Patent Publication Number: US-2020289142-A1

Title: Surgical Instrument With Single Drive Input for Two End Effector Mechanisms

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. Ser. No. 15/669,100 filed Aug. 4, 2017 (Allowed); which is a Continuation of U.S. Ser. No. 14/498,750 filed Sep. 26, 2014 (now U.S. Pat. No. 9,730,719); which is a Divisional of U.S. Ser. No. 13/484,143 filed May 30, 2012 (now U.S. Pat. No. 8,870,912); which claims the benefit of U.S. Provisional Application No. 61/491,821 filed May 31, 2011; the disclosures which are incorporated herein by reference in their entirety for all purposes. 
    
    
     BACKGROUND 
     Minimally invasive surgical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. As a consequence, the average length of a hospital stay for standard surgery may be shortened significantly using minimally invasive surgical techniques. Also, patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery. 
     A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient&#39;s abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately one-half inch or less) incisions to provide entry ports for laparoscopic instruments. 
     Laparoscopic surgical instruments generally include an endoscope (e.g., laparoscope) for viewing the surgical field and tools for working at the surgical site. The working tools are typically similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an extension tube (also known as, e.g., an instrument shaft or a main shaft). The end effector can include, for example, a clamp, grasper, scissor, stapler, cautery tool, linear cutter, or needle holder. 
     To perform surgical procedures, the surgeon passes working tools through cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon views the procedure from a monitor that displays an image of the surgical site taken from the endoscope. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like. 
     Minimally invasive telesurgical robotic systems are being developed to increase a surgeon&#39;s dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a telesurgery system, the surgeon is often provided with an image of the surgical site at a control console. While viewing a three dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console. Each of the master input devices controls the motion of a servo-mechanically actuated/articulated surgical instrument. During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of the master input devices. 
     Manipulation and control of these end effectors is a particularly beneficial aspect of robotic surgical systems. For this reason, it is desirable to provide surgical tools that include mechanisms that provide three degrees of rotational movement of an end effector to mimic the natural action of a surgeon&#39;s wrist. Such mechanisms should be appropriately sized for use in a minimally invasive procedure and relatively simple in design to reduce possible points of failure. In addition, such mechanisms should provide an adequate range of motion to allow the end effector to be manipulated in a wide variety of positions. 
     Non-robotic linear clamping, cutting and stapling devices have been employed in many different surgical procedures. For example, such a device can be used to resect a cancerous or anomalous tissue from a gastro-intestinal tract. Many known surgical devices, including known linear clamping, cutting and stapling devices, often have opposing jaws that are used to manipulate patient tissue. 
     In many existing minimally invasive telesurgical robotic systems, manipulation of the surgical instruments is provided by a surgical robot having a number of robotic arms. Each of the robotic arms has a number of robotic joints and a mounting fixture for the attachment of a surgical instrument. Integrated in with at least one of the mounting fixtures are a number of drive couplers (e.g., rotary drive couplers) that drivingly interface with corresponding input couplers of the surgical instrument. The surgical instrument includes mechanisms that drivingly couple the input couplers with an associated motion of the surgical instrument (e.g., main shaft rotation, end effector pitch, end effector yaw, end effector jaw clamping). In many existing minimally invasive telesurgical robotic systems, there are four drive couplers integrated in with each of the mounting fixtures (e.g., one drive coupler to actuate main shaft rotation, one drive coupler to actuate end effector pitch, one drive coupler to actuate end effector yaw, and one drive coupler to actuate end effector jaw articulation). 
     A problem arises, however, when it is desired to employ a surgical robot having a number of output couplers per mounting fixture (e.g., four) to manipulate a surgical instrument having more than that number of functions (e.g., five such as main shaft rotation, end effector pitch, end effector yaw, end effector jaw clamping, and tissue cutting). 
     Thus, there is believed to be a need for surgical assemblies and related methods that employ a single input drive for two end effector functions (e.g., two different mechanisms). 
     BRIEF SUMMARY 
     Methods for treating tissue, and surgical assemblies and related methods are disclosed in which a single input is used to sequentially articulate two members. The single input is moved through a range of motion. During a first portion of the range of motion, the input link is drivingly coupled with a first articulated member (e.g., a jaw operable to grip tissue). Then, during a second portion of the range of motion, the input link is drivingly coupled with a second articulated member (e.g., a cutter operable to cut tissue). Accordingly, a robotic arm having a number of output couplers per mounting fixture (e.g., four) can be used to manipulate a surgical instrument having more than that number of functions (e.g., five such as main shaft rotation, end effector pitch, end effector yaw, end effector jaw clamping, and tissue cutting). 
     Thus, in a first aspect, a surgical assembly is provided. The surgical assembly includes an end effector, a base supporting the end effector, an input link movable relative to the base through a range of motion between a first configuration and a second configuration, and an actuation mechanism. The end effector includes a first articulated member and a second articulated member. The actuation mechanism drivingly couples the input link to the first articulated member within a first portion of the range of motion and drivingly coupling the input link with the second articulated member within a second portion of the range of motion so that a movement of the input link from the first configuration to the second configuration articulates the first articulated member and then articulates the second articulated member. 
