Surgical stapling apparatus

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/779,631, filed Mar. 13, 2013, the entire disclosure of which is incorporated by reference herein.

[0002] Technical Field

[0003] The present disclosure relates to surgical stapling apparatuses. More particularly, the present disclosure relates to surgical stapling apparatuses including working end drive lockout mechanisms.

[0004] Description of Related Art

[0005] Surgical stapling apparatus configured to staple, and subsequently sever tissue are well known in the art. Such stapling apparatuses typically include a housing or handle and an elongated member that extends from the housing. In certain instances, single use or multi use loading unit (MULU) reload may be configured to releasably couple to a distal end of the elongated member. In either of the aforementioned reload configurations, a tool assembly including an anvil and a cartridge may be provided on respective jaws of the reload to staple tissue. The tool assembly can include a knife to sever the stapled tissue. The reload can include a drive member having a working end which supports the knife and advances an actuation sled through the tool assembly to staple and sever tissue.

[0006] While the aforementioned reload configurations provide numerous advantages, it may be desirable to prevent inadvertent advancement of the drive member of the reload when a staple cartridge is absent from the tool assembly or has been fired.

[0007] As can be appreciated, surgical stapling apparatuses that include a drive lockout mechanism may prove useful in the surgical arena.

[0008] Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user.

[0009] An aspect of the instant disclosure provides a surgical stapling apparatus. The surgical stapling apparatus includes a housing and an elongated member therefrom. A tool assembly is supported on a distal end of the elongated member and includes a first jaw member and a second jaw member. A cartridge assembly is releasably supported on the first jaw member and includes an actuation sled and a slide. An anvil is operably supported on the second jaw member. A drive member having a working end is configured to translate through the tool assembly when the first and second jaw members are in a closed configuration. A lock assembly including a latch is movable from a locked position to an unlocked position. The latch is urged to the locked position to engage the working end of the drive member to prevent distal translation of the drive member through the tool assembly. The slide is configured to move the latch from the locked position to the unlocked position upon installation of an unspent cartridge assembly onto the first jaw member. The slide being movable by the drive member upon actuation of the stapling apparatus to allow the latch to move back to the locked position.

[0010] The lock assembly may be operably coupled to a pivot assembly of the reload. The lock assembly may include a cam pin, at least one resilient member and at least one washer. The cam pin may be positioned through an aperture defined through the pivot assembly and configured to rotate therein to move the latch from the locked position to the unlocked position when contacted by the slide.

[0011] The working end may include at least one recess that is configured to selectively engage the latch. The slide may be configured to releasably couple to the actuation sled. The slide may include at least one mechanical interface that is configured to couple to a corresponding mechanical interface disposed within the cartridge assembly when the actuation sled is moved distally. The mechanical interfaces may be disposed on the slide deflector and within the cartridge assembly form a dovetail joint.

[0012] An aspect of the instant disclosure provides a reload. The reload includes a tool assembly including a first jaw member and a second jaw member. A cartridge assembly is releasably supported on the first jaw member and includes an actuation sled and a slide. An anvil is operably supported on the second jaw member. A drive member having a working end is configured to translate through the tool assembly when the first and second jaw members are in a closed configuration. A lock assembly including a latch is movable from a locked position to an unlocked position. The latch is urged to the locked position to engage the working end of the drive member to prevent distal translation of the drive member through the tool assembly. The slide is configured to move the latch from the locked position to the unlocked position upon installation of an unspent cartridge assembly onto the first jaw member. The slide is movable by the drive member upon actuation of the stapling apparatus to allow the latch to move back to the locked position.

[0013] The lock assembly may be operably coupled to a pivot assembly of the reload. The lock assembly may include a cam pin, at least one resilient member and at least one washer. The cam pin may be positioned through an aperture defined through the pivot assembly and configured to rotate therein to move the latch from the locked position to the unlocked position when contacted by the slide.

[0014] The working end may include at least one recess that is configured to selectively engage the latch. The slide may be configured to releasably couple to the actuation sled. The slide may include at least one mechanical interface that is configured to couple to a corresponding mechanical interface disposed within the cartridge assembly when the actuation sled is moved distally. The mechanical interfaces may be disposed on the slide deflector and within the cartridge assembly form a dovetail joint.

