Screw anti-loose fastener and processing equipment thereof

Abstract

The invention discloses a screw anti-loosening fastener and processing equipment thereof, and relates to the technical field of connecting structures, the screw anti-loosening fastener comprises a fixing screw and a processing device, and the surface of the fixing screw is provided with a connecting structure; a connecting sleeve is arranged on the top surface of the fixing nut; connecting grooves are formed in the centers of the fixing nut and the connecting sleeve; a mounting inclined groove is formed in the surface of the fixing nut, an arc-shaped communicating groove is formed in the fixing nut, and a flexible strip is slidably arranged in the arc-shaped communicating groove; a connecting structure and a fastening structure are arranged, so that the flexible strip can enter through a mounting chute; and then a plurality of abutting round teeth on the surface of the flexible strip are clamped with thread gaps on the surface of the fixing screw, so that the fixing screw is prevented from rotating. The processing device is arranged, the processing device can fix the flexible strip, and the processing device drives the flexible strip to move in the arc-shaped communicating groove to install the flexible strip; and when the flexible strip is detached, the reinforcing bolts can be prized with the fixing columns after being detached.

Description

Technical Field

[0001] The invention relates to the technical field of connection structures, and in particular to a screw anti-loosening fastener and processing equipment thereof. Background Art

[0002] Screw anti-loosening fasteners refer to a type of fasteners used to prevent screws (including bolts, screws, etc.) from loosening or falling off due to environmental factors such as vibration, impact or temperature changes. This type of fastener is widely used in machinery manufacturing, automobiles, motorcycles, aerospace, rail transportation, construction engineering and other fields.

[0003] In the prior art, the anti-loosening of screws is carried out by specific fasteners, and the corresponding fasteners are generally disassembled and assembled by specific installation equipment. For example, a kind of anti-loosening fastener and its installation device with publication number CN112963428A includes a movable rod body and a fixed head body, one end of the movable rod body is provided with a threaded rod, the middle position of the fixed head body is provided with a threaded groove, the inner wall of the threaded groove is provided with an internal thread matching the threaded rod, and the middle position of the fixed head body is provided with an anti-loosening block extending outward; the threaded groove passes through the anti-loosening block; the side wall of the anti-loosening block is provided with a clamping groove, and the clamping piece is provided in the clamping groove.

[0004] The fastener of this screw is engaged with the arc-shaped clamping piece of the installation device. However, due to the presence of the folded ears when the arc-shaped clamping piece is inserted into the nut, the clamping piece needs to be elastically deformed for installation. The clamping piece cannot be too thick to cause deformation, thereby reducing the strength of the clamping piece itself. At the same time, the corresponding installation device cannot remove the clamping piece, which is difficult to remove for maintenance. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the clamping piece of the above-mentioned background technology needs to be elastically deformed for installation, resulting in its thickness being too thin to affect its own strength and the installation device cannot remove it, and to propose a screw anti-loosening fastener and its processing equipment.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A screw anti-loosening fastener comprises a fixing screw, a connection structure is arranged on the surface of the fixing screw; a fixing nut of the connection structure is threadedly connected with the surface of the fixing screw, a connection sleeve is arranged on the top surface of the fixing nut, and a connection groove is provided in the center of the fixing nut and the connection sleeve; a mounting oblique groove is provided on the surface of the fixing nut, an arc-shaped connecting groove is arranged inside the fixing nut, and the two ends of the arc-shaped connecting groove are respectively connected with the mounting oblique groove and the connecting groove; a reinforcing bolt is arranged on the top surface of the connecting sleeve, and the bottom end of the reinforcing bolt extends into the arc-shaped connecting groove;

[0008] A fastening structure is arranged in the installation inclined groove and the arc-shaped connecting groove, and a flexible strip of the fastening mechanism slides in the installation inclined groove and the arc-shaped connecting groove; a plurality of abutting round teeth are arranged at one end of the flexible strip, a reinforcing threaded hole is opened on the top surface of the flexible strip, and the bottom end of the reinforcing bolt is threadedly connected with the reinforcing threaded hole; a disassembly column is fixedly connected to the surface of the flexible strip;

[0009] The processing device comprises a positioning plate, a first connecting rod is rotatably arranged on one side of the positioning plate, a disassembly plate is arranged at one end of the first connecting rod, and two clamping plates are slidably arranged on the surface of the disassembly plate.

[0010] As a further solution of the present invention: a setting groove is provided on the top surface of the connecting sleeve, a threaded circular groove is provided at the bottom of the setting groove, and the bottom end of the threaded circular groove is connected to the arc-shaped connecting groove.

[0011] As a further solution of the present invention: a positioning circular groove is provided at the top of the connecting sleeve, the positioning circular groove is located at the center of the setting groove, and the shape of the positioning circular groove is adapted to the shape of the reinforcing bolt and nut.

[0012] A processing device for screw anti-loosening fasteners comprises a processing device, a first connecting rod is rotatably provided on one side of a positioning disk of the processing device, a disassembly plate is provided at one end of the first connecting rod, and two clamping plates are slidably provided on the surface of the disassembly plate.

[0013] As a further solution of the present invention: a positioning cavity is provided on the bottom surface of the positioning disk, and the shape of the positioning cavity is the same as the shape of the connecting sleeve.

