 A comprising the first positively-angled tissue-contacting surface  514 A. The first positively-angled tissue-contacting surface  514 A does not extend distally along the length of the first jaw member  512 A into the first distal textured portion  519 A. The second distal textured portion  519 B of the second jaw member  512 B is disposed distal and directly adjacent to the proximal tissue gripping element  517 B of the second jaw member  512 B comprising the second positively-angled tissue-contacting surface  514 B. The second positively-angled tissue-contacting surface  514 B does not extend distally along the length of the second jaw member  512 B into the second distal textured portion  519 B. The first and second distal textured portions  519 A and  519 B of the first and second jaw members  512 A and  512 B may be opposed and may allow the end effector  510  to grip, pass, and/or manipulate surgical implements such as needles for suturing tissue, in addition to gripping tissue, for example, during dissection operations. This gripping, passing, and/or manipulating functionality is described, for example, in connection with  FIGS. 116-131 and 154-164 . 
     The first jaw member  512 A and the second jaw member  512 B comprise a first gripping portion  521 A and second gripping portion  521 B, respectively. The first gripping portion  521 A is disposed on an outwardly-facing surface of the first jaw member  512 A, and the second gripping portion  521 B is disposed on an outwardly-facing surface of the second jaw member  512 B. The gripping portions  521 A and  521 B may function to aid in tissue dissection as described, for example, in connection with  FIGS. 116-131 and 154-164 . 
       FIG. 141  is a perspective view of an end effector  510 ′ similar to the end effector  510  shown in  FIGS. 139 and 140 , but comprising electrodes  522  located in the second tissue gripping element  517 B of the second jaw member  516 B and located between the second positively-angled tissue-contacting surface  514 B and the second negatively-angled tissue-contacting surface  516 B. The electrodes  522  may be configured to deliver RF energy to tissue clamped between the first jaw member  512 A and the second jaw member  512 B when in a closed position to weld/fuse the tissue, which may be transected by translating the I-beam member  518  comprising a cutting member. Although  FIG. 141  shows two electrodes  522 , it is understood that an end-effector in accordance with the embodiments described in this specification may comprise at least one or more electrodes comprising any suitable shape and orientation, as described, for example, in this specification. The second jaw member  516 B also comprises an offset electrode  524  at the distal tip  525  configured to deliver RF energy to tissue during dissection operations, for example. In some embodiments, the first distal textured portion  519 A and second distal textured portion  519 B may also be electrodes configured, for example, to deliver RF energy to tissue during dissection operations. This electrode functionality is described, for example, in connection with  FIGS. 154-164 . 
     Referring to  FIG. 142 , an end effector  530  comprises a first jaw member  532 A and a second jaw member  532 B shown in a closed position clamping tissue  545  between the jaw members. The first jaw member  532 A comprises a first positively-angled tissue-contacting surface  534 A and a first negatively-angled tissue-contacting surface  536 A. The second jaw member  532 B comprises a second positively-angled tissue-contacting surface  534 B and a second negatively-angled tissue-contacting surface  536 B. The tissue  545  physically contacts the angled tissue-contacting surfaces  534 A,  534 B,  536 A, and  536 B. The physical contact between the tissue  545  and the angled tissue-contacting surfaces  534 A,  534 B,  536 A, and  536 B compresses the tissue  545  between the first jaw member  532 A and the second jaw member  532 B. As shown in  FIG. 142 , the clamping of the tissue between the first jaw member  532 A and the second jaw member  532 B compresses the tissue  545  between the mutually opposed tissue-contacting surfaces  536 A and  534 B, and also between the mutually opposed tissue-contacting surfaces  534 A and  536 B, which establishes a tortuous deformation in the compressed tissue  545 . The tortuous deformation improves the clamping action of the end effector  530  on the tissue  545 , which in turn, improves the welding/fusion of the tissue  545  and/or the transection of the tissue  545 . The tissue  545  can be welded/fused, for example, by the application of RF energy through electrodes  542  located in the tissue gripping element of the second jaw member  532 B and located between the second positively-angled tissue-contacting surface  534 B and the second negatively-angled tissue-contacting surface  536 B. The tissue  545  can be transected, for example, by translating the I-beam member  538 , which translates the cutting member  541  through the clamped tissue  545 . 
     In some embodiments, an end effector may comprise a first jaw member comprising a first positively-angled tissue-contacting surface and a first negatively-angled tissue-contacting surface, and a second jaw member comprising a second positively-angled tissue-contacting surface and a second negatively-angled tissue-contacting surface. The angled tissue-contacting surfaces may form angles (α) relative to a clamping plane as described, for example, in connection with  FIG. 138 . The magnitude of the angle (α) between a tissue contacting surface and a clamping plane may range from 5-degrees to 85-degrees or any sub-range subsumed therein such as, for example, from 10-degrees to 80-degrees, from 20-degrees to 70-degrees, from 30-degrees to 60-degrees, from 40-degrees to 50-degrees, from 25-degrees to 50-degrees, or from 30-degrees to 45-degrees. 
     In some embodiments, angled tissue-contacting surfaces may independently form angles relative to respective clamping planes. The angle formed by the angled tissue-contacting surfaces may be substantially the same or different in a given end effector. For example, two opposed angled tissue-contacting surfaces (e.g., a first positively-angled tissue-contacting surface and an opposed second negatively-angled tissue-contacting surface) may both form a common angle (α 1 ) relative to respective clamping planes, and two other opposed angled tissue-contacting surfaces (e.g., a first negatively-angled tissue-contacting surface and an opposed second positively-angled tissue-contacting surface) may both form a common angle (α 2 ) relative to respective clamping planes, wherein |α 1 |≠|α 2 |. 
     In some embodiments, an angled tissue-contacting surface may extend a predetermined distance normal to a respective clamping plane coincident with a horizontal tissue contacting portion of a jaw member. For example, referring to  FIG. 138 , the first positively-angled tissue-contacting surface  504 A′ extends a distance normal to the first clamping plane  505 A, and the second positively-angled tissue-contacting surface  5043  extends a distance normal to the second clamping plane  505 B. Likewise, the first negatively-angled tissue-contacting surface  506 A′ extends a distance normal to the first clamping plane  505 A, and the second negatively-angled tissue-contacting surface  506 B′ extends a distance normal to the second clamping plane  505 B. In some embodiments, an angled tissue-contacting surface may extend a distance between 0.025 inch to 0.25 inch normal to a respective clamping plane, or any sub-range subsumed therein such as, for example, 0.025 inch to 0.01 inch or 0.025 inch to 0.05 inch. 