     In many embodiments of the surgical assembly, the first and second articulated members are configured to manipulate tissue. For example, the first articulated member can have a first articulation range configured for a first desired manipulation of tissue. And the second articulated member can have a second articulation range configured for a second desired manipulation of tissue. The movement of the input link can actuate the first articulated member throughout the first articulation range primarily within the first portion of the range of motion, and can actuate the second articulated member throughout the second articulation range within the second portion of the range of motion. The first and second portions of the range of motion are separate so as to facilitate independently effecting the first and second desired manipulations of tissue. In many embodiments, the first articulated member includes a jaw operable to grip tissue and the second articulated member includes a cutter operable to cut tissue. 
     In many embodiments of the surgical assembly, the input link is drivingly coupled with the jaw through a spring that deflects during the second portion of the range of motion to at least partially decouple motion of the jaw from motion of the input link during the second portion of the range of motion. For example, the spring can inhibit relative movement between the input link and a first output link during the first portion of the range of motion, the first output link being drivingly coupled with the jaw. The spring can deflect to allow relative motion between the input link and the first output link during the second portion of the range of motion. And the input link can drive a second output link during the second portion of the range of motion, the second output link being drivingly coupled with the cutter. 
     Any suitable type of spring can be used. For example, the spring can include an extension spring. And linear motion of the input link relative to the base can be used to induce articulation of the jaw and the cutter. As another example, the spring can include a torsion spring. And rotation of the input link relative to the base can be used to induce articulation of the jaw and the cutter. 
     The actuation mechanism can include a cam surface drivingly coupled with the input link and shaped to inhibit driving of the cutter during the first portion of the range of motion and drive the cutter during the second portion of the range of motion. For example, a rotation of the input link relative to the base can be used to induce a rotation of the cam surface relative to the base. The actuation mechanism can include a member with a slot that defines the cam surface and a follower that engages the slot and is drivingly coupled with the cutter by a linkage. The slotted member can be mounted for rotation relative to the base about an axis of rotation. The slot can include a first segment having a centerline with a constant radius relative to the axis of rotation and a second segment having a centerline with a varying radius relative to the axis of rotation. The follower can engage the first segment during the first portion of the range of motion and can engage the second segment during the second portion of the range of motion. 
     The actuation mechanism can include two separate cam surfaces that are drivingly coupled with the input link. For example, a first cam surface can be drivingly coupled with the input link and shaped to actuate the first articulated member. And a second cam surface can also be coupled with the input link and shaped to actuate the second articulated member. The first cam surface can be part of a first slotted member that is drivingly coupled with the input link. And the second cam surface can be part of a second slotted member that is drivingly coupled with the input link. The first and second articulated members can be drivingly coupled with respective followers that engage the first and second cam surfaces, respectively. 
     The actuation mechanism can include one or more cam surfaces such as disclosed herein and the input link can be drivingly coupled with the jaw through a spring that deflects to at least partially decouple motion of the jaw from motion of the input link such as disclosed herein. Such a combined embodiment can be used to provide flexibility with regard to the amount of jaw articulation that occurs prior to the articulation of the cutter, such as when items of different sizes are gripped by the jaw. 
     In another aspect, a method of treating tissue is provided. The method includes moving an input link relative to a base through a range of motion, articulating a jaw within a first portion of the range of motion so as to grasp the tissue, and articulating a cutter within a second portion of the range of motion so as to cut the tissue, the articulating of the jaw and the cutter being primarily independent. 
     In many embodiments of the method of treating tissue, the articulation of the jaw includes inhibiting relative movement between the input link and an output link during the first portion of the range of motion with a spring coupled with the input link and the output link, the output link being drivingly coupled with the jaw. The articulation of the cutter can include deflecting the spring to at least partially decouple motion of the output link from the input link during the second portion of the range of motion. 
     Any suitable type of spring can be used. For example, the spring can include an extension spring. And the method can include translating the input link relative to the base to induce the articulation of the jaw and the cutter. As another example, the spring can include a torsion spring. And the method can include rotating the input link relative to the base to induce the articulation of the jaw and the cutter. 
     In many embodiments, the method of treating tissue includes rotating a member having a slot in response to rotation of the input link and engaging the slot with a follower that is drivingly coupled with the cutter. The method of treating tissue can include rotating the slotted member about an axis of rotation relative to the base. The slot can include a first segment having a centerline with a constant radius relative to the axis of rotation and a second segment having a centerline with a varying radius relative to the axis of rotation. The method of treating tissue can include engaging the first segment with the follower during the first portion of the range of motion and engaging the second segment with the follower during the second portion of the range of motion. 
     The method of treating tissue can include both rotating a member having a slot in response to rotation of the input link and engaging the slot with a follower that is drivingly coupled with the cutter such as disclosed herein, and inhibiting relative movement between the input link and an output link with a spring coupled with the input link and the output link, the output link being drivingly coupled with the jaw, such as disclosed herein. And the method can include deflecting the spring to at least partially decouple motion of the output link from the input link such as disclosed herein. Such a combined embodiment can be used to provide flexibility with regard to the amount of jaw articulation that occurs prior to the articulation of the cutter, such as when items of different sizes are gripped by the jaw. 
     In another aspect, a method is provided for articulating an end effector of a surgical assembly. The method includes moving an input link relative to a base through a range of motion, articulating a first member of the end effector within a first portion of the range of motion, and articulating a second member of the end effector within a second portion of the range of motion, the first and second members being different and the articulating of the first and second members being primarily independent. 