[0015] An aspect of the instant disclosure provides a surgical stapling apparatus. The surgical stapling apparatus includes a housing and an elongated member therefrom. A tool assembly is supported on a distal end of the elongated member and includes a first jaw member and a second jaw member. A cartridge assembly is releasably supported on the first jaw member and includes an actuation sled including at least one mechanical interface. An anvil is operably supported on the second jaw member and includes at least one spring and defines a stop. A drive member having a working end includes at least one mechanical interface. The spring is configured to urge the working end of the drive member to position the working end of the drive member in alignment with the stop on the anvil to prevent the working end of the drive member being advanced distally. The at least one mechanical interface on the actuation sled is positioned to engage the at least one mechanical interface on the working end of the drive member to retain the working end of the drive member out of engagement with the stop to allow advancement of the drive member through the tool assembly.

[0016] The at least one mechanical interface on the actuation sled may be a protuberance having a slanted configuration that extends proximally and the at least one mechanical interface on the working end is a recess having a configuration that complements the slanted configuration of the protuberance. The actuation sled may include a detent that may be configured to releasably engage a corresponding indent disposed within the cartridge assembly.

[0017] The spring may be configured to contact a top portion of the working end of the drive member for biasing the working end in the generally downward direction. The wave spring may be a wave spring.

[0018] An aspect of the instant disclosure provides a reload. The reload includes a tool assembly including a first jaw member and a second jaw member. A cartridge assembly is releasably supported on the first jaw member and includes an actuation sled including at least one mechanical interface. An anvil is operably supported on the second jaw member and includes at least one spring and defines a stop. A drive member having a working end includes at least one mechanical interface. The spring is configured to urge the working end of the drive member to position the working end of the drive member in alignment with the stop on the anvil to prevent the working end of the drive member being advanced distally. The at least one mechanical interface on the actuation sled is positioned to engage the at least one mechanical interface on the working end of the drive member to retain the working end of the drive member out of engagement with the stop to allow advancement of the drive member through the tool assembly.

[0040] Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

[0041] In accordance with the instant disclosure, various drive lockout mechanisms are disclosed herein and are configured for use with surgical stapling apparatus adapted to receive replaceable staple cartridge. The various drive lockout mechanisms described below are configured to prevent firing of the surgical stapling apparatus prior to installing a cartridge, or including a spent or empty cartridge installed.

[0042] FIG. 1 illustrates a powered surgical stapling apparatus shown generally as 100. FIG. 2 illustrates a manual surgical stapling apparatus shown generally as 200. The powered apparatus includes one or more motors and an internal or external power source for mechanically actuating the stapling apparatus, whereas the manual apparatus 200 has a movable handle 236 for manually actuating the stapling apparatus. See U.S. Pat. Nos. 5,865,361; 5,782,396; International WO 04/032,760; U.S. Patent Publication No. 2010/0276741; and U.S. patent application Ser. No. 13/444,228, the entire contents of each of these disclosures is hereby incorporated herein by reference.

[0043] Briefly, the surgical stapling apparatus 100 includes a housing or stationary handle 102 having an actuator 136 and an elongated member 104 extending from housing 102 (FIG. 1). Likewise, surgical stapling apparatus 200 includes a housing or stationary handle 202 supporting a movable handle 236 and an elongated member 204 extending from housing 202. Surgical stapling apparatus 200 includes a retraction mechanism 217 (FIG. 2) that can be manually grasped and pulled proximally to retract a firing mechanism of the apparatus 200. Each of elongated members 104, 204 is configured to removably couple to a reload 106. Although the embodiments described herein disclose a reload 106 including a tool assembly 107 which is releasably coupled to the elongate member 104, 204, it is envisioned that the tool assembly can be fixedly secured to the distal end of the elongated member 104, 204.

