Patent Publication Number: US-2021161529-A1

Title: Stapler with composite cardan and screw drive

Description:
RELATED APPLICATIONS 
     This patent application is a continuation of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 15/772,527, filed on Apr. 30, 2018, which is a U.S. National Stage Filing under 35 U.S.C. 371 from International Application No. PCT/US2016/059527, filed on Oct. 28, 2016, and published as WO 2017/083125 A1 on May 18, 2017, which claims priority to and the benefit of the filing date of U.S. Provisional Patent Application 62/255,123, entitled “STAPLER WITH COMPOSITE CARDAN AND SCREW DRIVE” filed Nov. 13, 2015, each of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Minimally invasive surgical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. As a consequence, the average length of a hospital stay for standard surgery may be shortened significantly using minimally invasive surgical techniques. Also, patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery. 
     Minimally invasive teleoperated surgical systems have been developed to increase a surgeon&#39;s dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a teleoperated surgical system, the surgeon is often provided with an image of the surgical site at a control console. While viewing a three dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console. Each of the master input devices controls the motion of a servo-mechanically actuated/articulated surgical instrument. During the surgical procedure, the teleoperated surgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, stapling tissue, or the like, in response to manipulation of the master input devices. 
     SUMMARY 
     In one aspect, a surgical instrument a surgical instrument includes a first jaw having a first jaw axis and that includes a proximal portion pivotally mounted to a base to be pivotable about a pivot axis between an open and a closed positions and including a distal portion. A second jaw has a second jaw axis and includes a proximal portion secured to the base and includes a distal portion. A first cam surface secured to the first jaw that includes a distal cam portion that extends parallel to the first jaw axis and a proximal cam portion that is inclined at an angle relative to the distal cam portion. A second cam surface secured to the second jaw that extends parallel to the second jaw axis. A drive member includes a cross-beam, which is sized to slideably engage the first and second cam surfaces, a first transverse beam portion, and a second transverse beam portion. A lead screw configured to advance the drive member in a distal direction parallel to the second jaw axis. While the first jaw is in the open position, the distal cam portion and the second cam surface are disposed to contact the first and second transverse beam portions, respectively, and the distal cam portion is disposed to impart a rotational force to the first jaw about the pivot axis as the lead screw advances the drive member in the distal direction. While the first jaw is in the closed position, the proximal cam portion and the second cam surface are disposed, to contact the first and second transverse beam portions, respectively, and to impart a clamp force to the first and second jaws as the lead screw advances the drive member in the distal direction. 
     In another aspect, a universal double joint includes a first rotatable bearing has a first spherical surface formed of a plastic material. At least one first metal pin is configured to receive the imparted drive force and to impart the imparted drive force to the first rotatable bearing. A second rotatable bearing has a second spherical surface formed of a plastic material. At least one second metal pin configured to receive the imparted drive force and to impart the imparted drive force to the second rotatable bearing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
         FIG. 1  is an illustrative plan view illustration of a teleoperated surgical system in accordance with some embodiments. 
         FIG. 2  is an illustrative perspective view of the Surgeon&#39;s Console in accordance with some embodiments. 
         FIG. 3  is an illustrative perspective view of the Electronics Cart in accordance with some embodiments. 
         FIG. 4  is an illustrative bock diagram diagrammatically representing functional relationships among components of a teleoperated surgery system in accordance with some embodiments. 
         FIGS. 5A-5B  are illustrative drawings showing a Patient Side Cart and a surgical tool  62 , respectively in accordance with some embodiments. 
         FIG. 6  is an illustrative drawing showing an example surgical tool in accordance with some embodiments. 
         FIG. 7  is perspective view of a portion of a torque transmitting mechanism for transmitting torque through an angle, in accordance with some embodiments. 
         FIG. 8  is an exploded perspective view of the torque transmitting mechanism of  FIG. 1  in accordance with some embodiments. 
         FIG. 9  is a perspective partially cut away view of the torque transmitting mechanism of  FIGS. 7-8  shown as assembled in accordance with some embodiments. 
         FIG. 10A  is illustrative cross-sectional view of the torque transmitting mechanism of  FIGS. 7-9  in an inline position in accordance with some embodiments. 
         FIG. 10B  is illustrative cross-sectional view of the torque transmitting mechanism of  FIGS. 7-9  in an articulated position in accordance with some embodiments. 
         FIG. 11  is an illustrative cross-sectional view of the torque transmitting mechanism of  FIGS. 7-10B , illustrating the configuration of the proximal and distal transverse slots in accordance with many embodiments. 
         FIG. 12A  is an illustrative side elevation view of a torque transmitting mechanism along a view direction normal to the axes of coupling pins in accordance with some embodiments. 
         FIG. 12B  is an illustrative side elevation view of a torque transmitting mechanism along a view direction parallel to the axes of coupling pins in accordance with some embodiments. 
         FIG. 13  is an illustrative drawing shows a portion of a torque transmitting mechanism with the coupling member removed and a “see through” driven shaft plastic bearing to show the cross mounting of a distal coupling pin to a distal cross pin in accordance with some embodiments. 
         FIG. 14A  is an illustrative perspective view showing details of proximal and distal cross pin bores of respective drive shaft plastic bearing and driven shaft plastic bearing in accordance with some embodiments. 
         FIG. 14B  is an illustrative perspective view showing details of proximal transverse slot and the distal transverse slot of the respective drive shaft plastic bearing and driven shaft plastic bearing in accordance with some embodiments. 
         FIG. 15  is an illustrative perspective drawing, with a partial cutaway, of a surgical tool assembly in accordance with some embodiments. 
         FIG. 16  is an illustrative perspective view, with a partial cutaway, of the end effector of  FIG. 9  with an empty second jaw from which the stapler cartridge is removed in accordance with some embodiments. 
         FIG. 17  is an illustrative exploded view of a detachable stationary second jaw in accordance with some embodiments. 
         FIG. 18  is an illustrative cross sectional view of the end effector of  FIGS. 15-17  in accordance with some embodiments. 
         FIG. 19A  is a top elevation view of the first cam surface in accordance with some embodiments. 
         FIG. 19B  is a cross-section view showing edges of one side of the first cam surface in accordance with some embodiments. 
         FIG. 20  is an illustrative bottom elevation view of the longitudinally extending second cam surface in accordance with some embodiments. 
         FIG. 21  is an illustrative perspective view of the drive member in accordance with some embodiments. 
         FIGS. 22A-22F  are schematic cross-sectional views representing stages in the articulation of the first jaw as the drive member is moved in a linear motion longitudinally toward a distal end of the end effector and interacts with the first cam surface in accordance with some embodiments. 
         FIG. 23A  shows the cross-sectional view without the pusher shuttle shown within the cartridge in accordance with some embodiments. 
         FIG. 23B  shows the cross-sectional view with the pusher shuttle shown within the cartridge in accordance with some embodiments. 
         FIG. 24A  is an illustrative cross-sectional view of a portion of the end effector of showing the first jaw in an open position and the drive member in a starting position in accordance with some embodiments. 
         FIG. 24B  is an illustrative cross-sectional view of a portion of the view of  FIG. 24A  showing a spring used to keep the jaws open prior to gripping and clamping operations in accordance with some embodiments. 
         FIG. 25  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member in grip positions in accordance with some embodiments. 
         FIG. 26  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member in a first clamp positions in accordance with some embodiments. 
         FIG. 27  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member in a staple pushing positions in accordance with some embodiments. 
         FIG. 28  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member in a stapler fully fired position in accordance with some embodiments. 
         FIG. 29  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member during return of the drive member to the start position in accordance with some embodiments. 
         FIG. 30  is an illustrative cross-sectional view of a portion of the end effector showing the first jaw and the drive member in a complete configuration with the drive member back in the to the start position in accordance with some embodiments. 
         FIG. 31  is an illustrative drawing showing a lockout mechanism in accordance with some embodiments. 
