Actuation mechanism for surgical instruments and surgical instruments incorporating the same

Abstract

A surgical instrument includes a housing, an end effector assembly, a deployable component, and a trigger assembly. The trigger assembly includes a trigger pivotably coupled to the housing and defining at least one cam slot, and a slider including at least one cam body received within the at least one cam slot such that actuation of the trigger translates the slider along a longitudinal axis to deploy the deployable component relative to the end effector assembly. The trigger may define a substantially linear force profile throughout movement of the trigger from an unactuated position to an actuated position and / or the force vector applied from the trigger to the at least one cam body may define a variable angle relative to the longitudinal axis is equal to or less than about 30 degrees throughout movement of the trigger.

Description

ACTUATION MECHANISM FOR SURGICAL INSTRUMENTS AND SURGICAL INSTRUMENTS INCORPORATING THE SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of the filing date of provisional U.S. Patent Application No. 63 / 584,467 filed on September 21, 2023, the entire content of each of which is incorporated herein by reference.FIELD

[0002] The present disclosure relates to surgical instruments and, more particularly, to an actuation mechanism for surgical instruments such as, for example, a trigger assembly configured to actuate a cutting element of a surgical instrument to cut tissue.BACKGROUND

[0003] Various different surgical instruments employ actuation mechanisms to actuate one or more operable components of the surgical instrument. A surgical forceps, for example, is a plierslike instrument that relies on mechanical action between its jaw members to grasp, clamp, and constrict tissue. Electrosurgical forceps utilize both mechanical clamping action and energy to heat tissue to treat, e.g., coagulate, cauterize, or seal, tissue. Typically, once tissue is treated, the surgeon has to accurately sever the treated tissue. Accordingly, many electrosurgical forceps are designed to incorporate a cutting element that is actuated to cut the treated tissue. Such electrosurgical forceps may include one or more actuation mechanisms to enable selective closure of the jaw members to grasp tissue for treating the grasped tissue and / or actuation of the cutting element to cut the treated tissue.SUMMARY

[0004] As used herein, the term “distal” refers to the portion that is being described which is farther from an operator (whether a human user (surgeon, nurse, etc.) or a surgical robot), while the term “proximal” refers to the portion that is being described which is closer to the operator. Terms including “generally,” “about,” “substantially,” and the like, as utilized herein, are meant to encompass variations, e.g., manufacturing tolerances, material tolerances, use and environmental tolerances, measurement variations, design variations, and / or other variations, up to and including plus or minus 10 percent. Further, to the extent consistent, any or all of the aspects detailed herein may be used in conjunction with any or all of the other aspects detailed herein.

[0005] Provided in accordance with the present disclosure is a surgical instrument including a housing, an end effector assembly distally spaced from the housing, a deployable component movable relative to the end effector assembly from a retracted position to an extended position, and a trigger assembly. The trigger assembly includes a trigger pivotably coupled to the housing about a pivot and defining at least one cam slot, and a slider including at least one cam body received within the at least one cam slot of the trigger such that rotational actuation of the trigger about the pivot from an unactuated position towards an actuated position moves the at least one cam body through the at least one cam slot and translates the slider along a longitudinal axis from a proximal position to a distal position. The slider is coupled to the deployable component such that translation of the slider from the proximal position towards the distal position moves the deployable component from the retracted position towards the extended position.

[0006] In an aspect of the present disclosure, the trigger defines a substantially linear force profile throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position.

[0007] In another aspect of the present disclosure, the at least one cam slot is curved and defines a proximally facing concave curvature.

[0008] In still another aspect of the present disclosure, a distance extending perpendicular to the longitudinal axis is defined between the pivot and the at least one cam body. The at least one cam slot, in such or other aspects, is curved to define a radius of curvature, wherein a ratio of the distance to the radius of curvature is from about 0.9 to about 1.1.

[0009] In yet another aspect of the present disclosure, the trigger imparts force to the at least one cam body disposed within the at least one cam slot along a force vector that defines a variable angle relative to the longitudinal axis throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position. In such aspects, the variable angle is equal to or less than about 30 degrees throughout movement of the trigger from the unactuated position to the actuated position and / or a variation of the variable angle is equal to or less than about 10 degrees.

[0010] In still yet another aspect of the present disclosure, the trigger is rotatable through a trigger angle of from about 40 degrees to about 50 degrees from the unactuated position to the actuated position and the slider is translated a distance of from about 0.9 inches to about 1.1 inches in response to actuation of the trigger from the unactuated position to the actuated position.

[0011] In another aspect of the present disclosure, the pivot is proximally spaced from the at least one cam body in a direction parallel to the longitudinal axis in each of the unactuated position and the actuated position.

[0012] In another aspect of the present disclosure, the trigger assembly further includes a biasing spring configured to bias the slider towards the proximal position. In such aspects, the trigger may define the substantially linear force profile inclusive of effects of the biasing spring.

[0013] In yet another aspect of the present disclosure, the deployable component is a knife configured to cut tissue during advancement of the knife from the retracted position to the extended position.

[0014] In still another aspect of the present disclosure, the end effector assembly includes first and second jaw members, at least one of which is movable relative to the other from a spaced apart position to an approximated position to grasp tissue therebetween. In such aspects, the knife is advanceable between the first and second jaw members to the approximated position to cut the grasped tissue.BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other aspects and features of the present disclosure will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals identify similar or identical elements.

