Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     
         
         
           
             This application is: 
              a divisional of U.S. patent application Ser. No. 11/491,626, filed on Jul. 24, 2006, now U.S. Pat. No. 8,579,176, (which application claims the priority, under 35 U.S.C. §119, of U.S. Provisional Patent Application No. 60/702,643, filed on Jul. 26, 2005, U.S. Provisional Patent Application No. 60/760,000, filed on Jan. 18, 2006, and U.S. Provisional Patent Application No. 60/811,950, filed on Jun. 8, 2006); 
             a divisional of U.S. patent application Ser. No. 11/540,255, filed on Sep. 29, 2006, now U.S. Pat. No. 7,404,508; 
             a divisional of U.S. patent application Ser. No. 11/541,105, filed on Sep. 29, 2006; 
             a divisional of U.S. patent application Ser. No. 11/844,406, filed on 
           
         
       
    
     Aug. 24, 2007, now U.S. Pat. No. 7,419,080;
         a divisional of U.S. patent application Ser. No. 12/139,142, filed on Jun. 13, 2008, now U.S. Pat. No. 8,245,898;   a divisional of U.S. patent application Ser. No. 12/633,292, filed on Dec. 8, 2009, now U.S. Pat. No. 8,034,077,
 
the entire disclosures of which are hereby incorporated herein by reference in their entireties.
       

    
    
     FIELD OF INVENTION 
     The present invention lies in the field of medical devices, in particular, in the field of surgical stapling instruments and methods for use thereof that are capable of applying lines of staples to tissue while cutting the tissue between those staple lines and, more particularly, to improvements relating to stapler instruments and improvements in processes for forming various components of such stapler instruments that include an articulating shaft. The device and methods can be used, particularly, for stapling and cutting tissue during endoscopic or laparoscopic surgical procedures. 
     BACKGROUND OF THE INVENTION 
     Endoscopic surgical instruments are often preferred over traditional open surgical devices because a smaller incision tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.). 
     Positioning the end effector is constrained by the trocar. Generally, these endoscopic surgical instruments include a long shaft between the end effector and a handle portion manipulated by the clinician. This long shaft enables insertion to a desired depth and rotation about the longitudinal axis of the shaft, thereby positioning the end effector to a degree. With judicious placement of the trocar and use of graspers, for instance, through another trocar, often this amount of positioning is sufficient. Surgical stapling and severing instruments, such as described in U.S. Pat. No. 5,465,895 to Knodel et al., are an example of an endoscopic surgical instrument that successfully positions an end effector by insertion and rotation. 
     One stapler manufactured by United States Surgical Corporation and described in U.S. Pat. Nos. 6,644,532 and 6,250,532 to Green et al. have an end effector that pivotally moves along a single plane in steps dependent upon activation of a lever that correspondingly moves along a single plane in similar steps. See FIGS. 31 and 32 therein. The U.S. Surgical Corp. stapler, however, is limited by the predetermined angles that it can achieve and by the limited side to side pivoting (−45 degrees to +45 degrees) that requires two hands for operation. 
     Depending upon the nature of the operation, it may be desirable to further adjust the positioning of the end effector of an endoscopic surgical instrument rather than being limited to insertion and rotation. In particular, it is often desirable to orient the end effector at an axis transverse to the longitudinal axis of the shaft of the instrument. The transverse movement of the end effector relative to the instrument shaft is conventionally referred to as “articulation.” This articulated positioning permits the clinician to more easily engage tissue in some instances. In addition, articulated positioning advantageously allows an endoscope to be positioned behind the end effector without being blocked by the instrument shaft. 
     While the aforementioned non-articulating stapling and severing instruments have great utility and may be successfully employed in many surgical procedures, it is desirable to enhance their operation with the ability to articulate the end effector, thereby giving greater clinical flexibility in their use. Articulating surgical instruments generally use one or more firing bars that move longitudinally within the instrument shaft and through the articulation joint to fire the staples from the cartridge and to cut the tissue between the innermost staple lines. One common problem with these surgical instruments is control of the firing bar through the articulation joint. At the articulation joint, the end effector is longitudinally spaced away from the shaft so that the edges of the shaft and end effector do not collide during articulation. This gap must be filled with support material or structure to prevent the firing bar from buckling out of the joint when the single or multiple firing bars is subjected to longitudinal firing loads. What is needed is a support structure that guides and supports the single or multiple firing bars through the articulation joint and bends or curves as the end effector is articulated. 
     U.S. Pat. No. 5,673,840 to Schulze et al. describes a flexible articulation joint that is formed from an elastomeric or plastic material that bends at the flexible joint or “flex neck.” The firing bars are supported and guided through a hollow tube within the flex neck. The flex neck is a portion of the jaw closure mechanism and moves longitudinally relative to the end effector, shaft, and firing bars when the jaws are closed on tissue. The firing bars then move longitudinally within the flex neck as the staples are fired and tissue is cut. 
     U.S. Pat. No. 5,797,537 to Oberlin et al. (owned by Richard-Allan Medical Industries, Inc.) describes an articulation joint that pivots around a pin, rather than bends around a flex joint. In this instrument, firing bars are supported between a pair of spaced support plates connected at one end to the shaft and at another end to the end effector. At least one of those connections is a slidable connection. The support plates extend through the articulation joint adjacent to the flexible drive member in the plane of articulation such that the support plates bend through the gap in the plane of articulation and the flexible firing bar bends against the support when the tip is articulated in one direction from its aligned position. U.S. Pat. No. 6,330,965 to Milliman et al. from U.S. Surgical teaches the use of support plates that are fixedly attached to the shaft and slidably attached to the end effector. 
     Although these known support plates guide a firing bar through an articulation joint, it is believed that performance may be enhanced. For instance, it is often desirable for the firing bar to be rapidly accelerated during firing to ensure sufficient momentum for severing tissue effectively. Rigidly attached support plates may tend to dislodge in response, allowing the firing bar to blow out from the articulation joint. As a further example, it is desirable for the instrument to operate in the same manner whether articulated or not. Increased friction when articulated would be inconvenient and distracting to the clinician if required to exert a varying amount of firing force. 
     Consequently, a significant need exists for an improved articulation mechanism for a surgical instrument mechanism that provides enhanced support to a firing bar through the articulation joint. 
     As mentioned above, as used in the art and as used herein, transverse movement of a medical end effector relative to an instrument shaft is conventionally referred to as “articulation.” In prior art medical devices having articulation control, the articulation movement is directed actively from the device handle. This active control can be mechanical and/or electrical. For example, some prior art devices have levers at the top of the control handle and, when pivoted left the end effector articulates left and when pivoted right the end effector articulates right. Some operate with opposite movement. To effect this articulation, it is very difficult for the operator to use only one hand. Thus, often, the operator must hold the handle with one hand and pivot the articulation lever with the other hand. As is known, the trend for laparoscopic and other similar medical devices is to make them operable with a single hand because surgeons often lose control of the device held in the second hand when it is necessary to remove their second hand from that device in order to operate the articulation lever. Loss of device control is undesirable and extends the surgical procedure if the device falls outside the view of the operating surgeon. One prior art device uses electrical measures to actively control articulation. In U.S. Pat. No. 7,213,736 to Wales et al., electrical power is supplied to an electrically actuated polymer to articulate the end effector actively in the desired direction. These prior art devices can be characterized by referring to them as “active articulation” devices, in which an articulation control device is present on the handle and extends through the articulation joint to force the articulation in either articulation direction. In other words, the forces required to perform articulation are generated internally in the device. 
     Thus, a significant need also exists for an improved articulation mechanism for a surgical instrument mechanism that is operable with only a single hand. The articulation assembly of the present invention has no mechanical control device in the handle to effect direct control of articulating movement of the end effector. There is no articulation control device present on the handle that extends through the articulation joint to force the end effector to articulate in a direction. Instead, articulation of the end effector is dependent upon pressure between a surface of the environment in which the end effector exists and an exterior surface of the end effector, for example, at a location distal of the articulation joint. A torque to pivot the inventive end effector about the articulation axis arises from forces external to the device. One force is present by the user holding the handle. The other force acts distal of the articulation joint and imparted by the environment in which the end effector is present and against which the end effector is being held. In other words, the forces required to perform articulation are external to the device. This motion can be referred to herein as “passive articulation” and the “articulation joint” of the present invention operates with passive articulation—it requires a torque external to the device to articulate the end effector about the axis of the passive articulation joint. 
     BRIEF SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a method for operating a surgical stapling and cutting device that overcomes the hereinabove-mentioned disadvantages of the heretofore-known devices and method of this general type. 
     With the foregoing and other objects in view, there is provided, in accordance with the invention. A method for operating a surgical end effector of a medical device includes the steps of operably associating a passive articulation joint with a surgical end effector to allow articulation of the end effector, retaining the passive articulation joint in a still position with an articulation lock, releasing the articulation lock to free the passive articulation joint from its still position thereby permitting the end effector to articulate through the passive articulation joint dependent upon forces that are external to the device and are applied to the end effector, and passively articulating the end effector into a desired articulated position by pressing a portion of the end effector against a feature of the environment. 
     In accordance with a further mode of the invention, there is provided the step of locking the articulation lock to maintain the end effector in its articulated position. 
     In accordance with an added mode of the invention, the retaining, releasing, articulating, and locking steps are carried out with a single hand. 
     In accordance with an additional mode of the invention, the environment is a surgical site internal to a body of a patient. 
     In accordance with yet another mode of the invention, there is provided the step of effecting a surgical stapling procedure with the end effector in its articulated position. 
     In accordance with yet a further mode of the invention, the passive articulation joint connects the end effector to a control handle having an articulation joint actuator. 
