# Patent

## Title
Stapling device with features to prevent inadvertent firing of staples

## Abstract

A surgical device includes a handle assembly, an elongated body, and a tool assembly. The handle assembly includes an actuation assembly operatively associated with an actuation shaft to advance the actuation shaft and configured to prevent advancement of the actuation shaft when the actuation shaft is in a fully retracted position and a moveable handle is in a non-compressed position and/or to prevent advancement of the actuation shaft when a grasping pawl is extended within a grasping slot of the actuation shaft. The actuation shaft including a vertical pawl locking surface near a distal end configured to engage a locking notch of a vertical pawl. The actuation assembly including a grasping pawl having a radial detent configured to engage a proximal surface of a grasping slot of the actuation shaft when the grasping pawl is positioned within the grasping slot.

## Background
BACKGROUND
1. Technical Field
The present disclosure relates to a surgical stapling device and, more particularly, to a surgical stapling device including a safety device to prevent inadvertent firing of staples.
2. Background of Related Art
Surgical devices wherein tissue is first grasped or clamped between opposing jaw structure and then joined by surgical fasteners are well known in the art. The fasteners are typically in the form of surgical staples, but two-part polymeric fasteners can also be utilized.
Such devices can include a tool assembly with a pair of jaws which are used to capture or clamp tissue. Typically, one of the jaws carries a staple cartridge which houses a plurality of staples arranged, for example, in at least two lateral rows while the other jaw supports an anvil that defines a surface for forming the staple legs as the staples are driven from the staple cartridge. The stapling operation may be effected by cam bars that travel longitudinally through the staple cartridge and act on staple pushers for sequentially ejecting the staples from the staple cartridge. The stapling device can include a knife which travels between the staple rows for longitudinally cutting the stapled tissue between the rows of staples. Known staplers are disclosed in U.S. Pat. Nos. 6,250,532 and 6,241,139, each of which is commonly owned with the present disclosure, and is incorporated herein by reference in its entirety.
In endoscopic and laparoscopic procedures (hereinafter “endoscopic procedures”), surgery is performed through small incisions or through small diameter cannulas inserted through small entrance wounds in the skin. Thus, access to the surgical site is limited. During an endoscopic procedure, it is often necessary to manipulate tissue to properly position the tissue between the jaws of the surgical device. Some known endoscopic and laparoscopic surgical devices have firing and grasping modes of operation. In the grasping mode of operation, a trigger is operable to open and close the jaws to grasp and manipulate tissue. In the firing mode of operation, the trigger is operable to staple and cut tissue. It would be of great benefit to provide a stapling device which includes a safety feature to prevent inadvertent firing of staples.
SUMMARY
According to an aspect of the present disclosure, a surgical stapling device is provided which incorporates a grasping function and a safety mechanism to prevent the stapling device from premature firing of the staples. The surgical stapling device includes a handle assembly, an elongated body, a tool assembly, and an actuation assembly. The handle assembly includes an actuation shaft, a stationary handle, and a moveable handle. The moveable handle has a non-compressed position positioned away from the stationary handle and is compressible towards the stationary handle such that movement of the moveable handle effects axial movement of the actuation shaft. The elongated body extends distally from the handle assembly and defines a longitudinal axis. The tool assembly is supported on a distal end of the elongated body. The tool assembly includes a cartridges assembly having a plurality of staples therein and an anvil assembly. The cartridge assembly and the anvil assembly are movable in relation to each other between open and closed positions. The actuation assembly is operatively associated with the actuation shaft to advance the actuation shaft upon movement of the moveable handle. The actuation assembly is configured to prevent the actuation shaft from advancing when the actuation shaft is in a fully retracted position and the moveable handle is in the non-compressed position.
In embodiments, the actuation assembly includes a vertical pawl having a locking notch and the actuation shaft includes a vertical pawl locking surface. The locking notch of the vertical pawl engages the vertical pawl locking surface when the actuation shaft is in the fully retracted position and the moveable handle is in the non-compressed position to prevent advancement of the actuation shaft. In some embodiments, the actuation assembly includes a disconnect link operatively associated with the moveable handle having a ramp extending distally from a proximal end. The ramp configured to engage a slot of the vertical pawl to move the vertical pawl out of engagement with the actuation shaft when the moveable handle is compressed. In particular embodiments, the actuation assembly includes an actuation pawl pivotally coupled to the moveable handle, an actuation arm, an actuation button moveable between a first or centered position and a second or non-centered position and a grasping pawl coupled to an end of the actuation arm. The grasping pawl moveable between an extended position, when the actuation button is in the centered position, and a retracted position, when the actuation button is in the off-centered position. When the grasping pawl is in the extended position the grasping pawl is positioned within a grasping slot of the actuation shaft and in the retracted position the grasping pawl is out of engagement with the actuation shaft. The grasping pawl can be configured to prevent the action shaft from advancing when the grasping pawl is in the extended position. In certain embodiments, the grasping pawl includes a radial detent configured to engage a distal surface of the grasping slot of the actuation shaft when the grasping pawl is in the extended position to prevent advancement of the actuation shaft.
According to other aspects of the present discourse, a surgical stapling device includes a retraction assembly having a retraction handle operatively associated with a release plate. The release plate is configured to extend below a portion of the actuation shaft to disengage a vertical pawl from the action shaft when the retraction handle is pulled proximally to retract the actuation shaft. In embodiments, the release plate extends below the actuation shaft from a fire mode locking surface to a proximal end of the actuation shaft. In some embodiments, the vertical pawl engages the actuation shaft from a grasping chamfer to a vertical pawl locking surface as the actuation shaft is retracted.
According to yet another aspect of the present disclosure, a surgical stapling device includes a handle assembly, an elongated body, a tool assembly, and an actuation shaft. The handle assembly includes an actuation shaft, a stationary handle, and a moveable handle. The moveable handle has a non-compressed position positioned away from the stationary handle and is compressible towards the stationary handle such that movement of the moveable handle effects axial movement of the actuation shaft. The elongated body extends distally from the handle assembly and defines a longitudinal axis. The tool assembly is supported on a distal end of the elongated body. The tool assembly includes a cartridges assembly having a plurality of staples therein and an anvil assembly. The cartridge assembly and the anvil assembly are movable in relation to each other between open and closed positions. The actuation assembly is operatively associated with the actuation shaft to advance the actuation shaft upon movement of the moveable handle. The actuation assembly includes a grasping pawl moveable between an extended position and a retracted position. In the extended position the grasping pawl is positioned within a grasping slot of the actuation shaft and is configured to prevent advancement of the actuation shaft. In the retracted position, the grasping pawl is positioned below the actuation shaft. In embodiments the grasping pawl includes a redial detent configured to engage a distal surface of a grasping slot of the actuation shaft when the grasping pawl is in the extended position to prevent advancement of the actuation shaft. In some embodiments, the actuation assembly is configured to prevent the actuation shaft from advancing when the actuation shaft is in a fully retracted position and the movable handle is in the non-compressed position. The actuation assembly can include a vertical pawl having a locking notch and a the actuation shaft can have a vertical pawl locking surface configured to engage the locking notch when the actuation shaft is in a fully retracted position and the moveable handle is in the non-compressed position.



BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the presently disclosed surgical stapling device are disclosed herein with reference to the drawings wherein:
FIG. 1 is a side perspective view of a surgical stapling device provided in accordance with the present disclosure;
FIG. 2 is a cross-sectional view taken along the section line 2-2 of FIG. 1;
FIG. 3A is an enlarged view of the indicated area of detail area of FIG. 2;
FIG. 3B is an enlarged view of the detail area 3A of FIG. 2 after the grasping pawl is moved to the retracted position and the moveable handle is compressed;
FIG. 4 is a side perspective view of the actuation shaft, vertical pawl, and distal link of the surgical stapling device of FIG. 1; and
FIG. 5 is a side view of the internal components of the handle with certain components shown in phantom.



DETAILED DESCRIPTION OF THE EMBODIMENTS
Embodiments of the presently disclosed surgical stapling device including a universal handle safety mechanism will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” will refer to the portion of the device closest to the clinician and the term “distal” will refer to the portion of the device furthest from the clinician.
FIG. 1 illustrates an embodiment of a presently disclosed surgical stapling device 10. Device 10 includes a handle assembly 12, an elongated body 14 extending distally from handle assembly 12 defining a longitudinal axis, and a tool assembly 25 supported on a distal end of the elongated body 14. Tool assembly 25 can be part of a reload 20 which is releasably secured to a distal end of elongated body 14 and includes a proximal body portion 21, which forms an extension of elongated body 14, and a tool assembly 25. Tool assembly 25 is supported on a distal end of proximal body 24 and includes a first jaw 26 supporting a cartridge assembly 26a and a second jaw 27 supporting an anvil assembly 27a. Alternatively, tool assembly 25 can be secured directly to the distal end of the elongated body 14. In an embodiment, tool assembly 25 is pivotally connected to body portion 21 about an axis substantially perpendicular to the longitudinal axis of elongated body 14.
Cartridge assembly 26a houses a plurality of staples and is movable in relation to anvil assembly 27a between an open position spaced from anvil assembly 27a and an approximated or closed position in juxtaposed alignment with anvil assembly 27a. Tool assembly 25 may be arranged such that cartridge assembly 26a is moveable and anvil assembly 27a is stationary (as shown) or, alternatively, such that anvil assembly 27a is movable and cartridge assembly 26a is stationary or such that both the anvil assembly 27a and the cartridge assembly 26a are movable. In an embodiment, tool assembly 25 is configured to apply linear rows of staples measuring from about 30 mm to about 60 mm in length (including about 45 mm in length) to tissue clamped between the cartridge assembly 26a and the anvil assembly 27a. Tool assemblies having linear rows of staples of other lengths and/or different staple array configurations are also envisioned. In embodiments, cartridge assembly 26a can be removably supported on first jaw 26 to facilitate reuse of stapling device 10 without replacement of reload 20 and/or where stapling device 10 does not include a reload 20.
Handle assembly 12 includes a housing 13 having a barrel portion 15 and a stationary handle 18. A movable handle 19 is pivotally supported on housing 13 adjacent stationary handle 18. In an embodiment, housing 13 is formed from molded half-sections 13a, 13b which are joined together by ultrasonic welding, adhesives, mechanical fasteners, or the like. A rotation control member 22 is rotatably mounted at the forward end of barrel portion 15 to facilitate rotation of elongated body 14 with respect to handle assembly 12. Rotation control member 22 also can be formed from molded plastic half-sections, although other materials, e.g., metals, and manufacturing methods are envisioned. An articulation lever 24 can also be mounted on the forward end of barrel portion 15 adjacent rotation control member 22 to facilitate articulation of tool assembly 25. U.S. Pat. No. 5,865,361 to Milliman et al. (the “'361 Patent”) and U.S. Pat. No. 7,967,178 to Scirica et al. (the “'178 Patent”), describe a rotation control assembly and articulation assembly for a surgical stapling apparatus each of which is commonly owned with the present disclosure and is hereby incorporated herein by reference in its entirety.