         FIGS. 32A-32B  are illustrative drawings showing details of a two degree of freedom wrist of the end effector with the torque transmitting mechanism in an inline position ( FIG. 32A ) and in a articulated position ( FIG. 32B ) in accordance with some embodiments. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following description is presented to enable any person skilled in the art to create and use a stapler with composite cardan and lead screw drive for use in a surgical system. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the inventive subject matter. Moreover, in the following description, numerous details are set forth for the purpose of explanation. However, one of ordinary skill in the art will realize that the inventive subject matter might be practiced without the use of these specific details. In other instances, well-known machine components, processes and data structures are shown in block diagram form in order not to obscure the disclosure with unnecessary detail. Identical reference numerals may be used to represent different views of the same item in different drawings. Flow diagrams in drawings referenced below are used to represent processes. A computer system may be configured to perform some of these processes. Modules within flow diagrams representing computer implemented processes represent the configuration of a computer system according to computer program code to perform the acts described with reference to these modules. Thus, the inventive subject matter is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
     Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,  FIG. 1  is an illustrative plan view of a teleoperated surgical system  10 , typically used for performing a minimally invasive diagnostic or surgical procedure on a Patient  12  who is lying down on an Operating table  14 . The system can include a Surgeon&#39;s Console  16  for use by a Surgeon  18  during the procedure. One or more Assistants  20  may also participate in the procedure. The teleoperated surgical system  10  can further include a Patient Side Cart  22  and an Electronics Cart  24 . The Patient Side Cart  22  can manipulate at least one removably coupled tool assembly  26  (hereinafter also referred to as a “tool”) through a minimally invasive incision in the body of the Patient  12  while the Surgeon  18  views the surgical site through the Console  16 . An image of the surgical site can be obtained by an endoscope  28 , such as a stereoscopic endoscope, which can be manipulated by the Patient Side Cart  22  to orient the endoscope  28 . The Electronics Cart  24  can be used to process the images of the surgical site for subsequent display to the Surgeon  18  through the Surgeon&#39;s Console  16 . The number of surgical tools  26  used at one time will generally depend on the diagnostic or surgical procedure and the space constraints within the operating room among other factors. 
       FIG. 2  is an illustrative perspective view of the Surgeon&#39;s Console  16 . The Surgeon&#39;s Console  16  includes a left eye display  32  and a right eye display  34  for presenting the Surgeon  18  with a coordinated stereo view of the surgical site that enables depth perception. The Console  16  further includes one or more input control devices  36 , which in turn cause the Patient Side Cart  22  (shown in  FIG. 1 ) to manipulate one or more tools. The input control devices  36  can provide the same degrees of freedom as their associated tools  26  (shown in  FIG. 1 ) to provide the Surgeon with telepresence, or the perception that the input control devices  36  are integral with the tools  26  so that the Surgeon has a strong sense of directly controlling the tools  26 . To this end, position, force, and tactile feedback sensors (not shown) may be employed to transmit position, force, and tactile sensations from the tools  26  back to the Surgeon&#39;s hands through the input control devices  36 . 
       FIG. 3  is an illustrative perspective view of the Electronics Cart  24 . The Electronics Cart  24  can be coupled with the endoscope  28  and can include a processor to process captured images for subsequent display, such as to a Surgeon on the Surgeon&#39;s Console, or on another suitable display located locally and/or remotely. For example, where a stereoscopic endoscope is used, the Electronics Cart  24  can process the captured images to present the Surgeon with coordinated stereo images of the surgical site. Such coordination can include alignment between the opposing images and can include adjusting the stereo working distance of the stereoscopic endoscope. 
       FIG. 4  is an illustrative bock diagram diagrammatically representing functional relationships among components of a teleoperated surgery system  50  (such as system  10  of  FIG. 1 ). As discussed above, a Surgeon&#39;s Console  52  (such as Surgeon&#39;s Console  16  in  FIG. 1 ) can be used by a Surgeon to control a Patient Side Cart (Surgical Robot)  54  (such as Patent Side Cart  22  in  FIG. 1 ) during a minimally invasive procedure. The Patient Side Cart  54  can use an imaging device, such as a stereoscopic endoscope, to capture images of the procedure site and output the captured images to an Electronics Cart  56  (such as the Electronics Cart  24  in  FIG. 1 ). As discussed above, the Electronics Cart  56  can process the captured images in a variety of ways prior to any subsequent display. For example, the Electronics Cart  56  can overlay the captured images with a virtual control interface prior to displaying the combined images to the Surgeon via the Surgeon&#39;s Console  52 . The Patient Side Cart  54  can output the captured images for processing outside the Electronics Cart  56 . For example, the Patient Side Cart  54  can output the captured images to a processor  58 , which can be used to process the captured images. The images can also be processed by a combination the Electronics Cart  56  and the processor  58 , which can be coupled together to process the captured images jointly, sequentially, and/or combinations thereof. One or more separate displays  60  can also be coupled with the processor  58  and/or the Electronics Cart  56  for local and/or remote display of images, such as images of the procedure site, or other related images. 
       FIGS. 5A-5B  are illustrative drawings showing a Patient Side Cart  22  and a surgical tool  62 , respectively in accordance with some embodiments. The surgical tool  62  is an example of the surgical tools  26 . The Patient Side Cart  22  shown provides for the manipulation of three surgical tools  26  and an imaging device  28 , such as a stereoscopic endoscope used for the capture of images of the site of the procedure. Manipulation is provided by teleoperated mechanisms having a number of robotic joints. The imaging device  28  and the surgical tools  26  can be positioned and manipulated through incisions in the patient so that a kinematic remote center is maintained at the incision to minimize the size of the incision. Images of the surgical site can include images of the distal ends of the surgical tools  26  when they are positioned within the field-of-view of the imaging device  28 . 
       FIG. 6  is an illustrative drawing showing an example surgical tool  70  that includes a proximal chassis  72 , an instrument shaft  74 , and a distal end effector  76  having a jaw  78  that can be articulated to grip a patient tissue. The proximal chassis includes input couplers that are configured to interface with and be driven by corresponding output couplers of the Patient Side Cart  22 . The input couplers are drivingly coupled with drive shafts that are disposed within the instrument shaft  74 . The drive shafts are drivingly coupled with the end effector  76 . 
       FIG. 7  is perspective view of a portion of a torque transmitting mechanism 102  for transmitting torque through an angle, in accordance with some embodiments. The torque transmitting mechanism  102  includes cardan drive shaft  104  and a cardan driven shaft  106  and a double universal joint  105 , also referred to herein as a cardan joint, in accordance with some embodiments. A cardan shaft is a shaft that has a universal joint at one or both ends enabling it to rotate freely when in varying angular relation to another shaft or shafts to which it is joined. A cardan joint is a universal joint in a shaft that enables the shaft to rotate together with another shaft to which it is joined when the two shafts are out of axial alignment. U.S. Pat. No. 8,852,174 (filed Nov. 12, 2010) issued to Burbank, which is incorporated herein in its entirety by this reference, discloses prior surgical tolls that include two degree of freedom wrists and double universal joints. 
       FIG. 8  is an exploded perspective view of the torque transmitting mechanism  102  of  FIG. 7 . The torque transmitting mechanism  102  includes a drive shaft  104 , a driven shaft  106  and a metal coupling member  108  disposed between them. The drive shaft  104 , the driven shaft  106 , or both drive shaft  104  and driven shaft  106 , may comprise metal. The drive shaft  104  includes a proximal end  110  and a distal end  112 . The driven shaft  106  includes a proximal end  114  and a distal end  116 . The distal end  112  of the drive shaft  104  includes opposed facing arms  118  with holes  120  that are aligned to define a drive axis clevis  122 . The proximal end  114  of the driven shaft  106  includes opposed facing arms  124  with holes  126  that are aligned to define a drive axis clevis  123 . 
     The metal coupling member  108  comprises a generally cylindrical sleeve structure that defines a proximal end opening  127  and a distal end opening  129 . A drive shaft plastic bearing  128  having a partially spherical outer surface portion  131  is sized to fit within the proximal end opening  127  for smooth partial rotation therein. A driven shaft plastic bearing  130  having a partially spherical outer surface portion  133  is sized to fit within the distal end opening  130  for smooth partial rotation therein. 