     In accordance with yet an added mode of the invention, the articulating step permits articulation of the end effector with respect to the control handle about an articulation axis. 
     In accordance with yet an additional mode of the invention, the retaining step further comprises positioning the articulation joint actuator to selectively connect with the articulation lock to retain the passive articulation joint in the still position. 
     In accordance with again another mode of the invention, the releasing step further comprises separating the articulation joint actuator from the articulation lock to free the passive articulation joint from its still position. 
     In accordance with again a further mode of the invention, the passive articulation joint connects the end effector to a control handle having an articulation joint actuator; and the locking step further comprises positioning the articulation joint actuator to selectively connect with the articulation lock to retain the passive articulation joint and maintain the end effector in its articulated position. 
     In accordance with again an added mode of the invention, there is provided the step of effecting a surgical stapling procedure with the end effector in its articulated position. 
     In accordance with again an additional mode of the invention, the control handle is comprised of a first portion of the passive articulation joint and the end effector is comprised of a second portion of the passive articulation joint, the first and second portions of the passive articulation joint connecting the end effector to the control handle. 
     In accordance with still another mode of the invention, the surgical end effector has at least one of a stapling device and a cutting device and the control handle has a stapler closing actuator operable to close the stapling device when actuated, a staple firing actuator operable to effect at least one of stapling tissue with the stapling device and cutting tissue with the cutting device when actuated, and the stapler closing actuator and the staple firing actuator are different from the articulation joint actuator. 
     In accordance with still a further mode of the invention, once the passive articulation joint is freed from its still position, the end effector will not articulate in the absence of a force that is external to the device and is applied to the end effector. 
     In accordance with a concomitant mode of the invention, once the passive articulation joint is freed from its still position, the end effector is incapable of an articulating movement in the absence of a feature of the environment external to the device coming into contact with the end effector. 
     Additional advantages and other features characteristic of the present invention will be set forth in the detailed description which follows and may be apparent from the detailed description or may be learned by practice of exemplary embodiments of the present invention. Still other advantages of the present invention may be realized by any of the instrumentalities, methods, or combinations particularly pointed out in the claims. 
     Although the invention is illustrated and described herein as embodied in a surgical stapling and cutting device and methods of use thereof, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
     Other features that are considered as characteristic for the present invention are set forth in the appended claims. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the present invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of embodiments the present invention will be apparent from the following detailed description of the preferred embodiments thereof, which description should be considered in conjunction with the accompanying drawings in which: 
         FIG. 1  is an enlarged, fragmentary, perspective view of a first embodiment of a distal stapling and cutting end effector and a portion of a shaft connected thereto according to the invention viewed from a distal end thereof with a staple cartridge approximately pulled out half-way from a staple cartridge jaw of the end effector and with an anvil of the stapler separated from a staple-actuating and tissue-cutting slide; 
         FIG. 2  is an enlarged, fragmentary, side elevational view of the end effector of  FIG. 1  with the distal cowling, the proximal castellation axial movement part, and the cartridge removed for clarity, and with the anvil of the stapler connected to the slide; 
         FIG. 3  is an enlarged, fragmentary, perspective view of the end effector of  FIG. 1  with the staple-actuating and tissue-cutting slide in a distal position but with the anvil of the stapler separated from the slide; 
         FIG. 4  is an enlarged, fragmentary, perspective view of the end effector of  FIG. 1  with the staple cartridge removed from the lower jaw/staple cartridge holder and with the clevis rotated in an approximately 45 degree angle with respect to center; 
         FIG. 5  is an enlarged, fragmentary, wireframe side elevational view of a distal portion of the end effector of  FIG. 1 ; 
         FIG. 6  is an enlarged, fragmentary, wireframe perspective view of a castellation axial movement assembly of the end effector of  FIG. 1  rotated approximately 90 degrees and with an end effector lateral movement locking pin and a proximal screw removed for clarity; 
         FIG. 7  is an enlarged, fragmentary, wireframe perspective view of the end effector of  FIG. 6  viewed from a bottom thereof with an end effector lateral movement locking pin engaging a tooth of the lateral movement sprocket, and with springs and the proximal screw removed for clarity; 
         FIG. 8  is an enlarged, fragmentary, wireframe bottom plan view of the end effector of  FIG. 7  with an end effector lateral movement locking pin engaging a tooth of the lateral movement sprocket; 
         FIG. 9  is an enlarged, fragmentary, longitudinal cross-sectional view of the end effector of  FIG. 8  viewed from a bottom thereof with the end effector lateral movement locking pin engaging a tooth of the lateral movement sprocket and with the springs removed for clarity; 
         FIG. 10  is an enlarged, fragmentary, perspective view of the end effector of  FIG. 2  rotated about the longitudinal axis with the clevis, the screw, and the distal castellation sleeve axial movement and spring parts removed for clarity; 
         FIG. 11  is an enlarged, fragmentary, bottom plan view of a distal portion of the end effector of  FIG. 1  with the staple-actuating and tissue-cutting slide in a proximal position; 
         FIG. 12  is an enlarged, fragmentary, bottom plan view of the distal portion of the end effector of  FIG. 11  with the staple-actuating and tissue-cutting slide in an intermediate position; 
         FIG. 13  is an enlarged, fragmentary, radially cross-sectional view through the stapling actuating and tissue-cutting slide of the end effector of  FIG. 2 ; 
         FIG. 14  is an enlarged, fragmentary, horizontal longitudinal cross-sectional view through a lower half of the end effector of  FIG. 1 ; 
         FIG. 15  is an enlarged, fragmentary, horizontal longitudinal cross-sectional view through an upper half of a proximal portion of the end effector of  FIG. 1 ; 
         FIG. 16  is an enlarged, fragmentary, vertical longitudinal cross-sectional view approximately through a longitudinal axis of a proximal portion of the end effector of  FIG. 1 ; 
         FIG. 17  is an enlarged, fragmentary, vertical longitudinal cross-sectional view through a right half of the proximal portion of the end effector of  FIG. 1 ; 
         FIG. 18  is an illustration of a left side of the surgical stapler according to the invention with the jaws of the end effector open in an at-rest position of an actuator handle; 
         FIG. 19  is an illustration of a left side of the surgical stapler of  FIG. 18  with the jaws of the end effector closed in an actuated position of a thumb trigger of the actuator handle; 
         FIG. 20  is an illustration of a left side from above the surgical stapler of  FIG. 18  with the lateral movement trigger depressed, with the distal end effector in a laterally free movement state position-dependent upon contact with the environment, such as a surface, and with the jaws of the end effector open in the at-rest position of the actuator handle and laterally positioned at an approximately 45 degree angle; 
         FIG. 21  is an illustration of a left side from above the surgical stapler of  FIG. 18  with the lateral movement trigger in an at-rest state, with the distal end effector in a laterally captured movement state, and with the jaws of the end effector open in the at-rest position of the actuator handle and laterally positioned at an approximately 30 degree angle; 
         FIG. 22  is a fragmentary illustration of a left side of the end effector of  FIG. 18  with the jaws open in the at-rest position and laterally positioned at an approximately 75 degree angle; 
         FIG. 23  is a fragmentary illustration of a left side of the end effector of the stapler of  FIG. 18  with the jaws open in the at-rest position and in a rotated first axial position; 
         FIG. 24  is a fragmentary illustration of a left side of the end effector of  FIG. 23  with the jaws open in the at-rest position and in a normal position rotated counter-clockwise with respect to  FIG. 23 ; 
         FIG. 25  is a perspective view from a distal end of a second embodiment of a surgical stapling device according to the invention with a removable end effector having a self-contained stapling motor, with the stapling jaws in an at-rest open position and at a right lateral position of approximately 45 degrees, with the ball release lever in an at-rest ball-capture position, and with the motor actuator button in an at-rest motor-off position; 
         FIG. 26  is an enlarged, perspective view of the removable end effector of  FIG. 25  with the jaws in an at-rest open position and with the slide removed for clarity; 
         FIG. 27  is a perspective view from a distal end of a third embodiment of a surgical stapling device according to the invention with a removable end effector having two ball-connection ends and a self-contained stapling motor, with the stapling jaws in an at-rest open position and at a right lateral position of approximately 45 degrees with staple jaws reversed and facing proximally, with the ball release lever in an actuated ball-released position, and with the motor actuator button in an at-rest motor-off position; 
         FIG. 28  is an enlarged, perspective view of the removable end effector of  FIG. 27  viewed from a right side and a distal end thereof with the jaws in an at-rest open position and with the slide removed for clarity; 
         FIG. 29  is a fragmentary, enlarged side cross-sectional wireframe view of a distal-most end of an actuating handle of the surgical stapling and cutting device of  FIGS. 25 and 26  and of a ball-joint of the removable stapling end effector of  FIGS. 25 and 26  in a captured and aligned state; 
         FIG. 30  is a fragmentary, enlarged side cross-sectional view of a distal-most end of opposite side of the actuating of  FIG. 29  with the ball-joint in an un-aligned and released state but still captured in between clamps of the actuating handle; 
         FIG. 31  is a perspective view from a proximal end of the stapling and cutting device according to the invention with an anvil removed; 
