WO2024187335A1

WO2024187335A1 - Alignment pin assemblies for surgical stapling apparatus

Info

Publication number: WO2024187335A1
Application number: PCT/CN2023/081039
Authority: WO
Inventors: Xijia LI; Xiliang Zhang; Tingting JIN; Peng ZHA
Original assignee: Covidien LP
Current assignee: Covidien LP
Priority date: 2023-03-13
Filing date: 2023-03-13
Publication date: 2024-09-19
Anticipated expiration: 2025-09-13

Abstract

A surgical stapling apparatus (10) includes an anvil assembly (22), a cartridge assembly (20), and an alignment pin (54). The stapling apparatus (10) further includes a clamp assembly (18c) defining a cam slot (76) that slidably receives a cam slot boss (65) of a pivotable cam (60). The cam slot (76) is defined by a driving surface (76c) that exerts a driving force through a center of the cam slot boss (65) when the alignment pin (54) is disposed in a locking position. The pivotable cam (60) is pivotable to move the alignment pin (54) into engagement with the anvil assembly (22) to maintain the anvil and cartridge assemblies (22,20) in alignment. In aspects, the stapling apparatus (10) defines a self-locking channel (82) that slidably receives a clamp connector pin (32) of the clamp assembly (18c). The self-locking channel (82) includes a locking portion that prevents the alignment pin (54) from advancing toward the anvil assembly (22) when a force applied to the clamp connector pin (32) exceeds a predetermined threshold.

Description

ALIGNMENT PIN ASSEMBLIES FOR SURGICAL STAPLING APPARATUS

TECHNICAL FIELD

This application relates to surgical stapling apparatus and, more particularly, to surgical stapling apparatus with alignment pin assemblies.

BACKGROUND

Surgical stapling apparatus for applying rows of staples through compressed living tissue are commonly used for closure of tissue or organs prior to transection or resection of the tissue or organs and for occlusion of organs during thoracic or abdominal procedures. Typically, stapling apparatus include an end effector that may have one of a variety of configurations including linear, curved, and circular. The end effector may also have one of a variety of different orientations with respect to a longitudinal axis of the stapling apparatus including aligned or transverse.

In transverse type stapling apparatus that have curved end effectors, the end effector includes an anvil assembly that is secured to a frame of the stapling apparatus and a cartridge assembly that is supported on a clamp assembly of the stapling apparatus. The clamp assembly is movable within the frame of the stapling apparatus to move the cartridge assembly towards the anvil assembly along the frame from an open position to a clamped position. An alignment pin assembly is supported in the cartridge assembly and is movable into engagement with the anvil assembly to facilitate alignment of the anvil and cartridge assemblies.

SUMMARY

According to one aspect, this disclosure is directed to a surgical stapling apparatus including an anvil assembly, a cartridge assembly, an alignment pin assembly, a clamp assembly, and a pivotable cam. The alignment pin assembly includes an alignment pusher and an alignment pin supported in the cartridge assembly. The alignment pusher is configured to move the alignment pin between an unlocked position in which the alignment pin is disposed within the cartridge assembly, a locking position in which alignment pin is disposed in close proximity to the anvil assembly, and a locked position in which the alignment pin is captured within the anvil assembly. The clamp assembly defines a cam slot having a first segment and a second segment. The first segment is defined by a driving surface. The driving surface includes a lower angled portion and an upper portion disposed at an angle relative to the lower angled portion. The pivotable cam includes a first plate and a second plate that are coupled together by an alignment rod. The alignment rod is selectively engageable with the alignment pusher to advance the alignment pin through the cartridge assembly and into engagement with the anvil assembly for maintaining the anvil and cartridge assemblies in alignment. The pivotable cam further includes a cam slot boss that is configured to slide through the cam slot of the clamp assembly as the pivotable cam pivots about a pivot axis so that the upper portion of the driving surface provides a driving force through a center of the cam slot boss when the alignment pin is disposed in the locking position.