     In many embodiments of the method for articulating an end effector of a surgical assembly, the first member includes a jaw configured to grip a tissue and the second member includes a cutter configured to cut the tissue. In many embodiments of the method for articulating an end effector of a surgical assembly, the jaw has a first articulation range configured to grip a tissue and the cutter has a second articulation range configured to cut the tissue. Movement of the input link actuates the jaw throughout the first articulation range primarily within the first portion of the range of motion, and actuates the cutter throughout the second articulation range within the second portion of the range of motion. The first and second portions of the range of motion are separate so as to facilitate independently gripping the tissue and cutting the gripped tissue. 
     For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings. Other aspects, objects and advantages of the invention will be apparent from the drawings and detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a minimally invasive robotic surgery system being used to perform a surgery, in accordance with many embodiments. 
         FIG. 2  is a perspective view of a surgeon&#39;s control console for a robotic surgery system, in accordance with many embodiments. 
         FIG. 3  is a perspective view of a robotic surgery system electronics cart, in accordance with many embodiments. 
         FIG. 4  diagrammatically illustrates a robotic surgery system, in accordance with many embodiments. 
         FIG. 5A  is a front view of a patient side cart (surgical robot) of a robotic surgery system, in accordance with many embodiments. 
         FIG. 5B  is a front view of a robotic surgery tool, in accordance with many embodiments. 
         FIG. 6A  is a perspective view of a robotic surgery tool that includes an end effector having opposing clamping jaws, in accordance with many embodiments. 
         FIG. 6B  is a close-up perspective view of the end effector of  FIG. 6A . 
         FIG. 7  is an exploded perspective view of the end effector of  FIG. 6A , illustrating a mechanism used to convert rotary motion of a drive shaft into articulation of the opposing clamping jaws. 
         FIGS. 8A and 8B  are perspective views of an end effector having opposing clamping jaws and a mechanism used to convert rotary motion of a drive shaft into articulation of the opposing clamping jaws, in accordance with many embodiments. 
         FIG. 9  is a simplified schematic illustrating an actuation mechanism in which a single input link is used to sequentially articulate two members, in accordance with many embodiments. 
         FIG. 10  is a simplified schematic illustrating a mechanism that actuates a cutter during a second portion of a range of rotational motion of an input link, in accordance with many embodiments. 
         FIG. 11  is a perspective view of a proximal chassis of a surgical instrument that includes a mechanism that actuations a cutter during a second portion of a range of rotational motion of an input link, in accordance with many embodiments. 
         FIG. 12  is a perspective view of a proximal chassis of another surgical instrument that includes a mechanism that actuations a cutter during a second portion of a range of rotational motion of an input link, in accordance with many embodiments. 
         FIG. 13A  schematically illustrates an actuation mechanism having two separate slotted members rotationally coupled with a common input link to drive two separate output links, in accordance with many embodiments. 
         FIG. 13B  schematically illustrates a first slotted member of the actuation mechanism of  FIG. 13A . 
         FIG. 13C  schematically illustrates a second slotted member of the actuation mechanism of  FIG. 13A . 
         FIG. 14  illustrates acts of a method for articulating two separate members of an end effector by using a single input, in accordance with many embodiments. 
         FIG. 15  illustrates acts of a method for treating tissue, in accordance with many embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described. 
     Minimally Invasive Robotic Surgery 
     Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,  FIG. 1  is a plan view illustration of a Minimally Invasive Robotic Surgical (MIRS) system  10 , typically used for performing a minimally invasive diagnostic or surgical procedure on a Patient  12  who is lying down on an Operating table  14 . The system can include a Surgeon&#39;s Console  16  for use by a Surgeon  18  during the procedure. One or more Assistants  20  may also participate in the procedure. The MIRS system  10  can further include a Patient Side Cart  22  (surgical robot) and an Electronics Cart  24 . The Patient Side Cart  22  can manipulate at least one removably coupled tool assembly  26  (hereinafter simply referred to as a “tool”) through a minimally invasive incision in the body of the Patient  12  while the Surgeon  18  views the surgical site through the Console  16 . An image of the surgical site can be obtained by an endoscope  28 , such as a stereoscopic endoscope, which can be manipulated by the Patient Side Cart  22  so as to orient the endoscope  28 . The Electronics Cart  24  can be used to process the images of the surgical site for subsequent display to the Surgeon  18  through the Surgeon&#39;s Console  16 . The number of surgical tools  26  used at one time will generally depend on the diagnostic or surgical procedure and the space constraints within the operating room among other factors. If it is necessary to change one or more of the tools  26  being used during a procedure, an Assistant  20  may remove the tool  26  from the Patient Side Cart  22 , and replace it with another tool  26  from a tray  30  in the operating room. 
       FIG. 2  is a perspective view of the Surgeon&#39;s Console  16 . The Surgeon&#39;s Console  16  includes a left eye display  32  and a right eye display  34  for presenting the Surgeon  18  with a coordinated stereo view of the surgical site that enables depth perception. The Console  16  further includes one or more input control devices  36 , which in turn cause the Patient Side Cart  22  (shown in  FIG. 1 ) to manipulate one or more tools. The input control devices  36  can provide the same degrees of freedom as their associated tools  26  (shown in  FIG. 1 ) so as to provide the Surgeon with telepresence, or the perception that the input control devices  36  are integral with the tools  26  so that the Surgeon has a strong sense of directly controlling the tools  26 . To this end, position, force, and tactile feedback sensors (not shown) may be employed to transmit position, force, and tactile sensations from the tools  26  back to the Surgeon&#39;s hands through the input control devices  36 . 