         FIG. 32  is a fragmentary, perspective view from a proximal end of the device of  FIG. 31  with the handle removed to show a proximal portion of an articulation release device with a pushrod therein; 
         FIG. 33  is an illustration an enlarged, exploded view of parts of the proximal end of an inner tube of the device of  FIG. 31 ; 
         FIG. 34  is a fragmentary, perspective view from a distal end of interior parts connecting the articulation release device to the articulation joint of the end effector with an outer tube removed; 
         FIG. 35  is a fragmentary, enlarged, vertically longitudinal cross-sectional view of the parts of  FIG. 34 ; 
         FIG. 36  is a fragmentary, enlarged, perspective view of a knife guide assembly of the device of  FIG. 31  from proximal of a knife guide to distal of a knife blade with outer and inner tubes removed; 
         FIG. 37  is a fragmentary, enlarged, vertically longitudinal cross-sectional view of a portion of the parts of  FIG. 35  at a proximal end of a pullband; 
         FIG. 38  is a fragmentary, enlarged, vertically longitudinal cross-sectional view of a portion of the parts of  FIG. 35  at a distal end of the pullband; 
         FIG. 39  is a fragmentary, enlarged, side elevational view of a stapler assembly, a drum sleeve, the articulation joint, and a clevis of the device of  FIG. 31  with an anvil in an open position; 
         FIG. 40  is a fragmentary, enlarged, side elevational view of the stapler assembly, the drum sleeve, the articulation joint, and the clevis of the device of  FIG. 31  moved distally with respect to  FIG. 39  and with the anvil in a closed, firing position; 
         FIG. 41  is a fragmentary, enlarged, perspective view of a knife guide sub-assembly from proximal of the knife guide to the knife blade with the knife guide, the clevis, the left hammock, the drum sleeve, and the cartridge holder removed; 
         FIG. 42  is a fragmentary, enlarged, vertically transverse cross-sectional view of the knife-pushrod pin joint of the device of  FIG. 31 ; 
         FIG. 43  is a fragmentary, enlarged, vertically transverse cross-sectional view of the pullband-aluminum tube pin joint of the device of  FIG. 31 ; 
         FIG. 44  is a fragmentary, enlarged, vertically transverse cross-sectional view of a proximal face of the clevis of the device of  FIG. 31 ; 
         FIG. 45  is a fragmentary, enlarged, vertically transverse cross-sectional view of plunger pin spring pockets and an articulation release pin of the device of  FIG. 31 ; 
         FIG. 46  is a fragmentary, enlarged, vertically transverse cross-sectional view of a plunger pin cam surface and an articulation locking sprocket of the device of  FIG. 31 ; 
         FIG. 47  is a fragmentary, enlarged, vertically transverse cross-sectional view of the end effector articulation joint of the device of  FIG. 31 ; 
         FIG. 48  is a fragmentary, enlarged, vertically transverse cross-sectional view of a distal pullband pin joint of the device of  FIG. 31 ; 
         FIG. 49  is a fragmentary, enlarged, vertically transverse cross-sectional view of an anvil/upper jaw pivot slot of the device of  FIG. 31 ; 
         FIG. 50  is a fragmentary, enlarged, horizontally longitudinal cross-sectional view of the articulation joint portion of the device of  FIG. 31  through spring rods; 
         FIG. 51  is an illustration of a test bed for knife guiding blades and hammocks of the device of  FIG. 31 ; 
         FIG. 52  is a fragmentary, enlarged, horizontally longitudinal cross-sectional view of the articulation joint portion of the device of  FIG. 31  through an articulation lock release slide; 
         FIG. 53  is an exploded perspective view of distal components of the device of  FIG. 31  viewed from the distal end thereof and without the anvil; 
         FIG. 54  is a perspective view of an articulating distal portion of a fourth embodiment of the end effector according to the invention with the inner and outer tubes removed; 
         FIG. 55  is a fragmentary, enlarged, and exploded perspective view of an articulating portion of the end effector of  FIG. 54  rotated with the top inward towards the viewer with the outer tube removed; 
         FIG. 56  is a fragmentary, enlarged, bottom plan view of the articulating portion of the end effector of  FIG. 54  with the lower clevis and the closure ring removed; 
         FIG. 57  is a fragmentary, horizontally longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a lower end of the dogbone guide; 
         FIG. 58  is a fragmentary, vertically longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through the spring rods with the inner tube and the pushrod-blade support removed; 
         FIG. 59  is a fragmentary, vertically transverse, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a distal end of the dogbone guide; 
         FIG. 60  is a fragmentary, vertically transverse, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a proximal end of a dogbone guide chamber of the lower clevis with the dogbone guide removed; 
         FIG. 61  is a fragmentary, horizontally longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a low intermediate portion of the dogbone guide; 
         FIG. 62  is a fragmentary, horizontally longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a high intermediate portion of the dogbone guide; 
         FIG. 63  is a fragmentary, vertically longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through a spring rod with the inner tube, the pushrod-blade support, an anvil, and a near half of the staple sled removed; 
         FIG. 64  is a fragmentary, vertically longitudinal, cross-sectional view of the articulating portion of the end effector of  FIG. 54  through the dogbone guide with a spring plate, the anvil, and the near half of the staple sled removed; 
         FIG. 65  is a fragmentary, vertically longitudinal, cross-sectional view of a distal end of the articulating portion of the end effector of  FIG. 54  with the inner tube, the pushrod-blade support, the anvil, the closure ring, and the near half of the staple sled removed; 
         FIG. 66  is a perspective view of the lower clevis, the lower dogbone clevis, the dogbone guide, and three adjacent knife blades of the end effector of  FIG. 54 ; 
         FIG. 67  is a fragmentary, wireframe, vertically transverse cross-sectional view of the end effector of  FIG. 54 ; 
         FIG. 68  is a fragmentary, wireframe, perspective view of an alternative embodiment of a distal connection of the pullbands of the end effector of  FIG. 54 ; 
         FIG. 69  is a fragmentary, vertically transverse cross-sectional view of the distal connection of  FIG. 68 ; and 
         FIG. 70  is a fragmentary perspective view from below of a portion of the distal connection of  FIG. 68 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. The figures of the drawings are not drawn to scale. 
     Alternate embodiments may be devised without departing from the spirit or the scope of the invention. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
     Before the present invention is disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms “a” or “an,” as used herein, are defined as one or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as comprising (i.e., open language). The term “coupled,” as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. 
     Referring now to the figures of the drawings in detail and first, particularly to  FIG. 1  thereof, there is shown a first exemplary embodiment of a stapling and cutting end effector  1  according to the present invention. The major parts of the end effector  1  include a clevis  10 , an anvil  20 , a cartridge holder  30  for receiving a staple cartridge  100 , an adapter sleeve  40 , and a lateral translation or articulation device  50 .  FIG. 1  illustrates the removability of the staple cartridge  100  from the cartridge holder  30 . 
     Connecting the anvil  20  to the cartridge holder  30  and the staple cartridge  100  is a staple-actuating and tissue-cutting slide  60 . This slide  60  operative engages both the anvil  20  and the cartridge holder  30  to keep the two parts  20 ,  30  in proper alignment so that the actuated staples inside the cartridge  100  hit their respective stapler anvils within the anvil  20  and secure the staples around tissue disposed between the anvil  20  and the cartridge  100 . The distal facing surface of the slide  60  contains a blade  62  for cutting the tissue disposed in the jaws  20 ,  30  as the tissue is being stapled together. Proximal movement of the slide is shown, diagrammatically, in  FIGS. 1 to 3 . So that the slide  60  can be seen in  FIGS. 1 and 3 , the anvil  20  is uncoupled from the top end of the slide  60 . In operation, however, the slide  60  must be coupled to the anvil  20  as shown in  FIG. 2  and, especially, in  FIG. 13 . 
       FIG. 2  illustrates the end effector  1  with the adapter sleeve  40  removed to make visible various features of the translation therein. 
     A first of two primary parts of the lateral translation device  50  are apparent in  FIGS. 1 to 3 . A proximal part  52  includes a proximal sprocket  522 , an intermediate castellated connector  524 , and a distal rod  526 . In the exemplary embodiment, the intermediate castellated connector  524  has four distally projecting teeth  5242 , clearly shown in  FIG. 2 . 
     Also visible in  FIG. 2  is a pull cable adapter  70 . The pull cable adapter  70  is connected to a pull cable  110  (dashed lines) at a proximal side and to the cartridge holder  30  at a distal side thereof. The pull cable adapter  70 , therefore, is used to pull or push the cartridge holder  30  with respect to the anvil  20  and, thereby, pivot the anvil  20  from an open position to a closed position, or vice-versa, dependent upon movement of the cartridge holder  30 . The proximal end of the anvil  20  has a cam follower  22  on either side thereof. The proximal end of the cartridge holder  30  defines two cam surfaces  32  on either side thereof and aligned to receive a respective one of the cam followers  22 . Accordingly, movement of the cartridge holder in a distal or proximal direction results in a corresponding opening or closing pivoting movement of the anvil  20 . 
       FIG. 4  shows the lateral articulating movement of the stapler  20 ,  30  with respect to the clevis  10 . 
     In  FIGS. 5 to 8 , all parts, including the adapter sleeve  40  and the clevis  10  are shown in wire frame, thereby, revealing features therein. The clevis  10  contains four lumens, two of which are shown in  FIG. 5  and all four are shown in  FIGS. 6 and 7 . A first  12  of the lumens is formed to contain a non-illustrated shaft for controlling distal and proximal movement of an end effector lateral movement locking pin  120 , which pin  120  is first shown in  FIGS. 8 and 9 . The two lateral lumens  14  are shaped to receive the pull-wire that moves the pull cable adapter  70  proximally (distal movement of the pull cable adapter  70  is caused by a spring). The other of the two lumens  14  is extra and can receive any number of possible additional instrumentation. The drive cable lumen  16  is the last of the four lumens and is shaped to receive the flexible drive cable that turns the drive screw  34  (see  FIG. 1 ), which controls movement of the slide  60 . 