[0044] Referring to FIG. 3A, the reload 106 includes a shaft portion 109 and a tool assembly 107 supported on a distal end of the shaft portion 109. The tool assembly 107 includes first and second jaw members 108, 110 which are movable from a spaced apart configuration (FIG. 2) for positioning tissue therebetween to an approximated configuration (not shown) for clamping tissue and subsequently stapling tissue. Jaw member 108 releasably supports a cartridge assembly 112 and jaw member 110 supports an anvil 111 that includes a plurality of buckets or depressions 120 that are configured to receive corresponding fasteners (not shown) when the fasteners are deployed from the cartridge 112.

[0045] Reference may be made to U.S. Pat. Nos. 5,865,361 and 7,225,963, the entire contents of which are incorporated herein by reference, for a more detailed discussion of the construction and operation of reload 106.

[0046] FIG. 3B illustrates the tool assembly 107 of the reload with the jaw members 108, 110 in an approximated configuration and with cartridge 112 separated from the jaw member 108. The reload 106 includes a locking mechanism that is configured to lock-out a drive member “D” (FIG. 5) so as to prevent firing of the apparatus when a cartridge 112 has not been installed in the jaw member 108 or when the cartridge 112 installed in jaw member 108 has already been fired.

[0047] A pivot assembly 150 (FIG. 3B) is provided at a distal end of shaft 109 which pivotally couples tool assembly 107 to shaft 109. Referring to FIGS. 4-5, pivot assembly 150 includes top and bottom portions 151a, 151b that are operably coupled to one another and to jaw members 108, 110, respectively, so as to allow articulation of jaw members 108, 110 (FIG. 3B) about an axis transverse to the longitudinal axis of the reload 106. Bottom portion 151b of pivot assembly 150 is configured to operably support a lock assembly 130 that is operable to prevent advancement of the working end 101 of drive member “D” distally when the cartridge 112 has been fired or is absent from the jaw member 108. Specifically, bottom portion 151b includes a pair of distally extending leg members 153a, 153b. Leg members 153a, 153b are spaced-apart from one another to receive a drive beam 103 of drive member “D” therebetween (FIGS. 4-5 and 7-8) so as to allow advancement of working end 101 though the cartridge 112, as will be described in greater detail below. Leg members 153a, 153b include a generally elongated configuration. In the illustrated embodiment, leg member 153b is slightly longer than leg member 153a and includes a distal end having a generally arcuate configuration. While leg member 153b is illustrated having a length that is greater than a length of leg member 153a, it is within the purview of the present disclosure to provide leg members 153a, 153b with the same length.

[0048] An aperture 155 extends through a distal end of leg member 153b to receive a cam pin 134 of lock assembly 130. A notch 156 is provided on leg member 153b adjacent aperture 155 and is positioned to receive a cam feature 144 of cam pin 134 to allow rotation of the cam pin 134 within aperture 155, as will be described in greater detail below.

[0049] Referring to FIGS. 4-8, lock assembly 130 includes a latch 132, cam pin 134 and a spring clip 131. Cam pin 134 is configured to rotate within aperture 155 as cartridge 112 is being installed on jaw member 108 in response to engagement with slide 160. To this end, cam pin 134 includes a generally elongated configuration including an upper portion 135 having a non circular configuration that is configured to be non-rotatably received within a corresponding aperture 137 that is defined through latch 132. As such, rotation of cam pin 134 causes corresponding rotation of latch 132 between locked (FIG. 7) and unlocked positions. A shelf 139 (FIG. 6) is provided on cam pin 134 adjacent top portion 135 and aligns with a top, planar surface of leg member 153b when cam pin 134 is seated within aperture 155. In embodiments, for example, shelf 139 may be utilized to help support latch 132 and/or raise latch 132 off of the top surface of leg member 153b.

[0050] Cam pin 134 includes a base 140 having a flange portion 138 that engages a bottom portion of leg member 153b adjacent notched portion 156 when cam pin 134 is seated within aperture 155 of leg member 153b. Flange portion 138 is provided adjacent base 140 and extends partially along an outer circumferential surface of cam pin 134. Flange 138 includes a cam feature 144 that is configured to engage a cam extension 162 disposed on a slide 160 (FIG. 9) that is releasably coupled to an actuation sled 115 of cartridge 112 when cartridge 112 is being installed on jaw member 108, as will be described in greater detail below.

