An electric anastomat with a novel bending mechanism

Abstract

The application belongs to the technical field of electric anastomat, and particularly relates to an electric anastomat with a novel bending mechanism, which comprises an electric anastomat body, a rotating knob rotatably connected to the left end of the electric anastomat body, an angle adjusting knob rotatably connected to the radial direction of the rotating knob, a shaft coaxially arranged with the rotating knob, the right end of the shaft fixedly connected to the left end of the rotating knob, a joint head rotatably connected to the left end of the shaft, a staple anvil assembly arranged at the left end of the joint head, a nail bin rotatably connected to the staple anvil assembly, and a cutting blade slidably connected to the nail bin. Through the double action of the semicircular block and the extrusion assembly, the branches of the owl-shaped surgical suture nail are bent outward, so that the coverage of a single owl-shaped surgical suture nail is larger, the branches are bent upward while being bent outward, the owl-shaped surgical suture nail can be more firmly embedded into the tissue, and the risk of unfirm anastomosis, bleeding or anastomotic leakage caused by too straight or insufficient bending of the nail leg is avoided.

Description

Technical Field

[0001] This invention belongs to the field of electric stapler technology, specifically an electric stapler with a novel bending mechanism. Background Technology

[0002] Electric staplers are commonly used medical devices in surgical procedures, especially in minimally invasive surgeries such as laparoscopy. They are powered by a battery pack and driven by a motor to advance the cutting blade and wedge-shaped pusher to achieve tissue anastomosis and cutting. After use, the staple cartridge can be replaced for continued use. The advent of electric staplers has made surgery more convenient and labor-saving.

[0003] Existing electric staplers typically rely solely on anvil compression for shaping, resulting in insufficient bending of the staples and the mechanical stress during repositioning, which can easily cause secondary damage to the sutured tissue. Summary of the Invention

[0004] The purpose of this invention is to provide an electric stapler with a novel bending mechanism to solve the problem in the above-mentioned background that the traditional structure relies solely on the extrusion molding of the anvil, which may result in the staple legs being too straight or not bent enough, making it impossible for the surgical staples to be firmly embedded in the tissue, thus leading to poor anastomosis.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An electric stapler with a novel bending mechanism includes an electric stapler body. A rotary knob is rotatably connected to the left end of the electric stapler body. An angle adjustment knob is rotatably connected to the radial direction of the rotary knob. A rod is coaxially arranged with the rotary knob. The right end of the rod is fixedly connected to the left end of the rotary knob. A joint head is rotatably connected to the left end of the rod. An anvil assembly is arranged at the left end of the joint head. A staple cartridge is rotatably connected to the end of the anvil assembly connected to the joint head. A cutting blade is slidably connected to the axial direction of the staple cartridge. The cutting blade is fixedly connected to the front and rear sides with triangular push block assemblies. The anvil assembly has a nail groove on the side facing the nail magazine. A semi-circular block is fixedly connected to the middle of the inner cavity of the nail groove. A pressing assembly is slidably connected in the nail groove. A push rod assembly is also connected to the upper side of the cutting blade. A reversing assembly is connected to the side of the anvil assembly opposite to the nail magazine.

[0006] Furthermore, the anvil assembly includes an anvil mounting compartment, the right end of which is fixedly connected to the joint head. An anvil board is fixedly connected to the inner cavity of the anvil mounting compartment. Several nail grooves are formed on the upper surface of the anvil board, and the semi-circular block is fixedly connected in the nail grooves.

[0007] Furthermore, the triangular push block assembly includes two triangular blocks, with a connecting rod between the two triangular blocks. The upper end of the connecting rod is fixedly connected to the cutting blade, and the lower ends of the two connecting rods are fixedly connected to the two triangular blocks.

[0008] Furthermore, the extrusion assembly includes two slide rods, each fitted with an extrusion spring. Both slide rods are located within the nail groove and on opposite sides of the semicircular block.

[0009] Furthermore, both slide rods are slidably connected to the nail anvil, and the upper ends of both slide rods are fixedly connected to a pressing plate, which is slidably connected in the nail groove. The lower ends of the two slide rods are fixedly connected by a connecting bridge, and the lower end of the connecting bridge is fixedly connected to a protrusion.

