Patent Publication Number: US-2023157715-A1

Title: Drive mechanisms for surgical instruments

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the filing date of provisional U.S. Patent Application No. 63/281,136 filed on Nov. 19, 2021. 
    
    
     INTRODUCTION 
     The present disclosure relates to surgical instruments and, more specifically, to drive mechanisms for surgical instruments for use in robotic surgical systems. 
     BACKGROUND 
     Robotic surgical systems are increasingly utilized in various surgical procedures. Some robotic surgical systems include a console supporting a robotic arm. One or more different surgical instruments may be configured for use with the robotic surgical system and selectively mountable to the robotic arm. The robotic arm provides one or more inputs to the mounted surgical instrument to enable operation of the mounted surgical instrument. 
     The number, type, and configuration of inputs provided by the robotic arm of a robotic surgical system are constraints in the design of surgical instruments configured for use with the robotic surgical system. That is, in designing a surgical instrument compatible for mounting on and use with the robotic arm of a robotic surgical system, consideration should be given to determining how to utilize the available inputs provided by the robotic arm to achieve the desired functionality of the surgical instrument. 
     SUMMARY 
     As used herein, the term “distal” refers to the portion that is being described which is further from a surgeon, while the term “proximal” refers to the portion that is being described which is closer to a surgeon. The terms “about,” substantially,” and the like, as utilized herein, are meant to account for manufacturing, material, environmental, use, and/or measurement tolerances and variations. Further, to the extent consistent, any of the aspects described herein may be used in conjunction with any or all of the other aspects described herein. 
     Provided in accordance with aspects of the present disclosure is a surgical instrument for use with a robotic surgical system. The surgical instrument includes a housing, a shaft extending distally from the housing, and first and second jaw members disposed at a distal end of the shaft. At least the first jaw member is movable relative to the second jaw member to grasp tissue therebetween. The surgical instrument also includes a knife blade configured to cut tissue. The surgical instrument also includes a drive input having a first plurality of teeth. The drive input is configured to receive a rotational input from a robotic surgical system to drive rotation of an input shaft and translate the knife blade. The surgical instrument also includes a knife blade lock having a second plurality of teeth. The knife blade lock is configured to move between a locked position wherein the second plurality of teeth interlock with the first plurality of teeth to prevent rotation of the drive input and an unlocked position wherein the second plurality of teeth is disengaged from the first plurality of teeth such that the drive input is permitted to rotate in response to receiving the rotational input to drive rotation of the input shaft. The surgical instrument also includes a spring coupled to a proximal end portion of the input shaft. The spring is configured to bias the knife blade lock into the locked position. 
     In an aspect of the present disclosure, the spring is tapered in a distal direction along the input shaft. 
     In another aspect of the present disclosure, the knife blade lock includes an annular body portion defining the second plurality of teeth. 
     In another aspect of the present disclosure, the second plurality of teeth is configured to interlock with the first plurality of teeth when the knife blade lock is in the locked position to prevent bi-directional rotation of the drive input. 
     In yet another aspect of the present disclosure, the knife blade lock includes a plurality of protrusions configured to extend proximally from a proximal end of the housing when the knife blade lock is in the locked position. 
     In still another aspect of the present disclosure, the drive input includes at least one distally extending finger disposed through an aperture defined by the knife blade lock, and the aperture is encircled by the second plurality of teeth. 
     In still yet another aspect of the present disclosure, the proximal end portion of the input shaft defines a bearing surface about which the spring is disposed. 
     In another aspect of the present disclosure, the knife blade lock is configured to be contacted and moved distally against the bias of the spring by an instrument interface of the robotic surgical system upon coupling of the surgical instrument to the robotic surgical system to move the knife blade lock to the unlocked position. 
     In another aspect of the present disclosure, the surgical instrument includes an input gear, a central gear, and a lead screw. The input gear is engaged to a distal end portion of the input shaft. Rotational input provided to the drive input drives rotation of the input shaft when the knife blade lock is in the unlocked position to drive rotation of the input gear. The central gear defines an internal threading and an external threading in meshed engagement with the input gear. The lead screw extends through the central gear and is threadingly engaged with the internal threading of the central gear. Rotation of the central gear in response to rotational input provided to the drive input translates the lead screw to move the knife blade between the first and second jaw members. 