     The Surgeon&#39;s Console  16  is usually located in the same room as the patient so that the Surgeon may directly monitor the procedure, be physically present if necessary, and speak to an Assistant directly rather than over the telephone or other communication medium. However, the Surgeon can be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures. 
       FIG. 3  is a perspective view of the Electronics Cart  24 . The Electronics Cart  24  can be coupled with the endoscope  28  and can include a processor to process captured images for subsequent display, such as to a Surgeon on the Surgeon&#39;s Console, or on another suitable display located locally and/or remotely. For example, where a stereoscopic endoscope is used, the Electronics Cart  24  can process the captured images so as to present the Surgeon with coordinated stereo images of the surgical site. Such coordination can include alignment between the opposing images and can include adjusting the stereo working distance of the stereoscopic endoscope. As another example, image processing can include the use of previously determined camera calibration parameters so as to compensate for imaging errors of the image capture device, such as optical aberrations. 
       FIG. 4  diagrammatically illustrates a robotic surgery system  50  (such as MIRS system  10  of  FIG. 1 ). As discussed above, a Surgeon&#39;s Console  52  (such as Surgeon&#39;s Console  16  in FIG. 1 ) can be used by a Surgeon to control a Patient Side Cart (Surgical Robot)  54  (such as Patent Side Cart  22  in  FIG. 1 ) during a minimally invasive procedure. The Patient Side Cart  54  can use an imaging device, such as a stereoscopic endoscope, to capture images of the procedure site and output the captured images to an Electronics Cart  56  (such as the Electronics Cart  24  in  FIG. 1 ). As discussed above, the Electronics Cart  56  can process the captured images in a variety of ways prior to any subsequent display. For example, the Electronics Cart  56  can overlay the captured images with a virtual control interface prior to displaying the combined images to the Surgeon via the Surgeon&#39;s Console  52 . The Patient Side Cart  54  can output the captured images for processing outside the Electronics Cart  56 . For example, the Patient Side Cart  54  can output the captured images to a processor  58 , which can be used to process the captured images. The images can also be processed by a combination the Electronics Cart  56  and the processor  58 , which can be coupled together so as to process the captured images jointly, sequentially, and/or combinations thereof. One or more separate displays  60  can also be coupled with the processor  58  and/or the Electronics Cart  56  for local and/or remote display of images, such as images of the procedure site, or other related images. 
       FIGS. 5A and 5B  show a Patient Side Cart  22  and a surgical tool  62 , respectively. The surgical tool  62  is an example of the surgical tools  26 . The Patient Side Cart  22  shown provides for the manipulation of three surgical tools  26  and an imaging device  28 , such as a stereoscopic endoscope used for the capture of images of the site of the procedure. Manipulation is provided by robotic mechanisms having a number of robotic joints. The imaging device  28  and the surgical tools  26  can be positioned and manipulated through incisions in the patient so that a kinematic remote center is maintained at the incision so as to minimize the size of the incision. Images of the surgical site can include images of the distal ends of the surgical tools  26  when they are positioned within the field-of-view of the imaging device  28 . 
     Tissue Gripping End Effectors 
       FIG. 6A  shows a surgical tool  70  that includes a proximal chassis  72 , an instrument shaft  74 , and a distal end effector  76  having a jaw  78  that can be articulated to grip a patient tissue. The proximal chassis includes an input coupler that is configured to interface with and be driven by an output coupler of the Patient Side Cart  22 . The input coupler is drivingly coupled with an input link of a spring assembly  80 . The spring assembly  80  is mounted to a frame  82  of the proximal chassis  72  and includes an output link that is drivingly coupled with a drive shaft that is disposed within the instrument shaft  74 . The drive shaft is drivingly coupled with the jaw  78 .  FIG. 6B  provides a close-up view of the jaw  78  of the end effector  76 . 
       FIG. 7  is an exploded perspective view of the end effector  76  of  FIG. 6A , illustrating a clamping mechanism used to convert rotary motion of a drive shaft  84  into articulation of opposing clamping jaws of the end effector  76 . The end effector includes an upper jaw  86 , a lower jaw  88 , a frame  90 , a pin  92  for pivotally mounting the upper jaw  86  and the lower jaw  88  to the frame  90 , and a lead screw mechanism  94  that is drivingly coupled with the drive shaft  84 . The lead screw mechanism  94  includes a lead screw  96  and a mating translating nut  98  that is advanced and retracted along a slot  100  in the frame  90  via rotation of the lead screw  96 . The translating nut  98  includes oppositely extending protrusions that interface with a slot  102  in the upper jaw  86  and with a slot  104  in the lower jaw  88 , thereby causing articulation of the upper jaw  86  and the lower jaw  88  about the pin  92  when the translating nut  98  is advanced or retracted along the slot  100 . 