[0010] Furthermore, the top rod assembly includes two guide rods, one end of which is fixedly connected to both sides of the cutting blade. The guide rods are slidably connected to the inner cavity of the slide tube. An extrusion wheel is rotatably connected to the outer wall of the slide tube, and a reversing spring is sleeved on the slide tube.

[0011] Furthermore, a hexagonal groove is provided on one side of the sliding tube on the nail anvil, and an extension rod is provided in the radial position of the sliding tube. One end of the extension rod is fixedly connected to the sliding tube, and the other end of the extension rod is fixedly connected to a slider, which is slidably connected in the hexagonal groove.

[0012] Furthermore, the reversing assembly includes a stop lever, which is fixedly connected to one side of the slide tube on the nail anvil. A rotating shaft is also provided on the side of the slide tube on the nail anvil. One end of the rotating shaft is rotatably connected to the side of the slide tube on the nail anvil, and a limit rod is fixedly connected to the other end of the rotating shaft. A torsion spring is sleeved on the rotating shaft.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Through the dual action of the semi-circular block and the extrusion component, the branches of the π-shaped surgical suture both bend outward, making the coverage area of ​​a single π-shaped surgical suture larger, and bend upward at the same time as the branches bend outward, which can make the π-shaped surgical suture more firmly embedded in the tissue, avoiding the risk of poor anastomosis, bleeding or anastomotic leakage caused by the suture legs being too straight or not bent enough. 2. The reversing assembly triggers misalignment when the push rod assembly reaches the end of the anvil assembly, causing the push rod assembly to separate from the compression assembly during the reset phase, eliminating mechanical stress during the reset process and protecting the sutured tissue from secondary damage. 3. The mechanism of automatic disengagement from unidirectional compression is achieved through the reversing component, ensuring that the compression component applies pressure to the circumferential surgical staple only during the forward movement of the cutting blade, and completely releases the constraint during resetting. This instantaneous forming and interference-free resetting mode can prevent the compression component from being squeezed again by the push rod component during the resetting process, which would cause the circumferential surgical staple to loosen. As a result, all the circumferential surgical staples in this electric stapler are only squeezed once by the compression component during the operation, thus ensuring that all the circumferential surgical staples suture the patient's wound to a consistent degree. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall front-view three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the overall front view of the present invention; Figure 3 This is a three-dimensional structural diagram of the anvil assembly of the present invention; Figure 4 This is a cross-sectional perspective view of the anvil assembly of the present invention. Figure 5 This is a three-dimensional sectional view of the staple cartridge of the present invention; Figure 6 This is a three-dimensional structural diagram of the nailing board of the present invention; Figure 7 This is a three-dimensional structural diagram of the cutting blade of the present invention; Figure 8 This is a top view of the three-dimensional structure of the nailing cutting board of the present invention; Figure 9 This is a three-dimensional structural cross-sectional view of the nailing anvil of the present invention; Figure 10 For the present invention Figure 9 Enlarged structural diagram at point A; Figure 11 This is a top-view perspective view of the top rod assembly of the present invention. Figure 12 This is a three-dimensional structural schematic diagram of the commutation component of the present invention; Figure 13 This is a top-view three-dimensional structural diagram of the hexagonal groove of the present invention.