     Also provided in accordance with aspects of the present disclosure is a surgical instrument for use with a robotic surgical system including a knife blade configured to cut tissue, a knife tube coupled to the knife blade and configured to translate to move the knife blade for cutting tissue, and a gearbox assembly. The gearbox assembly includes a drive input having a first plurality of teeth and configured to receive a rotational input from a robotic surgical system and an input shaft operably coupled to the drive input and the knife tube. The drive input is configured to drive rotation of the input shaft in response to rotational input received by the drive input to translate the knife tube. The surgical instrument also includes a knife blade lock operably coupled to the drive input of the gearbox assembly. The knife blade lock has a second plurality of teeth and is configured to move between a locked position wherein the second plurality of teeth interlocks with the first plurality of teeth to prevent rotation of the drive input and an unlocked position wherein the second plurality of teeth is disengaged from the first plurality of teeth such that the drive input is permitted to rotate in response to receiving the rotational input to translate the knife tube and move the knife blade. 
     In an aspect of the present disclosure, the surgical instrument includes a spring coupled to a proximal end portion of the input shaft and configured to bias the knife blade lock into the locked position. 
     In another aspect of the present disclosure, the proximal end portion of the input shaft defines a bearing surface about which the spring is disposed. 
     In another aspect of the present disclosure, the knife blade lock is configured to be contacted and moved distally against the bias of the spring by an instrument interface of the robotic surgical system upon coupling of the surgical instrument to the robotic surgical system to move the knife blade lock to the unlocked position. 
     In yet another aspect of the present disclosure, the knife blade lock includes an annular body portion defining the second plurality of teeth and a plurality of protrusions extending proximally from the annular body portion. 
     In still another aspect of the present disclosure, the drive input includes at least one distally extending finger disposed through an aperture defined by the annular body portion of the knife blade lock. 
     In still yet another aspect of the present disclosure, the gearbox assembly includes and input gear, a central gear, and a lead screw. The input gear is engaged to a distal end portion of the input shaft, wherein rotational input provided to the drive input drives rotation of the input shaft when the knife blade lock is in the unlocked position to drive rotation of the input gear. The central gear defines an internal threading and an external threading in meshed engagement with the input gear. The lead screw extends through the central gear and is threadingly engaged with the internal threading of the central gear, wherein rotation of the central gear in response to rotational input provided to the drive input translates the lead screw to translate the knife tube, thereby moving the knife blade to cut tissue. 
     Also provided in accordance with aspects of the present disclosure is a surgical instrument for use with a robotic surgical system including a knife blade configured to cut tissue and a drive input configured to operably couple to a robotic surgical system and to translate the knife blade for cutting tissue in response to a rotational input received from the robotic surgical system. The surgical instrument also includes a knife blade lock operably coupled to the drive input. The knife blade lock is configured to move from a locked position wherein a plurality of teeth defined by the knife blade lock interlock with a plurality of teeth defined by the drive input to prevent rotation of the drive input, to an unlocked position in response to coupling of the drive input to the robotic surgical system wherein the drive input is permitted to rotate to translate the knife blade for cutting tissue. 
     In an aspect of the present disclosure, the surgical instrument also includes a spring operably coupled to the knife blade lock and configured to bias the knife blade lock into the locked position. 
     In another aspect of the present disclosure, the surgical instrument also includes an input shaft operably coupled to the drive input, the drive input configured to drive rotation of the input shaft in response to the rotational input received by the drive input to translate the knife blade. 
     In yet another aspect of the present disclosure, the spring is tapered in a distal direction and disposed about a proximal end portion of the input shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects and features of the present disclosure are described hereinbelow with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views. 