     The drive shaft plastic bearing  128  defines a proximal plastic axial engagement structure  132  and the driven shaft plastic bearing  130  defines a complementary distal plastic axial engagement structure  134 . The proximal plastic axial engagement structure  132  and the distal axial engagement structure  134  have complementary shapes that cooperate during axial rotation of the drive shaft  104  and the driven shaft  106  to tie the relative angular orientation between the drive shaft  104  and the coupling member  108  to the relative angular orientation between the driven shaft  106  and the coupling member  108 . More particularly, the proximal plastic axial engagement structure  132  and the distal axial engagement structure  134  cooperate to constrain the coupling member  108  to be oriented at an equivalent relative angle to both the drive shaft  104  and the driven shaft  106 , such that any rotational speed differences between the drive shaft  104  and the coupling member  108  are effectively canceled when the rotation of the coupling member  108  is transferred to the driven shaft  106 , thereby substantially eliminating rotational speed differences between the drive shaft  104  and the driven shaft  106 . A torque transmitting mechanism for transmitting torque through an angle while substantially eliminating rotational speed differences between a drive shaft  104  and a driven shaft  106  is commonly referred to as a constant velocity (CV) joint. In accordance with some embodiments, the proximal plastic axial engagement structure  132  includes a first plastic spherical gear structure and the distal axial engagement structure  134  includes a first plastic spherical gear structure. 
     The first drive shaft plastic bearing  128  defines a proximal transverse bore  136  extending through the partially spherical outer surface portion  131  transverse to the first plastic engagement structure  132 . The first drive shaft plastic bearing  128  defines a proximal opening  140  sized to permit passage of the drive axis clevis  122  so as to align holes  120  with the proximal transverse bore  136 . The first drive shaft plastic bearing  128  defines a proximal transverse slot  138  that extends through the partially spherical outer surface portion  131  at a right angle to the transverse bore  136 . The proximal transverse slot  138  extends through a partial circumference of the first drive shaft plastic bearing  128  having an axis aligned with an axis of the proximal transverse bore  136 . 
     The second drive shaft plastic bearing  130  defines a distal transverse bore  142  extending through the partially spherical outer surface portion  133  transverse to the second plastic engagement structure  130 . The driven shaft plastic bearing  130  is secured to a distal hub  135  used to mount to the proximal portion of the end effector (described below). The driven shaft plastic bearing  130  is secured to a distal hub  135  define a distal opening  144  sized to permit passage of the driven axis clevis  123  so as to align holes  126  with the distal transverse bore  142 . The second drive shaft plastic bearing  130  defines a distal transverse slot  146  that extends through the partially spherical outer surface portion  133  at a right angle to the distal transverse bore  146 . The distal transverse slot  146  extends through a partial circumference of the second drive shaft plastic bearing  130  having an axis aligned with an axis of the distal transverse bore  142 . 
     The metal coupling member  108  defines opposed diametrically aligned proximal holes  148  extending through it adjacent its proximal end opening  127 . The first drive shaft plastic bearing  128  is inserted within the proximal end opening  127 , with the proximal end holes  148  aligned with the proximal transverse slot  138 . A proximal coupling pin  150  extends through the aligned proximal end holes  148  and the proximal transverse slot  138  and is matingly secured to opposed inner surfaces of the coupling member  108  to permit rotation of the first drive shaft plastic bearing  128  about an axis of the proximal coupling pin  150 . A proximal cross pin  152  defines a proximal cross pin bore  154  that extends therethrough. The proximal cross pin  152  extends through the proximal transverse bore  136  and is secured therein to permit rotation of the first drive shaft plastic bearing  128  about the axis of the proximal cross pin  152 . The proximal cross pin bore  154  is sized to permit passage of the proximal coupling pin  150 , which extends through it and has opposed ends secured to diametrically opposed sides of the metal coupling member  108 . Thus, the proximal coupling pin  150  and the proximal cross pin  152  maintain a perpendicular, cross, relationship with each other. 
     The metal coupling member  108  defines opposed diametrically aligned distal openings  156  extending through it adjacent its distal end opening  129 . The second drive shaft plastic bearing  130  is inserted within the distal end opening  129 , with the distal end holes  156  aligned with the distal transverse slot  146 . A distal coupling pin  158  extends through the aligned proximal end openings  156  and the proximal transverse slot  146  and is matingly secured to opposed inner surfaces of the coupling member  108  to permit rotation of the second drive shaft plastic bearing  130  about an axis of the distal coupling pin  156 . A distal cross pin  160  defines a distal cross pin bore  162  that extends therethrough. The distal cross pin  160  extends through the distal transverse bore  142  and is secured therein to permit rotation of the second drive shaft plastic bearing  130  about an axis of the distal cross pin  160 . The distal cross pin bore  162  is sized to permit passage of the distal coupling pin  158 , which extends through it and has opposed ends secured to diametrically opposed sides of the metal coupling member  108 . Thus, the distal coupling pin  158  and the proximal cross pin  160  maintain a perpendicular, cross, relationship with each other. 
       FIG. 9  is a perspective partially cut away view of the torque transmitting mechanism of  FIGS. 7-8   102  shown as assembled in accordance with some embodiments. The coupling member  108  is shown partially cut away to show the drive shaft plastic bearing  128  and the driven shaft plastic bearing  130  that are partially enclosed within it. A portion of the drive shaft  104  that is encompassed within the drive shaft plastic bearing  128  is illustrated using dashed lines. Similarly, a portion of the driven shaft  106  that is encompassed within the driven shaft plastic bearing  130  is illustrated using dashed lines.  FIG. 9  illustrates the torque transmitting mechanism  102  in an inline configuration in which the drive shaft  104  and the driven shaft  106  are longitudinally aligned. 
     The proximal coupling pin  150 , which passes through the proximal cross pin bore  154  formed in the proximal cross pin, is matingly secured within the proximal holes  148  formed on diametrically opposed sides of the coupling member  108  adjacent to its proximal opening  127 . Likewise, the distal coupling pin  158 , which passes through the distal cross pin bore  162  formed in the distal cross pin  160 , is matingly secured within the proximal holes  156  formed on diametrically opposed sides of the coupling member  108  adjacent to its distal opening  129 . Moreover, the proximal cross pin  152  is extends within and is rotatable relative to the holes  120  formed in the opposed facing arms  118  of the drive axis clevis  122  and extends within and is rotatable relative to the proximal transverse bore  136 . Likewise, the distal cross pin  160  extends within and is rotatable relative to the holes  126  formed in the opposed facing arms  124  of the driven axis clevis  123  and extends within and is rotatable relative to the distal transverse bore  142 . 
     Accordingly, the proximal cross pin  152  rotates about the drive shaft axis in unison with the drive shaft  104 . Similarly, the driven axis rotates about the driven axis in unison with the distal cross pin  160 . 
     The perpendicular cross mounting of the proximal coupling pin  150  to the proximal cross pin  152  imparts to the coupling pin  150 , rotation forces about the drive shaft axis that are imparted to the cross pin  152  due to rotation of the drive shaft  104 . Since the proximal coupling pin  150  and the distal coupling pin  160  each is matingly secured to the metal coupling structure  108 , a rotational force imparted to the proximal coupling pin  150  is imparted through the coupling member  108  to the distal coupling pin  158 . Moreover, the perpendicular cross mounting of the distal coupling pin  158  to the distal cross pin  160  imparts to the driven shaft  106 , rotation forces about the driven shaft axis that have the same magnitude as and that are responsive to rotation forces imparted about the drive shaft axis of the drive shaft  104 . 
     The first drive shaft plastic bearing  128  can move in two degrees of freedom (2-dof). Movement of the first drive shaft plastic bearing  128  in a first degree of freedom involves the first drive shaft plastic bearing  128  rotating about the axis of the proximal cross pin  152  with the proximal coupling pin  150 , which is in a fixed position relative to the coupling member  108 , sliding within the proximal transverse slot  138 . Movement of the first drive shaft plastic bearing  128  in a second degree of freedom involves the bearing  128  about the proximal coupling pin  150 , which is in a fixed position relative to the coupling member  108 . 
     Likewise, the second drive shaft plastic bearing  130  can move in two degrees of freedom (2-dof). Movement of the second drive shaft plastic bearing  130  in a first degree of freedom involves the second drive shaft plastic bearing  130  rotating about the axis of the distal cross pin  160  with the distal coupling pin  158 , which is in a fixed position relative to the coupling member  108 , sliding within the distal transverse slot  146 . Movement of the second drive shaft plastic bearing  130  in a second degree of freedom involves the bearing  130  rotating about the distal coupling pin  158 , which is in a fixed position relative to the coupling member  108 . 