     The end effector  76  further includes a cutter  106  operable to cut a gripped tissue. The cutter  106  is coupled to a drive member  108 . The cutter  106  is advanced distally by a corresponding distal advancement of the drive member  108  and is retracted proximally by a corresponding proximal retraction of the drive member  108 . Each of the upper jaw  86  and the lower jaw  88  include a slot  110  that can accommodate a portion of the cutter  106  throughout its range of travel, thereby serving to restrain and guide the cutter  106  throughout its range of motion. In many embodiments, the drive member  108  extends between the cutter  106  and the proximal chassis  72  and is drivingly coupled with an actuation mechanism disposed in the proximal chassis. The actuation mechanism in the proximal chassis can push the drive member  108  distally to advance the cutter  106  distally to cut a gripped tissue. The actuation mechanism can pull the drive member  108  proximally to return the cutter  106  to a retracted starting position. 
       FIG. 8A  and  FIG. 8B  illustrate the operation of a clamping mechanism similar to the clamping mechanism of  FIG. 7 . Rotating the drive shaft  84  in the direction shown causes a translating nut  98  to advance distally toward the pivot pin  92  by which the lower jaw  88  and the upper jaw  86  are pivotally mounted to the frame  90  of an end effector. As illustrated in  FIG. 8B , a protrusion of the translating nut  98  engages the slot  102  in the upper jaw  86 . Distal advancement of the translating nut  98  toward the pivot pin  92  causes the upper jaw to rotate in the direction shown, and causes the lower jaw  88  to rotate in the opposite direction, thereby opening the jaw. Similarly, proximal advancement of the translating nut  98  away from the pivot pin  92  cause the jaw to close. Accordingly, the jaw can be articulated to grip a patient tissue. 
     The end effector  76  can be used to sequentially grip a tissue and then cut the gripped tissue. For example, with the cutter  106  positioned at the retracted starting position (i.e., positioned proximal to the gripping surfaces of the jaw), the jaw  78  can be articulated to grip a tissue. Then, proximal advancement of the cutter  106  along the slots  110  can be accomplished to cut the gripped tissue. 
     Single Drive Input for Two End Effector Mechanisms 
       FIG. 9  schematically illustrates an actuation mechanism  120  in which a single input link  122  is used to sequentially articulate two members, in accordance with many embodiments. The actuation mechanism  120  includes the input link  122 , a first output link  124  that is drivingly coupled with the jaw  78  operable to grip tissue, a second output link  126  that is drivingly coupled with the cutter  106  operable to cut the gripped tissue, and a preloaded spring  128  coupled between the input link  122  and the first output link  124 . An input coupler  130  (also known as an input “dog”) is drivingly coupled with the input link  122 . 
     The input link  122  is driven by the input coupler  130  through a range of motion (e.g., from left to right in  FIG. 9 ). During a first portion of the range of motion, the preloaded spring  128  pulls the first output link  124  to the right, and thereby maintaining contact between the input link  122  and the first output link  124 . At some point during the range of motion, the jaw begins to either grip tissue or reaches a closed configuration, thereby causing the actuation force transferred to the jaw by the first output link  124  to increase. Once the actuation force transferred to the jaw by the first output link  124  exceeds a predetermined level corresponding to the preload force level in the preloaded spring  128 , further movement of the input link  122  to the right causes the preloaded spring  128  to extend, thereby allowing the input link  122  and the first output link  124  to separate. Further movement of the input link  122  to the right causes further extension of the preloaded spring  128 , thereby causing increased separation between the input link  122  and the first output link  124 . 
     During a second portion of the range of motion (i.e., after the first portion of the range of motion), the input link  122  comes into contact with the second output link  126 , which is drivingly coupled with the cutter  106 . Further movement of the input link  122  to the right drives the second output link  126  to the right, thereby causing actuation of the cutter  106 . During the second portion of the range of motion, extension of the preloaded spring  128  provides for an increasing amount of separation between a substantially non-moving first output link  124  and the input link  122  as the input link  122  drives the second output link  126  to the right. The second output link  126  and/or the cutter  106  can be attached to a return mechanism (e.g., a spring) that returns the second output link  126  and/or the cutter  106  to the retracted starting position in the absence of contact between the input link  122  and the second output link  126  (e.g., during the first portion of the range of motion of the input link). 
     While the actuation mechanism  120  is shown and described with respect to the preloaded spring  128  being an extension spring, any suitable spring can be used. For example, the preloaded spring  128  can be a torsion spring and rotational movement of the input coupler  130  can induce rotational movement of the input link  122 , rotational driving of the first output link  124 , rotational deflection of the preloaded torsion spring  128 , and rotational driving of the second output link  126 . 
       FIG. 10  schematically illustrates another actuation mechanism  140  in which a single input link  142  is used to sequentially articulate two members, in accordance with many embodiments. The actuation mechanism  140  includes the input link  142  mounted for rotation relative to a base around a rotation axis  144 , a first toggle link  146  mounted for rotation relative to the base around a first pivot point  148 , a connection link  150 , a second toggle link  152  mounted for rotation relative to the base around a second pivot point  154 , and a drive link  156 . The input link  142  includes a slot  158 . The first toggle link  146  includes a follower  160  that engages the slot  158 . The first toggle link  146  is coupled with the connection link  150  via a first connection pin  162 . The connection link  150  is coupled with the second toggle link  152  via a second connection pin  164 . The second toggle link  152  is coupled with the drive link  156  via a third connection pin  166 . 
