Firing assembly and circular tube stapler

Abstract

The present invention provides a firing assembly and a circular tube-type stapler, wherein the firing assembly comprises a nail pushing rod, a pull tab and a nail anvil pull rod, a boss is arranged on one side of the nail pushing rod, the nail pushing rod has an initial position and a firing position, and the distal end of the pull tab is connected to the nail anvil shaft; when the nail pushing rod moves from the initial position to the firing position, the boss contacts the pull tab and lifts the pull tab in a direction away from the axis of the stapler, so that the pull tab generates a pulling force toward the proximal side of the stapler on the nail anvil pull rod of the stapler. By adopting the present invention, during the stapler staple forming process, the interaction between the nail pushing rod and the pull tab causes the structural change of the pull tab, and a pulling force toward the proximal side of the stapler is applied to the distal side of the pull tab, and the pulling force applied to the pull tab is transmitted to the nail anvil shaft, thereby compensating for the movement of the nail anvil toward the distal side, so that the gap change between the nail anvil and the nail magazine assembly is minimized as much as possible, thereby improving the nail forming effect.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a firing assembly and a circular tubular stapler. Background Art

[0002] Digestive tract diseases are one of the most common diseases in humans. During the treatment process, circular tubular staplers are often used to replace the doctor's manual operation to anastomose physiological tissues such as the digestive tract. Circular tubular staplers are a common surgical instrument, most of which use axial internal stapling to form end-to-end or end-to-side anastomosis of physiological tissues such as the esophagus, stomach, and intestines during surgery. During the anastomosis, the two sections of tissue are contained inwardly in the stapler. After the firing is completed, a circular anastomosis is formed on the tissue, reconstructing the human body channel.

[0003] In the prior art, a circular tubular stapler includes a stapler body, an operating handle movably connected to the stapler body, and a nail anvil assembly matched with the body, wherein the nail anvil assembly includes a nail anvil and a nail anvil shaft. The stapler body includes a nail magazine assembly arranged on the distal side and a knob arranged on the proximal side of the body. In the present invention, the distal side and the proximal side are relative to the operator, the end closer to the operator is the proximal side, and the end farther from the operator, that is, the end closer to the surgical site is the distal side.

[0004] When firing the stapler, the operating handle is held to push the stapler pusher rod disposed in the stapler body, and the stapler pusher rod moves toward the distal end of the stapler, and drives the stapler pusher plate to push out the staples in the stapler magazine assembly, thereby realizing the formation of the staples on the surface of the anvil. In existing stapler products, when the staples are formed, the anvil will be pushed by the staples toward the distal end of the stapler and the squeezing force of the tissue toward the distal end of the stapler, and will have an axial movement toward the distal end of the stapler, thereby increasing the gap between the anvil and the stapler magazine assembly, affecting the staple forming effect. Summary of the invention

[0005] In view of the problems in the prior art, the purpose of the present invention is to provide a firing assembly and a circular tubular stapler, which can compensate for the movement of the anvil toward the distal side through the structural change of the pull tab during the stapler staple forming process, thereby improving the staple forming effect.

[0006] An embodiment of the present invention provides a firing assembly for a circular tube-type stapler, the stapler comprising a stapler body and an anvil assembly, the anvil assembly comprising an anvil located at the distal end of the stapler body and an anvil shaft located at the proximal end of the anvil, the firing assembly comprising a nail pushing rod, a pull tab and an anvil pull rod, a boss is provided on one side of the nail pushing rod, the nail pushing rod has an initial position and a firing position, and the distal end of the pull tab is connected to the anvil shaft through the anvil pull rod;

[0007] When the nail pushing rod moves from the initial position to the firing position, the boss contacts the pull tab and pushes the pull tab away from the axis of the stapler, so that the pull tab generates a pulling force on the nail anvil pull rod toward the proximal side of the stapler.

[0008] Optionally, the boss is integrally arranged with the nail pushing rod.

[0009] Optionally, a positioning groove is provided on one side of the nail pushing rod, a pin is provided in the positioning groove, and a top end of the pin protrudes from the surface of the nail pushing rod to form the boss.

[0010] Optionally, the distal side surface of the boss is a transition surface, and in a direction perpendicular to the axis of the stapler, the distance from the proximal side of the transition surface to the axis is greater than the distance from the distal side of the transition surface to the axis.