       FIG. 10A  is illustrative cross-sectional view of the torque transmitting mechanism  102  of  FIGS. 7-9  showing details of a drive shaft plastic bearing  128  outer spherical surface  131  interfacing with a first inner spherical surface  172  of the coupling member  108 , and also showing details of the driven shaft plastic bearing  130  outer spherical surface  133  interfacing with a second inner spherical surface  174  of the coupling member  108 . An advantage of using an outer spherical surface for plastic bearings is lower cost and accuracy of the components, since gear surfaces can be difficult to manufacture accurately from metal, which makes them very costly. With injection molding a more repeatably accurate part can be produced with much lower cost. Moreover, the plastic also can provide some lubrication. As discussed above, the constraint provided by the first coupling pin  150  axially and rotationally couples the drive shaft  104  and the drive shaft plastic bearing  128  mounted thereon, to the coupling member  108 , and the constraint provided by the second coupling pin  158  axially and rotationally couples the driven shaft  106  and the driven shaft plastic bearing  130  mounted thereon to the coupling member  108 . Additionally, the constraint provided by the interfacing spherical surfaces can further constrain the drive shaft  104  and the driven shaft  106  relative to the coupling member  108 . 
       FIG. 10B  is an illustrative cross-sectional view of the torque transmitting mechanism  102  of  FIGS. 7-10A , illustrating engagement between gear teeth  176  drive shaft plastic bearing  128  and gear teeth  178  of the driven shaft plastic bearing  130  for an angled configuration, in accordance with some embodiments. The cross-section illustrated includes the drive axis  164 , the driven axis  168 , and the coupling member axis  166 , and is taken along a view direction parallel to the axes of the first coupling pin  150  and the second coupling pin  158 . 
     In the angled configuration illustrated in  FIG. 10B , the driven axis of the driven shaft  106  deviates from the drive axis of the drive shaft  104  by 70 degrees. The constraint provided by engagement between the drive shaft gear teeth  176  of the drive shaft plastic bearing  128  and the gear teeth  178  of the driven shaft plastic bearing  130  results in the 70 degrees being equally distributed amongst a 35 degree deviation between the drive axis  164  and the coupling axis  166 , and a 35 degree deviation between the coupling axis  166  and the driven axis  168 . By constraining the coupling member  108  to be oriented at an equivalent relative angle to both the drive shaft  104  and the driven shaft  106 , any rotational speed differences between the drive shaft and the coupling member are effectively canceled when the rotation of the coupling member  108  is transferred to the driven shaft  106 , thereby substantially eliminating any rotational speed differences between the drive shaft  104  and the driven shaft  106 . 
     In some embodiments, the gear teeth  176  of the drive shaft plastic bearing  128  and the gear teeth  178  of the driven shaft plastic bearing  130  are spherically oriented so as to provide the above described constraint between the drive shaft  104  and the driven shaft  106  for any angular orientation of the torque transmitting mechanism  102 . For an angled configuration, rotation of the drive shaft  104  and a corresponding rotation of the driven shaft  106  causes different portions of the gear teeth  176  of the drive shaft plastic bearing  128  and the gear teeth  178  of the driven shaft plastic bearing  130  to be intersected by the coupling axis  108 . The use of spherical gear teeth allows this movement of the shafts while still providing the angular constraint necessary to orient the coupling member relative to the drive shafts. 
       FIG. 11  is an illustrative cross-sectional view of the torque transmitting mechanism  102  of  FIGS. 7-10B , illustrating the configuration of the proximal transverse slot  138  and the similar distal transverse slot  146 , in accordance with many embodiments. The proximal transverse slot  138  is configured to accommodate the first coupling pin  150  throughout a range of angles between a drive axis  164  and a coupling axis  166 . Likewise, the distal transverse slot  146  is configured to accommodate the second coupling pin  158  throughout a range of angles between the driven axis  168  and the coupling axis  166 . When the torque transmitting mechanism  102  is operated in an angled configuration, the position of the first coupling pin  150  within the proximal transverse slot  138  will undergo a single oscillation cycle for each 360 degree rotation of the drive shaft  104 . Likewise, the position of the second coupling pin  158  within the distal transverse slot  146  will undergo a single oscillation cycle for each 360 degree rotation of the driven shaft  106 . 
     The oscillation of the metal coupling pins  150 ,  158  within the transverse slots  138 ,  146  can be described with reference to  FIGS. 12A-12B .  FIG. 12A  is an illustrative side elevation view of the torque transmitting mechanism  102  along a view direction normal to the axes of the coupling pins  150 ,  158 .  FIG. 12B  is an illustrative side elevation view of torque transmitting mechanism  102  along a view direction parallel to the axes of metal coupling pins  150 ,  158 . In  FIGS. 12A-12B , the coupling member  108  is transparent and indicated with dashed lines to illustrate interactions between mechanism components. In the position shown in  FIG. 12A , to accommodate the angle between the drive shaft  104  and the coupling member  108 , the first coupling pin  150  is canted within the proximal transverse slot  138  (this can be visualized by considering the slot shape illustrated in  FIG. 11  in conjunction with the shaft angles illustrated in  FIG. 12A ). In  FIG. 12B , the coupling member  108  has an angular orientation that is 90 degrees from the coupling member orientation of  FIG. 12A , thereby aligning the metal coupling pins  150 ,  158  with the view direction. For the orientation shown in  FIG. 12B , the metal coupling pins  150 ,  158  are not canted within the respective proximal and distal transverse slots  138 ,  146  (similar to  FIG. 11 ). During a 360 degree revolution of the torque transmitting mechanism  102 , the position of the metal coupling pins  150 ,  158  within the respective proximal and distal transverse slots  138 ,  146  will complete an oscillation cycle. As explained above, advantages of using plastic include reduced cost and repeatability of manufacturing. In addition, plastic can provide an interface having less friction. Furthermore, plastic can be more forgiving than metal if there is some small amount of interference. The use of plastic also could eliminate the need for lubrication. 
       FIG. 13  is an illustrative drawing shows a portion of the torque transmitting mechanism  102  with the coupling member  108  removed and a “see through” driven shaft plastic bearing  130  to better illustrate the cross mounting of the distal coupling pin  158  to the distal cross pin  160 . The distal metal cross pin  160  is received within the distal transverse bore  142  of the driven shaft plastic bearing  130  and is rotatable within the distal transverse bore  142 . The distal coupling pin  158  is received within the distal cross pin bore  162  of the distal metal cross pin  160 . Relative rotation between the driven shaft  106  and the coupling member  108  about the centerline of the coupling pin  400  occurs via rotation of the distal coupling pin  158  relative to the coupling member  108  and/or rotation of the distal coupling pin  158  relative to the driven shaft metal cross pin  160  and within the distal transverse slot  146 . Similarly, the proximal metal cross pin  152  is received within the proximal cross pin bore  136  of the drive shaft plastic bearing  128  and it is rotatable within the proximal transverse bore  136 . The proximal coupling pin  150  is received within proximal cross pin bore  154  of the proximal metal cross pin  152 . Relative rotation between the drive shaft  104  and the coupling member  108  about the centerline of the proximal coupling pin  150  occurs via rotation of the proximal coupling pin  150  relative to the coupling member  108  and/or rotation of the coupling pin  150  relative to the proximal cross pin  152  and within the proximal transverse slot  138 . It will be appreciated that rotational load forces imparted during operation due to changes in shaft misalignment of the drive shaft  104  and the driven shaft  106  advantageously are supported using the metal coupling pins  150 ,  158  and metal cross pins  152 ,  160 . Thus, the spherical surfaces of the plastic bearing components  128 ,  130  are not exposed to rotational load forces imparted due to misalignment of the drive shaft  104  and the driven shaft  106 . 