[0016] FIG. 1 is a side view of an electrosurgical system in accordance with the present disclosure including an electrosurgical forceps and an electrosurgical generator;

[0017] FIG. 2 is a side, cutaway view of a proximal portion of the electrosurgical forceps of the system of FIG. 1;

[0018] FIG. 3 is a top, longitudinal, cross-sectional view taken along section line 3-3 of FIG. 2;

[0019] FIG. 4 is a perspective view of an end effector assembly of the electrosurgical forceps with first and second jaw members of the end effector assembly disposed in a spaced apart position;

[0020] FIG. 5 is a side, longitudinal, cross-sectional view of the end effector assembly of the electrosurgical forceps with the first and second jaw members disposed in the spaced apart position and a knife disposed in a retracted position;

[0021] FIG. 6 is a side, longitudinal, cross-sectional view of the end effector assembly of the electrosurgical forceps with the first and second jaw members disposed in an approximated position and the knife advanced between the first and second jaw members to an extended position;

[0022] FIGS. 7 and 8 are side views of a trigger assembly of the electrosurgical forceps with a trigger of the trigger assembly disposed in an unactuated position and an actuated position, respectively;

[0023] FIGS. 9 and 10 are force profile graphs of the trigger assembly of the forceps as the trigger is moved from the unactuated position to the actuated position, inclusive of effects from a biasing spring of the trigger assembly and exclusive of effects from the biasing spring, respectively.DETAILED DESCRIPTION

[0024] The present disclosure provides an actuation mechanism for surgical instruments such as, for example, a trigger assembly configured to actuate a cutting element, e.g., a knife, of a surgical instrument to cut tissue. Although described herein with respect to a trigger assembly for actuating a knife of an electrosurgical forceps, the actuation mechanism of the present disclosure is equally applicable for use with any other suitable surgical instrument and / or any other suitable actuation feature.

[0025] Referring to FIG. 1 , an electrosurgical system 2 provided in accordance with the present disclosure includes an electrosurgical forceps 10 and an electrosurgical generator 18. Forceps 10 includes a housing 20, a handle assembly 30, a rotating assembly 40, a trigger assembly 50, an activation assembly 60, an end effector assembly 70, and a drive assembly 80 (FIG. 2). End effector assembly 70 includes first and second jaw members 72, 74, at least one of which is pivotable relative to the other about a pivot pin 78 (FIG. 4; or other suitable pivot structure) to grasp tissue to enable sealing and / or dividing of the grasped tissue. End effector assembly 70 further includes a knife 90 (FIGS. 5 and 6) operably coupled to trigger assembly 50 to enable selective translation of knife 90 (FIGS. 5 and 6) between jaw members 72, 74 to cut tissue (e.g., previously sealed tissue) grasped between jaw members 72, 74, as described in greater detailed below.

[0026] Forceps 10 further includes an outer shaft 12 that defines a longitudinal axis “A- A” and has a proximal end portion 12a operatively engaged to housing 20 and a distal end portion 12b operably engaged to end effector assembly 70. Forceps 10 also includes an electrosurgical cable14 having a plug 16 configured to connect forceps 10 to generator 18. More specifically, plug 16 includes a plurality of pins 17 or other suitable contacts configured to mate with corresponding receptacles or other contacts of a port (not shown) of generator 18 to enable generator 18 to communicate with forceps 10 and control the supply of electrosurgical energy to end effector assembly 70 of forceps 10 for sealing tissue grasped between first and second jaw members 72, 74.

[0027] Referring to FIGS. 1-3, handle assembly 30 includes a fixed handle 32 and a movable handle 34. Fixed handle 32 is integrally associated with housing 20 and movable handle 34 is movable relative to fixed handle 32 to actuate drive assembly 80 of forceps 10. More specifically, movable handle 34 has an upper end portion 34a that is pivotally secured within housing 20 and operably engaged with drive assembly 80. Drive assembly 80 includes a plurality of linkages 82, a carriage 84, a compression spring 86, and a drive shaft 88. Upper end portion 34a of movable handle 34 operably couples to linkages 82 that cooperate to move carriage 84 distally against compression spring 86 in response to actuation of movable handle 34 towards fixed handle 32. Movement of carriage 84 distally against compression spring 86, in turn, regulates translation of drive shaft 88 through outer shaft 12 and relative to end effector assembly 70 to move either or both of jaw members 72, 74 relative to one another to grasp tissue between jaw members 72, 74 and regulate the closure force applied to tissue grasped between jaw members 72, 74.

[0028] With additional reference to FIGS. 4-6, movement of carriage 84 distally against compression spring 86 initially urges compression spring 86 to translate distally to thereby translate drive shaft 88 distally through outer shaft 12 to drive relative movement of cam pin 76 through cam slots 77, 79 defined within respective first and second jaw members 72, 74 to thereby urge jaw member 72 to pivot about pivot pin 78 and relative to jaw member 74 from a spaced apart position (FIGS. 4 and 5) to an approximated position (FIG. 6) to grasp tissue between first and second jaw members 72, 74 and apply a closure force to the grasped tissue. As an alternative to distal movement of drive shaft 88 closing jaw members 72, 74, it is also contemplated that the opposite configuration be provided, e.g., wherein proximal movement of drive shaft 88 closes jaw members 72, 74, or that other suitable closure mechanisms be provided, e.g., wherein rotation of a drive element closes jaw members 72, 74.