[0011] Optionally, the pull tab comprises a first connecting segment, a middle segment and a second connecting segment arranged in sequence from the proximal side to the distal side of the pull tab, and the width of the middle segment is greater than the width of the first connecting segment.

[0012] Optionally, when the nail pushing rod is in the initial position, the boss is located on one side of the first connecting section of the pull tab, and when the nail pushing rod is in the firing position, the boss contacts the middle section of the pull tab and pushes the middle section of the pull tab away from the axis of the stapler.

[0013] Optionally, two bosses are provided on the nail-pushing rod, and when the nail-pushing rod is in the initial position, the two bosses are respectively located on both sides of the first connecting section of the pull tab.

[0014] Optionally, the stapler also includes an adjustment shaft located inside the stapler body, the proximal side of the pull tab is connected to the adjustment shaft, the nail pushing rod is in the initial position, and when the pull tab moves along the axial direction of the stapler under the action of the adjustment shaft, the boss has relative movement relative to the pull tab along the extension direction of the first connecting section.

[0015] Optionally, a transition section with smooth side transition is provided between the middle section of the pull tab and the first connecting section.

[0016] Optionally, a center groove is provided on the pull tab, and when the push nail rod is in the initial position, the boss enters the center groove of the pull tab, and when the push nail rod moves from the initial position to the firing position, the boss detaches from the distal side of the center groove and contacts the inner side surface of the pull tab.

[0017] Optionally, the stapler also includes an adjustment shaft located inside the stapler body, the proximal side of the pull tab is connected to the adjustment shaft, the center groove extends along the axial direction of the stapler, the stapler push rod is in the initial position, and when the pull tab moves along the axial direction of the stapler under the action of the adjustment shaft, the boss is in the center groove, and the boss has relative movement with respect to the pull tab along the extension direction of the center groove.

[0018] An embodiment of the present invention further provides a circular tubular stapler, comprising the firing assembly described above.

[0019] An embodiment of the present invention further provides a circular tubular stapler, which includes the firing assembly.

[0020] The firing assembly and the circular tubular stapler provided by the present invention have the following advantages:

[0021] The present invention provides a firing assembly for a circular tubular stapler. During the stapler staple forming process, the interaction between a stapler push rod and a pull tab causes the structure of the pull tab to change, and a pulling force is applied to the distal end of the pull tab toward the proximal end of the stapler. The pulling force applied to the pull tab is transmitted to the anvil shaft through the anvil pull rod, thereby compensating for the movement of the anvil toward the distal end, reducing the gap change between the anvil and the staple magazine assembly as much as possible, and further improving the staple forming effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0023] Figure 1 is a partial structural schematic diagram of a circular tubular stapler according to a first embodiment of the present invention;

[0024] Figure 2 is a schematic structural diagram of a nail pushing rod according to a first embodiment of the present invention;

[0025] Figure 3 is a schematic structural diagram of a pull tab according to a first embodiment of the present invention;

[0026] Figure 4 It is a schematic structural diagram of the cooperation between the nail push rod and the pull tab in the first embodiment of the present invention;

[0027] Figure 5 Yes Figure 4 Enlarged image of the middle circle;

[0028] Figure 6 is a schematic structural diagram of a nail pushing rod according to a second embodiment of the present invention;

[0029] Figure 7is a cross-sectional view of the nail push rod and the pull tab in cooperation with each other according to the second embodiment of the present invention;

[0030] Figure 8 yes Figure 7 Enlarged image of the middle circle;

[0031] Fig. 9 It is a schematic diagram of the cooperation between the nail pushing rod and the pull tab according to the second embodiment of the present invention.

[0032] Reference numerals:

[0033] 1 Anvil assembly 4 First pull tab

[0034] 11 Anvil 41 Proximal side of pull tab

[0035] 12 Anvil shaft 42 Distal end side of pull tab

[0036] 2 Nail cartridge assembly 43 middle section

[0037] 3 Pushing rod 44 first connecting section

[0038] 31 proximal end side of the nail push rod 45 second connecting section

[0039] 32 distal end of the push rod 46 transition section

[0040] 33 boss 47 center groove

[0041] 331 first transition surface 5 second pull tab

[0042] 34 Positioning slot 6 Adjustment axis

[0043] 35 Pin 7 Anvil pull rod

[0044] 351 Second transition surface S axis DETAILED DESCRIPTION

[0045] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0046] In order to solve the technical problems in the prior art, the present invention provides a firing assembly for a circular tubular stapler and a circular tubular stapler including the firing assembly. The stapler includes a stapler body, an operating handle movably connected to the stapler body, and an anvil assembly matched with the stapler body. The anvil assembly includes an anvil located at the distal end of the stapler body and an anvil shaft located at the proximal end of the anvil. The stapler body includes a staple magazine assembly disposed at the distal end of the body and a knob disposed at the proximal end of the body. The firing assembly includes a nail pushing rod, a pull tab, and an anvil pulling rod disposed at the distal end of the pull tab. The nail pushing rod has an initial position and a firing position. The initial position refers to the position of the nail pushing rod when the operating handle is not held. The firing position refers to the position of the nail pushing rod when the operating handle is held and pushes the nail pushing rod to move toward the distal end of the stapler to push out the staples. The distal end side of the pull tab is connected to the proximal end side of the anvil pull rod and is connected to the anvil shaft through the anvil pull rod. The proximal end side of the pull tab is connected to the knob through an adjustment shaft.

[0047] During tumor surgery, after the tumor tissue is severed and removed, the anvil shaft of the anvil assembly is passed through the purse of the residual tissue and is arranged on the distal side of the stapler body. The knob is rotated to pull the anvil toward the proximal side of the stapler through the adjustment shaft, the pull tab, the anvil pull rod and the anvil shaft, so that the distance between the anvil and the stapler magazine assembly is gradually reduced to a suitable distance, and then the stapler can be fired. At this time, the operating handle is held, and the operating handle pushes the stapler push rod from the initial position to the firing position. The stapler push rod drives the stapler pusher to push out the staples in the stapler magazine assembly, thereby forming the staples on the surface of the anvil and firing the stapler.

[0048] When firing the stapler, the anvil will move axially after being squeezed by the tissue toward the distal side of the stapler and pushed by the stapler toward the distal side of the stapler. The movement of the anvil is the flexibility of the anvil assembly, and there are many reasons for the flexibility, such as the matching clearance of various parts in the stapler (including the anvil assembly, pull tab, screw rod, knob) and the rigidity of the material itself. Considering the difficulty and cost of changing the matching clearance between the anvil and the staple magazine assembly and the rigidity of the material itself, the present invention improves the structure of the firing assembly, and compensates for the flexibility of the anvil assembly with structural features without increasing the cost, so as to reduce the influence of the axial movement of the firing mechanism itself on the distance between the staple magazine and the anvil during firing.

[0049] Specifically, the present invention provides a boss on one side of the stapler push rod. When the stapler push rod moves from the initial position to the firing position, the boss contacts the pull tab and pushes the pull tab away from the axis of the stapler, so that the pull tab generates a pulling force on the anvil shaft toward the proximal side of the stapler. This pulling force can compensate for the thrust of the tissue and the staples on the anvil shaft toward the distal side of the stapler, so that the axial movement of the anvil is minimized when the stapler is fired, and the gap change between the anvil and the staple magazine assembly is minimized, thereby improving the staple forming effect. Here, in the stapler, the inner side and the outer side are relative to the axis of the stapler, the side close to the axis is the inner side, and the side away from the axis is the outer side.

[0050] Combine the following Figures 1 to 9 The structures of the stapler and the firing assembly in two embodiments of the present invention are described in detail. Figure 1 to Figure 5 The structure of the firing assembly of the first embodiment of the present invention is shown. Figure 6 to Figure 9 The structure of the firing assembly according to the second embodiment of the present invention is shown.