       FIG. 14A  is an illustrative perspective view showing details of the proximal and distal cross pin bores  136 ,  142  of the respective drive shaft plastic bearing  128  and driven shaft plastic bearing  130  in accordance with some embodiments.  FIG. 14B  is an illustrative perspective view showing details of the proximal transverse slot  138  and the distal transverse slot  146  of the respective drive shaft plastic bearing  128  and driven shaft plastic bearing  130  in accordance with some embodiments. In accordance with some embodiments, high-strength material is used to produce components that are subject to load forces imparted due to misalignment of the drive shaft  104  and the driven shaft  106  during use. The high strength materials include metal, such as steel or stainless steel, of an appropriate type and strength for the expected loading. The high strength components can be machined or MIM. Materials for ‘plastic’ can be PPA with Glass or Carbon, PEI (Ultem) with Glass or Carbon, PEEK with glass or carbon fill, PPSU (Radel) with Glass or Carbon fill, for example. The plastics could also have silicone or PTFE filler to help with lubricity. The plastic parts can be injection molded. During assembly, the plastic parts slip over the metal pins and are trapped within the larger diameter pins. The option to MIM the metal components and injection mold the spherical interface components can makes for an affordable option for a cardan in for single patient use devices. The plastic portion can be self-lubricating and reduce friction at the rotation interfaces. A possible tradeoff is strength at the spherical interface. 
       FIG. 15  is an illustrative perspective drawing, with a partial cutaway, of a surgical tool assembly  200  in accordance with some embodiments. The tool assembly  200  includes a proximal actuation assembly  202 , a main shaft  206 , a two degree of freedom (2-dof) wrist  208 , shown in partial cutaway, and an end effector  210 . The end effector  210  includes a first articulable jaw  214  rotatably secured to a base  212 , a stationary second jaw  216  detachably secured to the base  212  and a 2-dof wrist  208  operatively coupled between the main shaft  206  and the base  212 . The end effector base  212  includes a pivot member  217  about which a proximal end of the first jaw  214  pivots to achieve opening and closing movement of the first jaw  214  relative to the second jaw  216 . In some embodiments, the pivot member includes a pivot pin  217  that defines a pivot axis  213  about which the first jaw  214  pivots and that is secured between the end effector base  212  and a proximal end of the first jaw  214 . A proximal end of the first jaw  214  pivots about the pivot axis  213  to achieve opening and closing movement of the first jaw  214  relative to the second jaw  216 . In some embodiments, the actuation assembly  202  is operatively coupled with the wrist  208  so as to selectively reorient the end effector  210  relative to the main shaft  206  in two dimensions, and is operatively coupled with the end effector  210  so as to actuate one or more end effector features, such as the first articulable jaw  214 , relative to the end effector base  212 . A variety of actuation components can be used to couple the actuation assembly  202  with the wrist  208  and with the end effector  210 , for example, control cables, cable/hypotube combinations, drive shafts, pull rods, and push rods. In many embodiments, the actuation components are routed between the actuation assembly  202  and the wrist  208  and the end effector  210  through a bore of the main shaft  206 . The end effector  210  shown in  FIG. 15  includes a surgical stapler in which the second detachable stationary second jaw  216  includes an elongated stapler cartridge  218 , and in which an articulable first jaw  214  includes an anvil  220  against which staples are deformed to staple together tissue disposed between the first and second jaws  214 ,  216 . 
       FIG. 16  is an illustrative perspective view, with a partial cutaway, of the end effector  210  of  FIG. 15  with an empty second jaw  216  from which the stapler cartridge is removed. More particularly, the empty second jaw  216  includes a stapler cartridge support channel structure  221  that includes sidewalls  225  and an outer facing bottom wall  224  that are sized to receive the stapler cartridge  218 . As explained below, the support channel bottom wall  224 , which acts as a second jaw cam surface, defines a central second longitudinal cam slot  255  that runs most of the length of the bottom wall  224 . An elongated rotary drive screw  222 , which includes a distal end  222 - 2  and a proximal end  222 - 1 , extends longitudinally along the length of the second jaw  216 . The proximal end of the drive screw  222  is rotatably supported within the end effector base  212 . The distal end  222 - 2  of the drive screw  222  is received within and rotatably supported by an annular bearing  228 , which is secured to an upstanding base  230  such that the drive screw runs down the center of the support channel  221  between the upstanding walls  222  and above the bottom wall  224 . 
       FIG. 17  is an illustrative exploded view of a detachable stationary second jaw  216  in accordance with some embodiments. The second jaw  216  includes the support channel structure  221 , which includes a proximal end  221 - 1  and a distal end  221 - 2 . The support channel  221  includes the sidewalls  225  and the bottom wall  224 , which defines the second elongated longitudinal slot  232 , only a small distal portion of which is visible. The elongated cartridge  218  includes a proximal end  218 - 1  and a distal end  218 - 2 . The cartridge includes cartridge outer sidewalls  234  and an upper surface  236 . The upper surface  236  faces the anvil  220  of the first jaw, which acts as an anvil, when the second jaw is mounted to the end effector base  212 . The upper surface  236  of the cartridge  218  defines a central first longitudinal cartridge slot  238  that extends through the cartridge  218  and that is aligned with the second longitudinal cam slot  255  when the cartridge  218  is disposed within the support channel structure  221 . The cartridge upper surface portion includes inner opposed facing sidewalls  238 - 1 ,  238 - 2  that define the cartridge slot  238  and act as a cam surfaces to guide a drive member  250 , as described more fully below. The upper surface  236  also defines multiple rows of longitudinally spaced staple retention slots  240  that extend longitudinally along one side of the first cartridge slot  238  and defines multiple rows of longitudinally spaced staple retention slots  240  that extend longitudinally along an opposite side of the first cartridge slot  238 . Each staple retention slot  240  is sized to receive a fastener  242  and a staple pusher  244 . A pusher shuttle  246  includes a plurality of inclined upstanding cam wedges  246  and a knife edge  248  upstanding between and proximal to the cam wedges  246 . The cartridge  218  defines multiple longitudinal slots (not shown) in its underside along which the cam wedges  246  can slide with the knife upstanding from and sliding within the first cartridge slot  238 . Alternatively, in accordance with some embodiments, a knife (not shown) can be secured to the drive member  250  described below. 
     During operation of surgical stapler end effector  210 , pusher shuttle  246  translates through the longitudinal pusher slots  239 - 1 ,  239 - 2 , formed in an underside of the cartridge  218  to advance the cam wedges  246  into sequential contact with pushers  244  within the longitudinally spaced retention slots  240 , to cause pushers  244  to translate vertically within retention slots  240 , and to urge fasteners  242  from retention slots  240  into the staple deforming cavities (not shown) formed within the anvil  220  of the first jaw  214 . As the pusher shuttle  246  translates longitudinally, it pushes up fasteners  242 , which are deformation against the anvil  220 . Meanwhile, the knife edge  248  upstands through the first cartridge slot  238  and cuts tissue between tissue regions stapled through action of the cam wedges  246 , fasteners  242  and the anvil  220 . U.S. Pat. No. 8,991,678 (filed Oct. 26, 2012) issued to Wellman et al., which is incorporated herein in its entirety by this reference, discloses a surgical stapler cartridge and its operation. 
       FIG. 18  is an illustrative cross sectional view of the end effector  210  of  FIGS. 15-17  in accordance with some embodiments. Like the view in  FIG. 16 , the cartridge  218  is removed leaving the second jaw  216  as primarily consisting of the empty support channel structure  221 . The main shaft  206  encloses the distal drive shaft  104 , which extends through the center of the main shaft  206  between the proximal actuation assembly  202  and the drive shaft plastic bearing  128 . The proximal driven shaft  106  extends between the driven shaft plastic bearing  130  and the proximal end  222 - 1  of the rotary drive screw  222 . Referring back to  FIGS. 7-8 , it can be seen that a distal end  116  of the driven shaft  106  defines a female coupler  223  contoured to interfit with a complementary male coupler  227  at the distal end  222 - 2  of the drive screw so that the driven shaft  106  and the rotary drive screw  222  rotate in unison. The driven shaft  106  houses additional control components such as steering (hypo)tubes which are not shown in order to simplify the drawings. A screw driven drive member  250  is mounted to the end effector  210  between the first jaw and the second jaw. The drive member  250  defines a threaded bore through which the drive screw  222  is threaded. The drive member  250  is configured so that rotation of the drive screw in a first rotational direction within the threaded bore causes the drive member  250  to move in a longitudinal path defined by the rotary drive screw  222  in a direction in toward the drive screw distal end distal end  222 - 2 . Conversely, rotation of the rotary drive screw  222  in a second rotational direction within the threaded bore, opposite to the first rotational direction, causes the drive member  250  to move in a longitudinal path defined by the drive screw  222  in a direction in toward the drive screw proximal end distal end  222 - 1 . 