[0029] Upon reaching a threshold closure force applied to tissue grasped between first and second jaw members 72, 74, further movement of carriage 84 distally against compression spring86, e.g., in response to further actuation of movable handle 34 towards fixed handle 32, compresses compression spring 86 rather than translating compression spring 86 distally (due to the resistive force applied by tissue inhibiting further closure of jaw members 72, 74) such that drive shaft 88 and, thus, first and second jaw members 72, 74 are maintained in position grasping tissue therebetween. In this manner, the closure force applied to tissue grasped between jaw members 72, 74 is regulated to maintain a closure force or closure force within a closure force range.

[0030] In aspects, the closure force applied to the grasped tissue in the approximated position of jaw members 72, 74 may be regulated such that the closure pressure, measured at a jaw centroid along the lengths of jaw members 72, 74, may be in a range of (or the jaw pressure range may be) from about 70 psi to about 130 psi; in other aspects from about 80 psi to about 120 psi; and, in still other aspects, from about 90 psi to about 110 psi.

[0031] Continuing with reference to FIGS. 1-6, end effector assembly 70 is described as a unilateral assembly, e.g., wherein second jaw member 74 is fixed relative to outer shaft 12 and first jaw member 72 is pivotable relative to second jaw member 74 and outer shaft 12; however, a bilateral assembly, e.g., wherein both first and second jaw members 72, 74 are pivotable relative to one another and outer shaft 12, is also contemplated. Further, in order to drive relative movement of cam pin 76 through cam slots 77, 79, drive shaft 88 may be translationally fixed to cam pin 76 and outer shaft 12 translationally fixed to pivot pin 78 such that translation of drive shaft 88 moves cam pin 76 relative to jaw members 72, 74 (and, thus, cam slots 77, 79) to thereby drive relative movement of cam pin 76 through cam slots 77, 79 to pivot first jaw member 72 towards second jaw member 74 to grasp tissue therebetween and apply a closure force to the grasped tissue. Alternatively, drive shaft 88 may be translationally fixed to pivot pin 78 and outer shaft 12 translationally fixed to cam pin 76 such that translation of drive shaft 88 moves jaw members 72, 74 (and, thus, cam slots 77, 79) relative to cam pin 76 to thereby drive relative movement of cam pin 76 through cam slots 77, 79 to pivot first jaw member 72 towards second jaw member 74 from the spaced-apart position (FIGS. 4 and 5) towards the approximated position (FIG. 6) to grasp tissue between first and second jaw members 72, 74 and apply the closure force to the grasped tissue.

[0032] With reference to FIG. 4, each jaw member 72, 74 of end effector assembly 70 includes an electrically conductive tissue contacting surface 73, 75, respectively. Jaw members 72, 74 are configured to grasp tissue between electrically conductive tissue contacting surface 73, 75 in theapproximated position thereof. Electrically conductive tissue contacting surfaces 73, 75 are adapted to connect to generator 18 (FIG. 1), e.g., via suitable electrical lead wires, electrically conductive structures, or combinations thereof extending through outer shaft 12, housing 20, and electrosurgical cable 14 to corresponding pins 17 of plug 16 (FIG. 1), to enable energization of electrically conductive tissue contacting surface 73, 75 with electrosurgical, e.g., Radio Frequency (RF), energy at different potentials for conducting electrosurgical energy between electrically conductive tissue contacting surface 73, 75 and through tissue grasped therebetween to seal the tissue.

[0033] Either or both jaw members 72, 74 may further include one or more stop members 71 disposed on or otherwise associated with either or both tissue-contacting surfaces 73, 75 to maintain a minimum gap distance between tissue contacting surfaces 73, 75 (or to maintain a gap distance within a gap distance range between tissue contacting surfaces 73, 75) when jaw members 72, 74 are disposed in an approximated position, thus inhibiting electrical shorting. Stop member(s) 71 may be insulative, partly insulative, and / or electrically isolated from either or both tissue contacting surfaces 73, 75. In aspects, the minimum gap distance or the gap distance range may be from about 0.001 inches to about 0.010 inches; in other aspects from about 0.001 inches to about 0.008 inches; and, in still other aspects from about 0.001 inches to about 0.006 inches. Other suitable gap distances and ranges are also contemplated. The gap distance may be determined as the maximum gap distance between the tissue contacting surfaces 73, 75.

[0034] Referring also to FIGS. 5 and 6, either or both jaw members 72, 74 may additionally or alternatively include a longitudinally extending knife channel 92 defined therethrough. Knife channel(s) 92 is configured to receive a portion of knife 90 as knife 90 is translated between a retracted position (FIG. 5), wherein knife 90 is disposed proximally of or at the proximal ends of tissue contacting surfaces 73, 75, and an extended position (FIG. 6), wherein knife 90 extends between tissue contacting surfaces 73, 75 to cut tissue grasped therebetween. Knife 90 is operably coupled to trigger assembly 50 (FIGS. 1-3) which, as detailed below, is configured to enable the selective actuation of knife 90 between the retracted and extended positions.