     While the angled tissue-contacting surfaces shown in  FIGS. 132 through 142  are illustrated as being planar surfaces, it is to be appreciated that in some embodiments, the angled tissue-contacting surfaces may be curved surfaces or a combination of planar surfaces and curved surfaces. 
     In some embodiments, end effectors comprising angled tissue-contacting surfaces may be configured to operably couple to robotic surgical systems such as, for example, the robotic surgical systems described in connection with, for example,  FIGS. 1-45 . In some embodiments, end effectors having angled tissue-contacting surfaces may be configured to operably couple to hand-held surgical devices such as, for example, the hand-held surgical devices described in connection with  FIGS. 46-63 . 
     The angled tissue-contacting surfaces described in connection with  FIGS. 132 through 142  provide various advantages to end effectors configured to grip/clamp tissue, weld/fuse tissue, transect tissue, or any combination of these operations. For example, in some embodiments, as illustrated in  FIGS. 132 through 142 , the positively-angled tissue contacting surfaces are integral with the outer surfaces of the jaw members (i.e., formed from a single piece of material). As such, the positively-angled tissue contacting surfaces provide for a thicker jaw member structure in the thickness dimension (labeled dimension T in  FIGS. 141 and 142 ). The thicker jaw member structure increases the strength and stiffness of the jaw members, which provides improved gripping/clamping load to tissue. In some embodiments, for example, a thicker jaw member structure provided by positively-angled tissue contacting surfaces may increase the moment of inertia of the jaw members by 20-30% relative to jaw members comprising co-planar tissue-contacting surfaces. An increased moment of inertia may provide an improved weld zone for fusing and cauterizing tissue clamped in an end effector comprising angled tissue-contacting surfaces by providing a more focused area for RF energy to enter and fuse tissue. 
     Any of the electrosurgical tools described herein may be energized utilizing current/energy paths extending from the generator or other signal source (such as generator  3002 ) through conductors, such as the supply  3012  and return 3014 conductors (see  FIG. 6 ), through the shaft assembly to the electrode or electrodes. Within the shaft assembly, the current paths may be provided by wires that extend through the shaft assembly. Wires, however, must be configured to avoid kinking, twisting or other deformation at the various articulation and rotation joints of the tools, including the articulation joint  3500  described herein. In the illustrated embodiments, an electrosurgical tool may utilize components of the shaft assembly as current paths for energizing electrosurgical electrodes. This may eliminate the need for wires and simplify articulation and rotation of the surgical tool. 
     In the illustrated embodiments, a rotary connector assembly may be utilized to allow a rotary drive shaft or other internal component of the shaft assembly to provide an energized current path between a generator and the end effector and/or an electrode thereof. The rotary connector may be configured to maintain a connection between the energized current path and the end effector despite rotation of the shaft and/or end effector. In bi-polar configurations, a return path may be formed by conductive components of the shaft and end effector such as, for example, a skin of the shaft, the I-beam member or other knife, portions of the various jaw members, etc., as described herein 
       FIGS. 143-146  illustrate one embodiment of a rotary connector assembly  1100  installed in an end effector  550  and shaft assembly  560  as described herein with respect to  FIGS. 64-81 .  FIG. 143  is a cross-sectional view of one embodiment of the end effector  550  and shaft assembly  560  illustrating an example installation of the rotary electrode assembly  1100 .  FIG. 144  is an exploded view of one embodiment of the end effector  550  and shaft assembly  560  showing the rotary electrode assembly  1100  both installed on the rotary drive shaft  630  (indicated by reference numbers  1100 ′,  1104 ′,  1106 ′) and exploded (indicated by reference numbers  1100 ,  1104 ,  1106 ).  FIG. 145  is a cross-sectional view of one embodiment of the end effector  550  and shaft assembly  560  showing the rotary electrode assembly  1100  with a rotary drive head  632  in a proximal position.  FIG. 146  is a cross-sectional view of one embodiment of the end effector  550  and shaft assembly  560  showing the rotary electrode assembly  1100  with the rotary drive head  632  in a distal position. 
     The rotary electrode assembly  1100  may be positioned within the end effector drive housing  608  and may comprise an outer contact  1102  and an inner contact  1103 . The outer contact  1102  may be positioned around an inner wall  1108  of the end effector drive housing  608 . In the illustrated embodiment, and in functionally similar embodiments, the outer contact  1102  may be in the shape of a cylinder or other figure of revolution. The outer contact  1102  may be in electrical communication with one or more electrodes  1112  in the end effector  550  via one or more leads, such as lead  1110 . The lead  1110  may be in physical contact with the outer contact  1102  and may extend through the lower jaw member  602 B to the electrode  1112  as shown. The lead  1110  may be fastened to the electrode  1112  in any suitable manner including, for example, with a solder or other similar joint. For example, multiple energized electrodes may be utilized with one lead  1110  directed to each electrode. In the illustrated embodiment, the lead  1110  may be insulated so as to avoid electrical communication with other portions of the end effector  550  and shaft assembly  560 . 
     The inner contact  1103  may be physically coupled to the rotary drive shaft  630 , for example, proximal from the hex coupling portion  634 , as shown. The inner contact  1103  may be in electrical contact with the outer contact  1102 . For example, the inner contact  1103  may be in physical contact with the outer contact  1102 . In the illustrated embodiment and in functionally similar embodiments, the inner contact  1103  may maintain electrical contact with the outer contact  1102  as the rotary drive shaft  630  and/or the end effector  560  rotates. For example, the outer contact  1102  may be a figure of revolution such that the inner contact  1103  is in physical contact with the contact  1102  as the rotary drive shaft  630  rotates. 