[0015] In the diagram: 1. Electric stapler body; 2. Rotary knob; 201. Slide rod; 202. Compression spring; 203. Compression plate; 204. Connecting bridge; 205. Protrusion; 3. Angle adjustment knob; 4. Rod body; 5. Joint head; 6. Anvil assembly; 61. Staple groove; 62. Anvil mounting compartment; 63. Anvil plate; 631. Hexagonal groove; 7. Staple cartridge; 8. Cutting blade; 9. Triangular push block assembly; 91. Triangular block; 92. Connecting rod; 10. Semicircular block; 20. Compression assembly; 30. Push rod assembly; 301. Guide rod; 302. Slide tube; 303. Compression wheel; 304. Reversing spring; 305. Extension rod; 306. Slider; 40. Reversing assembly; 401. Stop bar; 402. Rotating shaft; 403. Limiting rod; 404. Torsion spring. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] like Figures 1-9 As shown, an electric stapler with a novel bending mechanism includes an electric stapler body 1. A rotary knob 2 is rotatably connected to the left end of the electric stapler body 1. An angle adjustment knob 3 is rotatably connected to the radial direction of the rotary knob 2. A rod body 4 is coaxially arranged with the rotary knob 2. The right end of the rod body 4 is fixedly connected to the left end of the rotary knob 2. Rotating the rotary knob 2 can cause the rotary knob 2 to drive the rod body 4 to rotate. A joint head 5 is rotatably connected to the left end of the rod body 4. A staple anvil assembly 6 is arranged at the left end of the joint head 5. A staple cartridge 7 is rotatably connected to the end of the staple anvil assembly 6 connected to the joint head 5. When in use, the staple cartridge can be fixed in the staple chamber 7. The staple cartridge can be manually disassembled. When the surgical sutures in the staple cartridge are used up, the staple cartridge in the staple chamber 7 can be manually disassembled and replaced. By rotating the angle adjustment knob 3, the joint head 5 drives the anvil assembly 6 and the staple chamber 7 to rotate synchronously. The transmission components between the rotary knob 2 and the rod body 4 and between the angle adjustment knob 3 and the joint head 5 are not shown. When performing surgery on a patient using an electric stapler, first adjust the articular head 5, anvil assembly 6, and staple cartridge 7 to be coaxial with the rod body 4. Then, insert the anvil assembly 6 and staple cartridge 7 into the patient's body. At this time, the anvil assembly 6 and staple cartridge 7 are in a closed state. Then, turn on the control switch on the electric stapler body 1 to control the motor inside the electric stapler body 1 to rotate. Then, through the transmission mechanism, the anvil assembly 6 and staple cartridge 7 are opened. The control switch, motor, and transmission mechanism are existing technologies and are widely used in electric staplers, not shown in the figure. Then, by rotating the angle adjustment knob 3, the articular head 5 drives the anvil assembly 6 and staple cartridge 7 to rotate synchronously, so that the patient's lesion is just between the anvil assembly 6 and staple cartridge 7. The electric stapler bends by rotating the angle adjustment knob 3 to make the articular head 5 drive the anvil assembly 6 and staple cartridge 7 to rotate synchronously. Then, press the control switch on the electric stapler body 1 again to make the anvil assembly 6 and staple cartridge 7 gradually close until the patient's lesion is clamped. The staple cartridge 7 is slidably connected to the cutting blade 8. The front and rear sides of the cutting blade 8 are fixedly connected to the triangular push block assembly 9. During the operation, the medical staff operates the electric stapler body 1 to move the triangular push block assembly 9 to the left, which in turn drives the cutting blade 8 to move synchronously. When the cutting blade 8 moves to the left, it removes the lesion held between the staple cartridge 7 and the anvil assembly 6. At the same time, when the triangular push block assembly 9 moves to the left, it pushes the surgical suture in the staple cartridge out through the inclined surface, so that the lower end of the surgical suture pierces the patient's surgical site and moves towards the anvil assembly 6. The surgical suture is in the shape of a dovetail. The anvil assembly 6 and the staple cartridge 7 have a staple groove 61 on their opposite sides. Under the pressure of the triangular pusher assembly 9, the convex surgical staple pierces the surgical site and moves towards the staple groove 61. A semi-circular block 10 is fixedly connected to the middle of the inner cavity of the staple groove 61. As the convex surgical staple moves towards the staple groove 61, the two branches below it bend to the left and right sides due to the pressure from the curved surface of the semi-circular block 10, thus increasing the angle between the two branches. Simultaneously, the triangular pusher assembly 9 and the cutting blade 8 move as the convex surgical staple moves towards the staple groove 61. A compression assembly 20 is slidably connected within the staple groove 61. A push rod assembly 30 is also connected to the upper side of the cutting blade 8. As the plate 8 moves, it drives the push rod assembly 30 to move synchronously. When the triangular push block assembly 9 pushes the π-shaped surgical suture staple towards the staple groove 61, the push rod assembly 30 lifts the extrusion assembly 20, so that the semicircular block 10 exerts extrusion force on the two branches below the π-shaped surgical suture staple. This causes the two branches to bend outward and upward at the same time, so that the π-shaped surgical suture staple is more firmly embedded in the tissue, avoiding the risk of poor anastomosis, bleeding or anastomotic leakage caused by the staple legs being too straight or not bent enough. Compared with the traditional structure that relies solely on the anvil extrusion molding method, it improves the sealing of the anastomosis. Through the dual action of the semicircular block 10 and the extrusion assembly 20, the branches of the π-shaped surgical suture staple bend outward, making the coverage area of ​​a single π-shaped surgical suture staple larger. A reversing assembly 40 is connected to the opposite side of the anvil assembly 6 and the staple cartridge 7. When the cutting blade 8 moves the push rod assembly 30 to the end of the anvil assembly 6, the push rod assembly 30 pushes the reversing assembly 40 to deflect, and then passes over the reversing assembly 40 to enter another path that is offset from the movement path of the cutting blade 8 when cutting the patient's lesion site, so that the push rod assembly 30 is misaligned with the compression assembly 20. Then the cutting blade 8 drives the push rod assembly 30 to reset. During the reset process, the push rod assembly 30 releases the compression of the compression assembly 20, eliminates the mechanical stress during the reset process, and protects the sutured tissue from secondary damage. The reversing assembly 40 realizes the mechanism from unidirectional compression to automatic disengagement, ensuring that the compression assembly 20 only applies pressure to the convex surgical staple during the forward phase of the cutting blade 8, and completely releases the constraint during reset.