     At the distal end of the drive cable lumen  16 , the clevis  20  defines an oblong cavity  18  for receiving therein the lateral movement locking pin  120 .  FIGS. 6 to 9 , in particular, show an exemplary shape of this cavity  18 . Because the lateral movement locking pin  120  is oblong in circumferential shape, the pin  120  does not rotate away from an aligned position with the teeth of the sprocket  522 . 
     Also visible under the top side of the clevis  10  in  FIG. 5  are two centering springs  130 . These springs  130  are also shown in  FIGS. 6 to 9  and, in particular,  FIG. 10 . To prevent undesired interaction between the springs  130 , a dividing plate  140  is sandwiched between the springs  130 .  FIG. 10  illustrates the two springs  130  with the dividing plate  140  therebetween. 
     The features underneath the transparent sleeve  40  are better explained with respect to  FIGS. 7 to 10 . The sleeve  40  defines two exterior structures and two internal bores. The first exterior structure is a proximal cylinder  42 . The proximal cylinder  42  defines castellations  422  at a proximal end thereof. These castellations  422  match and interact with the intermediate castellated connector  524  of the proximal part  52 . The proximal cylinder  42  also defines a first bore  44  that is shaped to receive the distal rod  526  of the proximal part  52 . There is a cylindrical, tubular radial clearance between the rod  526  and the interior surface of the first bore  44  and a longitudinal clearance between the proximal end of the cable adapter  70  and the proximal inside surface of the first bore  44 . This tubular-shaped clearance can receive a first tubular biasing device (e.g., a coil spring), which is not illustrated for clarity. The first biasing device is positioned to apply a proximally directed force on the proximal-most end of the adapter sleeve  40 . In such a configuration, the force applied by the first biasing device presses the distal castellations  422  towards and against the proximal castellations  5242 . 
     The second exterior structure of the sleeve  40  is a distal cylinder  46 . The distal cylinder  46  defines a second bore  48  that is shaped to receive therein the pull cable adapter  70 . The pull cable adapter  70  also defines an interior bore  72  that is shaped to receive the distal rod  526  of the proximal part  52 . For clarity in the figures, the rod  526  is shown extending entirely into the interior bore  72  only by the dashed lines in  FIG. 9 . In operation, the rod  526  extends entirely into the interior bore  72 . The interior bore  72  is coaxial and, in an exemplary embodiment, has the same interior diameter of the first bore  44 . Accordingly, there exists a cylindrical, tubular radial clearance between the rod  526  and the interior surface of the interior bore  72  and a longitudinal clearance between the distal surface of the cable adapter  70  and the inside distal surface of the interior bore  72 . This is because it is also shaped to house a second tubular biasing device (e.g., a coiled spring), also not illustrated for clarity. The second biasing device is provided to impart a distally directed biasing force against the pull cable adapter  70 . Such a force keeps the jaws  20 ,  30  in an open position. Accordingly, the jaws  20 ,  30  have an at-rest open position. 
     Without providing an intermediate part, the two non-illustrated biasing devices connect and, therefore, form a single spring. However, it is desirable to not have the two biasing devices interact because separation of the castellated parts causes an unwanted force to be applied to the cartridge holder  30  and movement of the cartridge holder  30  may loosen the connection of the castellated parts. Accordingly, a non-illustrated washer is disposed between the two biasing devices in the cylindrical cavity  74  defined by the proximal end surface of the pull cable adapter  70  and the distal end surface of the second bore  48 .  FIG. 7  particularly illustrates the proximal side for holding this washer, which is shaped to only receive the distal rod  526  therethrough. Accordingly, because the washer is trapped between the pull cable adapter  70  and the sleeve  40 , the two springs are decoupled and provide their respective biasing forces independent of one another. 
     The underside view of  FIGS. 11 and 12  illustrate the drive shaft  34  of the slide  60  and the proximal idler bushing  36  that holds the drive shaft  34  in place within the cartridge holder  30 . At the position of the idler bushing  36 , the drive shaft  34  does not have threads. However, distal to the idler bushing  36 , the drive shaft  34  has threads (which are not illustrated) extending towards the distal end of the drive shaft  34 .  FIGS. 11 and 12  do not show the thrust bearing  38  on the opposite end of the drive shaft  34 , but  FIG. 1  clearly illustrates this bearing  38 . Also illustrated in  FIGS. 11 ,  12 , and  13  is the bottom of the slide  60  in the form of a drive nut  64 . In an exemplary embodiment, this drive nut  64  is a part that is separate from the blade  62  of the slide  60  but is fixedly connected at the bottom of the blade  62 . The illustrated shape of the drive nut  64  has a dumbbell-shaped cross-section to relieve some of the forces exerted upon the threads. In  FIG. 11 , the drive nut  64  is in a proximal position where the anvil  20  is in an opened position.  FIGS. 12 and 13 , in contrast, show the drive nut  64  in intermediate positions where the anvil  20  is in a partially closed position. 
       FIG. 13  is especially useful in illustrating the shape and configuration of the slide  60 , including the blade  62  and the drive nut  64 . 
     The horizontal cross-section along approximately the longitudinal axis of the end effector in  FIGS. 14 and 15  is particularly useful in viewing the bores around the distal rod  526 . Again, for clarity, the rod  526  is not shown extending all the way to the distal surface of the bore  72  in the pull cable adapter  70  even though it does extend all the way to this surface. Around the proximal end of the rod  526  is the first bore  44  in the adapter sleeve  46 . Just distal of the first bore  44  is the cavity  74  for receiving the washer therein and, just distal of the cavity  74 , is the interior bore  72  of the pull cable adapter  70  for receiving the second biasing device. 
     The vertical cross-section along approximately the longitudinal axis of the end effector in  FIG. 16  is particularly useful in viewing the connection between the drive nut  64  and the drive shaft  34 . Again, for clarity, the rod  526  is not shown extending all the way to the proximal surface of the bore  72  in the pull cable adapter  70 . 
     The vertical cross-section along approximately the longitudinal axis of the end effector in  FIG. 17  is particularly useful in viewing the connection between the slide  60  and both the anvil  20  and the cartridge holder  30 . Two upper wings  66  are disposed in a groove inside the anvil  20  and two lower wings  68  form an upper holding surface of the I-shape formed by the lower wings  68  and the drive nut  64 . 
       FIGS. 18 to 24  are illustrations of the entire longitudinal extent of the stapling device according to the invention with the distal end effector  1  and a first exemplary embodiment of the actuating handle  2 . As shown in  FIG. 60 , the jaws  20 ,  30  are at rest in an open position. 
     The thumb trigger is connected to the proximal end of the pull cable that ends at the pull cable adapter  70 . Thus, when the thumb trigger  3  is actuated (see  FIG. 19 ), the cartridge holder  30  is pulled in a proximal direction. Due to the shape of the cam surfaces  32 , the cam followers  22  are caused to move and, thereby, pivot the anvil  20  approximately into its stapling position. As set forth above, it is not the thumb trigger  3  that insures correct parallel orientation of the anvil  20  with respect to the cartridge holder  30  and, thereby, the staple cartridge  100 . Rather, it is the slide  60  that insures the proper parallel orientation. 
       FIGS. 20 to 22  illustrate how the end effector  1  is passively articulated in a lateral direction. When the index finger trigger  4  is depressed, the lateral movement locking pin  120  is moved rearward to disengage from the sprocket  522 . If no force is applied to the end effector  1 , then, due to the two centering springs  130 , the end effector  1  remains in the axial aligned orientation shown in  FIGS. 18 and 19 . However, when an external force is applied to the end effector  1  (as shown in  FIG. 20 ), the laterally free end effector  1  can be moved about the axis of the sprocket  522  into any position, e.g., an approximately 45 degree left position shown in  FIG. 20 , or into any other orientation. See, e.g.,  FIG. 22 . When the index finger trigger  4  is released, the lateral movement is prevented by returning the distal end of the locking pin  120  in between two teeth of the sprocket  522 . Thus, as shown for example in  FIGS. 21 and 22 , the end effector can be locked into a significant number of laterally articulated positions. It is noted that the staple cartridge  100  is not illustrated in  FIGS. 18 to 24  for clarity. 
       FIGS. 23 and 24  illustrate the axial rotational control of the end effector. Such axial control is provided by the two respective castellated features  422 ,  5242  of the adapter sleeve  40  and the lateral translation device  50 , respectively. In  FIG. 23 , the castellations are engaged and the anvil is in the 90 degree position with respect to the handle. To disengage the castellations, a force sufficient to overcome the first biasing device is exerted on the end effector  1  and the castellation features  422 ,  5242  separate. Then, the end effector  1  can be rotated clockwise or counter-clockwise.  FIG. 68  shows, for example, the anvil  20  rotated counter-clockwise into an approximately 9 o&#39;clock position. 
       FIGS. 1 to 3  can be used to illustrate the operation of the motorized stapling function of the stapling device of the present invention. In  FIG. 1 , the slide  60  is in a proximal position. A reversible motor is housed inside the handle. A three-way switch is connected to the motor. When in a middle position, for example, the motor is off. When in a proximal position, the motor is turned on and will rotate the drive shaft  34  so that the slide  60  moves in a proximal direction. In contrast, when the switch is in a distal position, the motor is turned on and will rotate the drive shaft  34  so that the slide  60  moves in a distal direction. Of course, the switch can be merely a two-way switch without an off position. 
       FIGS. 25 and 26  illustrate a second exemplary embodiment of the stapling and cutting system  200  according to the invention. This system  200  is different than the first embodiment in that the motorized stapling assembly is entirely contained in the end effector  210 . Therefore, the handle  220  only needs to have two actuating devices. The first actuating device  222  is a ball joint releasing lever and the second actuating device is the stapling/cutting motor on/off button  224 . 