     In the illustrated embodiment and in functionally similar embodiments, the inner contact  1103  may also be a figure of revolution. For example, as illustrated, the inner contact  1103  may comprise a ringed brush  1104  and a grooved conductor  1106 . The grooved conductor  1106  may be positioned around the rotary drive shaft  630  proximal from the hex coupling portion  634 . The grooved conductor  1106  may define a groove  1107  to receive the ringed brush  1104 . The ringed brush  1104  may have a diameter larger than that of the groove  1107 . In the illustrated embodiment and in functionally similar embodiments, the ringed brush  1104  may define a slot  1105 . For example, the slot  1105  may allow the diameter of the ringed brush  1104  to expand and contract. For example, the diameter of the ringed brush  1104  may be expanded in order to place it over the remainder of the grooved conductor  1106  and into the slot  1107 . Also, when the inner contact  1103  is placed within the outer contact  1102 , its diameter may be contracted. In this way, the tendency of the ringed brush  1104  to resume its original diameter may cause the ringed brush  1104  to exert an outward force on the outer contact  1102  tending to keep the ringed brush  1104  and outer contact  1102  in physical and electrical contact with one another. 
     The inner contact  1103  may be in electrical communication with a suitable shaft component, thus completing the current path from the electrode  1112  to a generator, such as the generator  3002  described herein above with respect to  FIG. 6  and/or an internal generator. In the illustrated embodiment, the inner contact  1103 , and particularly the grooved conductor  1106 , is in physical and electrical contact with a coiled wire component  1114  wrapped around the rotary drive shaft  630 . The coiled wire component  1114  may extend proximally through the shaft where it may be coupled directly or indirectly to the generator. As described herein, the coiled wire component  1114  may also act as a spring to provide rigidity to the rotary drive shaft  630  around an articulation joint, for example, as described herein with respect to  FIGS. 31-31  and spring  3612 . In some embodiments, the rotary drive shaft  630  may comprise an outer insulated sleeve. The inner contact  1103  may be in electrical contact with the outer insulated sleeve in addition to or instead of the coiled wire component  1114 . An example insulated sleeve  1166  is described herein with respect to  FIG. 151 . Another example of a potential insulated sleeve is the constraining member  3660  described herein above with respect to  FIG. 45 . 
     In the illustrated embodiment, the a current return path from the electrode  1112  may be provided by various components of the end effector  550  and shaft assembly  560  including, for example, the jaw members  602 A,  602 B, the end effector drive housing  608  and other shaft members extending proximally. Accordingly, portions of the energized current path may be electrically isolated from other components of the end effector  550  and shaft assembly  560 . For example, as described above, the lead  1110  between the outer contact  1102  and electrode  1112  may be surrounded by an electrical insulator  1111 , as shown. Also, the outer contact  1102  and inner contact  1103  may be isolated from other components of the end effector  550  and shaft assembly  560 . For example, an insulator  1118  may be positioned to electrically isolate the outer contact  1102  from the end effector drive housing  608 . An insulator  1116  may be positioned to isolate the outer contact  1102  and inner contact  1103  from the rotary drive shaft  630 . The insulator  1118  may be an additional component or, in some embodiments, may be provided as a TEFLON or other insulating coating. As illustrated in  FIGS. 145-146 , the insulator  1116  may extend proximally, also isolating the coiled wire component  1114  from both the rotary drive shaft  630  and from other components of the shaft assembly  560  such as, for example, the end effector drive housing  608 . 
     In the embodiment illustrated in  FIGS. 145-146 , the outer contact  1102  may be extended proximally and distally such that electrical contact between the outer contact  1102  and inner contact  1103  is maintained with the rotary drive shaft  630  and rotary drive head  632  in different proximal and distal positions. For example, in  FIG. 145 , the rotary drive shaft  630  and rotary drive head  632  are pulled proximally such that the male hex coupling portion  636  of the drive shaft head  632  is received by hex shaft coupling portion  609  of the end effector drive housing  608 . In this position, rotation of the rotary drive shaft  630  may cause rotation of the end effector drive housing  608  and end effector  550 , as described herein. Additionally, as illustrated in  FIG. 145 , the inner contact  1103  may be in physical and electrical contact with the outer contact  1102 . In  FIG. 146 , the rotary drive shaft  630  and rotary drive head  632  are pushed distally such that the hex coupling portion  634  of the rotary drive head  632  receives the threaded rotary drive nut  606 . In this position, rotation of the rotary drive shaft  630  may cause rotation of the threaded rotary drive nut  606  that, in turn, causes rotation of the threaded rotary drive member  604  and distal and/or proximal translation of the I-beam member  620 . Additionally, as illustrated in  FIG. 146 , the inner contact  1103  may be in physical and electrical contact with the outer contact  1102 . 
       FIGS. 147-148  are cross-sectional views of one embodiment of the end effector  550  and shaft assembly  560  where a longitudinal length of the outer contact  1102  is selected such that the rotary connector assembly  1100  alternately creates and breaks an electrical connection limited by the longitudinal position of the inner contact  1103 . For example, in  FIG. 147 , the rotary drive shaft  630  and rotary drive head  632  are positioned proximally such that the male hex coupling portion  636  is received into the hex shaft coupling portion  609  of the distal shaft portion  608 . As illustrated, the inner contact  1103  (and specifically the ring brush  1104 ) may contact not the contact  1102 , but instead may contact the insulator  1118 . In this way, there may not be a completed electrical connection between the electrode  1112  and the generator when the rotary drive shaft  630  and rotary drive head  632  are in the proximal position shown in  FIG. 147 . When the rotary drive shaft  630  and rotary drive head  632  are positioned distally to contact the threaded drive nut  606 , as illustrated in  FIG. 148 , the inner contact  1103  may be in electrical (and physical) contact with the contact  1102 , completing the current path between the electrode  1112  and generator. The configuration illustrated in  FIGS. 147-148  may be useful in various different contexts. For example, it may be undesirable to energize the electrode  1112  when the jaw members  602 A,  602 B are open. In the illustrated embodiment, the jaw members  602 A,  602 B are closed by the rotary drive shaft  630  when the shaft  630  is positioned distally ( FIG. 148 ) and not when the shaft  630  is positioned proximally ( FIG. 147 ). Accordingly, in the configuration of  FIGS. 147-148 , the current path from the generator to the electrode  1112  is complete only when the rotary drive shaft  630  and rotary drive head  632  are positioned distally. 