     The input link  142  and the output link  156  are used to sequentially articulate the two members. The input link  142  is drivingly coupled with an actuation mechanism that articulates a first of the two members. For example, the input link  142  can be drivingly coupled with an actuation mechanism that articulates an end effector jaw that is operable to grip a tissue. Motion of the drive link  156  causes articulation of a second of the two members. For example, motion of the drive link  156  can be used to articulate a cutter operable to cut a tissue, for example, a tissue gripped by an end effector jaw. 
     The actuation mechanism  140  is configured to produce substantially no movement of the drive link  156  during a first portion of a range of motion of the input link  142  and to produce substantially axial movement of the drive link  156  during a second portion of the range of motion of the input link  142 . The input link  142  includes the slot  158  and the first toggle link  146  includes the follower  160  that engages the slot  158 . The slot  158  includes a first segment  168  having a centerline with a substantially constant radius relative to the rotation axis  144  and a second segment  170  having a centerline with a varying radius relative to the rotation axis  144 . The follower  160  engages the slot  158  along the first segment  168  during the first portion of the range of motion of the input link  142  and engages the slot  158  along the second segment  170  during the second portion of the range of motion of the input link  142 . 
     During the first portion of the range of motion of the input link  142 , the substantially constant radius of the first segment  168  of the slot  158  produces no movement of the first toggle link  146 , thereby producing no movement of the drive link  156 . During the second portion of the range of motion of the input link  142 , the varying radius of the second segment  170  of the slot  158  produces clockwise movement of the first toggle link  146  about the first pivot point  148 , which produces a corresponding clockwise motion of the second toggle link  152  about the second pivot point  154 , which produces an upward substantially axial movement of the drive link  156 . By reversing the motion of the input link  142 , an opposite downward substantially axial movement of drive link  156  occurs during the second portion of the range of motion, thereby returning the drive link  156  to its starting position. 
     In many embodiments, the input link  142  is coupled to the first of the two members through a mechanism that allows the first of the two members to be substantially stationary during the second portion of the range of motion of the input link  142 . For example, when the input link  142  is drivingly coupled with an actuation mechanism that articulates a jaw operable to grip a tissue, a spring loaded mechanism similar to the actuation mechanism  120  described above can be used to provide for relative movement during the second portion of the range of motion of the input link  142  between the input link  142  and an output link that is drivingly coupled with the actuation mechanism that articulates a jaw operable to grip a tissue. Additional approaches for coupling the input link  142  to the first of the two members so as to allow for relative movement between the input link  142  and the first of the two members during the second portion of the range of motion of the input link  142  are described in U.S. Provisional Application No. 61/491,804, entitled “Grip Force Control in a Robotic Surgical Instrument,” filed on May 31, 2011, (Attorney Docket No. ISRG 03320/US), the full disclosure of which is incorporated herein by reference. 
       FIG. 11  shows a proximal chassis  170  of a surgical instrument that includes an actuation mechanism  172  in which a single input link  174  is used to sequentially articulate two members, in accordance with many embodiments. The actuation mechanism  122  includes the input link  174  mounted to a base  176  for rotation about a rotation axis  178 , a first link  180  mounted to the base to translate in one direction relative to the base, a toggle link  182  mounted for rotation relative to the base around a pivot point  184 , and a drive link  186 . The input link  174  includes a slot  188  and the first link  180  includes a follower  190  that engages the slot  188 . The slot  188  includes a first segment having a centerline with a substantially constant radius relative to the rotation axis  178  and a second segment having a centerline with a varying radius relative to the rotation axis  178 . The follower  190  engages the slot  188  along the first segment during the first portion of the range of motion of the input link  174  and engages the slot  188  along the second segment during the second portion of the range of motion of the input link  174 . During the first portion of the range of motion of the input link  174 , the substantially constant radius of the first segment of the slot  188  produces no movement of the first link  180 , thereby producing no movement of the drive link  186 . During the second portion of the range of motion of the input link  174 , the varying radius of the second segment of the slot  188  produces axial movement of the first link  180 , which produces a clockwise motion of the toggle link  182  about the pivot point  184 , which produces a distal substantially axial movement of the drive link  186 . By reversing the motion of the input link  174 , an opposite proximal substantially axial movement of drive link  186  occurs during the second portion of the range of motion, thereby returning the drive link  186  to its starting position. 
     As described above with regard to the input link  142  of the actuation mechanism  140 , the input link  174  of the actuation mechanism  172  can be coupled to the first of the two members through a mechanism that allows the first of the two members to be substantially stationary during the second portion of the range of motion of the input link  174  using similar approaches. 
       FIG. 12  shows a proximal chassis  191  of another surgical instrument that includes an actuation mechanism  192  in which a single input link  194  is used to sequentially articulate two members, in accordance with many embodiments. The actuation mechanism  192  is configured and operates similar to the actuation mechanism  172  discussed above. The actuation mechanism  192  does include some addition features. These additional features include a first link  196  that includes a double shear clevis  198  having a guide slot  200 . The double shear clevis  198  provides double shear support of the follower that engages the slot in the input link  194 . The guide slot  200  serves to restrain the follower end of the first link  196  against any movement of the follower end transverse to the direction in which the first link is mounted to translate relative to the base. An end restraint  202  is also provided adjacent to the connection between the first link  196  and the toggle link  182  to restrain the end of the first link against any movement transverse to the direction in which the first link is mounted to translate relative to the base. 