         FIG.  1 A  is a perspective view of a surgical instrument provided in accordance with the present disclosure configured for mounting on a robotic arm of a robotic surgical system; 
         FIG.  1 B  is an enlarged, perspective view of the area of detail indicated as “ 1 B” in  FIG.  1 A , illustrating an end effector assembly of the surgical instrument of  FIG.  1 A  with one of the jaw members thereof removed; 
         FIG.  2 A  is a front, perspective view of a proximal portion of the surgical instrument of  FIG.  1 A  with an outer shell removed; 
         FIG.  2 B  is a rear, perspective view of the proximal portion of the surgical instrument of  FIG.  1    with the outer shell removed; 
         FIG.  3    is a front, perspective view of the proximal portion of the surgical instrument of  FIG.  1    with the outer shell and additional internal components removed; 
         FIG.  4    is a schematic illustration of an exemplary robotic surgical system configured to releasably receive the surgical instrument of  FIG.  1   ; 
         FIG.  5    is an enlarged, perspective view of the area of detail “ 5 ” in  FIG.  2 B ; 
         FIG.  6    is an enlarged, perspective view illustrating a drive input of the surgical instrument of  FIG.  1   ; 
         FIG.  7    is an enlarged, perspective view illustrating a knife blade lock of the surgical instrument of  FIG.  1   ; 
         FIG.  8 A  is a transverse, cross-sectional view taken along section line “ 8 - 8 ” of  FIG.  2 B ; 
         FIG.  8 B  is a side, perspective view of a portion of the surgical instrument of  FIG.  1    with the outer shell and additional internal components removed; 
         FIG.  9 A  is an enlarged, perspective view of the area of detail “ 9 A” in  FIG.  8 A  illustrating the knife blade lock in a locked position; and 
         FIG.  9 B  is an enlarged, perspective view of the area of detail “ 9 B” in  FIG.  8 A  illustrating an instrument interface of the exemplary robotic surgical system of  FIG.  4    operably coupling with a proximal portion of the instrument of  FIG.  1    to transition the knife blade lock towards an unlocked position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS.  1 A- 3   , a surgical instrument  10  provided in accordance with the present disclosure generally includes a housing  20 , a shaft  30  extending distally from housing  20 , an end effector assembly  40  extending distally from shaft  30 , and a gearbox assembly  100  disposed within housing  20  and operably associated with end effector assembly  40 . Instrument  10  is detailed herein as an articulating electrosurgical forceps configured for use with a robotic surgical system, e.g., robotic surgical system  1000  ( FIG.  4   ). However, the aspects and features of instrument  10  provided in accordance with the present disclosure, detailed below, are equally applicable for use with other suitable surgical instruments and/or in other suitable surgical systems. 
     With particular reference to  FIG.  1 A , housing  20  of instrument  10  includes first and second body portion  22   a ,  22   b  and a proximal face plate  24  that cooperate to enclose gearbox assembly  100  therein. Proximal face plate  24  includes apertures defined therein through which drive inputs  110 - 140  of gearbox assembly  100  extend. A pair of latch levers  26  (only one of which is illustrated in  FIG.  1   ) extending outwardly from opposing sides of housing  20  enable releasable engagement of housing  20  with a robotic arm of a surgical system, e.g., robotic surgical system  1000  ( FIG.  4   ). An aperture  28  defined through housing  20  permits thumbwheel  440  to extend therethrough to enable manual manipulation of thumbwheel  440  from the exterior of housing  20  to, as detailed below, permit manual opening and closing of end effector assembly  40 . 
     Shaft  30  of instrument  10  includes a distal segment  32 , a proximal segment  34 , and an articulating section  36  disposed between the distal and proximal segments  32 ,  34 , respectively. Articulating section  36  includes one or more articulating components  37 , e.g., links, joints, etc. A plurality of articulation cables  38 , e.g., four (4) articulation cables, or other suitable actuators, extend through articulating section  36 . More specifically, articulation cables  38  are operably coupled to distal segment  32  of shaft  30  at the distal ends thereof and extend proximally from distal segment  32  of shaft  30 , through articulating section  36  of shaft  30  and proximal segment  34  of shaft  30 , and into housing  20 , wherein articulation cables  38  operably couple with an articulation sub-assembly  200  of gearbox assembly  100  to enable selective articulation of distal segment  32  (and, thus end effector assembly  40 ) relative to proximal segment  34  and housing  20 , e.g., about at least two axes of articulation (yaw and pitch articulation, for example). Articulation cables  38  are arranged in a generally rectangular configuration, although other suitable configurations are also contemplated. 