Referring now to FIGS. 2-4, handle assembly 12 includes an actuation assembly 40, a retraction assembly 70, and an actuation member or actuation shaft 90. As best shown in FIG. 4, actuation shaft 90 includes a distal recess 91, a vertical pawl locking surface 92, a grasping chamfer 93, a fire mode locking surface 94, a distal cutout 95, a shoulder 96, a grasping slot 97 (FIG. 3A), and a toothed rack 98. Actuation shaft 90 is movably supported within handle assembly 12 along the longitudinal axis of elongated body 14 and supports toothed rack 98 to facilitate distal advancement of actuation shaft 90 as described in detail below. Distal recess 91 is configured to receive the proximal end of a control rod 14a that is operably associated with tool assembly 25 and can be advanced in the manner discussed in the '361 Patent to clamp tissue and eject staples from cartridge assembly 26a. 
Referring to FIGS. 3A-4, actuation assembly 40 includes a locking assembly 50. Locking assembly 50 includes a vertical pawl 150, a vertical pawl biasing member 151, and a disconnect link 157. As shown, vertical pawl 150 is substantially rectangular and includes a slot 152, an upper camming surface 153, and a locking notch 154. Vertical pawl biasing member 151 is supported by housing 13 at a position to urge upper camming surface 153 of vertical pawl 150 into engagement with actuation shaft 90. In embodiments, locking assembly 50 includes a proximal link 58 having a proximal end coupled to a boss 59 formed on a moveable handle 19 and a distal end coupled to the proximal end of disconnect link 157. Disconnect link 157 includes a first portion 158 having a first height, a distal disconnect arm 159 having a second height which is greater than the first height extending distally from first portion 158, and a ramp 158a interconnecting the first portion 158 to the second portion 159. Disconnect link 157 is moveably supported within housing 13 and is positioned to pass through slot 152 of vertical pawl 150. Alternatively, other vertical pawl configurations are envisioned.
Locking assembly 50 is moveable between an engaged position (FIG. 3A) and a disengaged position (FIG. 3B). In the engaged position, disconnect arm 159 of disconnect link 157 is positioned within slot 152 of vertical pawl 150 such that vertical pawl 150 is biased upwardly by biasing member 151 into engagement with actuation shaft 90. In the disengaged position, ramp 158 of disconnect link 157 is positioned within slot 152 of vertical pawl 150 such that ramp 158 presses vertical pawl 150 downwardly against vertical pawl biasing member 151 and out of engagement with actuation shaft 90.
Referring to FIG. 3A, actuation shaft 90 is in a fully retracted or proximal position, moveable handle 19 is in the non-compressed position, and locking assembly 50 is in the engaged position with locking notch 154 of vertical pawl 150 engaging vertical pawl locking surface 92 of actuation shaft 90 to prevent advancement of actuation shaft 90. When moveable handle 19 is compressed towards stationary handle 18 (FIG. 1), moveable handle 19 advances ramp 158 of disconnect link 157 into slot 152 of vertical pawl 150 to press the vertical pawl 150 downwardly and to transition locking assembly 50 to the disengaged position to permit advancement of actuation shaft 90 as shown in FIG. 3B. When moveable handle 19 is returned to the non-compressed position, locking assembly 50 returns to the engaged position (FIG. 3A) such that vertical pawl 150 engages actuation shaft 90 to prevent retraction of actuation shaft 90 as described in detail below.
With continued reference to FIG. 3A, actuation assembly 40 also includes an actuation pawl 140, an actuation arm 144, and an actuation button 146. Actuation pawl 140 is pivotally supported about a pivot member 51 on an upper end of movable handle 19 and includes a distal finger 141 for engaging toothed rack 98 of actuation shaft 90. The '178 patent, which has been incorporated herein by reference, describes a similar actuation assembly. Grasping pawl 142 is pivotally supported within a slot (not shown) formed in an end 144a of actuation arm 144 and includes a radial recess 142a. A grasping pawl biasing member 143 is positioned to urge grasping pawl 142 in a counter-clockwise direction, as viewed in FIG. 3A, to allow grasping pawl 142 to ratchet or slide over toothed rack 98 of actuation shaft 90. Actuation arm 144 is disposed within a recess 19a defined within movable handle 19.
Actuation arm 144 and grasping pawl 142 are moveable between an extended position (FIG. 3A) and a retracted position (FIG. 3B) in response to transverse movement of articulation button 146 as described in the '178 patent. In embodiments, actuation assembly 40 includes an actuation arm biasing member 144a positioned within recess 19a to urge actuation arm 144 upwardly within recess 19a. In the extended position, grasping pawl 142 of actuation arm 144 is received within grasping slot 97 of actuation shaft 90. In the retracted position, grasping pawl 142 is positioned beneath actuation shaft 90.