     The end effector  210  is connected to the distal end of the actuation shaft  226  of the handle  220  at a ball-joint connector  228 . The end effector  210  has, at its distal-most end, a ball joint  212 . The ball joint  212  has two opposing cup-shaped clamps  2122 ,  2124 . The interior surfaces of the clamps  2122 ,  2124  are shaped to correspond to the outer shape of the ball joint  212 . The clamps  2122 ,  2124  translate towards or away from one another based upon an actuation of the lever  222 . 
     The clamps  2122 ,  2124  are biased towards one another in a closed position such that, when the ball joint  212  is disposed therein, the two clamps  2122 ,  2124  tightly grip the ball joint  212 . Actuation of the lever  222  causes the clamps  2122 ,  2124  to separate and, thereby, allow the ball joint  212  to rotate freely in between the two clamps  2122 ,  2124 . Thus, when the lever  222  is actuated, the end effector  210  is “free” to move based upon pressure against structures in the environment, such as tissue near a stapling/cutting site. The lever  222  can be pushed down sufficiently far to allow the ball joint  212  to move entirely out of the clamps  2122 ,  2124 . Therefore, if a first end effector  210  is clamped at a first site and a second end effector  210  is desired to clasp and cut a second site, the first end effector  210  can be left clamped at the first site, the shaft  226  can be removed from the body and loaded with a second end effector  210 , and the second end effector  210  can be guided to the second site. 
     The second actuating device  224  is needed when the user desires to effect the stapling and cutting with the end effector  210 . When the end effector  210  is at the desired position for stapling/cutting, the actuator  224  (e.g., button) is depressed. This actuation, preferably, completes (or interrupts) a circuit that connects power to the motor inside the end effector  210 , thereby causing the slide  60  to move distally and effect the stapling and cutting functions of the jaws. 
       FIG. 25  illustrates the complete freedom for orienting the end effector  210  in any position with respect to the ball joint  212 . In  FIG. 25 , the end effector  210  is shown in a right lateral orientation of approximately 45 degrees and with an anvil orientation of approximately 90 degrees. 
       FIGS. 27 and 28  illustrate a variation of the second embodiment of the end effector shown in  FIGS. 25 and 26 . In particular, the handle  220  is the same as in  FIGS. 25 and 26 . However, the end effector  310  is different. Specifically, the end effector  310  has a proximal ball joint  312  similar to the ball joint  212  in  FIGS. 25 and 26 , but also has a second, distal ball joint  314 , having a shape virtually identical to the proximal ball joint  312 . Therefore, when the lever  222  is pressed down to release the ball joint  312 ,  314 , the end effector  310  can be allowed to rest within the body and the opposite end can be grasped between the clamps  2122 ,  2124 . In such an orientation, shown in  FIG. 27 , the stapling/cutting can be actuated when the jaw opening is facing the user. 
     It is also noted that placement of an end effector  210 ,  310  at a surgical site sometimes requires the access to the surgical site to be rather small in comparison to the opened jaws of the end effector  210 ,  310 . With the ability to reverse the end effector  310 , some difficult-to-reach sites may be accessed that are not reachable with the single ball joint end effector  210 . 
       FIGS. 29 and 30  show the clamps  2122 ,  2124  at the distal-most end of the actuating shaft  226  of the surgical stapling and cutting device  200 ,  300  of  FIGS. 25 to 28  holding a ball-joint  212 ,  312 ,  314  of the end effector  210 ,  310  of  FIGS. 25 to 28 . These figures illustrate that the lever  222  is connected to a push rod  230  having at its distal end a plunger  232 . This plunger  232  has a cup-shaped surface  234  at its distal-most end with a shape corresponding to the outer shape of the ball joint  212 ,  312 ,  314 . Thus, when the plunger  232  is in its distal-most position in contact with the ball joint  212 ,  312 ,  314 , the ball is captured and does not move or rotate. In contrast, when the plunger  232  is moved proximally as shown in  FIG. 30 , the ball of the ball joint  212 ,  312 ,  314  is free to rotate between the clamps  2122 ,  2124 . 
     The endostapler illustrated in  FIGS. 31 to 70  add various different alternative and/or additional features to the endostapler illustrated in  FIGS. 1 to 30 . 
     In all of  FIGS. 31 to 70 , the top jaw or anvil  1020  is only shown in  FIGS. 39 and 40  for the sake of clarity. Further, the anvil  20  is described above in detail with regard to  FIGS. 1 to 30  and, therefore, any repetitive description is avoided hereinafter. 
     The exemplary handle shown in  FIG. 31  is manufactured by Ethicon Endo-Surgery, Inc., and can be found, for example, on Ethicon&#39;s linear cutter model ECHELON 60 Endopath Stapler. Description of this handle is, therefore, believed to be redundant as parts and functional descriptions of this handle are published in the art. Such description is hereby incorporated herein by reference in its entirety. 
     As set forth above, the distal end of the endostapler of the present invention is configured to house a standard staple cartridge  100 . This cartridge  100 , too, is described in prior publications and does not need to be repeated here. The publications are, therefore, hereby incorporated herein by reference in their entireties. 
       FIG. 31  illustrates portions of an alternative embodiment of the endostapler  1000  of the present invention. It is noted that two distal actuation levers on the handle  1200  of the endostapler  1000  are hidden from view in  FIG. 31  for the sake of clarity. 
     The distal end of the handle  1200  includes a bell-shaped actuator  1100 , which provides two degrees of control for the articulating portions of the endostapler  1000 . First, the bell actuator  1100  freely rotates about the central axis of the endostapler  1000  on distal end of the handle  1200 . Because the bell actuator  1100  is rotationally fixedly connected to the outer tube  1110 , when the bell actuator  1100  is rotated clockwise or counterclockwise, the entire distal end of the endostapler  1000  rotates correspondingly. Second, the bell actuator  1100  can be displaced over a given distance in a proximal direction on the distal end of the handle  1200 . As will be described below in further detail, proximal displacement of the bell actuator  1100  causes a corresponding movement of the articulation lock release slide  120 ,  1120  to allow the distal end effector  1002  to articulate at the translation device  50 ,  1050 . A non-illustrated bias device (i.e., a compression spring) located, for example, in the distal portion of the bell actuator  1100  is used to bias the bell actuator  1100  and the articulation lock release slide  1120  in a distal direction so that the articulation lock release slide  120 ,  1120  remains in the actuated or locked position while the bell actuator  1100  is in an un-actuated state. See, i.e.,  FIGS. 8 and 9 . This bias device is housed inside the bell actuator  1100  but is not shown in  FIG. 32  for clarity. Also not shown is a snap ring that fits into a groove  1139  around the inner tube  1130 . The bias device is delimited on the proximal side of the rod pullblock  1105  (see  FIG. 34 ) and the distal side of the snap ring. In such a configuration, when the bell actuator  1100  is pulled proximally, the actuator  1100  forces the rod pullblock  1105  proximally to, thereby, move the articulation lock release slide  120 ,  1120  into an unlocked position. A keyhole on the interior surface of the bell actuator  1100  form-lockingly surrounds the rod pullblock  1105  so that rotation of bell actuator  1100  about the longitudinal axis of the inner tube  1130  forces the rod pullblock  1105  into a corresponding rotation. A form-locking or form-fitting connection is one that connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements. As such, the inner tube and the entire distal assemblies of the device  1000  rotates as well. In an alternative configuration, the longitudinal movement of the bell actuator  1100  can function similar to a standard ball point pen by a first actuation placing the slide  120 ,  1120  in an unlocked state and a second actuation placing the slide  120 ,  1120  in a locked state. 
     With the bell actuator  1100  of the present invention, a physician is able to operate every function of the endostapler  1000  with one hand. 
       FIG. 32  illustrates the proximal end of the endostapler  1000  without the handle  1200 . Coaxially disposed inside the bell actuator  1100  is a pushrod  1102  that will be used to move the cutting blade  1060  when the stapler is in the firing orientation. 
       FIG. 33  is an illustration of the parts at the proximal end of endostapler  1000  that axially fixedly and rotationally freely connect the distal assembly to the bell actuator  1100 . More specifically, an inner tube  1130  (to be disposed inside the outer tube  1110 ) has a proximal extension  1132  defining an inner tube coupling chamber  1134 . A clam-shell bushing  1131  has a length substantially equal to the extension  1132  of the inner tube  1130  and a bushing coupling chamber  1133  corresponding to the coupling chamber  1134  of the proximal extension  1132 . A rotational couple  1141  has a distal T-shaped rotation link  1143  having an outer shape corresponding to both of the coupling chambers  1133  and  1134  so that, when the link  1143  is disposed between the extension  1132  and the bushing  1131 , the link  1143  is free to rotate therein. This couple  1141  is fixed inside the handle  1200  through a proximal port  1145  on a proximal end of the couple  1141 . 
     When placed together, the inner tube  1130  is axially held with respect to the couple  1141  but is rotationally independent of the couple  1141 . Because the three coupling parts  1130 ,  1131 ,  1141  are sized to fit inside the outer tube  1110 , when the parts are placed inside the outer tube  1110 , the outer tube  1110  becomes a form-locking connection that prevents any separation of the inner tube  1130  and the bushing  1131  (so long as the outer tube  1110  sufficiently covers this area). Thus, when the bell actuator  1100  is rotated about the longitudinal axis of the inner tube  1130 , the inner and outer tubes  1110 ,  1130  are able to rotate about the coaxial axis of the tubes  1110 ,  1130  but remain longitudinally stable with respect to the couple  1141 , which is longitudinally fixed inside the handle  1200 . 