[0051] A top surface 146 of flange portion 138 is generally planar and is positioned to abut a bottom surface of leg member 153b such that cam feature 144 is disposed within notch 156 of leg member 133b when cam pin 134 is positioned through aperture 155 (as best seen in FIG. 8). Cam feature 144 is movable within the recess 156 as to allow rotation of cam pin 134 within aperture 155 when cartridge 112 is being installed and when working end 101 of drive member “D” is returned to the retracted position. Cam pin 134 is rotatable within aperture 155 from a position in which latch 132 obstructs movement of the drive member “D” (FIG. 7) to a position in which latch 132 is spaced from drive member “D,” as will be discussed in further detail below.

[0052] A protrusion 148 is provided on base 140 of cam pin 134 and is received between spaced-apart resilient leg portions 133a, 133b of spring clip 131 (as best seen in FIG. 8). Protrusion 148 is positioned between the leg portions 133a, 133b such that rotation of cam pin 134 within aperture 155 causes resilient leg portions 133a, 133b deflect outwardly (FIG. 13). Leg portions 133a, 133b are configured to contact protrusion 148 to retain cam pin 134 and, thus, latch 132 in the locked position, as shown in FIG. 7. In the locked position, latch 132 is positioned to engage a recess 116 provided on working end 101 of drive member “D” (FIG. 5) to prevent distal advancement of drive member “D.” In the locked position, protrusion 148 extends parallel to and between leg portions 133a, 133b (FIG. 8) and the leg portions 133a, 133b are unbiased. When cartridge 112 is installed in jaw member 108, cam extension 162 of slide 160 contacts cam feature 144 and moves cam feature 144 proximally, which, in turn, rotates cam pin 134 and, thus, rotates protrusion 148 into contact with leg portions 133a, 133b (FIG. 13) to deflect leg portions 133a, 133b of spring clip 131 outwardly. As a result thereof, latch 132 is rotated out of engagement with recess 116 of working end 101 to facilitate distal advancement of the drive member “D.” Cam extension 162 of slide 160 remains engaged with cam feature 144 of cam pin 134 until such time that working end 101 is advanced and caused to engage actuation sled 115. When this occurs, movement of cam extension 162 out of engagement with cam feature 144 allows protrusion 148 to return to the locked out configuration as a result of the biasing force provided by leg portions 133a, 133b of spring clip 131 on protrusion 148.

[0053] Leg portions 133a, 133b of spring clip 131 meet at a generally arcuate proximal end 133c of spring clip 131 (FIG. 5). The arcuate configuration of proximal end 133c provides a suitable spring constant that allows leg portions 133a, 133b to bias the protrusion 148 such that the latch 132 is moved to the locked position when slide 160 is disengaged from cam feature 144 of cam pin 134.

[0054] An aperture 133d of spring clip 131 is provided adjacent proximal end 133c and is configured to receive a corresponding rivet 154 (or other suitable device) that is provided on a bottom portion 151b of pivot assembly 150 (FIGS. 5 and 8). A washer 158 may be utilized to couple to rivet 154 for securing lock assembly 130 to bottom portion 151b.

[0055] Latch 132 is configured to prevent distal advancement of working end 101 of drive member “D” when the latch 132 is in a locked position. Latch 132 includes an end 145a that defines the aperture 137. A generally elongated member 145b extends from end 145a and includes a tip 145c that is configured to be releasably received within recess 116 (FIG. 7) of working end 101 of the drive member “D.”

[0056] With reference again to FIG. 5, drive member “D” includes a drive beam 103 which supports the working end 101. Working end 101 has an I-beam configuration having top and bottom flanges 118a, 118b and includes a distal abutment surface 118c which engages a central support wedge 113a (FIG. 9) of the actuation sled 115 (FIG. 9). Working end 101 is configured to move through the tool assembly 107 which includes knife channel portions 114a (FIG. 3A), 114b (FIG. 9) that are defined through an anvil 111 which is supported on the jaw member 110 and jaw member 108, respectively. Specifically, the working end 101 of the drive beam 103 moves from a retracted position to an extended position to advance the working end 101 and the actuation sled 115 through a cartridge 112 to staple and sever tissue. The knife 105 is positioned to travel slightly behind the actuation sled 115 during a stapling procedure to form an incision between the rows of stapled tissue.