With continued reference to FIGS. 3A and 3B, actuation button 146 is slidably positioned through a bore 53 formed in movable handle 19. Bore 53 is positioned substantially orthogonally to recess 19a within movable handle 19 such that an actuation button cam 147 of actuation button 146 is slidably positioned between upper and lower cam surfaces 145a, 145b of actuation arm 144. Actuation cam member 147 is engaged with or positioned to engage the upper and lower cam surfaces 145a, 145b such that lateral or transverse movement of actuation button 146 from a centered position to one of two lateral positions transitions actuation arm 144 from the extended position to the retracted position. Actuation cam member 147 may include notches (not shown) to retain actuation arm 146 in the retracted position.
In a grasping mode as shown in FIG. 3A, actuation button 146 is in its first or centered position and actuation arm 144 and grasping pawl 140 are positioned in the extended position. In the extended position, actuation cam member 147 is engaged with upper cam surface 145a of actuation arm 144 and grasping pawl 142 is positioned within grasping slot 97 formed in actuation shaft 90. In the extended position, when movable handle 19 is compressed, actuation pawl 140 engages shoulder 96 on actuation shaft 90 to advance the actuation shaft 90 and control rod 14a distally. Distal movement of control rod 14a effects movement of the jaws of tool assembly 25 to the closed position. When moveable handle 19 is returned to its non-compressed position, either manually or by a handle biasing member 19b (FIG. 2), grasping pawl 142 engages a proximal surface 97a defining a proximal end of slot 97 to retain movable handle 19 in an intermediate position between the non-compressed and compressed positions. A handle biasing member 19b can be associated with moveable handle 19. Handle biasing member 19b is positioned to return movable handle 19 to the non-compressed position after the moveable handle 19 is released by a clinician. In some embodiments handle biasing member 19b is a light spring which is not strong enough to move actuation shaft 90 and control rod 14a proximally because of friction associated with the components of tool assembly 25 (FIG. 1) driven by actuation shaft 90. However, a clinician can manipulate movable handle 19 to move actuation shaft 90 and control rod 14a to move tool assembly 25 (FIG. 1) between the open position and the closed position.
When device 10 is in the grasping mode, movable handle 19 is prevented from moving to the non-compressed position by engagement of grasping pawl 142 with proximal surface 97a defining the grasping slot 97. More specifically, grasping pawl 142 is positioned within grasping slot 97 such that an edge of proximal surface 97a is received within a recess 142a of grasping pawl 142. In embodiments, the recess 142a is shaped such that if a distal force is applied to actuation shaft 90 when device 10 is in the grasping mode, proximal surface 97a engages an inwardly curved portion of grasping pawl 142 which defines recess 142a of grasping pawl 142 to urge grasping pawl 142 towards the extended position. As described above, in the extended position actuation shaft 90 is prevented from advancing to fire staples. Thus, if a clinician were to push on retraction handle 170 in a distal direction when device 10 is in the grasping mode (for example, to further compress tissue positioned between the first and second jaws 26, 27), the interaction of proximal surface 97a with the curved surface defining recess 142a prevents device 10 from inadvertently shifting into the firing mode.
In the intermediate position of movable handle 19, actuation pawl 140 is prevented from engaging toothed rack 98 of actuation shaft 90. More specifically, when movable handle 19 is in the intermediate position, actuation pawl 140 is positioned to slide along a flat surface 90a (FIGS. 3a and 4) on a bottom of actuation shaft 90.
Referring to FIG. 3B, when movable handle 19 is moved to the compressed position and actuation button 146 is depressed from the centered position to the off-center position, v-shaped cam member 147 engages cam surface 145b on actuation arm 144 to retract actuation arm 144 within recess 19a of movable handle 19 and retract grasping pawl 142 to a position below grasping slot 97 of actuation shaft 90. In embodiments, when grasping pawl 142 is positioned below actuation shaft 90, the handle biasing member 19b returns movable handle 19 to its non-compressed position (FIG. 1). When moveable handle 19 returns to its non-compressed position, vertical pawl 150 is moved by vertical pawl biasing member 151 into engagement with fire mode locking surface 94 of actuation shaft 90 to prevent proximal retraction of actuation