       FIG. 13A ,  FIG. 13B , and  FIG. 13C  schematically illustrate an actuation mechanism  210  in which a single input link is used to sequentially articulate two output links, in accordance with many embodiments. The actuation mechanism  210  includes an input link  212 , a first output link  214 , a second output link  216 , a first slotted member  218 , and a second slotted member  220 . 
     The input link  212  is mounted for rotation relative to a base  222  (e.g., a proximal chassis of a surgical instrument as described herein). The input link  212  is attached to an input coupler  224  that is configured to interface with and be rotationally driven by an output coupler of the Patient Side Cart  22 . Each of the first and second slotted members  218 ,  220  is attached to the input link  212  to rotate therewith. 
     The first output link  214  is constrained to translate along a direction of motion and includes a follower  226  that engages a slot  228  in the first slotted member  218 .  FIG. 13B  illustrates the slot  228 , which includes a first segment  230  having a varying radius relative to a rotational center  232  of the first slotted member  218 , and a second segment  233  having a substantially constant radius relative to the rotational center  232 . In many embodiments, the first output link  214  is constrained to translate along a line that intersects or passes relatively close to the rotational center  232  so as to substantially align the force applied to the first output link  214  by the first slotted member  218  with the direction of motion of the first output link  214 . Rotation of the first slotted member  218  by the input link  212  causes translation of the first output link  214  along its direction of motion when the follower  226  is engaged by the first segment  230  of the slot  228 . This translation of the first output link  214  is caused by the change in radial position between the follower  226  and the rotational center  232  when the follower  226  is engaged by the first segment  230 . And rotation of the first slotted member  218  by the input link  212  produces substantially zero translation of the first output link  214  along its direction of motion when the follower  226  is engaged by the second segment  233  of the slot  228 . The substantially zero translation of the first output link  214  results from the constant radial position between the follower  226  and the rotational center  232  when the follower  226  is engaged by the second segment  233 . 
     The second output link  216  is constrained to translate along a direction of motion and includes a follower  234  that engages a slot  236  in the second slotted member  220 .  FIG. 13C  illustrates the slot  236 , which includes a first segment  238  having a substantially constant radius relative to a rotational center  240  of the second slotted member  220 , and a second segment  242  having a varying radius relative to the rotational center  240 . In many embodiments, the second output link  216  is constrained to translate along a line that intersects or passes relatively close to the rotational center  240  so as to substantially align the force applied to the second output link  216  by the second slotted member  220  with the direction of motion of the second output link  216 . Rotation of the second slotted member  220  by the input link  212  produces substantially zero translation of the second output link  216  along its direction of motion when the follower  234  is engaged by the first segment  238  of the slot  236 . The substantially zero translation of the second output link  216  results from the constant radial position between the follower  234  and the rotational center  240  when the follower  234  is engaged by the first segment  238 . And rotation of the second slotted member  220  by the input link  212  causes translation of the second output link  216  along its direction of motion when the follower  234  is engaged by the second segment  242  of the slot  236 . This translation of the second output link  216  is caused by the change in radial position between the follower  234  and the rotational center  240  when the follower  234  is engaged by the second segment  242 . 
     In operation, the first output link  214  translates and the second output link  216  remains stationary during a first portion of a range of rotation of the input link  212 , and the first output link  214  remains stationary and the second output link  216  translates during a second portion of a range of rotation of the input link  212 . During the first portion of the range of rotation of the input link  212 , the first output link follower  226  is engaged by the first segment  230  of the slot  228  in the first slotted member  218  and the second output link follower  234  is engaged by the first segment  238  of the slot  236  in the second slotted member  220 . During the second portion of the range of rotation of the input link  212 , the first output link follower  226  is engaged by the second segment  233  of the slot  228  in the first slotted member  218  and the second output link follower  234  is engaged by the second segment  242  of the slot  236  in the second slotted member  220 . 
     The actuation mechanism  210  can be used to articulate an end effector jaw operable to grip tissue, such as the end effector jaw  78  described herein, and an additional end effector mechanism, such as the cutter  106  described herein. For example, the first output link  214  can be drivingly coupled with an end effector jaw operable to grip a patient tissue and the second output link  216  can be drivingly coupled with a cutter operable to cut the gripped patient tissue. In such an arrangement, rotation of the input link  212  through the first range of rotation causes articulation of the end effector jaw to grip a patient tissue along with no substantial movement of the cutter. Then, further rotation of the input link  212  through the second range of rotation causes no further articulation of the end effector jaw along with articulation of the cutter to cut the gripped tissue. Other end effector mechanisms (e.g., a mechanism for deploying staples) can also be articulated by the actuation mechanism  210 . For example, the first output link  214  can be drivingly coupled with a staple deploying mechanism and the second output link  216  can be drivingly coupled with a cutter mechanism, thereby providing for a sequential deployment of staples followed by actuation of the cutter to cut the stapled tissue. 