[0057] The recess 116 is provided at a proximal end of working end 101 of drive member “D” adjacent top flange 118a and is defined by a sidewall 119a and a back wall 119b. Sidewall 119a is angled and extends distally from back wall 119b. The recess 116 is configured to slidably receive distal tip 145c of elongated member 145b and guide distal tip 145c towards back wall 119b to lock out working end 101, as best seen in FIG. 7.

[0058] In accordance with the instant disclosure, prior to installing cartridge 112 onto jaw member 108, working end 101 of drive member “D” is retracted and in the locked out position. More specifically, leg portions 133a, 133b of spring clip 131 are positioned to retain protrusion 148 of cam pin 134 at an orientation to position latch 132 in the locked put position (FIG. 7). In order to move the latch 132 from the locked position, an unfired cartridge 112 must be installed on jaw member 108 as discussed below.

[0059] With reference to FIGS. 9-14, jaw member 108 of tool assembly 107 is configured to support removable cartridge assembly 112 thereon. Cartridge 112 includes the plurality of fasteners and a plurality of pusher members (not shown) that are operatively engaged with the fasteners. Cartridge 112 also includes one or more retention slots 119 that are positioned longitudinally along a tissue contacting surface 121 of cartridge 112 and are configured to house a plurality of fasteners (not shown). A cartridge housing 123 (FIG. 9) is coupled to jaw member 108. In any of the embodiments disclosed herein, cartridge 112 may be coupled to jaw 108 using detents 125 (FIG. 9), latches, clips or the like. A removable and replaceable cartridge is disclosed in U.S. patent application Ser. No. 13/280,880 entitled Multi-Use Loading Unit, the entire disclosure of which is hereby incorporated by reference herein.

[0060] An actuation sled 115 is positioned at a proximal end of cartridge 112 and is held in place within cartridge 112 via an indent/detent configuration. Specifically, an indent 164a is provided on a side surface 165 of a central wedge support 113a and engages a corresponding detent 164b that is provided on a left interior side wall 149c of cartridge 112 (FIG. 10). Detent 164b is configured to release from indent 164a when working end 101 of drive member “D” contacts actuation sled 115 and is advanced distally through cartridge 112.

[0061] Slide 160 has a generally elongated configuration with proximal and distal ends 163a, 163b. The cam extension 162 (a generally elongated protrusion, detent or the like) is provided at the proximal end 163a of slide 160 and is positioned on actuation sled 115 to engage the cam feature 144 of lockout assembly 130 to rotate latch 132 into the unlocked position when cartridge 112 is being coupled to jaw member 108 (FIGS. 12-13).

[0062] Slide 160 is supported between raised wedge supports of the actuation sled 115 to releasably couple the slide 160 to the actuation sled 115. Specifically, slide 160 is coupled to actuation sled 115 between the central wedge support 113a and a right wedge support 113b of actuation sled 115 (FIG. 9). More specifically, slide 160 releasably couples to actuation sled 115 via a resilient member in the form of a spring 172 (band, coil or the like) having proximal and distal ends 175a, 175b. Proximal end 175a of spring 172 is configured to bias proximal end 163a of the slide 160 against a proximal end of the right support wedge 113b such that slide 160 remains coupled to actuation sled 115 as cartridge 112 is being installed onto jaw member 108 and cam extension 162 engages cam feature 144 to move latch 132 out of engagement with recess 116 of working end 101 of the drive member “D.” Spring 172 may also be utilized to facilitate biasing detent 164b of cartridge 112 into engagement with indent 164a of actuation sled 115. Spring 172 is press or friction fit into a pair of corresponding recesses 174a, 174b that are provided on a sidewall 166. Specifically, recess 174b is disposed distal of recess 174a and is configured to receive the distal end 175b of spring 172. The proximal end 175a of spring 172 is received within recess 174a.