shaft 90 and thus, retain tool assembly 25 in the closed position. With tool assembly 25 in the closed position and device 10 in the firing mode, when moveable handle 19 moves to the non-compressed position, the actuation pawl 140 is positioned to engage toothed rack 98 of actuation shaft 90 as shown in FIG. 5. Thus, when movable handle 19 is again compressed, actuation pawl 140 engages toothed rack 98 of actuation shaft 90 to distally advance actuation shaft 90 to effect firing of tool assembly 25. As actuation shaft 90 is distally advanced in the firing mode, camming surface 153 of vertical pawl 150 ratchets or slides over and engages teeth 98a of toothed rack 98 of shaft 90 as shaft 90 is advanced distally to prevent retraction of actuation shaft 90 when the movable handle 19 cycles between its compressed and non-compressed positions.
With reference to FIGS. 2 and 5, a retraction assembly 70 includes a retraction handle 170 connected to the proximal end of actuation shaft 90 by a coupling rod 176. Coupling rod 176 includes right and left engagement portions (not shown) for receiving refraction handle 170 and a central portion (not shown) which is dimensioned and configured to translate within a pair of longitudinal slots 99 formed in actuation shaft 90 adjacent the proximal end thereof. A release plate 172 is operatively associated with actuation shaft 90 and is mounted for movement with respect thereto in response to manipulation of retraction handle 170. A pair of spaced apart pins 172b extend outwardly from a lateral face of actuation shaft 90 and are received by a pair of corresponding angled cam slots 172a formed in release plate 172. Upon proximal movement of retraction handle 170, pins 172b cam release plate 172 downwardly with respect to actuation shaft 90 and with respect to toothed rack 98 such that the bottom portion of release plate 172 extends below toothed rack 98 to disengage finger 151 of actuation pawl 150 and vertical pawl 140 from toothed rack 98 as indicated by the dashed line in FIG. 5. In embodiments, the distal end of release plate 172 is positioned proximal to vertical pawl locking surface 92 such that release plate 172 does not disengage vertical pawl 150 from vertical pawl locking surface 92 when actuation shaft 90 is in the fully retracted position. A transverse slot 172c is formed at the proximal end of release plate 172 to accommodate the central portion 176c of coupling rod 176 and elongated slots 76 (FIG. 1) are defined in the barrel portion 15 of handle 13 to accommodate the longitudinal translation of coupling rod 90 as retraction handle 170 is pulled proximally to retract actuation shaft 90 and thus retract the control rod 14a. Coupling rod 176 is biased distally in relation to actuation shaft 90 by retraction biasing member 174 which is secured at one end to coupling rod 176 via connector 173 and at the other end to a portion of actuation shaft 90. A similar retraction device is disclosed in U.S. Pat. No. 6,330,965 and the '178 Patent, each of which is commonly owned with the present disclosure and is incorporated herein by reference in its entirety.
Referring to 1-5, when a clinician compresses movable handle 19 from the non-compressed position towards stationary handle 18, moveable handle 19 advances disconnect link 157 to position ramp 158 within slot 152 of vertical pawl 150 to disengage vertical pawl 150 from vertical pawl locking surface 92 of actuation shaft 90. As movable handle 19 is compressed, finger 141 of actuation pawl 140 engages shoulder 96 of actuation shaft 90 to advance actuation shaft 90 distally. Distal advancement of actuation shaft 90 transitions tool assembly 25 to the closed position. Once actuation shaft 90 moves distally such that vertical pawl 150 is positioned proximal to vertical pawl locking surface 92 of actuation shaft 90, actuation shaft 90 is prevented from returning to the retracted position without the clinician actuating retraction assembly 70 as discussed below.
In the grasping mode (FIG. 3A), camming surface 153 of vertical pawl 150 engages actuation shaft 90 between vertical pawl locking surface 92 and fire mode locking surface 94. In embodiments, camming surface 153 of vertical pawl 140 engages grasping chamfer 93 when device 10 is in the grasping mode. As discussed above, actuation arm 144 is normally urged to the extended position by actuation button 146 such that grasping pawl 142 of actuation arm 144 extends within grasping slot 97 of actuation shaft 90 between a proximal surface 97a and a distal surface 97b of actuation shaft 90. In the grasping mode, cycling of moveable handle 19 toward and away from stationary handle 18 causes proximal retraction and distal advancement of actuation shaft 90 and control rod 14a and correspondingly transitions tool assembly 25 between the open and closed positions. As discussed above, proximal surface 97a defines grasping slot 97 is received within recess 142a of grasping pawl 142 to prevent inadvertent advancement of actuation shaft 90 when a distal force is applied to retraction handle 170 such that fire mode locking surface 94 of actuation shaft 90 is advanced beyond vertical pawl 150.