     In some of the embodiments described herein, the end effector  550  may be removable from the end effector drive housing  608  and, for example, may be interchangeable with other end effectors (not shown). Examples of mechanisms for implementing interchangeable electrodes are provided herein with respect to  FIGS. 106-115 . In such implementations, the lead  1110  may comprise an end effector portion and a shaft portion connected by a connector assembly.  FIGS. 149-150  illustrate one embodiment of the end effector  550  and shaft assembly  560  showing a configuration including the lead portions  1130 ,  1132  and connector assembly  1120 . For example, as illustrated in  FIGS. 149-150  and as described herein, a proximal portion  603  of the jaw member  602 B may be received within the end effector drive housing  608 . The proximal portion  603  of the jaw member  602 B is illustrated within the end effector drive housing  608  in  FIG. 149  and separated from the end effector drive housing  608  in  FIG. 150 . The connector assembly  1120  may comprise an end effector side-lead  1122  and a shaft-side lead  1124 . The respective leads may be brought into physical and electrical contact with one another when the proximal portion  603  is received into the distal shaft portion  608 , as illustrated in  FIG. 149 . In various embodiments, the connector assembly  1120  may be configured so as to maintain electrical isolation of the energized current path from other components of the end effector  550  and shaft  560 . For example, insulation  1126 ,  1128  may electrically isolate the connector leads  1122 ,  1124 . In the illustrated embodiment and in functionally similar embodiments, the insulation  1126 ,  1128  may take the form of plastic or other insulating shrink tubes positions over all or part of the leads  1122 ,  1124 . In some embodiments, the insulation  1126 ,  1128  may comprise a TEFLON or other insulating coating applied to portions of the leads  1122 ,  1124  and/or surrounding material. 
       FIG. 151  illustrates a cross-sectional view of an alternate embodiment of an end effector  1140  and shaft assembly  1142  showing another context in which a rotary connector assembly  1147  may utilized. The end effector  1140  may comprise jaw members  1146 A,  1146 B that may operate similar to the jaw members  3008 A,  3008 B,  602 A,  602 B, etc., described herein above. For example, the jaw members  1146 A,  1146 B may be actuated by an I-beam member  1156  that, in the illustrated embodiment, may comprise a cutting edge  1148  for severing tissue between the jaw members  1146 A,  1146 B. The I-beam member  1156  may be driven distally and proximally by rotation of a threaded I-beam member shaft  1154 . The I-beam member shaft  1154  may be rotated via a main drive shaft  1149 . For example, the main drive shaft  1149  may be coupled to a gear  1150 . The gear  1150  may be in mechanical communication with a gear  1152  coupled to the I-beam member shaft  1154  as illustrated. 
     The end effector  1140  may comprise an electrode  1158  that may operate in a manner similar to that of electrode  1112 , etc., described herein above. An insulated lead  1160  may be electrically coupled to the electrode  1158  and may extend proximally to an outer contact  1162 . The outer contact  1162  may be positioned on an inner wall of a shaft member  1141  in a manner similar to that in which the contact  1102  is coupled to the inner wall  1108  of the end effector drive housing  608 . A inner contact  1164  (e.g., brush) may be positioned around the main drive shaft  1149  such that the brush  1164  is in electrical contact with the contact  1162 . The brush  1164  may also be in electrical contact with a conductive sleeve  1166  positioned around the main drive shaft  1149 . The sleeve  1166  may be electrically isolated from the main drive shaft  1149  and from the remainder of the shaft  1142 , for example, by insulators  1168 ,  1170 . 
     It will be appreciated that the rotary electrode assembly  1100  may be utilized with any of the end effector and/or shaft assembly embodiments described herein. For example,  FIG. 152  illustrates a cross-sectional view of one embodiment of the end effector and shaft assembly of  FIGS. 83-91  illustrating another example installation of a rotary electrode assembly  1100  including the outer contact  1102  and inner contact  1103  as described herein. 
       FIGS. 153-168  illustrate various embodiments of an electrosurgical end effector  700  comprising a proximal tissue treatment zone  706  and a distal tissue treatment zone  708 . The proximal tissue treatment zone  706  utilizes various electrodes and cutting edges to treat tissue, for example, as described herein above with respect to end effector  3000  shown in  FIGS. 6-10 . Treatment provided by the proximal tissue treatment zone  706  may include, for example, clamping, grasping, transsection, coagulation, welding, etc. The distal tissue treatment zone  708  may also comprise one or more electrodes  742  and may be utilized to apply treatment to tissue and, in some embodiments, to perform other surgical tasks such as grasping and manipulating suturing needles and/or other surgical implements. 
       FIG. 153  illustrates one embodiment of the end effector  700 . The end effector  700  may be utilized with various surgical tools including those described herein. As illustrated, the end effector  700  comprises a first jaw member  720  and a second jaw member  710 . The first jaw member  720  may be movable relative to the second jaw member  710  between open positions (shown in  FIGS. 153-156 ) and closed positions (shown in  FIGS. 166 and 165 ). For example, the jaw members  720 ,  710  may be pivotably coupled at a pivot point  702 . The jaw members  710 ,  720  may be curved with respect to a longitudinal tool axis “LT,” as illustrated. In some embodiments, the jaw members  710 ,  720  may be instead straight, as illustrated with respect to jaw members  3008 A,  3008 B shown in  FIGS. 6-8 . In use, the end effector  700  may be transitioned from an open position to a closed position to capture tissue between the jaw members  720 ,  710 . The tissue captured between the jaw members  720 ,  710  may be clamped or grasped along portions of the jaw members  710 , 720  for application of one or more tissue treatments such as transection, welding, dissection, and electrocauterization. 