     With respect to articulation of end effector assembly  40  relative to proximal segment  34  of shaft  30 , articulation cables  38  are actuated in pairs. More specifically, in order to pitch end effector assembly  40 , the upper pair of cables  38  are actuated in a similar manner while the lower pair of cables  38  are actuated in a similar manner relative to one another but an opposite manner relative to the upper pair of cables  38 . With respect to yaw articulation, the right pair of cables  38  are actuated in a similar manner while the left pair of cables  38  are actuated in a similar manner relative to one another but an opposite manner relative to the right pair of cables  38 . 
     With reference to  FIGS.  1 A and  1 B , end effector assembly  40  includes first and second jaw members  42 ,  44 , respectively. Each jaw member  42 ,  44  includes a proximal flange portion  43   a ,  45   a  and a distal body portion  43   b ,  45   b , respectively. Distal body portions  43   b ,  45   b  define opposed tissue-contacting surfaces  46 ,  48 , respectively. Proximal flange portions  43   a ,  45   a  are pivotably coupled to one another about a pivot  50  and are operably coupled to one another via a cam-slot assembly  52  including a cam pin slidably received within cam slots defined within the proximal flange portion  43   a ,  45   a  of at least one of the jaw members  42 ,  44 , respectively, to enable pivoting of jaw member  42  relative to jaw member  44  and distal segment  32  of shaft  30  between a spaced-apart position (e.g., an open position of end effector assembly  40 ) and an approximated position (e.g. a closed position of end effector assembly  40 ) for grasping tissue between tissue-contacting surfaces  46 ,  48 . As an alternative to this unilateral configuration, a bilateral configuration may be provided whereby both jaw members  42 ,  44  are pivotable relative to one another and distal segment  32  of shaft  30 . 
     Longitudinally-extending knife channels  49  (only knife channel  49  of jaw member  44  is illustrated; the knife channel of jaw member  42  is similarly configured) are defined through tissue-contacting surfaces  46 ,  48 , respectively, of jaw members  42 ,  44 . A knife assembly  60  including a knife tube  62  extending from housing  20  through shaft  30  to end effector assembly  40  and a knife blade  64  disposed within end effector assembly  40  between jaw members  42 ,  44  is provided to enable cutting of tissue grasped between tissue-contacting surfaces  46 ,  48  of jaw members  42 ,  44 , respectively. Knife tube  62  is operably coupled to a knife drive sub-assembly  300  of gearbox assembly  100  ( FIGS.  2 A- 2 B ) at a proximal end thereof to enable selective actuation thereof to, in turn, move the knife blade  64  (e.g., longitudinally along a longitudinal axis defined by shaft  30 ) between jaw members  42 ,  44  to cut tissue grasped between tissue-contacting surfaces  46 ,  48 . 
     Referring still to  FIG.  1 A , a drive rod  484  is operably coupled to cam-slot assembly  52  of end effector assembly  40 , e.g., engaged with the cam pin thereof, such that longitudinal actuation of drive rod  484  pivots jaw member  42  relative to jaw member  44  between the spaced-apart and approximated positions. More specifically, urging drive rod  484  proximally pivots jaw member  42  relative to jaw member  44  towards the approximated position while urging drive rod  484  distally pivots jaw member  42  relative to jaw member  44  towards the spaced-apart position. However, other suitable mechanisms and/or configurations for pivoting jaw member  42  relative to jaw member  44  between the spaced-apart and approximated positions in response to selective actuation of drive rod  484  are also contemplated. Drive rod  484  extends proximally from end effector assembly  40  through shaft  30  and into housing  20  wherein drive rod  484  is operably coupled with a jaw drive sub-assembly  400  of gearbox assembly  100  ( FIGS.  2 A- 2 B ) to enable selective actuation of end effector assembly  40  to grasp tissue therebetween. 