In the grasping mode, the clinician is free to open and close the jaws 26, 27 (FIG. 1) of the tool assembly 25 to grasp, manipulate, and release tissue as needed to properly position device 10 in relation to tissue. When tissue is properly positioned between jaws 26 and 27 of tool assembly 25, the clinician depresses actuation button 146 to retract actuation arm 144 and withdraw grasping pawl 142 from within grasping slot 97 to transition device 10 to the firing mode. Thereafter, movable handle 19 is moved to the non-compressed position and back to the compressed position such that actuation pawl 150 advances past fire mode locking surface 94 of actuation shaft 90. In the firing mode, the clinician may desire to fire staples from first jaw or cartridge assembly 26 through the clamped tissue as described below. Alternatively, a clinician may also release the tissue from within tool assembly 25 by actuation of retraction assembly 70 as discussed below.
When the clinician moves moveable handle 19 to the non-compressed position, disconnect arm 159 of disconnect link 157 is positioned within slot 152 of vertical pawl 150 such that vertical pawl 150 engages fire mode locking surface 94 of actuation shaft 90 to prevent retraction of actuation shaft 90 such that the jaws 26, 27 of tool assembly 25 remain in a clamped or closed position. Device 10 may also be positioned in the firing mode without entering grasping mode if the clinician holds actuation button 146 depressed to retract actuation arm 144 and then cycles moveable handle 19 from the non-compressed position to the compressed position and back to the non-compressed position such that the vertical pawl 150 engages fire mode locking surface 94 of actuation shaft 90.
To fire staples from cartridge assembly 26 (FIG. 1), movable handle 19 is compressed from the non-compressed position towards stationary handle 18, to advance finger 141 of actuation pawl 140 into engagement with a portion of toothed rack 98 of actuation shaft 90 to advance actuation shaft 90 distally. As actuation shaft 90 advances, camming surface 153 of vertical pawl 150 passes over cutout 95, shoulder 96, and teeth 98a of toothed rack 98 of actuation shaft 90, such that vertical pawl 150 sequentially engages teeth 98a to prevent retraction of actuation shaft 90 when actuation pawl 140 is disengaged from toothed rack 98. In embodiments, once device 10 is in the firing mode, vertical pawl 150 prevents retraction of actuation shaft 90 regardless of the position of distal link 157 through engagement with teeth 98a of toothed rack 98. When device 10 is in the firing mode, cycling of moveable handle 19 continues to advance actuation shaft 90 and fire staples from cartridge assembly 26a. 
After the clinician fires the staples or desires to release the tissue from tool assembly 25, the clinician engages retraction assembly 70 by pulling retraction handle 170 proximally. When retraction handle 170 is pulled proximally, coupling rod 176 moves from its distal position towards its proximal position to cam release plate 172 downwardly below toothed rack 98 as discussed above. When retraction plate 172 extends below toothed rack 98, retraction plate 172 disengages finger 141 of actuation pawl 140 and vertical pawl 150 from actuation shaft 90. Proximal movement of retraction handle 170 retracts actuation shaft 90 and thus retracts control rod 14a to transition tool assembly 25 from the closed position to the open position and release the tissue from within tool assembly 25. When refraction handle 170 is released, retraction biasing member 174 returns coupling rod 176 to the distal position and moves retraction plate 172 above toothed rack 98 allowing device 10 to be reused.
It will be understood that various modifications may be made to the embodiments disclosed herein. For example, it is envisioned that the surgical stapling device disclosed may be used in association with other surgical devices, e.g., clip appliers, dissectors, electrosurgical scaling devices, etc. Further, the device may also include tool assemblies other than staplers or those devices which eject a fastener, e.g., sealing devices (electrosurgical and non-electrosurgical), etc. The button or other actuator for changing the mode of operation for the device may be provided on one side or both sides of the handle assembly. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