[0035] Referring back to FIGS. 1 and 2, movable handle 34 includes a flange 36 extending proximally from a lower end portion 34b of movable handle 34. Flange 36 is configured to extend through an aperture 31 defined within fixed handle 32 and ultimately engage a latch 38 within fixed handle 32 that is configured to selectively lock and unlock the fixed and movable handles32, 34 relative to one another upon sufficient actuation of movable handle 34. Upon initial movement of flange 36 through aperture 31 to engage latch 38, in response to an initial actuation of movable handle 34 towards fixed handle 32, fixed and movable handles 32, 34 are locked relative to one another to thereby latch first and second jaw members 72, 74 in the approximated position. Upon subsequent movement of flange 36 within aperture 31, in response to a subsequent actuation of movable handle 34 towards fixed handle 32, flange 36 is disengaged from latch 38 such that fixed and movable handles 32, 34 are unlocked permitting return of movable handle 34 towards its initial position and return of jaw members 72, 74 towards the spaced-apart position. In aspects, flange 36 and latch 38 are omitted and movable handle 34 is manually maintained in approximation with fixed handle 32 to thereby maintain first and second jaw members 72, 74 in the approximated position.

[0036] Lower end portion 34b of movable handle 34 further includes a grasping portion 37 configured to be grasped and manipulated by a user. Grasping portion 37 includes a finger loop 39. Finger loop 39 may be closed (as shown) or may be an open loop such as, for example, defining a shepherd’s hook configuration. In either configuration, the interior of finger loop 39 is configured to receive a user’s fingers to enable grasping and manipulation of movable handle 34 relative to fixed handle 32, which is configured to be grasped by the user’s palm and thumb.

[0037] Rotating assembly 40 includes a rotation wheel 42 engaged with outer shaft 12 within housing 20 and extending outwardly from either side of housing 20 to enable a user to manually control the orientation of outer shaft 12 and thus, end effector assembly 70, relative to housing 20, e.g., by manipulating rotation wheel 42. In aspects, rotating assembly 40 is infinitely rotatable in either direction about the longitudinal axis “A-A” to similarly rotate end effector assembly 70 relative to housing 20. Alternatively, rotating assembly 40 may have a defined range of motion. In aspects, rotating assembly 40 is positioned in close proximity to trigger assembly 50 to facilitate a user manipulating rotation wheel 42 of rotating assembly 40 with a finger, e.g., enabling the user to move their trigger finger from manipulation portion 53a of trigger 52 (or finger loop 39 of movable handle 34) to rotation wheel 42 to manipulate rotation wheel 42 to rotate rotating assembly 40.

[0038] Activation assembly 60 is configured to signal generator 18 to initiate the supply of electrosurgical energy to first and second jaw members 72, 74 for sealing tissue. Activation assembly 60 includes an activation button 62 supported by a body 22 of housing 20. Activationbutton 62 is movable between an unactuated position and an actuated position to thereby transition an underlying electrical switch 64 between a first state and a second state. Electrical switch 64, in turn, is adapted to electrically connect to generator 18, e.g., via one or more electrical lead wires extending from electrical switch 64 through housing 20 and electrosurgical cable 14 to one of the pins 17 (or other contact) of plug 16 to enable communication of the state of the electrical switch to generator 18. Generator 18, more specifically, may be configured to read an output of a corresponding pin 17, e.g., the presence of a resistance, voltage, current, etc. and / or a value of the resistance, voltage, current, etc., to detect the state of electrical switch 64 and, thus, to detect whether the user has activated activation button 62. For example, generator 18 may read the first state of electrical switch 64 as corresponding to an unactivated state and the second state of electrical switch 64 as corresponding to an activated state.

[0039] With reference to FIGS. 1-3, 5, and 6, trigger assembly 50 enables selective actuation of knife 90 relative to jaw members 72, 74 to cut tissue grasped between jaw members 72, 74, e.g., once the grasped tissue is sealed. Knife 90 may be configured for mechanically cutting tissue or electromechanically cutting tissue wherein knife 90 is energized (e.g., with electrosurgical energy) to facilitate tissue cutting. Trigger assembly 50 includes a trigger 52, a slider 54, a drive link 56, and a biasing spring 58. Trigger assembly 50 is coupled to knife drive rod 94 which, in turn, is engaged to knife 90. In aspects, knife 90 is welded to a distal end portion of knife drive rod 94. Further, the term “drive rod” as utilized herein is not limited to a cylindrical or solid component(s) but, rather, includes any elongated drive structure or combination of drive structures (including structures integrally formed with knife 90) configured to transfer input motion from trigger assembly 50 into output motion of knife 90. Regardless of the particular configuration of knife drive rod 94, actuation of trigger 52 of trigger assembly 50 from an unactuated position (FIG. 7) to an actuated position (FIG. 8) deploys knife 90 relative to first and second jaw members 72, 74 from the retracted position (FIG. 5) to the extended position (FIG. 6).

[0040] Referring to FIGS. 2, 3, 7, and 8, trigger 52 includes a manipulation portion 53a, a body portion 53b, and an actuation portion 53c. Body portion 53b of trigger 52 is pivotably engaged to housing 20 within housing 20 about a pivot 26. In aspects, pivot 26 is defined by first and second bosses (as shown) extending outwardly from opposing sides of body portion 53b of trigger 52 and pivotably received within corresponding recesses (not shown) defined within housing 20, although other configurations are also contemplated (such as, for example, a continuous pivot pin extendingthrough body portion 53b of trigger 52 and pivotably coupled to housing 20). Manipulation portion 53a of trigger 52 extends from body portion 53b and through an opening in housing 20 such that at least a portion of manipulation portion 53a is exposed exteriorly of housing 20 to enable manual manipulation of trigger 52 by a user. In aspects, manipulation portion 53a extends at an angle relative to body portion 53b, e.g., substantially perpendicular relative to body portion 53b. In aspects where rotating assembly 40 is positioned in close proximity to trigger assembly 50, trigger 52 (e.g., body portion 53b thereof) may define a recess 44 configured to receive a portion of rotation wheel 42 in the actuated position of trigger 52, thus enabling the positioning of rotating assembly 40 in close proximity to trigger assembly 50 to facilitate a user’ s reach to rotating assembly 40 while still allowing the full range of motion of trigger 52. In such aspects, recess 44 may be complementary to the portion of rotation wheel 42 configured for receipt therein, e.g., both defining arcuate configurations, although other configurations may also be provided.