In aspects, the surgical stapling apparatus may further include a body that supports the clamp assembly and the pivotable cam. The body may have a trigger that is pivotably coupled to the body, wherein the clamp assembly advances distally in response to actuation of the trigger to cause the pivotable cam to pivot about the pivot axis. The surgical stapling apparatus may further include a link assembly coupled to the clamp assembly, the trigger selectively engageable with the link assembly to cause the clamp assembly to distally advance. The body may support a frame. The link assembly may be connected to the clamp assembly by a clamp connector pin that is slidably received within a channel defined within the frame. The channel may be in the form of a self-locking channel including a locking curve that receives the clamp connector pin when a force exerted through the link assembly is greater than or equal to a first predetermined threshold and causes the clamp connector pin to bend upwardly into the locking curve for preventing clamp connector pin from distally advancing. The channel may further include a sliding curve disposed adjacent to the locking curve. The sliding curve may be configured to guide the clamp connector pin toward a straight portion of the channel when the force exerted through the link assembly is less than the first predetermined threshold, but is greater than or equal to a second predetermined threshold. The second predetermined threshold may be indicative of a minimum force exerted through the link assembly that causes the clamp connector pin to bend upwardly into the sliding curve. When the force exerted through the link assembly is below the second predetermined threshold, the clamp connector pin may avoid contacting the sliding curve and the locking curve. The cam slot boss may include a curved surface and a flat surface, the curved surface engageable with the driving surface. The cam slot may be further defined by a sliding surface, the flat surface of the cam slot boss being configured to slide across the sliding surface of the cam slot.

In aspects, the alignment pusher includes a cam hook that is configured to receive the alignment rod of the pivotable cam to cause the alignment pusher to advance distally as the pivotable cam pivots relative to the alignment pusher. The alignment rod may include a curved surface and a flat surface, the curved surface configured to contact the cam hook to impart drive force through alignment pusher.

According to another aspect, this disclosure is directed to a surgical stapling apparatus including an anvil assembly, a cartridge assembly, an alignment pin, a clamp assembly, and a pivotable cam. The alignment pin assembly includes an alignment pin and an alignment pusher engaged with the alignment pin. The clamp assembly defines a cam slot having a vertical segment and horizontal segment, the vertical segment having a driving surface that is perpendicular to the horizontal segment. The pivotable cam includes a first plate and a second plate that are coupled together by an alignment rod. The alignment rod is selectively engageable with the alignment pusher to advance the alignment pin into engagement with the anvil assembly for maintaining the anvil and cartridge assemblies in alignment. The pivotable cam further includes a cam slot boss that is configured to slide through the cam slot of the clamp assembly as the pivotable cam pivots about a pivot axis so that the driving surface provides a driving force through a center of the cam slot boss when a distal end of the alignment pin is disposed between the anvil assembly and the cartridge assembly.

According to still another aspect, this disclosure is directed to a surgical stapling apparatus including an anvil assembly, a cartridge assembly, an alignment pin, a clamp assembly, and a frame. The alignment pin is supported in the cartridge assembly and movable relative to the anvil and cartridge assemblies. The clamp assembly supports a clamp connector pin. The frame defines a self-locking channel that slidably receives the clamp connector pin for enabling the alignment pin to move to a position in which the alignment pin extends between the anvil and cartridge assemblies for maintaining alignment between the anvil and cartridge assemblies. The self-locking channel includes a straight portion and a locking portion that receives the clamp connector pin for preventing the alignment pin from advancing toward the anvil assembly when a force applied to the clamp connector pin exceeds a predetermined threshold.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of this disclosure will be apparent in light of the following detailed description when taken in conjunction with the accompanying drawings, which are incorporated in and constitute a part of this specification, wherein:

FIG. 1 is a perspective view of a surgical stapling apparatus in accordance with the principles of this disclosure, portions of the surgical stapling apparatus shown with broken lines for clarity;

FIG. 2 is an enlarged, perspective view of an end effector of the surgical stapling apparatus of FIG. 1 with portions of the end effector shown with broken lines for clarity;

FIG. 3 is an enlarged, perspective view of a proximal end portion of the surgical stapling apparatus of FIG. 1 with portions removed for clarity;

FIG. 4 is a perspective view, with parts separated, of various components of the surgical stapling apparatus of FIG. 1;

FIG. 5 is an enlarged, perspective view of a pivotable cam of the surgical stapling apparatus of FIG. 1;

FIG. 6 is a side, cross-sectional view as taken along section line 6-6 shown in FIG. 5;

FIG. 7 is an enlarged view of the indicated area of detail shown in FIG. 4;

FIGS. 8-13 are progressive views illustrating components of the surgical stapling apparatus of FIG. 1 being advanced as the surgical stapling apparatus moves from an initial position to a clamped position; and

FIGS. 14-18 are progressive views illustrating a self-locking feature in a frame of the surgical stapling apparatus of FIG. 1 cooperating with a clamp connector pin of the surgical stapling apparatus.