       FIG. 34  illustrates the proximal end of the endostapler  1000  without the handle  1200 , the bell actuator  1100 , and the outer tube  1110 . As can be seen, the inner tube  1130  is hollow and receives therethrough the pushrod  1102 , which will be described in further detail below. Also shown in these figures are the clevis  1010  and the drum sleeve  1040 , which, together, form the articulating connection or joint  1050  of the endostapler  1000 . 
     It is noted at this point that the lower jaw/staple cartridge holder  1030  is longitudinally fixed with respect to the handle  1200 . This fixation contrasts with the upper anvil  1020 , which can be pivoted and be moved somewhat longitudinally when sliding through the keyhole shaped cam surfaces  32  to close and/or open the jaws (described in further detail below/above with respect to cam surfaces  1032 ). 
     To form the longitudinally fixed connection of the staple cartridge holder  1030  and the handle  1200 , the inner tube  1130  must be connected to the staple cartridge holder  1030 . But, at the same time, the staple cartridge holder  1030  must be able to articulate with respect to the longitudinal extent of the inner tube  1130 . Thus, an axially fixed but laterally articulating connection must exist between the two parts  1030 ,  1130 . 
     To provide such a connection, the present invention includes at least one pullband  1140 , shown, for example, in  FIGS. 35 to 38 . In an exemplary configuration, multiple pullbands  1140  are provided, one next to the other. Three or four bands form two possible configurations. With two pullbands  1140  as opposed to one, the longitudinal strength remains approximately the same but the force needed to laterally bend the pullbands  1140  is reduced. The same is true for three or four pullbands  1140 .  FIG. 37  illustrates the proximal end of the pullband  1140 , which is longitudinally pinned to the distal end of the inner tube  1130  with a proximal pullband pin  1142 . To provide a strong connection between the pullband  1140  and the inner tube  1130 , a proximal guide block  1150 , for example, made of brass, is disposed between the distal end of the inner tube  1130  and the pullband  1140 . 
     The pullband  1140  spans the entire extent of the articulation joint  1050 , as shown in  FIG. 35 , and is connected, as shown in  FIG. 38 , to a distal guide block  1160 . The distal guide block  1160  (also, e.g., made of brass) has at least one projection that fits into at least one recess on the proximal end of the staple cartridge holder  1030 . Later figures illustrate the measures by which the distal guide block  1160  is connected to the staple cartridge holder  1030  so that, finally, the staple cartridge holder  1030  is axially fixedly connected to the handle  1200  while being able to articulate with respect to the inner tube  1130 . As shown in  FIG. 38 , a distal pullband pin  1144  axially locks the distal end of the pullband  1140  to the distal guide block  1160 . 
     A first embodiment of jaw  20 ,  30  movement is described in the text above. There, the staple cartridge  30  moves axially and the anvil  20  is relatively stationary. In the configuration of the endostapler  1000  shown in  FIG. 31  et seq., movement is operationally opposite. 
     Noting that the staple cartridge holder  1030  is longitudinally fixed with respect to the handle  1200 , there still must be an assembly that permits closure of the two jaws  20 ,  30 ;  1020 ,  1030 . Closure is, therefore, accomplished by movement of the upper jaw/anvil  1020  as set forth in the following text. 
     A first of the two levers of the handle  1200  (e.g., a proximal handle) is operatively connected to the outer tube  1110  to move the outer tube  1110  distally when the first lever is compressed/actuated. Because the clevis  1010 , the articulation joint  1050 , and the drum sleeve  1040  are axially fixedly connected to the outer tube  1110  (and because the outer tube  1110  can slide longitudinally along the inner tube  1130 ), an actuation of the first lever moves the drum sleeve  1040  distally. 
       FIG. 39  illustrates the anvil  1020  in an open state. As can be seen therein, a gap  1031  exists between the distal end of the drum sleeve  1040  and a proximal shelf at the bottom of the staple cartridge holder  1030 . In such an orientation, the drum sleeve  1040 , the clevis  1010 , and the outer tube  1110  are proximally disposed at a distance from the shelf. 
       FIG. 40  illustrates the anvil  1020  in a closed state. As can be seen therein, no gap  1031  exists between the distal end of the drum sleeve  1040  and the proximal shelf of the staple cartridge holder  1030 . In such an orientation, the drum sleeve  1040 , the clevis  1010 , and the outer tube  1110  are in a position where the drum sleeve  1040  contacts the shelf. 
     In contrast to the axially fixed position of the staple cartridge holder  1030  with respect to the handle  1200 , and similar to the movement of the drum sleeve  1040 , the knife  60 ,  1060  must translate with respect to the handle  1200  along the longitudinal axis.  FIGS. 35 ,  36 , and  38  to  41  illustrate the axially displaceable connection of the knife  1060  to the knife-moving features of the handle  1200 . 
     With regard to  FIG. 35 , a pushrod  1102  extends from the handle  1200  and is connected to a second non-illustrated lever (e.g., a distal lever) of the handle  1200 . The distal end of the pushrod  1102  is connected to at least one flexible knife blade  1062  through a pushrod pin  1122 . The distal end of the knife blade  1062  is connected to the proximal side of the cutting blade  1060  such that the cutting blade  1060  moves distally or proximally to follow corresponding movement of the pushrod  1102 . It is noted that the knife blade  1062  has a proximal, upwardly extending flange  1064  that houses a bore for receiving the pushrod pin  1122 . This off-axis connection between the pushrod  1102  and the knife blade  1062  causes the distal end of the knife blade  1062  to be forced downwardly when pushed in the distal direction and, therefore, to stay in position inside a pushrod-blade support  1070  shown, for example, in  FIGS. 36 and 42 . 
     The knife blade  1062  is flexible enough to bend in any way that the articulation joint  1050  bends. Therefore, the knife blade  1062  is also flexible enough to possibly kink if it was not supported. The present invention, therefore, provides a pushrod-blade support  1070 , which is shown in  FIGS. 36 and 42 . Therein, the proximal end of the pushrod-blade support  1070  clearly reveals the rectangular blade channel  1072  for supporting slidably the rectangular knife blade  1062 . Also shown therein is a curved pushrod channel  1074  for supporting slidably the curved (e.g., cylindrical) exterior of the pushrod  1102 . Thus, the pushrod-blade support  1070  supports the pushrod  1102  at locations where the pushrod  1102  is inside the support  1070  and also supports the knife blade  1062  where the knife blade  1062  is inside the support  1070 . 
       FIG. 36  shows the connection of the support  1070  and its relation to the proximal guide block  1150 . 
     Like the pullbands  1140 , more than one knife blade  1062  can be next to one another. In such a configuration, the multiple blades  1062  have the same longitudinal stiffness but provide greater flexibility when there is a bend in the articulation joint  1050 . 
     Revealed in  FIG. 41  is the articulation lock release slide  1120  that locks the articulation of the jaws  1020 ,  1030 . 
       FIGS. 42 to 50  illustrate a vertical cross-section of the tube portion distal of the handle  1200  along planes that are orthogonal to the longitudinal axis of the endostapler  1000 . 
       FIG. 42  shows the cross-section of the connection junction of the knife blade  1062  and the pushrod pin  1122 . The pushrod pin  1122  passes through the entirety of two adjacent blades  1062  and the pushrod  1102  but does not extend outside the pushrod&#39;s outer surface. This figure also illustrates the relationship of the inner and outer tubes  1130 ,  1110  and the pushrod-blade support  1070 . Also apparent in this figure is an unlock pullrod  1104  used for unlocking the lock release slide  1120 . The longitudinal extent of the unlock pullrod  1104  is first shown in  FIG. 35  and is also shown in  FIGS. 36 ,  37 ,  41 , and  52  and  53 . Most particularly, with exterior parts hidden,  FIG. 41  shows how the pullrod  1104  connects the bell actuator  1100  to the articulation lock release slide  1120 . With the distal end of the pullrod  1104  passed through and wrapped around the distal end of the articulation lock release slide  1120  as shown in  FIG. 37 , the unlock pullrod  1104  establishes a longitudinally fixed connection between the bell actuator  1100  and the articulation lock release slide  1120 . As such, when the bell actuator  1100  is moved proximally, the articulation lock release slide  1120  moves in a corresponding proximal direction to separate the distal teeth  1121  of the articulation lock release slide  1120  and the spokes  1041  of the sprocket  1522 . See, in particular,  FIGS. 46 and 52 . It is noted that the wrapped connection between the pullrod  1104  and the articulation lock release slide  1120  is only an exemplary embodiment. Other form-locking or force-locking connections are possible as well. 
       FIG. 43  shows the connection through the pullband  1140  and inner tube  1130  pin joint. As set forth above, the proximal pullband pin  1142  passes entirely through the blades  1062 , the proximal guide block  1150 , and the inner tube  1130  but not through the outer tube  1110 . 
       FIG. 44  shows the area immediately proximal of the proximal end of the articulation lock release slide  1120 . In this exemplary embodiment, two pullbands  1140  are disposed above two blades  1062 . To provide support to at least one of the pullbands  1140  and the blades  1062 , a pair of hammocks  1066  is placed along sides of the articulating portions of the pullbands  1140  and blades  1062 . Each of the hammocks  1066  has a U-shape (along a longitudinal cross-section) so that the proximal arm of each hammock  1066  bends around the proximal surface of the clevis  1010  and the distal arm of each hammock  1066  bends around a catching surface within the drum sleeve  1040 , as shown in  FIG. 50 , for example. 
     Inside the clevis  1010  are disposed two spring rods  1012  about which are respective spring rod collars  1014 , the function of which is to bias laterally the entire assembly distal of the articulation joint  1050  towards and along the longitudinal axis. The spring rods and collars  1012 ,  1014  will be described in further detail below. 