[0041] Actuation portion 53c of trigger 52 extends from body portion 53b further into housing 20, e.g., substantially opposite manipulation portion 53a, such that body portion 53b is disposed between manipulation portion 53a and actuation portion 53c. Actuation portion 53c is operably coupled to slider 54 which, in turn, is slidably disposed about outer shaft 12 within housing 20. More specifically, actuation portion 53c defines a bifurcated configuration including a pair of spaced apart flanges 53d each defining a cam slot 53e. Slider 54 includes a housing 55a and a cam body 55b protruding outwardly from opposing sides of housing 55a. Cam body 55b may be formed from first and second cam bosses integrally formed with and protruding outwardly from opposing sides of housing 55a, although other configurations are also contemplated (such as, for example, a continuous cam pin extending through and from opposing sides of housing 55a). Slider 54 is disposed between flanges 53d of actuation portion 53c of trigger 52 with cam bodies 55b extending into corresponding cam slots 53e.

[0042] Drive link 56 is rotatably captured within housing 55a of slider 54 such that drive link 56 is longitudinally fixed but rotatable within and relative to slider 54. Drive link 56 couples knife drive rod 94 within slider 54. As such, actuation of manipulation portion 53a of trigger 52 proximally from an unactuated position (FIG. 7) towards an actuated position (FIG. 8) pivots trigger 52 relative to housing 20 such that actuation portion 53c of trigger 52 is moved distally within housing 20. This distal movement of actuation portion 53c urges slider 54 distally along outer shaft 12 as cam bodies 55b of slider 54 move through cam slots 53e of actuation portion 53cof trigger 52. The distal sliding of slider 54 along outer shaft 12 likewise slides drive link 56 distally relative to outer shaft 12 to, in turn, move knife drive rod 94 through outer shaft 12. Since knife 90 (FIGS. 5 and 6) is engaged with knife drive rod 94, this distal movement of knife drive rod 94 through outer shaft 12 advances knife 90 (FIGS. 5 and 6) relative to first and second jaw members 72, 74 from the retracted position (FIG. 5) to the extended position (FIG. 6).

[0043] Biasing spring 58 is disposed about outer shaft 12 within housing 20 between slider 54 and a collar 24 (FIG. 2) supported within housing 20. Biasing spring 58 is positioned to bias slider 54 proximally within housing 20 and relative to outer shaft 12, thereby biasing drive link 56 and knife drive rod 94 proximally such that knife 90 (FIGS. 5 and 6) is biased towards the retracted position. Further, this bias provided by biasing spring 58 biases trigger 52 towards the unactuated position. Biasing spring 58, in aspects, is a coil compression spring. Biasing spring 58 may define a variable spring rate of, in aspects, from about 1.0 Ib / in to about 2.0 Ib / in; in other aspects, from about 1.3 Ib / in to about 1.7 Ib / in; and, in still other aspects, from about 1.5 Ib / in to about 1.6 Ib / in. Other suitable biasing springs and / or spring rates thereof are also contemplated, including constant spring rates within any of the above detailed ranges or any other suitable constant spring rate.

[0044] Continuing with reference to FIGS. 7 and 8, trigger assembly 50 is configured to provide an ergonomic range of motion for manipulation portion 53a of trigger 52 from the unactuated position (FIG. 7) to the actuated position (FIG. 8) to facilitate deployment of knife 90 (FIGS. 5 and 6) from the retracted position (FIG. 5) to the extended position (FIG. 6). More specifically, trigger assembly 50 utilizes mechanical advantage and a variable effective lever length to convert a relatively compact rotational input to manipulation portion 53a of trigger 52 into a relatively long translational output of slider 54 along longitudinal axis “A-A” to thereby fully deploy knife 90 (FIGS. 5 and 6) from the retracted position (FIG. 5) to the extended position (FIG. 6). While providing the above, trigger assembly 50 further achieves a substantially linear force profile throughout the actuation stroke of trigger 52, thereby providing an intuitive feel for the user during actuation of trigger 52. The aspects and features of trigger assembly 50 that, at least in part, enable these advantages are detailed below.

[0045] The rotation (or rotational input) of manipulation portion 53a of trigger 52 is defined by a trigger angle (|>. More specifically, trigger 52 defines a rotational range of motion equal to a difference between the trigger angle in the unactuated position of trigger 52, c[) (unactuated), and the trigger angle in the actuated position of trigger 52, c[) (actuated). For convention, c[) (unactuated)is defined as zero and, thus, the rotational range of motion of trigger 52 equals c|) (actuated). In aspects, c|) (actuated) is from about 35 degrees to about 55 degrees; in other aspects, from about 40 degrees to about 50 degrees; and in still other aspects, from about 43 degrees to about 47 degrees.