DETAILED DESCRIPTION

Aspects of this disclosure will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. Throughout this description, the term “proximal” refers to a portion of a structure, or component thereof, that is closer to a user, and the term “distal” refers to a portion of the structure, or component thereof, that is farther from the user. Directional reference terms, such as “top, ” “bottom, ” “side, ” “upper, ” “lower, ” and the like, are used to ease description of the aspects and are not intended to have any limiting effect on the ultimate orientation of a structure or any part thereof. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, surgeons, and support personnel.

In the following description, well-known functions or constructions are not described in detail to avoid obscuring this disclosure in unnecessary detail.

Surgical stapling apparatus, such as curved surgical stapling apparatus, can be utilized, for example, to simultaneously staple and transect a colon during a lower anterior resection (LAR) procedure to create a curved anastomosis.

With reference to FIGS. 1-13, a surgical stapling apparatus, shown generally as 10 in FIG. 1, includes a body 12 defining a central longitudinal axis “L” and having a stationary handle 14, a trigger 16 pivotably mounted to body 12 between an extended (initial) position (FIG. 1) and a retracted position (not explicitly shown) , and an elongated shaft assembly 18 that extends distally from body 12. Elongated shaft assembly 18 includes a first frame 18a and a second frame 18b that are secured to body 12. Elongated shaft assembly 18 further includes a clamp assembly 18c, and a thrust bar 18d, that are positioned to axially translate relative to first and second frames 18a, 18b between proximal and distal positions in response to pivotal movement of trigger 16 relative to handle 14. An end effector 19 on a distal end portion of elongated shaft assembly 18 includes a cartridge assembly 20 having a cartridge plate 20a and an anvil assembly 22 having an anvil plate 22a. Cartridge assembly 20 supports staples (not shown) that form against anvil assembly 22 for fastening tissue clamped between the cartridge and anvil assemblies 20, 22 when surgical stapling apparatus 10 is fired. Elongated shaft assembly 18 further includes an alignment pin assembly 18e that is movable between proximal and distal positions to facilitate alignment between cartridge and anvil assemblies 20, 22.

Body 12 of surgical stapling apparatus 10 supports a release mechanism 24 having a release actuator 26 positioned on the proximal end of body 12, and link assembly 28 disposed within body 12. Link assembly 28 is pivotably coupled to release actuator 26 by an actuator connector pin 30 and a proximal end portion of clamp assembly 18c by a clamp connector pin 32. Link assembly 28 may be in the form of a bi-link assembly and includes a proximal link 28a and a distal link 28b that are pivotably coupled together by a pivot pin 28c. Link assembly 28 is movable between a retracted position (FIG. 3) and an extended position (not explicitly shown) to move clamp assembly 18c between unclamped (retracted) and clamped (extended) positions, respectively. In the clamped position, cartridge assembly 20 is disposed adjacent to anvil assembly 22, and in the unclamped position, cartridge assembly 20 is spaced from anvil assembly 22 (as shown in FIG. 1) . Release actuator 26 is depressible to pivot link assembly 28 from the extended position to the retracted position to enable cartridge assembly 20 to separate from anvil assembly 22 whereby cartridge assembly 20 moves proximally relative to anvil assembly 22 from a clamped position to an unclamped position.

For a detailed description of the above-noted structure and function, or structure and function of exemplary surgical stapling apparatus, one or more components of which may be included, or modified for use with the disclosed aspects, reference may be made to U.S. Patent No. 6,817,508, the entire contents of which are incorporated herein by reference. Although described herein in connection with a transverse staplers (e.g., with curved end effectors) , it should be appreciated that principles of this disclosure are equally applicable to surgical stapling apparatus having other configurations such as, for example, laparoscopic staplers, open staplers, and end-to-end anastomosis staplers, each of which may house staples and/or surgical fasteners other than staples. Some of these types of staplers are described, for instance, in U.S. Patent Nos. 11,432,818; 8,256,656; 7,819,896; 7,128,253; 7,334,717; 5,964,394; and 5,915,616, the entire contents of each of which are incorporated herein by reference.