## Claims

1. A surgical device comprising:
a handle assembly including a housing, an actuation shaft, a stationary handle, and a movable handle, the movable handle being moveable in relation to the stationary handle from a non-compressed position to a compressed position and being operably associated with the actuation shaft such that movement of the movable handle towards the compressed position effects axial movement of the actuation shaft;
an elongated body extending distally from the handle assembly, the elongated body defining a longitudinal axis;
a tool assembly supported on a distal end of the elongated body, the tool assembly including a cartridge assembly having a plurality of staples supported therein and an anvil assembly, the anvil assembly and the cartridge assembly being movable in relation to each other between open and closed positions; and
an actuation assembly supported within the housing, the actuation assembly being positioned to translate movement of the movable handle into linear movement of the actuation shaft to advance the actuation shaft, the actuation assembly including a locking assembly configured to prevent the actuation shaft from advancing when the actuation shaft is in a fully retracted position and the moveable handle is in the non-compressed position.

2. The device of claim 1, wherein the locking assembly includes a vertical pawl having a locking notch and the actuation shaft defines a vertical pawl locking surface configured to engage the locking notch of the vertical pawl to prevent advancement of the actuation shaft when the actuation shaft is in the fully retracted position and the moveable handle is in the non-compressed position.

3. The device of claim 2, wherein the locking assembly further includes a distal link operatively associated with the moveable handle, the distal link defining a ramp which interconnects a first portion of the distal link to a second portion of the distal link, the distal link slidably positioned within a slot of the vertical pawl wherein the ramp is configured to engage the vertical pawl as the ramp moves through the slot to move the vertical pawl out of engagement with the vertical pawl locking surface of the actuation shaft when the moveable handle is moved towards the compressed position.

4. The device of claim 2, wherein the device includes a retraction assembly including a retraction handle operatively associated with a release plate, the release plate positioned to disengage the vertical pawl from the actuation shaft when retraction handle is pulled proximally to retract the actuation shaft.