       FIG. 45  illustrates the open area in the center of the articulation lock release slide  1120  that receives the bend portion of the pullrod  1104  (not illustrated in this figure). Also shown are the cavities  1016  in which the non-illustrated bias springs of the spring rods  1012  rest. This cross-sectional area also includes portions of the two pullbands  1140  disposed above the two knife blades  1062 . 
       FIG. 46  illustrates the open area in which the distal end of spring rods  1012  acts against cam surfaces  1018 . It is noted that the cam surfaces  1018  are arcuate in shape so that contact between the spring rods  1012  and the cam surfaces  1018  always act in an axial direction normal to the surface at the distal-most end of the spring rods  1012 . See, for example,  FIG. 56 . In such a configuration, the force that is applied by the spring rods  1012  against the cam surfaces  1018  to bias the distal articulating assembly (e.g., anvil  1020 , staple cartridge holder  1030 , drum sleeve  1040 ) towards the longitudinal axis of the inner and outer tubes  1130 ,  1110  is always at the same radius about the articulation axis of the articulating staple cartridge holder  1030 . One advantage of such a configuration lies in the fact that the spring rods  1012  are not forced laterally in any way, in which case, the distal-most end of the spring rods  1012  could catch and lock on the cam surface  1018 . 
       FIG. 47  illustrates, in cross-section, the area within the endostapler articulation joint  1050 . Again, this area includes portions of the two pullbands  1140 , of the two blades  1062 , and of the two hammocks  1066 . Upper and lower axle pucks  1152  are inserted in orifices  1042  above and below on surfaces of the drum sleeve  1040 . Connection of the clevis  1010  to the drum sleeve  1040  at the articulation joint  1050  is symmetrical on the top and bottom. The pucks  1152  are inserted into the orifices  1042  in the top and bottom of the proximal end of the drum sleeve  1040 . In this orientation, the assembly is inserted into the distal end of the clevis  1040  to align screw holes  1011  with center threaded bores  1153  of the pucks  1152 . When aligned, screws  1013  are threaded respectively into the pucks  1152  to axially secure the drum sleeve  1040  into the clevis  1010  while allowing the drum sleeve  1040  to articulate about the axis defined by the longitudinal axis of the two screws  1013 . 
       FIG. 48  illustrates the area of the distal pullband pin joint. In this area, the distal ends of the pullbands  1140  are secured by the distal pullband pin  1144  disposed inside the bore of the distal guide block  1160 . The distal guide block  1160  is disposed in the staple cartridge holder  1030  and secured thereto as set forth above. 
       FIG. 49  illustrates the area just proximal of the cutting blade  1060  and the fixed connection of the two knife blades  1062  inside a proximal orifice of the cutting blade  1060 . This view also clearly shows the cam surfaces  1032  that allow the anvil  1020  to pivot and translate with respect to the staple cartridge holder  1030 . 
       FIG. 50  shows a longitudinal cross-section through the spring rods  1012 . Visible in this view is the entire longitudinal extent of the hammocks  1066 . The distal sections of the hammocks  1066  articulate about a vertical axis near the distal end of the hammocks  1066 . In  FIG. 50 , there exists a substantial gap between the spring rods  1012  and the hammocks  1066 . If the hammocks  1066  were not present, there exists the possibility that the thin knife blades  1062  could bend and warp or kink into these gaps. By placing the hammocks  1066  therebetween, any possibility of impermissible bending of the knife blades  1062  is prevented.  FIG. 51  is provided to show the extreme bending extent of the hammocks  1066  and the blades  1062  therebetween in a test bed made for such a purpose. It is noted that the upper hammock  1066  is not utilized in an upward bend with respect to  FIG. 51  because it tracks the inside surface of the curve at the critical bending area. In contrast, the lower hammock  1066  is utilized to substantially prevent the knife blades  1062  therebetween (two in this exemplary embodiment) from impermissibly bending into the gap of the test bed. Because each hammock  1066  is held rigidly at either end and is made out of a substantially non-elastic material (e.g., of stainless steel), it forms a sling or “hammock” that supports the bent knife blade(s)  1062  therebetween. 
       FIG. 52  illustrates a cross-section through the articulation lock release slide  1120  and clearly shows the distal connection bend of the unlock pullrod  1104  inside the slide  1120 . In such a configuration, proximal displacement of the unlock pullrod  1104  causes a corresponding proximal displacement of the slide  1120  to unlock the teeth  1121  of the slide  1120  from between the corresponding teeth  1041  on the proximal side of the drum sleeve  1040 . A distal bias is imparted upon the articulation lock release slide  1120  by a non-illustrated bias device that resides in a hollow  1123  and presses against the distal end of the hollow  1123  and a block  1124  that is fixed with respect to the clevis  1010 . 
       FIG. 35  shows the connection between the unlock pullrod  1104  and the handle  1200 . A rod pullblock  1105  has a longitudinal bore  1107  for receiving therein the pullrod  1104 . The rod pullblock  1105  also has transverse bores  1109  for receiving non-illustrated set screws therein for securing the pullrod  1104  inside the rod pullblock  1105 . An interior portion of the bell actuator  1100  is shaped to engage the rod pullblock  1105  (for example, in a form-fitting connection such as a keyhole) and displace the rod pullblock  1105  proximally when the bell actuator  1100  is moved proximally. 
       FIG. 53  is an exploded perspective view of the distal parts of the endostapler as viewed from the distal end thereof. 
     It is noted that the clevis  1010  in  FIGS. 34 to 53  is a one-piece part. Alternatively, the clevis  1010  can be molded in two halves. In such a case, the pucks  1152  can be eliminated and, instead, form parts of each of the two clevis halves, thereby eliminating the need for the screws  1013  because the outer tube  1110  will hold the two halves together when attached to the proximal end of the clevis  1010 . Such a configuration is illustrated in the endostapler embodiment of  FIG. 54  et seq. 
       FIG. 54  shows some internal parts of this fourth embodiment of the end effector. The anvil  1020  is disposed opposite the staple cartridge holder  1030  and a closure ring  1040  surrounds the proximal end of the staple cartridge holder  1030 . The inner and outer tubes  1130 ,  1110  are removed so that the articulation lock release slide  1120 , the pushrod  1102 , and the pushrod-blade support  1070  can be seen clearly. A screen door  1103  is mounted around the pushrod  1102  and inside the inner and outer tubes  1130 ,  1110  and the bell actuator  1100 . The handle  1200  and bell actuator  1100  are removed for clarity. The screen door  1103  restricts movement of the pushrod  1102  to only one direction—distal—because the knife/cutting blade  1060  only moves in the distal direction. 
     The two-part clevis is best illustrated in the views of  FIGS. 55 and 56 . These figures show various internal features of the end effector of  FIG. 54  with the outer tube  1110  removed. In the exploded view of  FIG. 55 , connection of the pullband(s)  1140  to the staple cartridge holder  1030  is apparent. A non-illustrated pin (see also  FIG. 59 ) passes through a first proximal flange of the holder  1030 , a first spacer  1170 , a distal flange of the pullband  1140 , a second spacer  1170 , and a second opposing proximal flange of the holder  1030 , respectively. The closure ring  1040 , as shown in  FIG. 59 , holds the pin therein to provide the longitudinal connection of these components. 
     Various features of the knife/cutting blade  1060  are also revealed in  FIG. 55 . The blade  1060  has a proximal recess  1061  for connecting a distal end of the knife blade  1062  thereto. In the exemplary embodiment, the recess  1061  and distal end form a keyhole-shaped lock. The upper half of the blade  1060  has two opposing guide wings  1063  having an exterior shape that fits into a corresponding groove inside the bottom surface of the upper anvil  1020 . The lower half of the blade  1060  also has two opposing guide wings  1065 . The holder  1030  has a groove inside the top surface thereof for receiving the lower wings  1065  therein. These two pairs of wings  1063 ,  1065  ensure that the anvil  1020  and the holder  1030  are at a fixed parallel position when the blade  1060  is traversing there along in the cutting and stapling process. Also disposed on the lower half of the blade  1060  is a proximally extending flange  1067 . A plate spring  1090  is attached to the staple cartridge holder  1030  by rivets  1036 . The plate spring  1090  and other features of the blade  1060  will be described in greater detail below. 
       FIGS. 55 and 56  also show various portions of the two-part clevis  2010 ,  2020 . As can be seen in  FIGS. 56 and 58 , the interior surface of the upper clevis half  2010  defines two cavities  2011  that each house a respective spring rod  1012  and the non-illustrated bias device for that spring rod  1012 . In the exemplary embodiment shown, the upper clevis half  2010  defines the entire cavity  2011  for the spring rods  1012  and the lower clevis half  2020  defines the bottom cavity portion  2021  for accommodating only the bias device. The clevis halves  2010 ,  2020  also define articulation ports  2012 ,  2022  for receiving therein articulation bosses  2031 ,  2041  on each of the two dogbone clevis parts  2030 ,  2040 . 
       FIGS. 56 and 57  illustrate the longitudinal connectivity of the features within the outer tube  1110 . The pushrod-blade support  1070  is disposed inside a lower channel of the inner tube  1130 . This pushrod-blade support  1070  also has a distal extension  1071  with a narrow proximal neck  1074  and a relatively wider distal head  1075 . With a corresponding recess  2023  in the bottom of the lower clevis half  2020 , the distal extension  1071  can be longitudinally fixed to the clevis half  2020  and, therefore, the remainder of the clevis. 