As best seen in FIGS. 1-6, alignment pin assembly 18e of surgical stapling apparatus 10 includes an alignment pusher 50, a pin coupler 52 that connects to a distal end of alignment pusher 50, and an alignment pin 54 that is supported in cartridge assembly 20. Alignment pin 54 is receivable through cartridge alignment hole 20b defined in cartridge plate 20a and an anvil alignment hole 22b defined in anvil plate 22a. Alignment pusher 50 includes a pair of spaced-apart arms 50a, 50b supported on a proximal end portion of alignment pusher 50 that are connected by a flange 50c. Flange 50c includes a cam hook 50d extending proximally from flange 50c. Each of arms 50a, 50b includes a finger 50e extending laterally outward from a side surface of a respective one of the arms 50a, 50b for supporting knobs 50f that are manually actuatable to slide alignment pin assembly 18e between proximal and distal positions. An elongated shaft 50f extends distally from flange 50c to a hook 50g supported on a distal end portion of elongated shaft 50f that couples to pin coupler 52.

Pivotable cam 60 of surgical stapling apparatus 10 includes a first plate 62 and a second plate 64 that are disposed in mirrored relationship. First and second plates 62, 64 are coupled together by a pin 66 on a lower end of pivotable cam 60 and an alignment rod 68 on an upper end of pivotable cam 60. Pin 66 and alignment rod 68 extend between inner surfaces of first and second plates 62, 64. Pivotable cam 60 is pivotably supported in body 12 by a pair of nubs 61 projecting from outer surfaces of first and second plates 62, 64 at a lower end of pivotable cam 60. Nubs 61 define a pivot axis “P” about which pivotable cam 60 pivots. Alignment rod 68 has a cross-sectional profile including a curved surface 68a and a flat surface 68b. Alignment rod 68 is selectively engageable with cam hook 50d of alignment pusher 50. Each of first and second plates 62, 64 further includes a cam slot boss 65 extending inwardly from the respective inner surfaces of the first and second plates 62, 64. Each cam slot boss 65 may have a half-cylinder shape with a curved surface 65a connected to a flat surface 65b.

Clamp assembly 18c of surgical stapling apparatus 10 includes a shaft assembly 70 having a proximal end portion 70a and a distal end portion 70b. Proximal end portion 70a defines a connector pin hole 72 for receiving clamp connector pin 32 and legs 74 depending from a bottom end of shaft assembly 70 adjacent, and distal to, connector pin hole 72. Each leg 74 defines a cam slot 76 on an outer side of each respective leg 74 (only one side being shown in FIG. 7 in the interest of brevity) . Each cam slot boss 65 of pivotable cam 60 is received within a respective one of cam slots 76 for slidably moving along the respective cam slot 76 as pivotable cam 60 pivots relative to clamp assembly 18c. Each cam slot 76 has a vertical segment 76a and a horizontal segment 76b that are disposed in fluid communication with one another. Vertical segment 76a has an angled arrangement (e.g., an acute angle relative to a centerline “CL” extending longitudinally through shaft assembly 70) . Each vertical segment 76 of each cam slot 76 is partially defined by a driving surface 76c having a lower angled portion 76d and an upper portion 76e. Lower angled portion 76d is disposed at an acute angle relative to upper portion 76e, centerline “CL” of shaft assembly 70, and horizontal segment 76b. Upper portion 76e is transverse (e.g., perpendicular) to centerline “CL” of shaft assembly 70 and horizontal segment 76b. Each horizontal segment 76b of each cam slot 76 is partially defined by a cam surface 76f along which flat surface 65b of cam slot boss 65 of pivotable cam 60 slides. Cam slot 76 further includes a corner 76g that separates vertical and horizontal segments 76a, 76b of cam slot 76. Curved surface 65a of each cam slot boss 65 of pivotable cam 60 facilitates sliding movement through cam slot 76, particularly as cam slot boss 65 transitions over the corner 76g separating vertical and horizontal segments 76a, 76b of cam slot 76.