     The first jaw  214  includes the anvil  220 , an outer top cover  251  that overlays a back side of the anvil  220 . A first cam surface  249 , which includes a longitudinally extending first jaw rotation cam surface  259  and a longitudinally extending first jaw clamping cam surface  252 , is disposed between the external cover  251  and the anvil  220 . The first cam surface is described more fully with reference to  FIG. 19B  and  FIGS. 22A-22F . The second jaw  216  defines a longitudinally extending second cam surface  254 . The first jaw rotation cam surface  259  cooperates with the driver member  250 , which acts as a cam follower driven by the screw drive  222 , to rotate the articulable first jaw  214  between open and closed positions. As explained below with reference to  FIG. 24B , a spring is used to keep the jaws open prior to gripping and clamping. With the first jaw  214  in the closed position, the first jaw clamping cam surface  252  and second cam surface  254  are longitudinally aligned and can cooperate with the driver member  250 , which acts as a cam follower driven by the screw drive  222 , to securely hold anatomical tissue between the first and second jaws  214 ,  216  to achieve tissue gripping and tissue clamping. 
       FIG. 19A  is a top elevation view of the first cam surface  249  in accordance with some embodiments.  FIG. 19B  is a cross-section view showing edges of one side of the first cam surface  249  in accordance with some embodiments. As explained above, the first cam surface  249  is securely mounted within the first jaw  214  between the anvil  220 . and the external top cover  251 . The first cam surface  249  includes a proximal end  249 - 1  and a distal end  249 - 2  having multiple functional segments between them: a rotation cam segment  259 , a clamping cam segment  252 , a distal cross-segment  273 , a proximal bridging segment  274  and a proximal base segment  275 . 
     The rotation cam segment  259  comprises a first elongated cam edge  259 - 1  and a parallel second elongated edge portion  259 - 2  (also referred to herein as a third pair of lateral side edges  259 - 1 ,  259 - 2 ), which are laterally spaced apart and which act as a proximal portion of the first cam surface  249 . A first jaw clamping cam segment  252  comprises a third elongated cam edge  252 - 1  and a parallel fourth elongated cam edge  252 - 2  (also referred to herein as a first pair of lateral side edges  252 - 1 ,  252 - 2 ), which acts as a distal cam portion of the first cam surface  249 . The first and third elongated cam edges  259 - 1 ,  252 - 1  are joined integrally so as to together define a first continuous edge. The second and fourth elongated cam edges  259 - 2 ,  252 - 2  are joined integrally so as to together define a second continuous edge. The first continuous edge comprising cam edges  259 - 1 ,  252 - 1  and the second continuous edge comprising cam edges  259 - 2 ,  252 - 2  together define a first elongated cam follower slot  253  between them. The first and third cam edges  259 - 1 ,  252 - 1  and the second and fourth cam edges  259 - 2 ,  252 - 2  are offset at an angle from each other. 
     The distal cross-segment  273  connects the distal ends of the third and fourth edges  252 - 1 ,  252 - 2  and is secured to a distal portion of the top cover  251 . The proximal base segment  275  includes parallel edges  275 - 1 ,  275 - 2  that are upstand substantially transverse to the third and fourth cam edges  252 - 1 ,  252 - 2  and that are secured to a proximal end portion of the top cover  251 . The proximal bridging segment  274  includes parallel edges  274 - 1 ,  274 - 2  that respectively integrally interconnect the first cam edge  259 - 1  with one of the base edges  275 - 1  and interconnect the second cam edge  259 - 2  with the other of the base edges  275 - 1 . 
       FIG. 20  is an illustrative bottom elevation view of the longitudinally extending second cam surface  254  in accordance with some embodiments. The second cam surface  254  is formed in the bottom wall  224  of the stapler cartridge support channel structure  221 . The second cam surface  254  includes fifth and sixth elongated cam edges  254 - 1 ,  254 - 2  (also referred to as a second pair of lateral side edges  254 - 1 ,  254 - 2 ), which are laterally spaced apart. The fifth and sixth elongated cam edges  254 - 1 ,  254 - 2  together define the second elongated cam follower slot  255  between them. Proximal and distal cross members  278 - 1  and  278 - 2  interconnect the fifth and sixth edges portions. 
       FIG. 21  is an illustrative perspective view of the drive member  250  in accordance with some embodiments. The drive member  250  has an I-beam contour that includes a cross-beam portion  258 , a first transverse beam portion  260  secured to a first end of the cross-beam portion  258 , and a second transverse beam  262  secured to a second end of the cross-beam  258  portion. The cross-beam portion  258  defines a threaded bore  261  that extends through it that is sized and contoured to engage a drive screw (not shown). The first and second transverse beam portions  260 ,  262  extend from the cross-beam  258  in a direction perpendicular to an axis of the threaded bore  261 . In operation, the cross-beam portion  258  acts as a cartridge slot cam follower. The cross-beam portion  258  is sized to slidably fit simultaneously within the first cam follower slot  253  and the second elongated cam follower slot  255 . The first transverse beam portion  260  defines a first inward facing surface  260 - 1  that acts as a first jaw cam follower. The second transverse beam  262  defines a second inward facing surface  260 - 2  that acts as a second jaw cam follower. 
       FIGS. 22A-22F  are schematic cross-sectional side views representing stages in the articulation of the first jaw  214  as the drive member  250  is moved in a linear motion longitudinally from a proximal starting position toward a distal end of the end effector  210  and interacts with the rotation cam  259  (also referred to herein as the third pair of lateral side edges  259 - 1 ,  259 - 2 ) and the first jaw clamping cam  252  (also referred to herein as the first pair of lateral side edges  252 - 1 ,  252 - 2  of the first cam surface  249  along the way, in accordance with some embodiments. Certain components of the end effector  210  are omitted to simplify the drawings. Moreover, in this cross-section side view, only the second side edges  259 - 2 , the fourth cam edge  252 - 2 , one parallel edge  274 - 2  and one base edge  275 - 2  are shown. In this description, the linear position of the drive member  250  is expressed in terms of an X N  positions along an X axis collinear with the axis of the drive screw  222 . A fastener  282  secures the first cam surface  249  to the first arm  214  (indicated by dashed lines). The first arm  214  is mounted to a pivot pin  217  secured to the end effector base  212  (not shown) so as to be rotatable about an axis of the pivot pin  217  relative to the base  212  and to the second jaw  216  (not shown), which is attached to the base  212  during operation. The drive member  250  is mounted upon the drive screw  222 . As most clearly shown in  FIGS. 16-17 , the drive screw  222  extends longitudinally (along the X axis) within the cartridge support channel structure  221  for substantially its entire length. In operation, the drive screw  222  rotatably extends through a longitudinal cavity (not shown) formed within the cartridge  218  beneath the rows of retention slots  240 . Forward rotation of the drive screw  222  causes the drive member  250  to move linearly along the drive screw toward the drive screw distal end  222 - 1 , which is disposed near a distal end of the second jaw  216 . 
       FIG. 22A  shows the first arm  214  fully open inclined at an angle of 60 degrees relative to a longitudinal axis of the second jaw  216  and with the drive member  250  located at starting linear position X 1 . It will be appreciated that different stated angles and different X N  positions are approximations and examples used for illustrative purposes. More specifically, the drive member  250  is disposed with its cross-beam portion  258  between the parallel edges  274 - 1 ,  274 - 2  of the bridging segment  274  and with its first transverse beam portion  260  spaced apart in a proximal direction from the first and second cam edges (the third pair of lateral side edges)  259 - 1 ,  259 - 2  of the rotation cam  259 . 
       FIG. 22B  shows the first arm  214  partially open inclined at an angle of 52 degrees relative to the longitudinal axis of the second jaw  216  and with the drive member  250  located at linear position X 2 . The drive member  250  is disposed with its cross-beam portion  258  partially between the a portion of the parallel first and second cam edges (the third pair of lateral side edges  259 - 1 ,  259 - 2 ) and between a portion of the parallel edges  274 - 1 ,  274 - 2  of the bridging segment  274  and with its first transverse beam portion  260  interacting as a cam follower with the first and second cam edges  259 - 1 ,  259 - 2  of the rotation cam  259 . The interaction between the first transverse beam portion  260  first and second cam edges  259 - 1 ,  259 - 2  during linear x-direction motion of the drive member  250  from X 1  to X 2  has caused the first arm  214  to rotate from a 60 degree angle to a 52 degree angle. 