     The proximal tissue treatment zone  706  of the end effector  700  may treat tissue in a manner similar to that described above with respect to the end effector  3000 . Tissue between the jaw members  720 ,  710  in the proximal tissue treatment zone  706  may be secured in place, for example, by teeth  734   a ,  734   b . See, e.g.,  FIGS. 154-159 . In the proximal tissue treatment zone  706 , the jaw members  720 ,  710  may each define respective longitudinal channels  812 ,  810 . An I-beam member  820  ( FIGS. 155 and 159 ) may traverse distally and proximally within the longitudinal channels  812 ,  810 , for example, as described herein above with respect to the end effector  3000  and axially movable member  3016 . In some embodiments, distal and proximal translation of the I-beam member  820  may also transition the jaw members  720 ,  710  between open and closed positions. For example, the I-beam member  820  may comprise flanges positioned to contact cam surfaces of the respective jaw members  720 ,  710 , similar to the manner in which flanges  3016 A,  3016 B contact cam surfaces  3026 A,  3026 B in the embodiment described with respect to  FIGS. 6-10 . The I-beam member  820  may also define a distally directed cutting element  822  that may transect tissue between the jaw members  720 ,  710  as the I-beam member  820  advances distally. In some embodiments, the jaw members  720 ,  710  may comprise tissue-contacting surfaces  730   a ,  730   b ,  732   a ,  732   b  similar to the tissue-contacting surfaces  504 A,  504 B,  506 A,  506 B described herein above with respect to  FIGS. 132-137 . 
     The proximal tissue treatment zone  706  may additionally comprise various electrodes and/or current paths for providing electrosurgical (RF) and/or other energy to tissue. The second jaw member  710  may comprise a supply electrode  848  positioned around the channel  810 . See e.g.,  FIGS. 153-155 and 157 . The supply electrode  848  may be in electrical communication with a generator for providing RF energy, such as the generator  3002  described herein above. For example, the supply electrode  848  may be coupled to one or more supply connector leads  846 . The supply connector leads  846  may extend distally through a shaft assembly to a tool interface  302  and/or handle  2500  and ultimately to a generator, such as the generator  3002  or an internal generator, as described herein. The supply electrode  848  may be electrically insulated from other elements of the end effector  700 . For example, referring to  FIG. 10 , the supply electrode (indicated on either side of the channel  810  by  848   a  and  848   b ) may be positioned on an insulating layer  844  (again indicated on either side of the channel  810  by  844   a ,  844   b ). The insulating layer  844  may be made of any suitable insulating material, such as ceramic, TEFLON, etc. In some embodiments, the insulating layer  844  may be applied as a coating to the jaw member  710 . The supply electrode  848  may operate in conjunction with a return path to apply bipolar RF energy to tissue, such as tissue  762  shown in  FIG. 159 . Current provided via the supply electrode  848  may flow through the tissue  762  and return to the generator via the return path. The return path may comprise various electrically conducting components of the end effector  700 . For example, in some embodiments, the return path may comprise bodies of the first and second jaws  720 ,  710 , the I-beam member  820 , the tissue-contacting surfaces  730   a ,  730   b ,  732   a ,  732   b , etc. 
     In the illustrated embodiments, the supply electrode  848  is offset from the return path. For example, the supply electrode  848  is positioned such that when the jaw members  720 ,  710  are in the closed position illustrated in  FIG. 159 , the electrode  848  is not in electrical contact (e.g., physical contact) with conductive portions of the end effector  700  that may serve and a return path for RF current. For example, the first jaw member  720  may comprise an opposing member  878  (indicated in  FIG. 159  as  878   a  and  878   b  on either side of the channel  812 ) positioned opposite the electrode  848  such that upon closure of the jaw members  720 ,  710 , the electrode  848  is in direct contact with the opposing member  878  and not with any other portions of the end effector  700 . The opposing member  878  may be electrically insulating. In this way, it may be possible to close the jaw members  720 ,  710  without shorting the supply electrode  848  to the return path. In some embodiments, the opposing member  878  may be selectively insulating. For example, the opposing member  878  may comprise a positive temperature coefficient (PTC) body, as described above, that is conductive below a temperature threshold (e.g., about 100° C.) and insulating at higher temperatures. In this way, the opposing member  878  may form part of the return path, but only until its temperature exceeds the temperature threshold. For example, if the supply electrode  848  were to be electrically shorted to an opposing member  878  comprising PTC or a similar material, the short would quickly drive the temperature of the opposing member  878  about the threshold, thus relieving the short. 
     The distal tissue treatment zone  708  may define distal grasping surfaces  790   a ,  790   b  positioned on jaw members  710 ,  720 , respectively. The distal grasping surfaces  790   a ,  790   b  may be positioned distally from the proximally treatment zone  706 . The distal grasping surfaces  790   a ,  790   b  may, in some embodiments, be configured to grasp and hold tissue. For example, the distal grasping surfaces  790   a ,  790   b  may comprise grip elements  741  for increasing friction between the grasping surfaces  790   a ,  790   b  and tissue and/or surgical implements, as described herein below. The grip elements  741  may comprise any suitable texture defined by the surfaces  790   a ,  790   b , a friction enhancing coating applied to the surfaces  790   a ,  790   b , etc. 
     In some embodiments, the distal tissue treatment zone  708  may also be configured to apply monopolar and/or bipolar electrosurgical (e.g., RF) energy. For example, the surface  790   a  may be and/or comprise a distal supply electrode  742 . For example, the surface  790   a  itself may be made from a conductive material and therefore be the distal supply electrode  742 . In some embodiments, as described herein, the conductive electrode  742  may comprise a conductive material coupled to an insulating layer  845 . The insulating layer  845  may be a dielectric layer and/or a coating applied to the jaw member  710 . The distal supply electrode  742  may be in electrical contact with a generator, such as the generator  3002  described herein above and/or an internal generator. In some embodiments, the distal supply electrode  742  may be in electrical contact with the supply electrode  848  of the proximal tissue treatment zone  706 . In this way, the distal supply electrode  742  may be energized when the proximal supply electrode  848  is energized. In some embodiments, the distal supply electrode  742  may be energized independent of the proximal supply electrode  848 . For example, the distal supply electrode  742  may be coupled to the generator via a dedicated supply line (not shown). 
     A return path for electrical energy provided by the distal supply electrode  742  may also comprise any suitable conductive portion of the end effector including, for example, the jaw member  710 , the jaw member  720 , the I-beam member  820 , etc. In some embodiments, the distal grasping surface  790   b  may also form a distal return electrode  748  that may be part of the return path from the distal supply electrode  742 . For example, the distal return electrode  748  may be in electrical contact with the jaw member  720  that may, in turn, be in electrical contact with a generator such as the generator  3000 . The distal return electrode  748  may be formed in any suitable manner. For example, the surface  790   b  may be conductive, thus forming the electrode  748 . In some embodiments, a conductive material may be applied to the surface  790   b , where the conductive material makes up the electrode  748 . 