[0063] Sidewall 166 of slide 160 defines a groove 167 configured to receive a corresponding guide member 168 which extends from a right interior sidewall 169b of cartridge 112 (FIG. 11). Right interior sidewall 169b including guide member 168 is positioned within cartridge 112 to allow distal translation of actuation sled 115 through cartridge 112. In one embodiment, groove 167 has a dovetail configuration and receives the guide member 168 of corresponding shape.

[0064] Referring to FIGS. 11-12, in accordance with the instant disclosure, when working end 101 of drive member “D” is advanced to contact and advance the actuation sled 115, working end 101 and actuation sled 115 including slide 160 initially move distally in unison (spring 172 maintains slide 160 and actuation sled coupled to one another). Continued distal translation of the working end 101 of the drive member “D” causes groove 167 to receive guide member 168. Guide member 168 guides slide 160 into engagement with an interior wall 169a of cartridge 112 (FIGS. 11-12) adjacent right interior sidewall 169b to prevent further distal movement of the slide 160. When distal end 163b of the slide 160 contacts interior wall 169a, slide 160 disengages from actuation sled 115. With groove 167 engaged with guide member 168, slide 160 is secured to interior sidewall 169b and prevented from further movement within cartridge 112. As such, when working end 101 of drive member “D” is moved back to the retracted configuration, the slide 160 is retained in the advanced position with the distal end 163b in contact with interior wall 169a.

[0065] In use, when a cartridge assembly 112 is not installed on jaw member 108, latch 132 is in a locked configuration with distal tip 145c of latch 132 positioned within recess 116 of working end 101 (FIG. 7). With distal tip 145c of latch 132 in this configuration, as the drive member “D” is advanced distally, engagement between distal tip 145c and back wall 119b of recess 116 prevents further advancement of drive member “D” (drive member “D” is locked out) (FIGS. 7-8).

[0066] When the cartridge 112 is installed in jaw member 108, cam extension 162 of slide 160 contacts cam feature 144 of cam pin 134 to rotate cam pin 134 within aperture 155. Rotation of cam pin 134 effects corresponding rotation of latch 132 to move latch 132 out of engagement with recess 116 of working end 101. In this position, protrusion 148 of cam pin 134 deflects leg portions 133a, 133b of spring clip 131 outwardly such that leg portions 133a, 133b of spring clip 131 urge cam pin 134 back to a position in which the latch 132 is in the locked position as described above, see FIGS. 13-14 for example. Moreover, slide 160 is maintained coupled to actuation sled 115 in a manner as described above.

[0067] With latch 132 and slide 160 in the pre-fired configuration, drive member “D” including working end 101 is allowed to translate distally past the distal tip 145c of the latch 132 and engage actuation sled 115 in a manner as described above. Distal translation of slide 160 moves cam extension 162 of slide 160 out of engagement with cam feature 144 and allows latch 132 to move back to the locked-out configuration via the biasing force provided by leg portions 133a, 133b of the spring clip 131.

[0068] After the cartridge 112 has been fired, refraction of the drive member “D” will cause working end 101 to engage and pivot the latch 132 out of the path of the working end 101 such that drive member “D” will move proximally past latch 132 until working end 101 of the drive member “D” returns to the retracted configuration. In the retracted configuration, latch 132 is engaged within recess 116 such that distal tip 145c of latch 132 is positioned to engage back wall 119b of recess 116 to prevent further advancement of drive member “D,” as described above.

[0069] The unique configuration of lock assembly 130 overcomes the aforementioned drawbacks that are, typically, associated with conventional surgical stapling apparatus. Specifically, lock assembly 130 prevents firing of a surgical stapling apparatus which does not have a cartridge 112 installed, or firing of a surgical stapling apparatus with a spent or empty cartridge 112 installed.

[0070] From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same.

[0071] For example, with reference to FIGS. 15-19, an alternate embodiment of locking mechanism is illustrated. Accordingly, only those features that are unique to the embodiment illustrated in FIGS. 15-19 are described herein.