[0051] like Figure 1 As shown, the stapler includes a stapler body and an anvil assembly 1, wherein the anvil assembly 1 includes an anvil 11 located at the distal side of the stapler body and an anvil shaft 12 located at the proximal side of the anvil, and a stapler magazine assembly 2 is provided at the distal side of the stapler body. The stapler magazine assembly 2 includes a stapler pushing piece. The interior of the stapler body is provided with a stapler pushing rod 3, pull tabs 4, 5 and an anvil pull rod 7 located at the distal side of the pull tab. In this embodiment, the pull tabs 4, 5 are provided with two pieces: a first pull tab 4 and a second pull tab 5. The functions and structures of the two pull tabs 4, 5 are the same, and the two pull tabs are provided overlappingly. The first pull tab 4 will be taken as an example for explanation hereinafter. In other embodiments, the number of pull tabs may also be changed, for example, only one pull tab is provided, or three pull tabs are provided, and so on. Figures 1 to 4 In the perspective of FIG. 1 , the distal end 32 of the nail pushing rod 3 is the left side in the figure, and the proximal end 31 of the nail pushing rod 3 is the right side in the figure. The distal end 32 of the nail pushing rod 3 is arranged close to the staple cartridge assembly 2, and the proximal end 31 of the nail pushing rod 3 is linked with the operating handle. When firing, the operating handle pushes the nail pushing rod 3 to move toward the distal end, and pushes the staples in the staple cartridge assembly 2 through the nail pushing sheet. The distal end 42 of the first pull tab 4 is the left end in the figure, and the proximal end 41 of the first pull tab 4 is the right end in the figure. The distal end 42 of the first pull tab 4 is connected to the proximal end of the nail anvil pull rod 7, and the proximal end 41 of the first pull tab 4 is connected to the knob (not shown in the figure) through the adjustment shaft 6. When the knob rotates, the first pull tab 4 and the second pull tab 5 can be driven to move along the axial direction of the stapler through the adjustment shaft 6, and then the nail anvil 11 can be driven to approach or move away from the nail cartridge assembly 2 through the nail anvil pull rod 7 and the nail anvil shaft 12.

[0052] In order to compensate for the flexibility of the anvil assembly 1 and reduce the movement of the anvil 11 when the stapler is fired, Figure 2 As shown, a boss 33 is provided on one side of the stapler push rod 3. When the stapler is fired, the stapler push rod 3 moves from the initial position to the firing position, and the boss 33 contacts the inner side of the first pull tab 4 and pushes the pull tabs 4, 5 away from the axis of the stapler, so that the pull tabs 4, 5 generate a pulling force toward the proximal side of the stapler on the anvil pull rod 7, and the pulling force compensates for the pushing force of the tissue and staples on the anvil 11 toward the distal side. In this solution, the inner side of the first pull tab 4 refers to the side of the first pull tab 4 facing the axis of the stapler, and the side opposite to it is the outer side of the first pull tab 4.

[0053] As Figure 2 As shown, in this embodiment, the boss 33 is integrally provided with the nail pushing rod 3. The distal side surface of the boss 33 is a first transition surface 331, and the proximal side of the first transition surface 331 is closer to the pull tabs 4, 5 relative to the distal side of the transition surface, that is, in the direction perpendicular to the axis, the distance from the proximal side of the first transition surface 331 to the axis is greater than the distance from the distal side of the first transition surface 331 to the axis. The surface of the first transition surface 331 can be an inclined surface or an arc surface. When the nail pushing rod 3 moves from the initial position to the firing position, the first transition surface 331 of the boss 33 first contacts the inner side surface of the first pull tab 4, so that the pull tabs 4, 5 can be smoothly pushed out by the boss 33.

[0054] like Figure 3 As shown, the first pull tab 4 includes a first connecting section 44, a middle section 43 and a second connecting section 45 arranged in sequence from the proximal side 41 to the distal side 42 of the first pull tab 4, the width of the middle section 43 is greater than the width of the first connecting section 44, and further, the width of the middle section 43 may be greater than the width of the second connecting section 45. Figure 4 As shown, when the push rod 3 is in the initial position, the boss 33 is located on one side of the first connecting section 44 of the first pull tab 4. Since the second pull tab 5 and the first pull tab 4 are overlapped and have the same structure, the boss 33 is also located on one side of the first connecting section of the second pull tab 5. In this embodiment, two bosses 33 are provided on the push rod 3, and the two bosses 33 are respectively provided on both sides of the first connecting section of the pull tabs 4 and 5. However, the present invention is not limited thereto, and only one boss 33 or multiple bosses 33 are provided, which are within the protection scope of the present invention.