     In the illustrated embodiments, the distal supply electrode  742  is not offset. For example, the distal supply electrode  742  is aligned with the return electrode  748 . Accordingly, the end effector  700  may be configured such that the distal supply electrode  742  does not come into contact with the return electrode  748  when the jaw members  720 ,  710  are in the closed position. For example, a gap  780  may exist between the distal supply electrode  742  and the distal return electrode  748  when the jaw members  720 ,  710  are in a closed position. The gap  780  is visible in  FIGS. 160, 161, 162, 163, 164 and 165 . 
     In various embodiments, the gap  780  may be generated as a result of the dimensions (e.g., thickness) of various components of the proximal tissue treatment zone  706 . For example, the opposing member  878  and the proximal supply electrode  848  may extend towards the axis LT such that when the electrode  848  and member  878  are in physical contact with one another (e.g., when the jaw members  720 ,  710  are in the closed position), the distal grasping surfaces  790   a,b  are not in physical contact with one another. Any suitable combination of the opposing member  878 , the supply electrode  848  and the insulating layer  844  may be utilized to bring about this result. 
     Referring now to  FIGS. 160, 163 and 164 , the insulating layer  844  and the insulating layer  845  may be continuous (e.g., form a continuous insulating layer). Similarly, the proximal supply electrode  848  and distal supply electrode  742  may be continuous (form a continuous electrode). The opposing member  878  is also illustrated. As illustrated, the electrode  848  (e.g., the portion of the continuous electrode in the proximal zone  706 ) is thicker than the electrode  742 . Accordingly, when the electrode  848  contacts the opposing member  878 , the thickness of the electrode  848  may prevent the distal grasping surfaces  790   a,b  from contacting one another, thus forming the gap  780 .  FIG. 161  illustrates an alternative embodiment of the end effector  700  where the electrode  742  and the electrode  848  are of the same thickness. The thickness of the opposing member  878 , however, is selected such that when the electrode  848  contacts the opposing member  878 , the distal grasping surfaces  790   a,b  do not contact one another, forming the gap  780 .  FIG. 162  illustrates another embodiment where the insulating layer  844  is thicker than the insulating layer  845 , thus preventing contact between the distal grasping surfaces  790   a, b  and forming the gap  780 . 
     In some embodiments, the distal supply electrode  742  may extend distally to a portion of a distal edge  886  of the jaw member  710 . For example,  FIG. 153  shows a distal electrode portion  744 . The distal electrode portion  744  may be utilized by a clinician to apply electrosurgical energy to tissue that is not necessarily between the jaw members  720 ,  710 . In some embodiments, the distal electrode portion  744  may be utilized to provide bipolar and/or monopolar cauterization. In bi-polar embodiments, the distal electrode portion  744  may utilize a return path similar to the return paths described herein. In some embodiments, the respective jaw members may comprise external depressions and/or protrusions  800 ,  802  similar to the protrusions described herein with respect to  FIGS. 116-131 . The depressions and/or protrusions  800 ,  802  may be conductive and may provide possible return paths for current passed via the distal electrode portion  744 . In some embodiments where the distal electrode portion  744  is present, the insulating layer  845  may extend distally under the distal electrode portion, as shown in  FIG. 164 . 
     It will be appreciated that the length of the respective tissue treatment zones  706 ,  708  may vary with different implementations. For example,  FIG. 165  shows an embodiment where the distal tissue treatment zone  708  is relatively shorter than the zone  708  shown in the other figures. For example, in  FIG. 165 , the distal tissue treatment zone  708  extends proximally by a lesser distance from the distal tip of the end effector  700  than the zones  708  illustrated elsewhere. 
     In some embodiments, the distal tissue treatment zone  708  may be utilized as a general surgical grasper. For example, the distal grasping surfaces  790   a,b  may be utilized to grasp and manipulate tissue. Also, in some embodiments, the distal grasping surfaces  790   a,b , may be utilized to grasp and manipulate artificial surgical implements such as needles, clips, staples, etc. For example,  FIGS. 160, 161, 162 and 163  show a surgical implement  896  secured between the distal grasping surfaces  790   a, b . In  FIGS. 160, 161 and 162  the surgical implement  896  has a round cross-section (e.g., a suturing needle). In  FIG. 163 , the surgical implement  896  has a non-round cross-section (e.g., a trailing end of a suturing needle, a clip, etc.). When used as a grasper, the distal treatment zone  708  may or may not apply electrosurgical energy to objects between the tissue surfaces  790   a,b . For example, it may not be desirable to apply electrosurgical energy to a needle or other surgical implement. 
     It will be appreciated that, as described above, some components of the proximal tissue treatment zone  706  may be common and/or continuous with some components of the distal tissue treatment zone  708 . For example,  FIG. 167  illustrates one embodiment of the jaw member  710  with the electrodes  878 ,  742  removed to illustrate the insulating layers  845 ,  844 . As illustrated, the insulating layers  845 ,  844  define a common, continuous layer  899 . A distal portion of the continuous layer  899  may make up the insulating layer  845  while a proximal portion of the insulating layer  899  may make up the insulating layer  844 . The insulating layer  844 , as illustrated, defines a notch  897  corresponding to the channel  810 , as shown, such that the I-beam member  820  may traverse the channel  810  without contacting the continuous layer  899 . Also, as illustrated, the insulating layer  845  defines a distal portion  843  that extends over a part of the distal end  886  of the jaw member  710 . The distal portion  843 , for example, may be positioned under the distal electrode portion  744 . 
       FIG. 166  illustrates an embodiment of the jaw member  710 , as illustrated in  FIG. 167 , with the electrodes  742 ,  848  installed. As illustrated, the proximal supply electrode may comprise regions  850   a ,  850   b ,  850   c  and the opposing member  878  may comprise corresponding regions  864   a ,  864   b ,  864   c . Regions  850   a  and  850   b  are positioned on either side of the channel  810 . Region  850   c  is positioned distal from a distal-most portion of the channel  810 .  FIG. 168  illustrates an alternate embodiment where the third region  850   c  is omitted. Accordingly, first and second regions  850   a ,  850   b  of the electrode  848  extend distally to the distal supply electrode  742 . 