[0046] In aspects, the translational output of slider 54 along longitudinal axis “A-A” is at least 0.90 inches; in other aspects, at least 0.95 inches; and in still other aspects, at least 1.00 inches. The deployment distance of knife 90 (FIGS. 5 and 6) is substantially equal to the translational output of slider 54. The translational output of slider 54 may be defined as the difference between H (actuated) and H (unactuated), wherein H (unactuated) is the longitudinal extent (parallel to or coaxial with longitudinal axis “A-A”) between a center of pivot 26 and a center of cam body 55b in the unactuated position of trigger 52 (see FIG. 7) and H (actuated) is the longitudinal extent (parallel to or coaxial with longitudinal axis “A-A”) between the center of pivot 26 and the center of cam body 55b in the actuated position of trigger 52 (see FIG. 8). In aspects, the translational output, H (actuated) minus H (unactuated), is from about 0.80 inches to about 1.20 inches; in other aspects, from about 0.90 inches to about 1.10; and, in still other aspects, from about 0.95 inches to about 1.05 inches. Alternatively or additionally, a ratio of H (actuated) to H (unactuated) may be, in aspects, from about 5.00 to about 6.00; in other aspects, from about 5.20 to about 5.80; and in still other aspects, from about 5.40 to about 5.60.

[0047] In aspects, rather than defining the translational output between the center of pivot 26 and the center of cam body 55b in each of the unactuated and actuated positions, the translational output may be defined between the center of pivot 26 and the tangent point along the proximal edges of flanges 53d that define cam slots 53e where the proximal edges of flanges 53d contact cam bodies 55b. These tangent points vary throughout actuation of trigger 52 from the unactuated position (FIG. 7) to the actuated position (FIG. 8), e.g., as cam bodies 55b slide through cam slots 53e. Using the above detailed tangent points as references, the translational output, in aspects, may likewise be from about 0.80 inches to about 1.20 inches; in other aspects, from about 0.90 inches to about 1.10; and, in still other aspects, from about 0.95 inches to about 1.05 inches. The above detailed ratios may also apply.

[0048] Still referring to FIGS. 7 and 8, cam slots 53e define curved configurations to facilitate a substantially linear force profile. More specifically, cam slots 53e define a proximally facing concave curvature (and, thus, a distally facing convex curvature). A radius of curvature of the proximal edges of flanges 53d that define cam slots 53e may be, in aspects, from about 0.85 inchesto about 1.15 inches; in other aspects, from about 0.90 inches to about 1.10 inches; and, in still other aspects, from about 0.95 inches to about 1.05 inches.

[0049] An angle, a, is defined between the above detailed tangent points (and extending through the center axis defined through cam bodies 55b) and longitudinal axis “A-A.” That is, the angle a is defined between the normal vector created from the line derived by the tangent points detailed above and longitudinal axis “A-A.” The angle a may vary throughout actuation of trigger 52 from the unactuated position (FIG. 7) to the actuated position (FIG. 8), dependent at least in part upon the curvature of cam sots 53e. Further, the smaller the angle a, the greater the proportion of force imparted from trigger 52 to slider 54 to translate slider 54 along and longitudinal axis “A- A,” as the angle a defines the force vector of force applied from trigger 52 to slider 54 at the tangent points. In aspects, in the unactuated position of trigger 52 (FIG. 7), a (unactuated) is from about 10 degrees to about 30 degrees; in other aspects, from about 15 degrees to about 25 degrees; and in still other aspects, from about 18 degrees to about 22 degrees. In aspects, in the actuated position of trigger 52 (FIG. 8), a (actuated) is from about 15 degrees to about 35 degrees; in other aspects, from about 20 degrees to about 30 degrees; and in still other aspects, from about 24 degrees to about 28 degrees. Further, in aspects, the maximum difference between the angle a at any two positions between (and including) the unactuated position (FIG. 7) and the actuated position (FIG. 8) may be equal to or less than about 10 degrees; in other aspects, equal to or less than about 8.5 degrees; and, in still other aspects, equal to or less than about 7 degrees. Alternatively or additionally, a ratio of a (actuated) to a (unactuated) may be from about 1.20 to about 1.55; in other aspects, from about 1.30 to about 1.45; and, in still other aspects, from about 1.35 inches to about 1.40 inches.

[0050] The distance between pivot 26 and cam bodies 55b in a direction perpendicular to the longitudinal axis “A-A” and perpendicular to the rotation axes of pivot 26 and cam bodies 55b is substantially constant in each of (and between) the unactuated position of trigger 52 (FIG. 7; V (unactuated)) and the actuated position of trigger 52 (FIG. 8; V (actuated)). That is, V (actuated) minus V (unactuated) is substantially equal to zero. V (actuated) and / or V (unactuated), in aspects, may be from about 0.85 inches to about 1.15 inches; in other aspects, from about 0.90 inches to about 1.10 inches; and, in still other aspects, from about 0.95 inches to about 1.05 inches. Further, a ratio of V (actuated) and / or V (unactuated) to the radius of curvature of the proximal edges offlanges 53d that define cam slots 53e may be, in aspects, from about 0.80 to about 1.20; in other aspects, from about 0.90 to about 1.10; and, in still other aspects, from about 0.95 to about 1.05.

[0051] Turning to FIGS. 9 and 10, in conjunction with FIGS. 7 and 8, as noted above, the radius of curvature of the proximal edges of flanges 53d that define cam slots 53e, as well as other parameters of trigger assembly 50, are selected such that a substantially linear force profile throughout the actuation stroke of trigger 52, e.g., as trigger 52 is moved from c|) (unactuated) to c|) (actuated), is achieved. That is, the load that is required to be overcome to move trigger 52 towards the actuated position varies substantially linearly as a function of the trigger angle (|). Further, the load that is required to be overcome for trigger 52 to move knife 90 (FIGS. 5 and 6) towards the extended position (FIG. 6) also varies substantially linearly as a function of deployment distance of knife 90 from the retracted position (FIG. 5). Thus, the user is provided with an intuitive feel during actuation of trigger 52 to deploy knife 90.