     Tissue-contacting surfaces  46 ,  48  of jaw members  42 ,  44 , respectively, are at least partially formed from an electrically conductive material and are energizable to different potentials to enable the conduction of electrical energy through tissue grasped therebetween, although tissue-contacting surfaces  46 ,  48  may alternatively be configured to supply any suitable energy, e.g., thermal, microwave, light, ultrasonic, ultrasound, etc., through tissue grasped therebetween for energy-based tissue treatment. Instrument  10  defines a conductive pathway (not shown) through housing  20  and shaft  30  to end effector assembly  40  that may include lead wires, contacts, and/or electrically-conductive components to enable electrical connection of tissue-contacting surfaces  46 ,  48  of jaw members  42 ,  44 , respectively, to an energy source (not shown), e.g., an electrosurgical generator, for supplying energy to tissue-contacting surfaces  46 ,  48  to treat, e.g., seal, tissue grasped between tissue-contacting surfaces  46 ,  48 . 
     With additional reference to  FIGS.  2 A,  2 B, and  3   , gearbox assembly  100  is disposed within housing  20  and includes an articulation sub-assembly  200 , a knife drive sub-assembly  300 , and a jaw drive sub-assembly  400 . Articulation sub-assembly  200  is operably coupled between first and second drive inputs  110 ,  120 , respectively, of gearbox assembly  100  and articulation cables  38  ( FIG.  1 A ) such that, upon receipt of appropriate inputs into first and/or second drive inputs  110 ,  120 , articulation sub-assembly  200  manipulates cables  38  ( FIG.  1 A ) to articulate end effector assembly  40  in a desired direction, e.g., to pitch and/or yaw end effector assembly  40 . 
     Knife drive sub-assembly  300  is operably coupled between third drive input  130  of gearbox assembly  100  and knife tube  62  such that, upon receipt of appropriate input into third drive input  130 , knife drive sub-assembly  300  manipulates knife tube  62  to move knife blade  64  ( FIG.  1 B ) between jaw members  42 ,  44  to cut tissue grasped between tissue-contacting surfaces  46 ,  48 . 
     Jaw drive sub-assembly  400  is operably coupled between fourth drive input  140  of gearbox assembly  100  and drive rod  484  such that, upon receipt of appropriate input into fourth drive input  140 , jaw drive sub-assembly  400  pivots jaw members  42 ,  44  between the spaced-apart and approximated positions to grasp tissue therebetween. 
     Gearbox assembly  100  is configured to operably interface with a robotic surgical system  1000  ( FIG.  4   ) when instrument  10  is mounted on robotic surgical system  1000  ( FIG.  4   ), to enable robotic operation of gearbox assembly  100  to provide the above-detailed functionality. That is, robotic surgical system  1000  ( FIG.  4   ) selectively provides inputs to drive inputs  110 - 140  of gearbox assembly  100  to articulate end effector assembly  40 , grasp tissue between jaw members  42 ,  44 , and/or cut tissue grasped between jaw members  42 ,  44 . However, it is also contemplated that gearbox assembly  100  be configured to interface with any other suitable surgical system, e.g., a manual surgical handle, a powered surgical handle, etc. For the purposes herein, robotic surgical system  1000  ( FIG.  4   ) is generally described. 
     Turning to  FIG.  4   , robotic surgical system  1000  is configured for use in accordance with the present disclosure. Aspects and features of robotic surgical system  1000  not germane to the understanding of the present disclosure are omitted to avoid obscuring the aspects and features of the present disclosure in unnecessary detail. 