     The outer tube  1110  and the lower clevis half  2020  are removed in  FIG. 56  to illustrate the configuration of the spring rods  1012  inside the spring rod cavities  2011 . Again, the spring rod bias devices (e.g., coil springs) are not shown in the cavities  2011  for clarity. With various parts removed, the articulating extent of the pullbands  1140  is clearly shown in  FIG. 56 . The supporting surfaces for the pullbands  1140  inside the upper clevis half  2010  are visible at the cross-section plane of  FIG. 58 . The upper dogbone clevis  2030  has two opposing supporting surfaces  2032  each at a similar acute angle with respect to the centerline of the un-articulated pullbands  1140 . Likewise, the upper clevis half  2010  has two opposing supporting surfaces  2013  each at an acute angle with respect to the centerline of the un-articulated pullbands  1140 . 
     The opposite viewing direction towards the interior of the lower clevis half  2020  is illustrated in  FIGS. 55 and 58 . The articulation section for the knife blades  1062  is illustrated along with the supporting surfaces  2042  for the dogbone  1080  inside the lower dogbone clevis  2040  and the supporting surfaces  2024  for the dogbone  1080  inside the lower clevis half  2010 . Also visible in this orientation are guiding and supporting surfaces for the dogbone guide  1080 . In  FIG. 57 , it is seen that the lower dogbone clevis has a kidney-shaped distal dogbone depression  2043  and the lower clevis half  2010  has a kidney-shaped proximal dogbone depression  2025 . These depressions  2025 ,  2043  and surfaces  2024 ,  2042  are also illustrated in  FIG. 66  and will be described in detail below. A further feature visible in  FIGS. 59 ,  62 , and  66  is the interior passage of the dogbone guide  1080  having left and right surfaces  1082  and will be describe in further detail below. 
     The distal end of the dogbone guide  1080  is shown in the vertical cross-section of  FIG. 59 . The distal dogbone depression  2043  houses the distal end of the dogbone guide  1080  and, when unarticulated, the dogbone guide  1080  does not touch the supporting surfaces  2042  of the lower dogbone clevis  2040 . 
     The proximal housing for the distal end of the dogbone guide  1080  is illustrated in  FIG. 60 . To better reveal the features of the proximal dogbone depression  2025 , the dogbone guide  1080  is removed from these figures. 
     Both of the depressions  2025 ,  2043  with the lower extending portions of the dogbone guide  1080  disposed therein are shown in horizontal, longitudinally transverse cross-section of  FIG. 57 . Also shown therein are the lower features of the pushrod-blade support  1070 , the cutting blade  1060 , and the staple sled  102  (which is a part of the removable staple cartridge  100 ). These features are enlarged in  FIGS. 61 and 62 . 
       FIGS. 63 ,  64 , and  65  illustrate the knife blade  1060  lock-out feature. In other words, the safety that prevents the knife blade  1060  from advancing when there is no staple cartridge  100  or a previously fired staple cartridge  100  in the staple cartridge holder  1030 . For ease of understanding, the only part of the staple cartridge  100  shown in these figures is the staple sled  102 . 
     The knife blade  1060  should be allowed to move distally only when the staple sled  102  is present at the firing-ready position, i.e., when the sled  102  is in the position illustrated in  FIG. 65 . If the sled  102  is not present in this position, this can mean one of two things, either there is no staple cartridge  100  in the holder  1030  or the sled  102  has already been moved distally—in other words, a partial or full firing has already occurred with the loaded staple cartridge  100 . Thus, the blade  1060  should not be allowed to move, or should be restricted in its movement. Accordingly, the sled  102  is provided with a lock-out contact surface  104  and the blade  1060  is provided with a correspondingly shaped contact nose  1069 . It is noted at this point that, the lower guide wings  1065  do not rest against a floor  1034  in the cartridge holder  1030  until the blade  1060  has moved distally past an edge  1035 . With such a configuration, if the sled  102  is not present at the distal end of the blade  1060  to prop up the nose  1069 , then the lower guide wings  1065  will follow the depression  1037  just proximal of the edge  1035  and, instead of advancing on the floor  1034 , will hit the edge  1035  and stop further forward movement of the blade  1060 . To assist with such contact when the sled  102  is not present, the staple cartridge  1030  has a plate spring  1090  (attached thereto by rivets  1036 ). With the plate spring  1090  flexed upward and pressing downward against the flange  1067  (at least until the flange  1067  is distal of the distal end of the plate spring  1090 ), a downwardly directed force is imparted against the blade  1060  to press the wings  1065  down into the depression  1037 . Thus, as the blade  1060  advances distally without the sled  102  being present, the wings  1065  follow the lower curve of the depression  1037  and are stopped from further distal movement when the distal edge of the wings  1065  hit the edge  1035 .  FIG. 63 , for example, shows the distal edge  1035  and two raised bosses  1038  that extend the height of the edge  1035  to insure that the wings  1065  cannot be forced over the edge  1035  when the sled  102  is not present. 
       FIG. 66  illustrates an exemplary movement of the dogbone  1080  within the lower clevis half  2020  and the lower dogbone clevis  2040 . In the fully left articulated position of  FIG. 66 , the distal bottom projection of the dogbone  1080  is in a rotated position within the distal dogbone depression  2043  and the proximal bottom projection is in a rotated position within the proximal dogbone depression  2025 . Importantly, the left vertical surface of the dogbone  1080  is almost fully supported on the left dogbone supporting surfaces  2024 ,  2042 . The shapes of the depressions  2025 ,  2043  and the bottom projections of the dogbone  1080  are selected such that there is no elongation or compression of the dogbone  1080  but, merely, a rocking left to right when articulation of the end effector occurs. 
     Three side-by-side knife blades  1062  are diagrammatically illustrated in  FIG. 66  within a left articulated position of the lower clevis halves  2020 ,  2040 . When bent to the left, the knife blades  1062  are pressed against the right interior surface  1082  of the dogbone  1080 . Accordingly, the interior surfaces  1082  are shaped dependent upon the extent that the end effector will be articulated. Due to the limitations of drafting the features of the invention, the blades  1062  are only shown in a diagrammatic, approximate curved orientation. 
     To better understand some features of the knife blades  1062 , enlarged views of the proximal connection to the pushrod  1102  and the pushrod-blade support  1070  are shown in  FIG. 67 . While a configuration having co-axially aligned knife blades  1062  and the pushrod  1102  is envisioned and possible, an offset connection shown, for example, in  FIGS. 41 and 67 , is used. As set forth above, the length of the knife blades  1062  make it desirable for the knife blades  1062  to be pressed down fully into the blade channel  1072  within the pushrod-blade support  1070 .  FIG. 41  shows a first embodiment for an offset connection that biases the blades  1062  into the channel  1072 .  FIG. 67  shows a second embodiment for this offset connection. In this second embodiment, the blades  1062  are not fixedly connected to the pushrod  1102  as in the first embodiment (connected by transverse pushrod pin  1122 ). Instead, the pushrod  1102  is formed with a chamber  1108  into which is inserted the proximal end of the blades  1062 . By forming the chamber  1108  in a shape that axially longitudinally holds the blades  1062  (e.g., with a transverse offset), there is no need for a fixed connection. In this embodiment, the chamber  1108  is approximately L-shaped in vertical cross-section to provide such a transverse offset, but it can be any number of different shapes. 
     The distal connection of the pullbands  1140  is shown particularly well in  FIG. 59 . It is noted that, in such a configuration, left or right articulation imparts a bend on each of the two, three, four, or more adjacent pullbands  1140 . Because each pullband  1140  has a fixed length, and because the pullbands  1140  are stacked alongside one another, articulation in a given direction bends each of the pullbands  1140  differently, even if the difference is very slight. To compensate for such differences in bending, an alternative embodiment of the distal connection is provided and is shown in  FIGS. 68 to 70 . For clarity and simplicity, only a portion of the upper dogbone clevis  2030  is shown diagrammatically in these figures. 
     This alternative embodiment replaces the spacers  1170  in the first embodiment. Here, five pullbands  1140  are disposed alongside one another. The upper dogbone clevis  2030  defines an interior bore  2033  (e.g., a circular bore) into which is inserted a piston  2050  having an exterior shape corresponding to the interior shape of the bore  2033 . The bore  2033  has a proximal window  2034  through which the pullbands  1140  project into the bore  2033 . The window  2034  has a width approximately equal (but just slightly larger than) the total width of the pullbands  1140 . 
     The piston  2050  has a transverse bore into which is threaded a proximal pullband pin  2060  that functions as an axle when threaded through the piston  2050  and through the distal pullband bore  1145  of each of the pullbands  1140 . See  FIG. 70 . The interior  2051  of the piston  2050  does not have a shape corresponding to the width of the stacked pullbands  1140 . Instead, the interior opening for receiving the distal end of the pullbands  1140  has a winged horizontally cross-sectional shape. 
     As the end effector articulates, the distal end of the pullbands  1140  are bent into a curve. When adjacent parallel plates such as the pullbands  1140  are bent together, the outside plates move differently than the middle or inner plates. This non-homogeneous movement is compensated for by the winged opening  2051  and the oval-shaped distal pullband bores  1145 . As the end effector is articulated, the bending forces imparted upon the pullbands  1140  cause the piston  2050  to rotate within the bore  2033  of the upper dogbone clevis  2030 . The more that the end effector articulates, the more the piston  2050  rotates, until full articulation presses the outside pullband  1140  against the inner surface of the winged opening  2051 . At this point, the proximal ends of each pullband  1140  are aligned but the distal ends shown in  FIGS. 68 to 70  are not. The presence of the ovular openings  1145  allow the pullbands  1140  to move slightly with respect to one another. 
     The foregoing description and accompanying drawings illustrate the principles, preferred embodiments and modes of operation of the invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiments discussed above will be appreciated by those skilled in the art. 
     Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to those embodiments can be made by those skilled in the art without departing from the scope of the invention as defined by the following claims.

Technology Category: a