[0052] FIGS. 9 and 10, more specifically, graphically illustrate the substantially linear (defining linearity of 1.0 plus or minus 10%) force profiles 900 and 1000, respectively, of trigger 52 as trigger 52 is moved from the unactuated position, c[) (unactuated) = 0, towards the actuated position (increasing (|>). Force profile 900 of FIG. 9 takes into account the force applied by biasing spring 58 (FIGS. 7 and 8) urging trigger 52 (FIGS. 7 and 8) towards the unactuated position, while the effects of biasing spring 58 (FIGS. 7 and 8) are removed from force profile 1000 of FIG. 10. As biasing spring 58 (FIGS. 7 and 8) provides a substantially linear spring rate, biasing spring 58 (FIGS. 7 and 8) does not change the linearity of the force profile throughout the actuation stroke of trigger 52 (FIGS. 7 and 8) although, as shown by comparison of FIGS. 9 and 10, the effects of biasing spring 58 (FIGS. 7 and 8) change the slope of the substantially linear force profile.

[0053] Aspects of this disclosure may be further described by reference to the following examples:

[0054] Example 1. A surgical instrument, comprising: a housing; an end effector assembly distally spaced from the housings deployable component movable relative to the end effector assembly from a retracted position to an extended position; and a trigger assembly, including: a trigger pivotably coupled to the housing about a pivot, the trigger defining at least one cam slot; and a slider including at least one cam body received within the at least one cam slot of the trigger such that rotational actuation of the trigger about the pivot from an unactuated position towards an actuated position moves the at least one cam body through the at least one cam slot and translatesthe slider along a longitudinal axis from a proximal position to a distal position, wherein the slider is coupled to the deployable component such that translation of the slider from the proximal position towards the distal position moves the deployable component from the retracted position towards the extended position, wherein the trigger defines a substantially linear force profile throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position.

[0055] Example 2. The surgical instrument according to example 1, wherein the at least one cam slot is curved and defines a proximally facing concave curvature.

[0056] Example 3. The surgical instrument according to example 2, wherein a distance extending perpendicular to the longitudinal axis is defined between the pivot and the at least one cam body, wherein the at least one curved cam slot defines a radius of curvature, and wherein a ratio of the distance to the radius of curvature is from about 0.9 to about 1.1.

[0057] Example 4. The surgical instrument according to example 1, wherein the trigger imparts force to the at least one cam body disposed within the at least one cam slot along a force vector, wherein the force vector defines a variable angle relative to the longitudinal axis throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position, and wherein a variation of the variable angle is equal to or less than about 10 degrees.

[0058] Example 5. The surgical instrument according to example 1, wherein the trigger is rotatable through a trigger angle of from about 40 degrees to about 50 degrees from the unactuated position to the actuated position and wherein the slider is translated a distance of from about 0.9 inches to about 1.1 inches in response to actuation of the trigger from the unactuated position to the actuated position.

[0059] Example 6. The surgical instrument according to example 1, wherein the pivot is proximally spaced from the at least one cam body in a direction parallel to the longitudinal axis in each of the unactuated position and the actuated position.

[0060] Example 7. The surgical instrument according to example 1, further comprising a biasing spring configured to bias the slider towards the proximal position.

[0061] Example 8. The surgical instrument according to example 7, wherein the trigger defines the substantially linear force profile inclusive of effects of the biasing spring.

[0062] Example 9. The surgical instrument according to example 1, wherein the deployable component is a knife configured to cut tissue during advancement of the knife from the retracted position to the extended position.

[0063] Example 10. The surgical instrument according to example 9, wherein the end effector assembly includes first and second jaw members, at least one of the first or second jaw members movable relative to the other from a spaced apart position to an approximated position to grasp tissue therebetween, and wherein the knife is advanceable between the first and second jaw members to the approximated position to cut the grasped tissue.

[0064] Example 11. A surgical instrument, comprising: a housing; an end effector assembly distally spaced from the housing; a deployable component movable relative to the end effector assembly from a retracted position to an extended position; and a trigger assembly, including: a trigger pivotably coupled to the housing, the trigger defining at least one cam slot; and a slider including at least one cam body received within the at least one cam slot of the trigger such that rotational actuation of the trigger about the pivot from an unactuated position towards an actuated position moves the at least one cam body through the at least one cam slot and translates the slider along a longitudinal axis from a proximal position to a distal position, wherein the slider is coupled to the deployable component such that translation of the slider from the proximal position towards the distal position moves the deployable component from the retracted position towards the extended position, wherein the trigger imparts force to the at least one cam body disposed within the at least one cam slot along a force vector, wherein the force vector defines a variable angle relative to the longitudinal axis throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position, and wherein the variable angle is equal to or less than about 30 degrees throughout movement of the trigger from the unactuated position to the actuated position.

[0065] Example 12. The surgical instrument according to example 11, wherein a variation of the variable angle throughout movement of the trigger from the unactuated position to the actuated position is equal to or less than about 10 degrees.

[0066] Example 13. The surgical instrument according to example 11, wherein the at least one cam slot is curved and defines a proximally facing concave curvature.