[0055] like Figure 5As shown, before firing, the push rod 3 is located at the initial position, the boss 33 is located on one side or both sides of the first connecting end 44 of the first pull tab 4, and the boss 33 is not in contact with the inner side of the first pull tab 4, so the first pull tab 4 and the second pull tab 5 will not be lifted. The push rod 3 moves from the initial position to the firing position, i.e., along Figure 5 When moving in the middle A direction, the boss 33 has a relative movement toward the distal side of the stapler relative to the first pull tab 4, and the boss 33 enters the range of the middle section of the first pull tab 4, thereby contacting the inner side surface of the middle section 43 of the pull tab and pushing up the middle sections of the pull tabs 4 and 5 in the direction away from the axis S of the stapler. After the stapler is fired, the nail pusher rod 3 will return from the firing position to the initial position, at which time the boss 33 will return to both sides of the first connecting section 44, so as to no longer contact the inner side surface of the first pull tab 4, and the first pull tab 4 and the second pull tab 5 will return to a straight state after losing the force of pushing outward.

[0056] In this embodiment, when the nail pushing rod 3 is in the initial position and the pull tabs 4, 5 move along the axial direction of the stapler under the action of the adjustment shaft 6, the boss 33 has a relative movement along the extension direction of the first connecting section 44. Therefore, when the nail pushing rod 3 is in the initial position, the boss 33 of the nail pushing rod 3 will not contact the inner side surface of the first pull tab 4, and will not affect the axial movement of the pull tabs 4, 5. By adjusting the knob, the anvil 11 can be driven away from or close to the staple cartridge assembly 2 through the adjustment shaft 6, the pull tabs 4, 5 and the nail anvil pull rod 7 in sequence, and the relationship between the rotation angle of the knob and the movement distance of the nail anvil 11 will not be changed due to the addition of the boss 33, that is, before the stapler is fired, the boss 33 will not affect the original function of the pull tabs 4, 5.

[0057] In this embodiment, the first transition surface 331 has a smooth transition from the distal end to the proximal end, and the first transition surface 331 forms a certain angle with the surface of the push rod. At the farthest end of the first transition surface 331, the angle can be set to be relatively gentle, that is, at the farthest end of the first transition surface 331, an obtuse angle is formed between the first transition surface 331 and the push rod 3. Further, the angle is preferably 120° to 150°. Before firing, when the push rod 3 is located at the initial position, even if the boss 33 is partially in contact with the inner side of the first pull tab 4, it will not affect the pull tabs 4, 5 to bulge out too much and affect their original functions.

[0058] In this embodiment, a transition section 46 with smooth side transition is provided between the middle section 43 of the first pull tab 4 and the first connecting section 44, so as to realize smooth transition of the boss 33 from the side of the first connecting section 44 to the inner side of the middle section 43. Furthermore, a transition section 46 with smooth side transition can also be provided between the second connecting section 45 and the middle section 43, and the side surfaces of the transition section 46 can be smoothly transitioned inclined surfaces or curved surfaces. However, the present invention is not limited thereto, and in other alternative embodiments, the transition section 46 may not be provided between the first connecting section 44 and the middle section 43, and between the second connecting section 45 and the middle section 43, but a straight surface transition may be provided.

[0059] In this embodiment, the pull tabs 4, 5 are preferably elastic pull tabs 4, 5, which can make the pull tabs 4, 5 more easily pushed out by the boss 33, and the pull tabs 4, 5 are further preferably elastic pull tabs 4, 5 made of metal foil, but the present invention is not limited to this, and the use of other materials such as plastics also falls within the protection scope of the present invention.

[0060] As Figures 6 to 9 FIG. 2 is a schematic diagram of the structure of the firing assembly of the second embodiment of the present invention. Compared with the first embodiment, this embodiment has two differences: (1) the boss is separately provided with the nail pushing rod 3, and the boss is formed by a pin 35 protruding from the surface of the nail pushing rod 3. (2) A center groove 47 is provided on the first pull tab 4. When the stapler is not fired, the pin 35 is located in the center groove 47 so as not to hinder the axial movement of the pull tabs 4 and 5 under the action of the knob. When firing, the pin 35 passes over the distal end of the center groove 47 and contacts the inner side surface of the pull tabs 4 and 5, so that the pull tabs 4 and 5 are ejected.