[0018] Reference Figure 6 and Figure 7 As shown, the anvil assembly 6 includes an anvil mounting chamber 62. The right end of the anvil mounting chamber 62 is fixedly connected to the articular head 5. An anvil plate 63 is fixedly connected in the inner cavity of the anvil mounting chamber 62. Several nail grooves 61 are opened on the upper surface of the anvil plate 63. A semi-circular block 10 is fixedly connected in the nail grooves 61. The lesion is clamped between the anvil plate 63 and the anvil chamber 7.

[0019] Reference Figure 5As shown, the triangular pusher assembly 9 includes two triangular blocks 91, with a connecting rod 92 between them. The upper end of the connecting rod 92 is fixedly connected to the cutting blade 8, and the lower ends of the two connecting rods 92 are fixedly connected to the two triangular blocks 91. When the medical staff operates the electric stapler body 1, the two triangular blocks 91 move from right to left, causing the connecting rod 92 and the cutting blade 8 to move synchronously. When the two triangular blocks 91 move, the inclined surfaces of the triangular blocks 91 push out the π-shaped surgical sutures in the staple cartridge, causing the π-shaped surgical sutures to move towards the bottom of the staple slot 61. At the same time, when the cutting blade 8 moves, it cuts the lesion area held between the staple anvil 63 and the staple cartridge 7, causing the two branches of the π-shaped surgical sutures to pierce the skin and suture the cut area. After the π-shaped surgical sutures pierce the skin, due to the compression of the curved surface of the semi-circular block 10 below, the two branches below the π-shaped surgical sutures bend to both sides.

[0020] Reference Figures 8-10 As shown, the extrusion assembly 20 includes two slide rods 201, and an extrusion spring 202 is sleeved on the slide rods 201. Both slide rods 201 are located in the nail groove 61 and are respectively located on both sides of the semicircular block 10.

[0021] Both slide rods 201 are slidably connected to the anvil plate 63. The upper ends of both slide rods 201 are fixedly connected to the compression plate 203. When the convex surgical suture nail is pressed down by the triangular block 91, it is subjected to the compression action of the semi-circular block 10, and the included angle between the two branches below it increases. That is, the two branches below it bend towards the position of the compression plate 203. The compression plate 203 is slidably connected in the nail groove 61. The lower ends of the two slide rods 201 are fixedly connected by the connecting bridge 204. The lower end of the connecting bridge 204 is fixedly connected to the protrusion 205.