[0067] Example 14. The surgical instrument according to example 13, wherein a distance extending perpendicular to the longitudinal axis is defined between the pivot and the at least onecam body, wherein the at least one curved cam slot defines a radius of curvature, and wherein a ratio of the distance to the radius of curvature is from about 0.9 to about 1.1.

[0068] Example 15. The surgical instrument according to example 11, wherein the trigger is rotatable through a trigger angle of from about 40 degrees to about 50 degrees from the unactuated position to the actuated position and wherein the slider is translated a distance of from about 0.9 inches to about 1.1 inches in response to actuation of the trigger from the unactuated position to the actuated position.

[0069] Example 16. The surgical instrument according to example 11, wherein the pivot is proximally spaced from the at least one cam body in a direction parallel to the longitudinal axis in each of the unactuated position and the actuated position.

[0070] Example 17. The surgical instrument according to example 11, further comprising a biasing spring configured to bias the slider towards the proximal position.

[0071] Example 18. The surgical instrument according to example 11 , wherein the trigger defines a substantially linear force profile throughout movement of the trigger from the unactuated position to the actuated position to move the deployable component from the retracted position to the extended position.

[0072] Example 19. The surgical instrument according to example 11, wherein the deployable component is a knife configured to cut tissue during advancement of the knife from the retracted position to the extended position.

[0073] Example 20. The surgical instrument according to example 19, wherein the end effector assembly includes first and second jaw members, at least one of the first or second jaw members movable relative to the other from a spaced apart position to an approximated position to grasp tissue therebetween, and wherein the knife is advanceable between the first and second jaw members to the approximated position to cut the grasped tissue.

[0074] Although the above detailed ranges are detailed inclusive of variation and / or tolerances, e.g., as denoted by use of the term “about” or the like, it is understood that the present disclosure also supports the above detailed ranges precisely. Further, while several aspects of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely asexemplifications of particular configurations. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A surgical instrument (10), comprising: a housing (20); an end effector assembly (70) distally spaced from the housing (20); a deployable component (90) movable relative to the end effector assembly (70) from a retracted position to an extended position; and a trigger assembly (50), including: a trigger (52) pivotably coupled to the housing (20) about a pivot (26), the trigger (52) defining at least one cam slot (53e); and a slider (54) including at least one cam body (55b) received within the at least one cam slot (53e) of the trigger (52) such that rotational actuation of the trigger (52) about the pivot (26) from an unactuated position towards an actuated position moves the at least one cam body (55b) through the at least one cam slot (53e) and translates the slider (54) along a longitudinal axis (A-A) from a proximal position to a distal position, wherein the slider (54) is coupled to the deployable component (90) such that translation of the slider (54) from the proximal position towards the distal position moves the deployable component (90) from the retracted position towards the extended position, characterized in that: the trigger (52) defines a substantially linear force profile throughout movement of the trigger (52) from the unactuated position to the actuated position to move the deployable component (90) from the retracted position to the extended position, and / or the trigger (52) imparts force to the at least one cam body (55b) disposed within the at least one cam slot (53e) along a force vector, wherein the force vector defines a variable angle (a) relative to the longitudinal axis (A-A) throughout movement of the trigger (52) from the unactuated position to the actuated position to move the deployable component (90) from the retracted position to the extended position, and wherein the variable angle (a) is equal to or less than about 30 degrees throughout movement of the trigger (52) from the unactuated position to the actuated position.

2. The surgical instrument (10) according to claim 1, wherein the at least one cam slot (53e) is curved and defines a proximally facing concave curvature.

3. The surgical instrument (10) according to claim 2, wherein a distance (V) extending perpendicular to the longitudinal axis (A- A) is defined between the pivot (26) and the at least one cam body (55b), wherein the at least one curved cam slot (53e) defines a radius of curvature, and wherein a ratio of the distance (V) to the radius of curvature is from about 0.9 to about 1.1.

4. The surgical instrument (10) according to any preceding claim, wherein the trigger (52) is rotatable through a trigger angle (c|)) of from about 40 degrees to about 50 degrees from the unactuated position to the actuated position.

5. The surgical instrument (10) according to claim 4, wherein the slider (54) is translated a distance of from about 0.9 inches to about 1.1 inches in response to actuation of the trigger (52) from the unactuated position to the actuated position.

6. The surgical instrument (10) according to any preceding claim, wherein the pivot (26) is proximally spaced from the at least one cam body (55b) in a direction parallel to the longitudinal axis (A- A) in each of the unactuated position and the actuated position.

7. The surgical instrument (10) according to any preceding claim, further comprising a biasing spring (58) configured to bias the slider (54) towards the proximal position.

8. The surgical instrument (10) according to claim 7, wherein the trigger (52) defines the substantially linear force profile inclusive of effects of the biasing spring (58).

9. The surgical instrument (10) according to any preceding claim, wherein the deployable component (90) is a knife (90) configured to cut tissue during advancement of the knife (90) from the retracted position to the extended position.

10. The surgical instrument (10) according to claim 9, wherein the end effector assembly (70) includes first and second jaw members (72, 74), at least one of the first or second jaw members (72, 74) movable relative to the other from a spaced apart position to an approximated position to grasp tissue therebetween, and wherein the knife (90) is advanceable between the first and second jaw members (72, 74) to the approximated position to cut the grasped tissue.

11. The surgical instrument (10) according to any preceding claim, wherein a variation of the variable angle (a) throughout movement of the trigger (52) from the unactuated position to the actuated position is equal to or less than about 10 degrees.

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