     Robotic surgical system  1000  generally includes a plurality of robot arms  1002 ,  1003 ; a control device  1004 ; and an operating console  1005  coupled with control device  1004 . Operating console  1005  may include a display device  1006 , which may be set up in particular to display three-dimensional images; and manual input devices  1007 ,  1008 , by means of which a person, e.g., a surgeon, may be able to telemanipulate robot arms  1002 ,  1003  in a first operating mode. Robotic surgical system  1000  may be configured for use on a patient  1013  lying on a patient table  1012  to be treated in a minimally invasive manner. Robotic surgical system  1000  may further include a database  1014 , in particular coupled to control device  1004 , in which are stored, for example, pre-operative data from patient  1013  and/or anatomical atlases. 
     Each of the robot arms  1002 ,  1003  may include a plurality of members, which are connected through joints, and mounted device which may be, for example, a surgical tool “ST.” One or more of the surgical tools “ST” may be instrument  10  ( FIG.  1 A ), thus providing such functionality on a robotic surgical system  1000 . 
     Robot arms  1002 ,  1003  may be driven by electric drives, e.g., motors, connected to control device  1004 . Control device  1004 , e.g., a computer, may be configured to activate the motors, in particular by means of a computer program, in such a way that robot arms  1002 ,  1003 , and, thus, their mounted surgical tools “ST” execute a desired movement and/or function according to a corresponding input from manual input devices  1007 ,  1008 , respectively. Control device  1004  may also be configured in such a way that it regulates the movement of robot arms  1002 ,  1003  and/or of the motors. 
     With reference to  FIGS.  2 A- 3  and  8 A , jaw drive sub-assembly  400  of gearbox assembly  100  is shown generally including an input shaft  410 , an input gear  420 , a drive gear  430 , a thumbwheel  440 , and a spring force assembly  450 . 
     Input shaft  410  includes a proximal end portion  412  operably coupled to fourth drive input  140  and a distal end portion  414  having input gear  420  engaged thereon such that rotational input provided to fourth drive input  140  drives rotation of input shaft  410  to, thereby, drive rotation of input gear  420 . Input gear  420  is disposed in meshed engagement with drive gear  430  such that rotation of input gear  420 , e.g., in response to a rotational input provided at fourth drive input  140 , effects rotation of drive gear  430  in an opposite direction. Thumbwheel  440  is also disposed in meshed engagement with drive gear  430  such that rotation of thumbwheel  440  effects rotation of drive gear  430  in an opposite direction, thus enabling manual driving of drive gear  430  via manipulation of thumbwheel  440 . Drive rod  484  includes a distal end portion operably coupled to cam-slot assembly  52  of end effector assembly  40  ( FIG.  1 A ). Drive rod  484  extends proximally through shaft  30 , housing  20 , and gearbox assembly  100  (see  FIG.  8 A ). 
     With reference to  FIGS.  5 - 9 B , a knife blade lock  132  is operably coupled to third drive input  130  and serves to prevent manipulation of knife tube  62  and thus, movement of knife blade  64  between jaw members  42 ,  44  until gearbox assembly  100  is operably interfaced with a suitable instrument interface of robotic surgical system  1000  (e.g., robotic surgical system  1000  shown in  FIG.  4    may include an instrument interface  1001  shown schematically in  FIG.  9 B ) to provide rotational input to drive inputs  110 - 140 . Knife blade lock  132  includes an annular body portion  136  ( FIG.  7   ) disposed within housing  20 . The annular body portion  136  defines an aperture  134  therethrough configured to receive a distally extending finger  126  of drive input  130  therethrough. A plurality of protrusions, e.g., four (4) protrusions  142   a - d , extend proximally from annular body portion  136  through the aperture defined in proximal face plate  24  through which drive input  130  extends. A plurality of teeth  138  are defined along an inner surface of body portion  136  and are configured to releasably interlock with a plurality of teeth  128  defined by drive input  130  to prevent rotation of drive input  130  in either rotational direction (e.g., clock-wise or counter clock-wise). The knife blade lock  132  is movable relative to proximal face plate  24  between a locked position ( FIG.  9 A ) and an unlocked position ( FIG.  9 B ). 