5. The device of claim 4, wherein the actuation shaft includes a distally located fire mode locking surface and a proximal end and the release plate extends below the actuation shaft between the fire mode locking surface and the proximal end of the actuation shaft.

6. The device of claim 4, wherein a vertical pawl engages the actuation shaft from a grasping chamfer to a vertical pawl locking surface as the actuation shaft is retracted.

7. The device of claim 2, wherein the vertical pawl locking surface is distal facing and perpendicular to the longitudinal axis.

8. The device of claim 1, wherein the actuation assembly further includes an actuation pawl pivotally coupled to the moveable handle, an actuation button, and a grasping pawl, wherein the actuation button is movable from a first position to a second position to move the grasping pawl from an extended position to a retracted position, wherein in the extended position the grasping pawl is positioned within a grasping slot of the actuation shaft and in the retracted position the grasping pawl positioned below the actuation shaft.

9. The device of claim 8, wherein the actuation assembly is configured to prevent the actuation shaft from advancing to a firing mode when the grasping pawl is in the extended position.

10. The device of claim 9, wherein the grasping pawl includes a recess, a proximal surface of the grasping slot received within the recess when the grasping pawl is in the extended position, such that forward movement of the actuation shaft urges the grasping pawl towards the extended position.

11. The device of claim 1, wherein the actuation assembly includes a vertical pawl biasing member configured to urge the vertical pawl into engagement with the actuation shaft.

12. The device of claim 1, wherein a vertical pawl prevents retraction of the actuation shaft when engaged with the actuation shaft after the actuation shaft is advanced.

13. A surgical device comprising:
a handle assembly including an actuation shaft, a stationary handle, and a movable handle, the actuation shaft defining an actuation slot, the movable handle being moveable from a non-compressed position to a compressed position and being operably associated with the actuation shaft such that movement of the movable handle effects axial movement of the actuation shaft;
an elongated body extending distally from the handle assembly, the elongated body defining a longitudinal axis;
a tool assembly supported on a distal end of the elongated body, the tool assembly including a cartridge assembly having a plurality of staples supported therein and an anvil assembly, the anvil assembly and the cartridge assembly being movable in relation to each other between open and closed positions; and
an actuation assembly operatively associated with the actuation shaft to advance the actuation shaft upon movement of the moveable handle, the actuation assembly including a grasping pawl moveable between an extended position, wherein the grasping pawl is positioned within the grasping slot of the actuation shaft, and a retracted position, wherein the grasping pawl is positioned below the actuation shaft, the grasping pawl defining a recess positioned to receive a surface of the actuation shaft defining the grasping slot, wherein the recess is configured such that distal movement of the actuation shaft, when received in the recess, urges the grasping pawl towards the extended position.

14. The device of claim 13, wherein the actuation assembly is configured to prevent the actuation shaft from advancing when the actuation shaft is in a fully retracted position and the moveable handle is in the non-compressed position.

15. The device of claim 14, wherein the actuation assembly includes a vertical pawl having a locking notch and the actuation shaft includes a vertical pawl locking surface configured to engage the locking notch of the vertical pawl to prevent advancement of the action shaft when the actuation shaft is in a fully retracted position and the moveable handle is in the non-compressed position.

16. The device of claim 15, wherein the actuation assembly further includes a distal link operatively associated with the moveable handle having a second portion, the distal link slidably positioned within a slot of the vertical pawl and the second portion configured to engage the slot to move the vertical pawl out of engagement with the vertical pawl locking surface of the actuation shaft when the moveable handle is compressed towards the fixed handle.

17. The device of claim 15, further including a retraction assembly including a retraction handle operatively associated with a release plate to extend the release plate below a portion of the actuation shaft to disengage the vertical pawl from the actuation shaft when retraction handle is pulled proximally to retract the actuation shaft.

18. The device of claim 17, wherein the actuation shaft includes a distally located fire mode locking surface and a proximal end, wherein the release plate extends below the actuation shaft between the fire mode locking surface and the proximal end of the actuation shaft to retract the actuation shaft.

19. The device of claim 17, wherein the actuation shaft includes a vertical pawl locking surface and a grasping chamfer, the vertical pawl engaging the actuation shaft from the grasping chamfer to the vertical pawl locking surface as the actuation shaft is retracted.

20. The device of claim 13, further comprising an actuation button moveable between a first position and a second position to move the grasping pawl between the extended position and the retracted position.