[0061] As Figure 6 As shown, in this embodiment, a positioning groove 34 is provided on one side of the push rod 3, and the pin 35 is provided in the positioning groove 34. The top end of the pin 35 protrudes from the surface of the push rod 3 to form the boss. The number and position of the pin 35 can be selected as needed. Figures 7 to 9As shown, the pull tabs 4 and 5 are provided with a central groove 47. When the push rod 3 is in the initial position, the pin 35 enters the central groove 47 of the pull tabs 4 and 5. When the push rod 3 moves from the initial position to the firing position, the pin 35 disengages from the distal end of the central groove 47 and contacts the inner surface of the pull tabs 4 and 5. The pin 35 pushes the pull tabs 4 and 5 away from the axis of the stapler, so that the pull tabs 4 and 5 generate a pulling force toward the proximal end of the stapler on the nail anvil rod 7. After the stapler is fired, the push rod 3 returns from the firing position to the initial position. At this time, the pin 35 returns to the central groove 47, so that it is no longer in contact with the first pull tab 4. After the first pull tab 4 and the second pull tab 5 lose the force of pushing outward, they will return to a straight state.

[0062] In the first embodiment, since the boss 33 and the push rod 3 are integrally formed, and the push rod 3 is often a plastic part, the boss 33 is also an integrally formed plastic part, and the plastic part and the metal pull tab 4 are prone to wear during long-term relative sliding friction, which will affect the compensation effect. Therefore, in the second embodiment, a pin 35 is used that is separated from the push rod 3, and the pin 35 is preferably a metal pin, and a metal-metal contact form is used instead of the plastic-metal contact form in the first embodiment, which can reduce wear and make the compensation effect more obvious.

[0063] like Figure 8 As shown, in order to achieve a smooth transition when the pin 35 is disengaged from the central groove 47, the distal side surface of the pin 35 is set as a second transition surface 351, and the second transition surface 351 can be an inclined surface or an arc surface to guide the pin 35 to smoothly disengage from the central groove 47. In this embodiment, the pin 35 adopts a ball head pin. In other alternative embodiments, the pin 35 can also be a slowly transitioned inclined pin, or have a cam surface, etc. Correspondingly, a guide surface is also provided on the distal side of the central groove 47 to better cooperate with the pin 35.

[0064] In this embodiment, the central groove 47 extends along the axial direction of the stapler, and when the nail pushing rod 3 is in the initial position and the pull tabs 4, 5 move along the axial direction of the stapler under the action of the adjustment shaft 6, the pin 35 is in the central groove 47 and has a relative movement along the extension direction of the central groove 47. Therefore, when the nail pushing rod 3 is in the initial position, the pin 35 of the nail pushing rod 3 will not contact the inner side surface of the first pull tab 4, and will not affect the axial movement of the pull tabs 4, 5. By adjusting the knob, the anvil 11 can be driven away from or close to the staple cartridge assembly 2 through the adjustment shaft 6, the pull tabs 4, 5, the nail anvil rod 7 and the nail anvil shaft 12 in sequence, and the relationship between the rotation angle of the knob and the movement distance of the nail anvil 11 will not change due to the addition of the pin 35, that is, before the stapler is fired, the pin 35 will not affect the original function of the pull tabs 4, 5.

[0065] The central groove 47 in this embodiment can be a through groove connecting the inner and outer sides of the pull tabs 4 and 5, or it can be a blind groove opened on the inner side of the first pull tab 4, can be opened at the corresponding positions of the first pull tab 4 and the second pull tab 5 at the same time, or can be opened only on the first pull tab 4, all of which are within the protection scope of the present invention.

[0066] The pull tabs 4, 5 in this embodiment can also be divided into a first connection section, a middle section, and a second connection section arranged in sequence from the proximal side to the distal side. The central groove 47 can be opened in the middle section and connected to the first connection section. The extension length of the central groove 47 can be determined according to the axial movement range of the pull tabs 4, 5. The central groove 47 can be opened at the central axis of the middle section, or can be set away from the central axis of the middle section, as long as it corresponds to the position of the pin 35.

[0067] In order to ensure the balance of the force on the pull tab, two pins 35 may be symmetrically arranged, and the central groove 47 also cooperates with each pin 35 to achieve a better compensation effect.

[0068] Figures 1 to 9The structures of the firing assembly and the stapler of two specific embodiments of the present invention are only shown by way of example. In other embodiments, the above two embodiments may also be combined with each other. For example, in the first embodiment, a central groove may be provided on the pull tabs 4 and 5, and when the push rod 3 is in the initial position, the boss 33 enters the central groove of the pull tabs 4 and 5. When the push rod 3 moves from the initial position to the firing position, the boss 33 disengages from the central groove of the pull tabs 4 and 5 and contacts the inner side surface of the first pull tab 4, thereby lifting the first pull tab 4 and the second pull tab 5. In the second embodiment, the position of the pin 35 may also be moved toward the proximal side of the push rod 3 to a position corresponding to the first connecting section 41. When the push rod is in the initial state, the pin 35 is located on one side of the first connecting section 41 and does not contact the inner side surface of the first pull tab 4. When the push rod 3 moves from the initial position to the firing position, the pin 35 moves to the middle section 43 of the first pull tab 4, thereby lifting the first pull tab 4 and the second pull tab 5.