     Turning to  FIGS.  3 ,  8 A, and  8 B , knife drive sub-assembly  300  includes input shaft  310 , an input gear  320 , a central gear  330  defining external threading and internal threading, and a lead screw  340 . Input shaft  310  extends parallel and offset relative to input shaft  410  and includes a proximal end portion  312  operably coupled to third drive input  130  of gearbox assembly  100  ( FIGS.  2 A and  2 B ) and a distal end portion  314  having input gear  320  engaged thereon such that rotational input provided to third drive input  130  drives rotation of input shaft  310  when knife blade lock  132  is in the unlocked position to, thereby, drive rotation of input gear  320 . Input gear  320  is disposed in meshed engagement with the external threading of central gear  330 . Central gear  330  is coaxial with and positioned distally of drive gear  430 . Lead screw  340  extends through central gear  330  and is threadingly engaged with the internal threading thereof such that rotation of central gear  330 , e.g., in response to a rotational input provided to third drive input  130 , translates lead screw  340 . Lead screw  340  is fixedly engaged about a proximal end portion of knife tube  62  such that translation of lead screw  340  translates knife tube  62  to thereby move the knife blade  64  between jaw members  42 ,  44  ( FIGS.  1 A and  1 B ). Lead screw  340  and knife tube  62  are coaxially disposed about drive rod  484 . When knife blade lockout  132  is in the locked position, third drive input  130  is unable to rotate in either rotational direction (e.g., clock-wise or counter clock-wise) due to interlocking engagement between teeth  138  of knife blade lock  132  and thus, third drive input  130  is prevented from driving rotation of input shaft  310  to move knife blade  64  distally or to move knife blade  64  proximally. 
     As shown in  FIGS.  8 A,  8 B, and  9 A , knife blade lock  132  is biased proximally into the locked position by a spring  135  operably coupled to knife blade lock  132 . As shown in  FIG.  8 B , an outer surface of proximal end portion  312  of input shaft  310  defines a bearing surface  316  that is encircled by spring  135 . In the illustrated embodiment, the spring  135  is a tapered spring that tapers in a distal direction along the input shaft  310 . In other embodiments, spring  135  may be another suitable type of spring, for example, a wave spring, a coil spring, or the like. When knife blade lock  132  is in the locked position, teeth  128  of drive input  130  are interlocked with teeth  138  of knife blade lock  132  to prevent rotation of drive input  130  and protrusions  142   a - d  extend distally from proximal face plate  24 . When knife blade lock  132  is in the unlocked position, protrusions  142   a - d  are depressed into the aperture defined in proximal face plate  24  through which protrusions  142   a - d  extend to move teeth  138  of knife blade lock  132  out of interlocking engagement with teeth  128  of drive input  130  such that drive input  130  is free to rotate and drive rotation of input shaft  310 . 
     As shown in  FIG.  9 B , surgical instrument  10  may be operably coupled to robotic surgical system  1000  via coupling of a proximal portion of surgical instrument  10 , including proximal face plate  24 , to instrument interface  1001 , which causes instrument interface  1001  to engage and depress protrusions  142   a - d  against the bias of spring  135  into the aperture defined in proximal face plate  24  through which protrusions  142   a - d  extend, thereby moving knife blade lock  132  distally to move teeth  138  of knife blade lock  132  distally and out of interlocking engagement with teeth  128  of drive input  130 . With teeth  138  of knife blade lock  132  out of interlocking engagement with teeth  128  of drive input  130 , drive input  130  is free to rotate and drive rotation of input shaft  310  to manipulate knife tube  62  to move knife blade  64  ( FIG.  1 B ) between jaw members  42 ,  44  to cut tissue grasped between tissue-contacting surfaces  46 ,  48 . Upon decoupling of instrument interface  1001  from surgical instrument  10 , the bias of spring  135  imparted on knife blade lock  132  returns knife blade lock  132  to the locked position. In this manner, knife blade  64  will not be permitted to move prior to interfacing surgical instrument  10  with robotic surgical system  1000 . As those skilled in the art will appreciate, preventing inadvertent movement of knife blade  64  will serve to prevent medical staff from being cut by the knife blade  64  during transit and/or handling of surgical instrument  10 . 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended thereto.