[0022] Reference Figures 9-13As shown, the push rod assembly 30 includes two guide rods 301. One end of each guide rod 301 is fixedly connected to both sides of the cutting blade 8, so that when the cutting blade 8 moves, i.e., when cutting the lesion site of the patient, it drives the two guide rods 301 to move synchronously. The guide rods 301 are slidably connected to the inner cavity of the slide tube 302. A compression wheel 303 is rotatably connected to the outer wall of the slide tube 302. When the guide rods 301 move with the cutting blade 8, they synchronously drive the slide tube 302 and the compression wheel 303 to move. When the compression wheel 303 moves to the position of the protrusion 205... When in position, the compression wheel 303 compresses the protrusion 205, causing the protrusion 205, connecting bridge 204, slide rod 201 and compression plate 203 to move synchronously. At the same time, the compression spring 202 is stretched, and the compression plate 203 moves away from the bottom of the nail groove 61. This causes the compression plate 203 to compress the two branches of the π-shaped surgical suture in the opposite direction to the movement of the π-shaped surgical suture, causing it to bend upward, i.e., bend in the opposite direction. When the compression wheel 303 disengages from the protrusion 205, all components are reset, and the reversing spring 304 is sleeved on the slide tube 302.

[0023] A hexagonal groove 631 is provided on one side of the sliding tube 302 on the nail cutting board 63. An extension rod 305 is provided in the radial position of the sliding tube 302. One end of the extension rod 305 is fixedly connected to the sliding tube 302, and the other end of the extension rod 305 is fixedly connected to a slider 306. The slider 306 is slidably connected in the hexagonal groove 631. When the guide rod 301 moves with the cutting blade 8, it synchronously drives the sliding tube 302 and the extension rod 305 to move, thereby driving the slider 306 to slide in the hexagonal groove 631. That is, the slider 306 slides from the left side of the hexagonal groove 631 to the right side.

[0024] The reversing assembly 40 includes a stop lever 401, which is fixedly connected to the side of the slide tube 302 on the nail anvil 63. A rotating shaft 402 is also provided on the side of the slide tube 302 on the nail anvil 63. One end of the rotating shaft 402 is rotatably connected to the side of the slide tube 302 on the nail anvil 63, and the other end of the rotating shaft 402 is fixedly connected to a limit rod 403. A torsion spring 404 is sleeved on the rotating shaft 402. The extension rod 305 drives the slider 306 to move from left to right within the hexagonal groove 631. The rightward sliding process can be divided into three stages: the slider 306 sliding in the inclined groove on the left side of the hexagonal groove 631, the slider 306 sliding in the straight groove in the middle of the hexagonal groove 631, and the slider 306 sliding in the inclined groove on the right side of the hexagonal groove 631. Simultaneously, the left side of the hexagonal groove 631 has two symmetrically arranged and connected inclined grooves, the middle has two parallel and horizontally arranged straight grooves, and the right side of the hexagonal groove 631 has two symmetrically arranged and connected inclined grooves. The inclined grooves on the left and right sides of the hexagonal groove 631... The inclined grooves are mirrored. When the cutting blade 8 moves to the right from its initial position, i.e., when cutting, it is blocked by the stop bar 401. At this time, the two sliders 306 enter the two adjacent straight grooves from the left side and reach the rightmost end. During this process, when the extension rod 305 drives the slider 306 to slide from the two adjacent inclined grooves to the two distant inclined grooves in the right end inclined groove, the extension rod 305 squeezes the limiting rod 403, causing the limiting rod 403 to drive the rotating shaft 402 to rotate. At this time, the torsion spring 404 deforms. When the limiting rod 403 disengages from the extension rod 305, the torsion spring 404 returns to its original position. At the same time, during the above process, the reversing spring 304 is compressed. Then the slider 306 enters the two distant straight grooves through the two adjacent inclined grooves on the right end and slides from right to left in the straight grooves. Then it returns to its original position after passing through the two distant straight grooves and the two distant inclined grooves on the left end in sequence.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, method, article, or apparatus.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electric stapler with a novel bending mechanism, characterized in that, The device includes an electric stapler body (1), a rotary knob (2) is rotatably connected to the left end of the electric stapler body (1), an angle adjustment knob (3) is rotatably connected to the radial direction of the rotary knob (2), a rod body (4) is coaxially arranged with the rotary knob (2), the right end of the rod body (4) is fixedly connected to the left end of the rotary knob (2), a joint head (5) is rotatably connected to the left end of the rod body (4), a staple anvil assembly (6) is arranged at the left end of the joint head (5), a staple cartridge (7) is rotatably connected to the end of the staple anvil assembly (6) connected to the joint head (5), and a cutting blade (8) is slidably connected to the axial direction of the staple cartridge (7). The front and rear sides of the cutting blade (8) are fixedly connected with triangular push block assemblies (9). The anvil assembly (6) and the nail magazine (7) are provided with a nail groove (61) on the side facing each other. A semi-circular block (10) is fixedly connected in the middle of the inner cavity of the nail groove (61). A pressing assembly (20) is slidably connected in the nail groove (61). The upper side of the cutting blade (8) is also connected with a push rod assembly (30). The side of the anvil assembly (6) opposite to the nail magazine (7) is connected with a reversing assembly (40).