[0069] The firing assembly and the circular tubular stapler provided by the present invention have the following advantages:

[0070] The present invention provides a firing assembly for a circular tubular stapler. During the stapler staple forming process, the interaction between a stapler push rod and a pull tab causes the structure of the pull tab to change, and a pulling force is applied to the distal end of the pull tab toward the proximal end of the stapler. The pulling force applied to the pull tab is transmitted to the anvil shaft, thereby compensating for the movement of the anvil toward the distal end, so that the change in the gap between the anvil and the staple magazine assembly is reduced as much as possible, thereby improving the staple forming effect.

[0071] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A firing assembly, characterized in that: Used for a circular tube-type stapler, the stapler comprises a stapler body and a nail anvil assembly, the nail anvil assembly comprises a nail anvil located at the distal end side of the stapler body and a nail anvil shaft located at the proximal end side of the nail anvil, the firing assembly comprises a nail pushing rod, a pull tab and a nail anvil pull rod, a boss is arranged on one side of the nail pushing rod, the nail pushing rod has an initial position and a firing position, the distal end side of the pull tab is connected to the nail anvil shaft through the nail anvil pull rod, the pull tab comprises a first connecting section, a middle section and a second connecting section arranged in sequence from the proximal end side to the distal end side of the pull tab, and the width of the middle section is greater than the width of the first connecting section; When the nail pushing rod is in the initial position, the boss is located on one side of the first connecting section of the pull tab, and when the nail pushing rod moves from the initial position to the firing position, the boss contacts the middle section of the pull tab and pushes the middle section of the pull tab away from the axis of the stapler, so that the pull tab generates a pulling force on the anvil pull rod toward the proximal side of the stapler.

2. The firing assembly according to claim 1, characterized in that: The boss is integrally arranged with the nail pushing rod.

3. The firing assembly according to claim 1, characterized in that: A positioning groove is arranged on one side of the nail pushing rod, a pin is arranged in the positioning groove, and the top end of the pin protrudes from the surface of the nail pushing rod to form the boss.

4. The firing assembly according to claim 1, characterized in that: The distal side surface of the boss is a transition surface. In a direction perpendicular to the axis of the stapler, the distance from the proximal side of the transition surface to the axis is greater than the distance from the distal side of the transition surface to the axis.

5. The firing assembly according to claim 1, characterized in that: The nail pushing rod is provided with two bosses. When the nail pushing rod is in the initial position, the two bosses are respectively located on both sides of the first connecting section of the pull tab.

6. The firing assembly according to claim 1, characterized in that: The stapler also includes an adjustment shaft located inside the stapler body, the proximal end side of the pull tab is connected to the adjustment shaft, the stapler pushing rod is in the initial position, and when the pull tab moves along the axial direction of the stapler under the action of the adjustment shaft, the boss has relative movement relative to the pull tab along the extension direction of the first connecting section.

7. The firing assembly according to claim 1, characterized in that: A transition section with smooth side transition is arranged between the middle section of the pull tab and the first connecting section.

8. The firing assembly according to claim 1, characterized in that: The pull tab is provided with a central groove, and when the push-nail rod is in the initial position, the boss enters the central groove of the pull tab, and when the push-nail rod moves from the initial position to the firing position, the boss detaches from the distal end side of the central groove and contacts the inner side surface of the pull tab.

9. The firing assembly according to claim 8, characterized in that: The stapler also includes an adjustment shaft located in the stapler body, the proximal side of the pull tab is connected to the adjustment shaft, the center groove extends along the axial direction of the stapler, the stapler pusher rod is in the initial position, and when the pull tab moves along the axial direction of the stapler under the action of the adjustment shaft, the boss is in the center groove, and the boss has relative movement with respect to the pull tab along the extension direction of the center groove.

10. A circular tubular stapler, characterized in that: A firing assembly comprising the firing assembly of any one of claims 1 to 9.

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