As best seen in FIGS. 8-13, when trigger 16 of surgical stapling apparatus 10 is actuated, as indicated by arrow “A” , trigger 16 engages link assembly 28 causing link assembly 28 to move to an extended position which drives clamp assembly 18c distally, as indicated by arrow “C” . As clamp assembly 18c moves distally, cam slot bosses 65 slide upwardly through vertical segments 76a of cam slots 76 so that curved surfaces 65a slides along driving surface 76c and facilitates pivotal movement of pivotable cam 60 about pivot axis “P” . During rotation, alignment rod 68 pushes cam hook 50d of alignment pusher 50 to advance alignment pusher 50 in a distal direction for advancing alignment pin 54 (FIG. 4) toward anvil assembly 22. When alignment pin 54 is just about to insert into anvil assembly 22, also known as at “locking point” (e.g., a locking or pre-clamping position) , cam slot bosses 65 are engaged with upper portion 76e of driving surface 76c of clamp assembly 18c to provide robust driving force directly through a center of cam slot bosses 65, as indicated by arrow “B” . In a situation where alignment pin 54 is blocked, such as when alignment pin 54 is not properly aligned with anvil alignment hole 22b defined in anvil plate 22a (see FIG. 15) , a clinician would, at such “locking point” , be prevented from clamping anvil and cartridge assemblies 22, 20 together, and would be prevented from firing surgical stapling apparatus 10, thereby reducing risk of patient damage. Such structure also advantageously facilitates proper alignment pin 54 deployment which benefits staple formation and anastomosis quality.

Turning now to FIGS. 14-18, frame 18b of surgical stapling apparatus 10 further includes an interior surface 80 that defines a self-locking channel 82 for slidably receiving clamp connector pin 32. Self-locking channel 82 includes a straight portion 88, a sliding curve 84, which is a slightly angled curve relative to straight portion 88, and a locking curve 86 which is disposed proximal to sliding curve 84. Sliding curve 84 and locking curve 86 are disposed along upper segment 80a of interior surface 80 at an intermediate portion of upper segment 80a. Locking curve 86 is rounded and separated by sliding curve 84 by an edge 87. Sliding curve 84 transitions to straight portion 88 distally and to locking curve 86 proximally. Locking curve 86 transitions to sliding curve 84 distally and to straight portion 88 proximally. Indeed, locking curve 86 has a hemispherical configuration, whereas sliding curve 84 has an angled wall 84a which may have a uniform slope along its length, although other configurations are contemplated.

When alignment pin 54 is blocked, pivotable cam 60 cannot rotate distally (e.g., in a counterclockwise direction) . Then, when a clinician continues to squeeze trigger 16 in the counterclockwise direction, force through distal link 28b, such as forces “D” or “E” (FIGS. 16 and 18, respectively) , will increase and make the proximal end portion of clamp assembly 18c and clamp connector pin 32 bend upwardly so that clamp connector pin 32 translates along sliding curve 84 and/or perhaps into locking curve 86, depending upon an amount of force applied. For instance, if alignment pin 54 penetrates into tissue “T” as seen in FIG. 17, but alignment pin 54 remains in proper alignment with anvil alignment hole 22b, some force “E” will be exerted, but not a significant amount. In this situation, clamp connector pin 32 will only contact sliding curve 84, not locking curve 86. Sliding curve 84 is configured to then guide clamp connector pin 32 to move in a distal direction, as indicated by arrow “F” in FIG. 18 as alignment pin 32 penetrates through tissue “T” such that surgical stapling apparatus 10 can be properly clamped and fired. By contrast, if alignment pin 54 is blocked outside of anvil assembly 22 as illustrated in FIG. 15, force “D” will increase to an extreme or abnormally high level so that clamp connector pin 32 consequently bends to a higher position into locking curve 86 such that surgical stapling apparatus 10 cannot clamp or fire until alignment pin 54 is properly positioned. Surgical stapling apparatus 10 can be released and adjusted as necessary when clamp connector pin 32 is urged into locking curve 86.

As can be appreciated, securement of any of the components of the presently disclosed apparatus can be effectuated using known securement techniques such welding, crimping, gluing, fastening, etc.

The various aspects disclosed herein may also be configured to work with robotic surgical systems and what is commonly referred to as “Telesurgery. ” Such systems employ various robotic elements to assist the clinician and allow remote operation (or partial remote operation) of surgical instrumentation. Various robotic arms, gears, cams, pulleys, electric and mechanical motors, etc. may be employed for this purpose and may be designed with a robotic surgical system to assist the clinician during the course of an operation or treatment. Such robotic systems may include remotely steerable systems, automatically flexible surgical systems, remotely flexible surgical systems, remotely articulating surgical systems, wireless surgical systems, modular or selectively configurable remotely operated surgical systems, etc.