     Non-Limiting Examples 
     In various embodiments, a surgical instrument can comprise an end effector and a shaft assembly coupled proximal to the end effector. The end effector comprises a first jaw member, a second jaw member, and a closure mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The shaft assembly comprises an articulation joint configured to independently articulate the end effector in a vertical direction and a horizontal direction. The surgical instrument also comprises at least one active electrode disposed on at least one of the first jaw member and the second jaw member. The at least one active electrode is configured to deliver RF energy to tissue located between the first jaw member and the second jaw member when in the closed position. 
     In various embodiments, a surgical instrument can comprise an end effector and a shaft assembly coupled proximal to the end effector. The end effector comprises a first jaw member, a second jaw member, and a closure mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The shaft assembly comprises a head rotation joint configured to independently rotate the end effector. The surgical instrument also comprises at least one active electrode disposed on at least one of the first jaw member and the second jaw member. The at least one active electrode is configured to deliver RF energy to tissue located between the first jaw member and the second jaw member when in the closed position. 
     A surgical tool can comprise an end effector, comprising a first jaw member, a second jaw member and a closure mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The surgical tool further comprises a shaft assembly proximal to the surgical end effector, wherein the surgical end effector is configured to rotate relative to the shaft assembly, and a rotary drive shaft configured to transmit rotary motions. The rotary drive shaft is selectively movable axially between a first position and a second position relative to the shaft assembly, wherein the rotary drive shaft is configured to apply the rotary motions to the closure mechanism when in the first axial position, and wherein the rotary drive shaft is configured to apply the rotary motions to the end effector when in the second axial position. In addition, the closure mechanism of the surgical tool comprises an I-beam member configured to translate in an axial direction to cam the first jaw member toward to the second jaw member. The I-beam member is connected to a threaded rotary drive member coupled to a rotary drive nut, wherein the rotary drive shaft is configured to engage with the rotary drive nut to transmit rotary motions to the rotary drive nut. Rotary motions of the rotary drive nut actuate translation of the threaded rotary drive member and the I-beam in the axial direction. Furthermore, the first jaw member and the second jaw member comprise channels configured to slidably engage with the I-beam member, wherein rotary motions of the rotary drive nut actuate translation of the I-beam in the channels between a proximally retracted position and a distally advanced position. 
     A surgical tool can comprise an end effector, comprising a first jaw member, a second jaw member, and a first actuation mechanism configured to move the first jaw member relative to the second jaw member between an open position and a closed position. The surgical tool further comprises a shaft assembly proximal to the surgical end effector, and a rotary drive shaft configured to transmit rotary motions. The rotary drive shaft is selectively moveable between a first position and a second position relative to the shaft assembly, wherein the rotary drive shaft is configured to engage and selectively transmit the rotary motions to the first actuation mechanism when in the first position, and wherein the rotary drive shaft is configured to disengage from the actuation mechanism when in the second position. In addition, the first actuation mechanism comprises an I-beam member configured to translate in an axial direction to cam the first jaw member toward to the second jaw member, the I-beam member connected to a threaded rotary drive member coupled to a rotary drive nut, wherein the rotary drive shaft is configured to engage with the rotary drive nut to transmit rotary motions to the rotary drive nut, and wherein rotary motions of the rotary drive nut actuate translation of the threaded rotary drive member and the I-beam in the axial direction. Furthermore, the first jaw member and the second jaw member comprise channels configured to slidably engage with the I-beam member, and wherein rotary motions of the rotary drive nut actuate translation of the I-beam in the channels between a proximally retracted position and a distally advanced position. 
     A surgical tool can comprise an end effector comprising a first jaw member, and a second jaw member, wherein the first jaw member is movable relative to the second jaw member between an open position and a closed position. The surgical tool also comprises first and second actuation mechanisms, and a clutch member configured to selectively engage and transmit rotary motion to either the first or the second actuation mechanism. In addition, the first actuation mechanism comprises an I-beam member configured to translate in an axial direction to cam the first jaw member toward the second jaw member, the I-beam member connected to a threaded rotary drive member coupled to a rotary drive nut, wherein the clutch member is configured to engage with the rotary drive nut to transmit rotary motions to the rotary drive nut, and wherein rotary motions of the rotary drive nut actuates translation of the threaded rotary drive member and the I-beam in the axial direction. Furthermore, the first jaw member and the second jaw member comprise channels configured to slidably engage with the I-beam member, and wherein rotary motions of the rotary drive nut actuate translation of the I-beam in the channels between a proximally retracted position and a distally advanced position. 
     A surgical tool can comprise an interchangeable end effector, a handle assembly and a shaft assembly. The interchangeable end effector comprises a first jaw member including a first electrode and a second jaw member including a second electrode. The first jaw member is moveable relative to the second jaw member between a first position and a second position. The handle assembly is proximal to said surgical end effector. The shaft assembly extends between the handle assembly and the interchangeable end effector. The shaft assembly comprises a rotary drive shaft configured to transmit rotary motions. The rotary drive shaft is selectively axially moveable relative to the shaft assembly between a plurality of discrete positions. A coupling arrangement can releasably attach the interchangeable end effector to the shaft assembly. 
     A surgical tool can comprise an interchangeable end and a shaft assembly. The interchangeable end may comprise a first jaw member including a first electrode, a second jaw member including a second electrode, a closure mechanism configured to move the first jaw member relative to the second jaw member between a first position and a second position, and an actuation driver configured to drive the closure mechanism. The shaft assembly extends proximal to the interchangeable end effector and comprises a rotary drive shaft configured to transmit rotary motions to the actuation driver. A coupling arrangement can releasably attach the interchangeable end effector to the shaft assembly. 
     A surgical tool can comprise, an interchangeable end effector and a shaft assembly. The end effector comprises a first jaw member including a first electrode, a second jaw member including a second electrode, a closure mechanism configured to move the first jaw member relative to the second jaw member between a first position and a second position, and an actuation driver configured to drive the closure mechanism. The shaft assembly extends proximal to the interchangeable end effector and comprises a rotary drive shaft configured to transmit rotary motions. The interchangeable end effector is releasably attached to the shaft assembly. The rotary drive shaft is selectively extendable axially to operably engage and transmit the rotary motions to the actuation driver. 