     In many embodiments, the first output link  214  and/or the second output link  216  is coupled to its respective end effector mechanism by a spring loaded mechanism similar to the actuation mechanism  120  describe herein so as to control the amount of force transferred to the end effector mechanism by providing for relative movement between the respective output link and the respective end effector mechanism. Additional approaches for coupling the output links  214 ,  216  to a respective end effector mechanism are described in U.S. Provisional Application No. 61/491,804, entitled “Grip Force Control in a Robotic Surgical Instrument,” filed on May 31, 2011, (Attorney Docket No. ISRG 03320/US), which has been incorporated by reference above. 
     Surgical Assembly Applications 
     The surgical assemblies and instruments disclosed herein can be employed in any suitable application. For example, the surgical assemblies disclosed herein can be employed in other surgical instruments, manual or powered, hand-held or robotic, directly controlled or teleoperated, for open or minimally invasive (single or multi-port) procedures. Examples of such instruments include those with distal components that receive torque actuating inputs (e.g., for grip control functions, component orientation control functions, component position functions, etc.). Illustrative non-limiting examples include teleoperated or hand-held instruments that include stapling, cutting, tissue fusing, imaging device orientation and position control, high force grasping, biopsy, and end effector and orientation control. 
     Methods for Articulating Two Members with a Single Drive Input 
       FIG. 14  illustrates acts of a method  250  for articulating an end effector of a surgical assembly, in accordance with many embodiments. The method  250  can be practiced, for example, with the surgical assemblies and/or instruments disclosed herein. 
     The method  250  includes moving an input link relative to a base through a range of motion (act  252 ), articulating a first member of the end effector within a first portion of the range of motion (act  254 ), and articulating a second member of the end effector within a second portion of the range of motion (act  256 ). The first and second members are different. And the articulation of the first member and the articulation of the second member are primarily independent. 
     In many embodiments, the end effector is configured to treat a tissue. For example, the articulated first member of the end effector can include a jaw configured to grip a tissue, and the articulated second member of the end effector can include a cutter configured to cut the tissue. The jaw can have a first articulation range configured to grip the tissue and the cutter can have a second articulation range configured to cut the tissue. Movement of the input link can actuate the jaw throughout the first articulation range primarily within the first portion of the range of motion, and can actuate the cutter throughout the second articulation range within the second portion of the range of motion. In many embodiments, the first and second portions of the range of motion are separate so as to facilitate independently gripping the tissue and cutting the gripped tissue. 
     Any other suitable combination of end effector articulated members can be used as the first and second members. For example, the articulated first member can include a mechanism for deploying staples into a tissue, and the articulated second member can include a cutter for cutting the stapled tissue. As another example, the articulated first member can include a jaw operable to grip a tissue, and the articulated second member can include a mechanism for deploying staples into the gripped tissue. 
       FIG. 15  illustrates acts of a method  260  of treating tissue, in accordance with many embodiments. The method  260  can be practiced, for example, with the surgical assemblies and/or instruments disclosed herein. 
     The method  260  includes moving an input link relative to a base through a range of motion (act  262 ), articulating a jaw within a first portion of the range of motion so as to grasp the tissue (act  264 ), and articulating a cutter within a second portion of the range of motion, the articulating of the jaw and the cutter being primarily independent (act  266 ). 
     In many embodiments of the method  260 , the articulation of the jaw includes inhibiting relative movement between the input link and an output link during the first portion of the range of motion with a spring coupled with the input link and the output link, the output link being drivingly coupled with the jaw. The articulation of the cutter can include deflecting the spring to at least partially decouple motion of the output link from the input link during the second portion of the range of motion. Any suitable type of spring can be used (e.g., an extension spring, a torsion spring). Any suitable type of motion of the input link relative to the base can be used to induce the articulation of the jaw and cutter (e.g., translation of the input link relative to the base, rotation of the input link relative to the base). 
     The cutter can be articulated by using a cam surface that is drivingly coupled with the input link and a follower that engages the cam surface and is drivingly coupled with the cutter. For example, the method  260  can include rotating a member having a slot in response to rotation of the input link, and engaging the slot with a follower that is drivingly coupled with the cutter. The slotted member can be rotated about an axis of rotation relative to the base. The slot can include a first segment having a centerline with a constant radius relative to the axis of rotation and a second segment having a centerline with a varying radius relative to the axis of rotation. The follower can engage the first segment during the first portion of the range of motion. And the follower can engage the second segment during the second portion of the range of motion. 
     Two or more slotted members can be used to drive a corresponding two or more end effector mechanisms. For example, the method  260  can include rotating a first member having a first slot in response to rotation of the input link, engaging the first slot with a first follower that is drivingly coupled with the jaw, rotating a second member having a second slot in response to rotation of the input link, and engaging the second slot with a second follower that is drivingly coupled with the cutter. 
     Method Applications 
     The methods disclosed herein can be employed in any suitable application. For example, the methods disclosed herein can be employed in surgical instruments, manual or powered, hand-held or robotic, directly controlled or teleoperated, for open or minimally invasive (single or multi-port) procedures. Examples of such instruments include those with distal components that receive actuating inputs (e.g., for grip control functions, component orientation control functions, component position functions, etc.). Illustrative non-limiting examples include teleoperated or hand-held instruments that include stapling, cutting, tissue fusing, imaging device orientation and position control, high force grasping, biopsy, and end effector and orientation control. 
     Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. 
     The term “force” is to be construed as encompassing both force and torque (especially in the context of the following claims), unless otherwise indicated herein or clearly contradicted by context. The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.