2. The electric stapler with a novel bending mechanism according to claim 1, characterized in that, The anvil assembly (6) includes an anvil mounting compartment (62), the right end of which is fixedly connected to the joint head (5). An anvil board (63) is fixedly connected in the inner cavity of the anvil mounting compartment (62). Several nail grooves (61) are provided on the upper surface of the anvil board (63), and the semi-circular block (10) is fixedly connected in the nail grooves (61).

3. The electric stapler with a novel bending mechanism according to claim 1, characterized in that, The triangular push block assembly (9) includes two triangular blocks (91), and a connecting rod (92) is provided between the two triangular blocks (91). The upper end of the connecting rod (92) is fixedly connected to the cutting blade (8), and the lower end of the two connecting rods (92) is fixedly connected to the two triangular blocks (91).

4. An electric stapler with a novel bending mechanism according to claim 2, characterized in that, The extrusion assembly (20) includes two slide bars (201), and an extrusion spring (202) is sleeved on the slide bars (201). Both slide bars (201) are located in the nail groove (61) and are respectively located on both sides of the semicircular block (10).

5. An electric stapler with a novel bending mechanism according to claim 4, characterized in that, Both slide rods (201) are slidably connected to the nail anvil (63). The upper ends of both slide rods (201) are fixedly connected to the pressing plate (203), which is slidably connected in the nail groove (61). The lower ends of the two slide rods (201) are fixedly connected by a connecting bridge (204), and the lower end of the connecting bridge (204) is fixedly connected to a protrusion (205).

6. An electric stapler with a novel bending mechanism according to claim 2, characterized in that, The top rod assembly (30) includes two guide rods (301), one end of which is fixedly connected to both sides of the cutting blade (8). The guide rods (301) are slidably connected to the inner cavity of the slide tube (302). A pressing wheel (303) is rotatably connected to the outer wall of the slide tube (302). A reversing spring (304) is sleeved on the slide tube (302).

7. An electric stapler with a novel bending mechanism according to claim 6, characterized in that, A hexagonal groove (631) is provided on one side of the sliding tube (302) on the nail anvil (63). An extension rod (305) is provided in the radial position of the sliding tube (302). One end of the extension rod (305) is fixedly connected to the sliding tube (302), and the other end of the extension rod (305) is fixedly connected to a slider (306). The slider (306) is slidably connected in the hexagonal groove (631).

8. An electric stapler with a novel bending mechanism according to claim 2, characterized in that, The reversing assembly (40) includes a stop lever (401), which is fixedly connected to the side of the slide tube (302) on the nail anvil (63). A rotating shaft (402) is also provided on the side of the slide tube (302) on the nail anvil (63). One end of the rotating shaft (402) is rotatably connected to the side of the slide tube (302) on the nail anvil (63). The other end of the rotating shaft (402) is fixedly connected to a limit rod (403). A torsion spring (404) is sleeved on the rotating shaft (402).

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