[0072] An anvil 211 includes a stop in the form of a notch 219 at a proximal end thereof that is configured to lock out a working end 201 of the drive member “D.” Specifically, notch 219 is configured to engage a top flange 218a of working end 201 of the drive member “D” to prevent working end 201 from translating distally past notch 219.

[0073] A resilient member in the form of a wave spring 231 (or other suitable spring, e.g., coil, torsion, etc.) is operably coupled (e.g., via laser or electron welding) to an upper interior surface 223 of the jaw member 210. One or more other suitable coupling methods may also be utilized to couple spring 231 to interior surface 223. For example, adhesives, various mechanical interfaces and the like may be utilized to couple spring 231 to interior surface 223. Spring 231 is positioned proximal of notch 219 and is configured to contact a top flange 218a of working end 201 to bias flange 218a in a generally downwardly direction. Specifically, spring 231 biases top flange 218a into alignment with notch 219 such that distal translation of the working end 201 of the drive member “D” causes top flange 218a of working end 201 to engage the notch 219 on the anvil 211 to prevent further advancement of the drive member “D.” In a compressed configuration, top flange 218a of the knife 205 will be positioned above notch 219 to allow further advancement of the drive member “D” through the cartridge.

[0074] A recess 216 is provided at a distal end of working end 201 adjacent a bottom flange 218b. Specifically, recess 216 is defined by a back wall 220 of working end 201 having a slanted configuration and is configured engage a corresponding protuberance in the form of a ramp 260 provided at a proximal end of the actuation sled 215. Engagement between recess 216 and ramp 260 raises top flange 218a above notch 219 against the biasing force of spring 231 to allow distal translation of working end 201 of the drive member “D” past notch 219.

[0075] Unlike actuation sled 115, actuation sled 215 is not configured to couple to a slide 160. Rather, ramp 260 extends proximally from the proximal end of actuation sled 215 and is positioned to engage back wall 220 of recess 216 when working end 201 of the drive member “D” is translated distally.

[0076] An indent/detent configuration (or other suitable mechanical interface) may be utilized to maintain actuation sled 215 in place while cartridge 212 is being installed on the jaw member (not shown for clarity purposes). In the embodiment illustrated in FIGS. 15-19, for example, an indent 240 (FIGS. 18-19) is provided on an interior bottom surface 242 of cartridge 212 and a corresponding detent 244 is provided on a bottom surface 246 of actuation sled 215 (FIGS. 15-17). Once knife 205 of the working end 201 contacts actuation sled 215, detent 244 releases from indent 240 and slides along interior bottom surface 242 with actuation sled 215.

[0077] In use, when cartridge assembly 212 is not installed on the jaw member, spring 231 is in a uncompressed state and configured to bias top flange 218a of the knife 205 in a manner as described above. With top flange 218a in the biased configuration, working end 201 of the drive member “D” is locked out and prevented from misfiring.

[0078] When cartridge 212 is installed on the jaw member, ramp 260 is positioned to engage recess 216 (FIGS. 15-16). Specifically, when the drive member “D” is advanced, ramp 260 of actuation sled 215 engages back wall 220 of recess 216 and raises top flange 218a of knife 205 above notch 219 on anvil 211 (FIG. 17) against the biasing force provided by spring 231. Spring 231 will remain in the compressed state until such time that ramp 260 is disengaged from recess 216. As a result thereof, drive member “D” is allowed to translate distally through cartridge 212 to staple and severe the stapled tissue (FIG. 18). Once top flange 218a of the working end 201 translates distally past notch 219, spring 231 will move back to the uncompressed configuration.

[0079] Working end 201 of the drive member “D” may then be moved proximally back to the retracted configuration. With the working end 201 in the retracted configuration, spring 231 will be in the uncompressed state for biasing top flange 218a of the knife 205 in a manner as described above to lock out the drive member “D” working end 201 and prevent firing of a surgical stapling apparatus which does not have a cartridge 212 installed, or firing of a surgical stapling apparatus with a spent or empty cartridge 112 installed.

[0080] While several embodiments 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 as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.