       FIG. 22C  shows the first arm  214  partially open inclined at an angle of 45 degrees relative to the longitudinal axis of the second jaw  216  and with the drive member  250  located at linear position X 3 . The drive members  250  is disposed with its cross-beam portion  258  fully between the parallel first and second cam edges (the third pair of lateral side edges)  259 - 1 ,  259 - 2  of the rotation cam and with its first transverse beam portion  260  interacting as a cam follower with the first and second cam edges  259 - 1 ,  259 - 2  of the rotation cam  259 . The interaction between the first transverse beam portion  260  first and second cam edges  259 - 1 ,  259 - 2  during linear x-direction motion of the drive member  250  from X 2  to X 3  has caused the first arm  214  to rotate from a 52 degree angle to a 45 degree angle. 
       FIG. 22D  shows the first arm  214  partially open inclined at an angle of 20 degrees relative to the longitudinal axis of the second jaw  216  and with the drive member  250  located at linear position X 4 . The drive members  250  is disposed with its cross-beam portion  258  fully between the parallel first and second cam edges (the third pair of lateral side edges)  259 - 1 ,  259 - 2  of the rotation cam and with its first transverse beam portion  260  interacting as a cam follower with the first and second cam edges  259 - 1 ,  259 - 2  of the rotation cam  259 . The interaction between the first transverse beam portion  260  first and second cam edges  259 - 1 ,  259 - 2  during linear x-direction movement of the drive member  250  from X 3  to X 4  has caused the first arm  214  to rotate from a 45 degree angle to a 20 degree angle. 
       FIG. 22E  shows the first arm  214  closed inclined at an angle of 0 degrees relative to the longitudinal axis of the second jaw  216  and with the drive member  250  located at linear position X. The drive members  250  is disposed with its cross-beam portion  258  still fully between the parallel first and second cam edges (the third pair of lateral side edges)  259 - 1 ,  259 - 2  of the rotation cam but with its first transverse beam portion  260  now interacting as a cam follower with the third and fourth cam edges (the first pair of lateral side edges)  252 - 1 ,  252 - 2  of the first jaw clamping cam  252 . The interaction between the first transverse beam portion  260  first and second cam edges  259 - 1 ,  259 - 2  during linear x-direction movement of drive member  250  from X 4  to X 5  has caused the first arm  214  to rotate from a 20 degree angle to a 0 degree angle. 
     In accordance with some embodiments, the first cam surface  249  is configured such that the first transverse beam portion  260  transitions from interacting with the first and second cam edges (the third pair of lateral side edges)  259 - 1 ,  259 - 2  of the rotation cam to interacting with the third and fourth cam edges (the first pair of lateral side edges)  252 - 1 ,  252 - 2  of the first jaw clamping cam  252  as the linear motion of the drive member  250  causes the first arm  214  to reach a 0 degree angle, parallel with the second jaw  216 . In accordance with some embodiments, there is a prescribed spacing that the I-beam maintains between the anvil and cartridge. The distance may be adjusted based upon by cartridge size (e.g., staple length). To achieve this each reload size has a different overall height to make the appropriate gape between anvil and cartridge. The I-beam is sized and dimensioned to maintain this distance. 
       FIG. 22F  shows the first arm  214  closed inclined at an angle of 0 degrees relative to the longitudinal axis of the second jaw  216  and with the drive member  250  located at linear position X 6 . The drive members  250  is disposed with its cross-beam portion  258  fully between the parallel the third and fourth cam edges (the first pair of lateral side edges)  252 - 1 ,  252 - 2  of the first jaw clamping cam  252  and with its first transverse beam portion  260  interacting with the third and fourth cam edges  252 - 1 ,  252 - 2  of the first jaw clamping cam  252 . The linear motion of the drive member  250  from X 5  to X 6  has caused the first arm  214  but the rotational angle of the first arm  214  has remained at 0 degree angle, parallel to the second arm  216 . 
       FIGS. 23A-23B  are schematic cross sectional views of the first and second jaws in a closed position in a proximal direction along the drive screw axis in accordance with some embodiments.  FIG. 23A  shows the cross-sectional view without the pusher shuttle  244  shown within the cartridge  218 .  FIG. 23B  shows the cross-sectional view with the pusher shuttle  244  shown within the cartridge  218 . Certain components of the jaws  214 ,  216  are omitted to simplify the drawings. 
       FIG. 23A  shows the drive member  250  disposed so that the first inward facing surface  260 - 1  of the first transverse beam  260  urges the respective third and fourth cam edges  252 - 1 ,  252 - 2  toward the fifth and sixth cam edges  254 - 1 ,  254 - 2  and so that conversely, the second inward facing surface  262 - 1  of the second transverse beam  262  urges the respective fifth and sixth cam edges  254 - 1 ,  254 - 2  toward the third and fourth cam edges  252 - 1 ,  252 - 2 . The cam follower surfaces  258 - 1  of cross-beam portion  258  interact with opposed cartridge inner sidewall cam surfaces  238 - 1 ,  238 - 2  of the cartridge slot  238  to guide the drive member  250  along the length of the cartridge  218 . The cartridge outer sidewalls  234  and the cartridge inner sidewalls  234  define first and second elongated pusher channels  239 - 1 ,  239 - 2  that are laterally spaced apart on opposite sides of the cartridge slot  238  and that extend substantially along the length of the cartridge  218 . 
       FIG. 23B  shows the illustrative cross-section distal end view of  FIG. 23B  with the addition of the pusher shuttle  244  disposed within the pusher channels  239 - 1 ,  239 - 2 . The drive member  250  drives the pusher shuttle  244  in front of it in a longitudinal direction from a proximal end toward distal ends of the cartridge  218  that is mounted within the second jaw  216 . It is noted that there is a gap  288  between the anvil surface  220  and the cartridge  218  in which tissue can be captured. 
       FIGS. 24A-30  are illustrative cross-sectional drawings of a portion of the end effector  210  of  FIGS. 15-18  showing the longitudinal movement of the drive member  250  and corresponding motion of the first and second jaws  214 ,  216  in response to rotation of the rotatable screw drive  222  in accordance with some embodiments. As shown in  FIG. 15 , the articulable first jaw  214  is pivotally mounted on first and second pivot pins  217  (only one shown) to allow it its proximal end to pivot so as to rotatably move its anvil surface  220  toward or way from the cartridge  218  disposed within the cartridge support channel structure  221  of the second detachable jaw  216 . It is noted that the pivot pins are not visible in the illustrative drawings of  FIGS. 24A-30 . 
       FIG. 24A  is an illustrative cross-sectional view of a portion of the end effector  210  of showing the first jaw  214  in an open position and the drive member  250  in a starting position in accordance with some embodiments. The view in  FIG. 24A  corresponds to the schematic view shown in  FIG. 22A .  FIG. 24B  is an illustrative cross-sectional view of a portion of the view of  FIG. 24A , enlarged to show a spring  291  seated in a recess disposed to urge the first jaw  214  away from the second jaw  216  to keep the jaws in an open position open prior to gripping and clamping operations in accordance with some embodiments. With the first jaw  214  is in an open position, a surgeon can maneuver the end effector  210  so as to position it to encompass anatomical tissue structures that is to be stapled between the first and second jaws  214 ,  216 . An open first jaw  214  is the default position in accordance with some embodiments. The drive member  250  is disposed in a starting position adjacent proximal ends of the first and second jaws  214 ,  216  and adjacent the proximal end  222 - 1  of the screw drive  222 . The drive member  250  is longitudinally spaced apart from the pusher shuttle  244  with the pusher shuttle  244  positioned at a more distal location within the cartridge  218 . The drive member first transverse beam  260  is disengaged from both the rotation cam surface  259  and from the first jaw clamping cam surface  252  first jaw flat cam surface  252 . It will be appreciated that in these cross-section views, only portions of the second rotation cam edge  259 - 2  and a portion of the fourth clamping cam edge  252 - 2  are shown. 