The robotic surgical systems may be employed with one or more consoles that are next to the operating theater or located in a remote location. In this instance, one team of clinicians may prep the patient for surgery and configure the robotic surgical system with one or more of the instruments disclosed herein while another clinician (or group of clinicians) remotely controls the instruments via the robotic surgical system. As can be appreciated, a highly skilled clinician may perform multiple operations in multiple locations without leaving his/her remote console which can be both economically advantageous and a benefit to the patient or a series of patients. For a detailed description of exemplary medical work stations and/or components thereof, reference may be made to U. S. Patent No. 8, 828, 023, and PCT Application Publication No.WO2016/025132, the entire contents of each of which are incorporated by reference herein.

Persons skilled in the art will understand that the structures and methods specifically described herein and illustrated in the accompanying figures are non-limiting exemplary aspects, and that the description, disclosure, and figures should be construed merely as exemplary of particular aspects. It is to be understood, therefore, that the present disclosure is not limited to the precise aspects described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, it is envisioned that the elements and features illustrated or described in connection with one exemplary aspect may be combined with the elements and features of another without departing from the scope of the present disclosure, and that such modifications and variations are also intended to be included within the scope of the present disclosure. Indeed, any combination of any of the presently disclosed elements and features is within the scope of the present disclosure. Accordingly, the subject matter of the present disclosure is not to be limited by what has been particularly shown and described.

Claims

A surgical stapling apparatus comprising:

an anvil assembly;

a cartridge assembly;

an alignment pin assembly including an alignment pin supported in the cartridge assembly and an alignment pusher, the alignment pusher configured to move the alignment pin between an unlocked position in which the alignment pin is disposed within the cartridge assembly, a locking position in which alignment pin is disposed in close proximity to the anvil assembly, and a locked position in which the alignment pin is captured within the anvil assembly;

a clamp assembly defining a cam slot having a first segment and a second segment, the first segment defined by a driving surface, the driving surface including a lower angled portion and an upper portion disposed at an angle relative to the lower angled portion; and

a pivotable cam including a first plate and a second plate that are coupled together by an alignment rod, the alignment rod being selectively engageable with the alignment pusher to advance the alignment pin through the cartridge assembly and into engagement with the anvil assembly for maintaining the anvil and cartridge assemblies in alignment, the pivotable cam further including a cam slot boss configured to slide through the cam slot of the clamp assembly as the pivotable cam pivots about a pivot axis so that the upper portion of the driving surface provides a driving force through a center of the cam slot boss when the alignment pin is disposed in the locking position.
The surgical stapling apparatus of claim 1, further comprising a body that supports the clamp assembly and the pivotable cam, the body having a trigger pivotably coupled to the body, wherein the clamp assembly advances distally in response to actuation of the trigger to cause the pivotable cam to pivot about the pivot axis.
The surgical stapling apparatus of claim 2, further comprising a link assembly coupled to the clamp assembly, the trigger selectively engageable with the link assembly to cause the clamp assembly to distally advance.
The surgical stapling apparatus of claim 3, wherein the body supports a frame, and wherein the link assembly is connected to the clamp assembly by a clamp connector pin that is slidably received within a channel defined within the frame.
The surgical stapling apparatus of claim 4, wherein the channel is in the form of a self-locking channel including a locking curve that receives the clamp connector pin when a force exerted through the link assembly is greater than or equal to a first predetermined threshold and causes the clamp connector pin to bend upwardly into the locking curve for preventing clamp connector pin from distally advancing.
The surgical stapling apparatus of claim 5, wherein the channel further includes a sliding curve disposed adjacent to the locking curve, the sliding curve configured to guide the clamp connector pin toward a straight portion of the channel when the force exerted through the link assembly is less than the first predetermined threshold, but is greater than or equal to a second predetermined threshold, the second predetermined threshold being indicative of a minimum force exerted through the link assembly that causes the clamp connector pin to bend upwardly into the sliding curve, and wherein when the force exerted through the link assembly is below the second predetermined threshold, the clamp connector pin avoids contacting the sliding curve and the locking curve.
The surgical stapling apparatus of claim 1, wherein the cam slot boss includes a curved surface and a flat surface, the curved surface engageable with the driving surface.
The surgical stapling apparatus of claim 7, wherein the cam slot is further defined by a sliding surface, the flat surface of the cam slot boss being configured to slide across the sliding surface of the cam slot.
The surgical stapling apparatus of claim 1, wherein the alignment pusher includes a cam hook configured to receive the alignment rod of the pivotable cam to cause the alignment pusher to advance distally as the pivotable cam pivots relative to the alignment pusher.
The surgical stapling apparatus of claim 9, wherein the alignment rod includes a curved surface and a flat surface, the curved surface configured to contact the cam hook to impart drive force through alignment pusher.
A surgical stapling apparatus comprising:

an anvil assembly;

a cartridge assembly;

an alignment pin assembly including an alignment pin and an alignment pusher engaged with the alignment pin;

a clamp assembly defining a cam slot having a vertical segment and horizontal segment, the vertical segment having a driving surface that is perpendicular to the horizontal segment; and

a pivotable cam including a first plate and a second plate that are coupled together by an alignment rod, the alignment rod being selectively engageable with the alignment pusher to advance the alignment pin into engagement with the anvil assembly for maintaining the anvil and cartridge assemblies in alignment, the pivotable cam further including a cam slot boss configured to slide through the cam slot of the clamp assembly as the pivotable cam pivots about a pivot axis so that the driving surface provides a driving force through a center of the cam slot boss when a distal end of the alignment pin is disposed between the anvil assembly and the cartridge assembly.
The surgical stapling apparatus of claim 11, further comprising a body that supports the clamp assembly and the pivotable cam, the body having a trigger that is pivotably coupled to the body, wherein the clamp assembly advances distally in response to actuation of the trigger to cause the pivotable cam to pivot about the pivot axis.
The surgical stapling apparatus of claim 12, further comprising a link assembly coupled to the clamp assembly, the trigger selectively engageable with the link assembly to cause the clamp assembly to distally advance.
The surgical stapling apparatus of claim 13, wherein the body supports a frame, and wherein the link assembly is connected to the clamp assembly by a clamp connector pin that is slidably received within a channel defined within the frame.
The surgical stapling apparatus of claim 14, wherein the channel is in the form of a self-locking channel including a locking curve that receives the clamp connector pin when a force exerted through the link assembly is greater than or equal to a first predetermined threshold and causes the clamp connector pin to bend upwardly into the locking curve for preventing clamp connector pin from distally advancing.
The surgical stapling apparatus of claim 15, wherein the channel further includes a sliding curve disposed adjacent to the locking curve, the sliding curve configured to guide the clamp connector pin toward a straight portion of the channel when the force exerted through the link assembly is less than the first predetermined threshold, but is greater than or equal to a second predetermined threshold, the second predetermined threshold being indicative of a minimum force exerted through the link assembly that causes the clamp connector pin to bend upwardly into the sliding curve, and wherein when the force exerted through the link assembly is below the second predetermined threshold, the clamp connector pin avoids contacting the sliding curve and the locking curve.
The surgical stapling apparatus of claim 11, wherein the cam slot boss includes a curved surface and a flat surface, the curved surface engageable with the driving surface.
The surgical stapling apparatus of claim 17, wherein the cam slot is further defined by a sliding surface, the flat surface of the cam slot boss being configured to slide across the sliding surface of the cam slot.
The surgical stapling apparatus of claim 11, wherein the alignment pusher includes a cam hook that is configured to receive the alignment rod of the pivotable cam to cause the alignment pusher to advance distally as the pivotable cam pivots relative to the alignment pusher.
A surgical stapling apparatus comprising:

an anvil assembly;

a cartridge assembly;

an alignment pin supported in the cartridge assembly and movable relative to the anvil and cartridge assemblies;

a clamp assembly supporting a clamp connector pin; and

a frame defining a self-locking channel that slidably receives the clamp connector pin for enabling the alignment pin to move to a position in which the alignment pin extends between the anvil and cartridge assemblies for maintaining alignment between the anvil and cartridge assemblies, the self-locking channel including a straight portion and a locking portion that receives the clamp connector pin for preventing the alignment pin from advancing toward the anvil assembly when a force applied to the clamp connector pin exceeds a predetermined threshold.