     A surgical end effector can comprise a first jaw member and a second jaw member. The first jaw member defines an exterior surface on a distal portion thereof. The second jaw member defines an exterior surface on a distal portion thereof. The first jaw member is moveable relative to the second jaw member between a first position and a second position. At least one of the exterior surfaces of the first and second jaw members includes a tissue gripping portion. 
     A surgical tool can comprise a surgical end effector, a handle assembly and a drive shaft. The surgical end effector comprises a first jaw member defining an exterior surface on a distal portion thereof and a second jaw member defining an exterior surface on a distal portion thereof. The first jaw member is moveable relative to the second jaw member between a first position and a second position. At least one of the exterior surfaces of the first and second jaw members includes a tissue gripping portion. The handle assembly is proximal to said surgical end effector. The drive shaft extends between said surgical end effector and said handle assembly and is configured to move the first jaw relative to the second jaw between the first position and the second position in response to actuation motions in the handle. 
     A surgical tool can comprise an actuation system, a surgical end effector and a shaft assembly. The actuation system is for selectively generating a plurality of control motions. The surgical end effector is operably coupled to said actuation system and comprises a first jaw member and a second jaw member. The first jaw member defines an exterior surface on a distal portion thereof. The second jaw member defines an exterior surface on a distal portion thereof. The first jaw member is movably supported relative to the second jaw member between an open position and a closed position in response to closure motions generated by said actuation system. At least one of the exterior surfaces of the first and second jaw members includes a tissue adhering portion. The shaft assembly is for transmitting said plurality of control motions to the surgical end effector. 
     An end effector can comprise a first jaw member and a second jaw member. The first jaw member is movable relative to the second jaw member between an open position and a closed position. The first jaw member comprises a first positively-angled tissue-contacting surface. The second jaw member comprises a second positively-angled tissue-contacting surface. At least one of the first jaw member and the second jaw member comprises at least one active electrode disposed on the jaw member adjacent to the positively-angled tissue-contacting surface. The at least one active electrode is configured to deliver RF energy to tissue located between the first jaw member and the second jaw member when in the closed position. 
     An end effector can comprise a first jaw member and a second jaw member. The first jaw member is movable relative to the second jaw member between an open position and a closed position. The first jaw member comprises a first positively-angled tissue-contacting surface and a first negatively-angled tissue-contacting surface. The second jaw member comprises a second positively-angled tissue-contacting surface and a second negatively-angled tissue-contacting surface. The first positively-angled tissue-contacting surface opposes the second negatively-angled tissue-contacting surface when the first and second jaw members are in the closed position. The first negatively-angled tissue-contacting surface opposes the second positively-angled tissue-contacting surface when the first and second jaw members are in the closed position. 
     An end effector can comprise a first jaw member and a second jaw member. The first jaw member is movable relative to the second jaw member between an open position and a closed position. The first jaw member comprises a first proximal tissue-contacting portion, a first distal textured portion adjacent to the first proximal tissue-contacting portion, a first positively-angled tissue-contacting surface disposed along the first proximal tissue-contacting portion, and at least one first electrode located in the first proximal tissue-contacting portion adjacent to the first positively-angled tissue-contacting surface. The second jaw member comprises a second proximal tissue-contacting portion, a second distal textured portion adjacent to the second proximal tissue-contacting portion, a second positively-angled tissue-contacting surface disposed along the second proximal tissue-contacting portion, and at least one second electrode located in the second proximal tissue-contacting portion adjacent to the second positively-angled tissue-contacting surface. The at least one first electrode and the at least one second electrode are in a bipolar configuration to deliver RF energy to tissue located between the first jaw member and the second jaw member when in the closed position. 
     A surgical tool can comprise an end effector. The end effector can comprise first and second jaw members, a shaft assembly, a rotatable drive shaft, a first electrical contact and a second electrical contact. The first and second jaw members are pivotable relative to one another from an open position to a closed position. An electrode is positioned on the first jaw member. The shaft assembly extends proximally from the end effector, is at least partially hollow, and defines an inner wall. The rotatable drive shaft extends proximally within the shaft assembly. The first electrical contact is coupled to the inner wall of the shaft assembly and positioned around at least a portion of the drive shaft. The second electrical contact is coupled to and rotatable with the drive shaft. The second electrical contact is positioned to be electrically connected to the first electrical contact as the drive shaft rotates. 
     A surgical end effector for use with a surgical tool can comprise a first jaw member and a second jaw member. The second jaw member is pivotable relative to the first jaw member from a first open position to a closed position, where the first and second jaw members are substantially parallel in the closed position. The second jaw member comprises an offset proximal supply electrode and a distal supply electrode. The offset proximal supply electrode is positioned to contact an opposing member of the first jaw member when the first and second jaw members are in the closed position. The distal supply electrode is positioned distal of the offset proximal electrode and is aligned with a conductive surface of the first jaw member when the first and second jaw members are in the closed position. When the first and second jaw members are in the closed position, the proximal supply electrode is in contact with the opposing member and the distal supply electrode is not in contact with the conductive surface of the first jaw member. 
     A surgical end effector for use with a surgical tool can comprise first and second jaw members pivotable from a first open position to a closed position. The first and second jaw members define a proximal tissue treatment region and distal tissue treatment region. The second jaw member comprises, in the proximal tissue treatment region, an offset proximal supply electrode positioned such that when the jaw members are in the closed position the proximal supply electrode is in physical contact with the first jaw member and is not in electrical contact with the first jaw member. The second jaw member further comprises, in the distal tissue treatment region, a distal supply electrode positioned such that when the jaw members are in the closed position, the distal supply electrode is aligned with a conductive surface of the first jaw member. When the jaw members are in the closed position, the jaw members define a physical gap between the distal supply electrode and the conductive surface of the first jaw member. 
     The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     Although the present invention has been described herein in connection with certain disclosed example embodiments, many modifications and variations to those example embodiments may be implemented. For example, different types of end effectors may be employed. Also, where materials are disclosed for certain components, other materials may be used. The foregoing description and following claims are intended to cover all such modification and variations. 
     Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.