     With the detachable second jaw  216  is attached, a male coupler  227  formed at the proximal end  222 - 1  of the rotatable screw drive  222 , is inserted into and engages the female coupler  223  located at the distal end  116  of the driven shaft  106 . It will be appreciated that a rotation force can be applied to the drive shaft  104 , which is mounted within the main shaft  206 , and that rotational force is transferred through the torque transmitting mechanism  102  to the driven shaft  106 , which is mounted within the end effector  210 , and that force also can be transferred to the drives the screw drive  222 , which extends longitudinally within the cartridge  218  mounted in the second jaw. Hypotubes  290  that can be used to achieve two degree of freedom movement of the end effector  210  also are shown housed within the main shaft. 
       FIG. 25  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  in grip positions in accordance with some embodiments. The view in  FIG. 25  corresponds to the schematic view shown in  FIG. 22E .  FIGS. 22B-22E  illustrate the transition of the first jaw  214  between the starting position shown in  FIG. 24A  and the grip position in  FIG. 25 . During the transition, the screw drive  222  drives the drive member  250  to advance distally longitudinally along the axis of the screw drive  222  so that the first transverse beam  260  interacts with the second rotation cam edge  259 - 2  to cause the first arm to rotate from the start position to the grip position. The pusher shuttle  244  defines a bore through which the screw drive  222  passes without affecting its longitudinal position. 
     In the grip position, the drive member  250  is disposed longitudinally spaced apart from the pusher shuttle  244  with the pusher shuttle  244  positioned at a more distal location within the cartridge  218 . Thus, the drive member  250  has not yet caused movement of the pusher shuttle  244  and no staples have been discharged. The first transverse beam  260  is engaged with the fourth clamping cam edge  252 - 2  and the second transverse beam  262  is engaged with the sixth clamping edge  254 - 2 . The first and second transverse beams  260 ,  262 , thereby cooperate to exert inward force on the second and fourth clamping edges  252 - 2 ,  254 - 2  so as to urge the first and second jaws  214 ,  216  into a closed position that allows a sufficient gap between them accommodate tissue gripped between them. 
     Once the first jaw  214  is in the grip position, a surgeon then may take some time to assess whether or not to staple the tissue captured within the jaws. In accordance with some embodiments, the surgeon can selectively actuate the screw drive  222  to move the driver member  250  back to the starting position to re-open the jaws and maneuver the jaws to capture a different portion of tissue. Thus, a surgeon can selectively grip and release tissue portions in search for the optimal tissue site that he wants to have between gripped between the jaws for insertion of staples. 
       FIG. 26  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  in a first clamp positions in accordance with some embodiments. The view in  FIG. 26  corresponds generally to the schematic view shown in  FIG. 22F . During a transition from the grip position to the first clamp position, the screw drive  222  drives the drive member  250  to advance distally longitudinally along the axis of the screw drive  222  to a position that is longitudinally closer to the pusher shuttle  244  but that does not in contact with the pusher shuttle  244 . Thus, no staples are pushed by the pusher shuttle  244  in response to the transition from the grip position to the first clamp position. In the first clamp position, like the grip position, the first and second transverse beams  260 ,  262  cooperate to exert inward force on the second and fourth clamping edges  252 - 2 ,  254 - 2  so as to urge the first and second jaws  214 ,  216  into a closed position that allows a sufficient gap between them accommodate tissue gripped between them. In accordance with some embodiments, tissue pressure imparted by the jaws can be determined indirectly based upon system torque on the lead screw. This can be determined during grip or during clamp. 
       FIG. 27  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  in a staple pushing positions in accordance with some embodiments. The view in  FIG. 27  also corresponds generally to the schematic view shown in  FIG. 22F . During a transition from the first clamp position to the to the staple pushing position, the screw drive  222  drives the drive member  250  to advance distally longitudinally along the axis of the screw drive  222  to a position in which it abuts against and imparts motion to the pusher shuttle  244  causing the pusher shuttle  244  to push staples through tissue and to cause their deformation against the anvil  202  as described above with reference to  FIG. 17 . In the staple pushing position, the first and second transverse beams  260 ,  262  cooperate to exert inward force on the second and fourth clamping edges  252 - 2 ,  254 - 2  so as to urge the first and second jaws  214 ,  216  into a closed position that allows a sufficient gap between them accommodate tissue gripped between them. It will be appreciated, therefore, that the pushing position constitutes a second clamping position similar to the first clamping position. 
       FIG. 28  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  in a stapler fully fired position in accordance with some embodiments. The pusher shuttle  244  abuts against the upstanding base  230  supporting the annular bearing  228  in which a distal end  222 - 2  of the drive screw  222  rotates. During a transition from the staple pushing position of  FIG. 27  to the to the stapler fully fired position of  FIG. 28 , the screw drive  222  drives the drive member  250  and the pusher shuttle  244 , which abuts against it, to traverse distally longitudinally along the entire remaining axis of the screw drive  222  causing the pusher shuttle  244  to push staples through tissue and to cause their deformation against the anvil  202  during the traversal. During the traversal, the first and second transverse beams  260 ,  262  cooperate to exert inward force on the second and fourth clamping edges  252 - 2 ,  254 - 2  as described above. The distal base  230  acts as a stop surface at the end of the traversal. 
       FIG. 29  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  during return of the drive member  250  to the start position in accordance with some embodiments. After all of the staples have been pushed out and the pusher shuttle  244  has reached the distal base  230 , the drive screw rotation is reversed so as to move the drive member  250  longitudinally in a proximal direction back to the start position. During the reverse traversal, the first and second transverse beams  260 ,  262  cooperate to exert inward force on the second and fourth clamping edges  252 - 2 ,  254 - 2  as described above. 
       FIG. 30  is an illustrative cross-sectional view of a portion of the end effector  210  showing the first jaw  214  and the drive member  250  in a complete configuration with the drive member  250  back in the to the start position in accordance with some embodiments. The drive member first transverse beam  260  is disengaged from both the rotation cam surface  259  and from the first jaw clamping cam surface  252  first jaw flat cam surface  252 . In accordance with some embodiments, a spring (not shown) can be used to re-open the jaws. causes the first jaw  214  to move to an open position. The pusher shuttle  244  has been left behind in abutment against the distal base  230 . 
       FIG. 31  is an illustrative drawing showing a lockout mechanism in accordance with some embodiments. The lockout mechanism comprises a lockout spring  297  that flexes in a proximal direction but does not flex in the distal direction The spring  297  is initially biased due to interaction with the drive member  250  so as to be recessed against a lateral side of the second jaw  216  when a reload cartridge  218  is installed. During firing of staples, the drive member  250  is driven toward the distal end of the cartridge  218  to discharge the staples. Since the lockout spring  297  is initially recessed against the lateral side of the second jaw  216 , it does not block passage of the drive member  250  during its initial drive toward the distal end of the second jaw  216 . When the drive member  250  member is returned to its initial position, the spring  297  flexes proximally against the lateral side of the second jaw  216 , allowing the drive member  216  to pass over it. Once the drive member passes over the spring  297 , the spring snaps out preventing the drive member  250  from advancing again toward the distal end of the second jaw  216 . 
       FIGS. 32A-32B  are illustrative drawings showing details of the two degree of freedom wrist  208  of the end effector  210  with the torque transmitting mechanism  102  in an inline position ( FIG. 32A ) and in a articulated position ( FIG. 32B ) in accordance with some embodiments. The drive shaft  104  extends through the center of the driven shaft  106  and engages with the coupling member  108  and the drive shaft plastic bearing  128  as described above. First arms  294  depend proximally from opposite sides of the base  212  of the end effector  210 . Each arm defines a pair of islets  295 . Hypotubes  290  extend longitudinally within the main shaft  206  about the drive axis and define hooks  296  at their proximal ends that engage the islets  295 . Second arms  298  extend distally from the main shaft offset ninety degrees form the first arms to define a clevis. The first and second arms  294 ,  298  enable a pitch and yaw pivot, which allows the assembly to act as a wrist  208  with two degrees of freedom while maintaining the center hollow for the cardan. In operation, and arms  294  enable yaw (up and down movement from the perspective of the drawing), and arms  298  enable pitch (left to right movement from the perspective of the drawing), Operation of the wrist  292  will be understood from U.S. Pat. No. 8,852,174, which is incorporated by reference above. 
     The foregoing description and drawings of embodiments in accordance with the present invention are merely illustrative of the principles of the invention. Therefore, it will be understood that various modifications can be made to the embodiments by those skilled in the art without departing from the spirit and scope of the invention, which is defined in the appended claims.