[0014] As a further solution of the present invention: a connecting disk is fixedly connected to the top surface of the positioning disk, a transmission ring is slidably provided on the surface of the connecting disk, and the transmission ring is fixedly connected to the first connecting rod.

[0015] As a further solution of the present invention: a disassembly plate is arranged on the side of the first connecting rod close to the positioning disk, a limiting groove is provided on the surface of the disassembly plate, two sliding plates are slidably connected in the limiting groove, and a clamping plate is slidably arranged on the side of the two sliding plates close to the positioning disk.

[0016] As a further solution of the present invention: a second connecting rod is fixedly connected to the surface of the connecting disk, and an interference rod is slidably provided on the surface of the second connecting rod.

[0017] As a further solution of the present invention: a toggle plate is arranged at one end of the abutment rod away from the positioning plate, a return spring is arranged between the toggle plate and the second connecting rod, and the return spring is sleeved on the surface of the abutment rod.

[0018] Beneficial effects of the present invention:

[0019] (1) A screw anti-loosening fastener and a processing device thereof of the present invention are provided with a connection structure and a fastening structure, wherein a fixing nut of the connection structure is fixed to a fixing screw; a mounting bevel groove is provided on the surface of the fixing nut, and an arc-shaped connecting groove is provided on the inner ring of the mounting bevel groove and the fixing nut; a flexible strip can enter through the mounting bevel groove, and one end of the flexible strip enters into the inner cavity of the fixing nut through the arc-shaped connecting groove; then, a plurality of abutting round teeth on the surface of the flexible strip are engaged with the thread gap on the surface of the fixing screw, thereby preventing the fixing screw from rotating itself;

[0020] (2) A screw anti-loosening fastener and its processing equipment of the present invention is provided with a reinforcing bolt, which can be set from the top surface of the connecting sleeve. When the flexible strip moves to the limit position, the bottom of the reinforcing bolt extends into the reinforcing threaded hole of the flexible strip to connect, thereby further reinforcing the flexible strip;

[0021] (3) A screw anti-loosening fastener and its processing equipment of the present invention are provided with a processing device, which can fix the flexible strip. The processing device is positioned and installed on the top surface of the connecting structure, and then the processing device drives the flexible strip to move in the arc-shaped connecting groove to install it; when disassembling the flexible strip, the reinforcing bolt can be pried with the fixing column after disassembly, so that the bottom of the reinforcing bolt can drive the flexible strip to move, so that an installation space for the processing device appears between the disassembly column and the installation inclined groove, allowing the processing device to drive the flexible strip to be taken out of the arc-shaped connecting groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] Figure 1 It is a schematic diagram of the installation structure of a screw anti-loosening fastener of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the connection structure of the present invention;

[0025] Figure 3 The present invention Figure 2 A partial enlarged view of the middle A;

[0026] Figure 4 is a cross-sectional view of the connection structure of the present invention from a top view perspective;

[0027] Figure 5 is a cross-sectional view of the connection structure of the present invention from a front view perspective;

[0028] Figure 6 is a structural schematic diagram of the fastening structure of the present invention;

[0029] Figure 7 It is a structural schematic diagram of a screw anti-loosening fastener processing device of the present invention;

[0030] Figure 8 The present invention is a bottom structural schematic diagram of a screw anti-loosening fastener processing device. Fig. 9 It is a partial structural schematic diagram of the processing device of the present invention.

[0031] In the figure: 1. fixing screw; 2. connecting structure; 21. fixing nut; 22. connecting sleeve; 23. connecting groove; 24. mounting inclined groove; 25. arc-shaped connecting groove; 26. setting groove; 27. positioning circular groove; 28. reinforcing bolt; 29. ​​mounting hole; 210. threaded circular groove; 211. fixing column; 3. fastening structure; 31. flexible strip; 32. conflicting round teeth; 33. reinforcing threaded hole; 34. disassembling column; 4. processing device; 41. positioning plate; 42. connecting plate; 43. transmission ring; 44. first connecting rod; 45. disassembling plate; 46. limiting groove; 47. sliding plate; 48. clamping plate; 49. double-headed screw; 410. rotating nut; 411. second connecting rod; 412. conflicting rod; 413. pulling plate; 414. reset spring; 415. positioning cavity; 5. mounting wall. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1-9As shown, the present invention is a screw anti-loosening fastener and its processing equipment, including a fixing screw 1, the fixing screw 1 is inserted through a threaded hole between two mounting walls 5, and the fixing screw 1 is threadedly connected to the threaded hole. The fixing screw 1 is inserted through the threaded hole between the two mounting walls 5, and the end of the fixing screw 1 away from the nut is threadedly connected to a connecting structure 2. The connecting structure 2 includes a fixing nut 21, a connecting sleeve 22 is fixedly provided on the top surface of the fixing nut 21, a connecting groove 23 is provided at the center of the fixing nut 21 and the connecting sleeve 22, and an internal thread is provided on the inner wall of the connecting groove 23. An installation bevel groove 24 is provided on the outer surface of the fixing nut 21, and an arc-shaped arc-shaped connecting groove 25 is provided inside the fixing nut 21, and the two ends of the arc-shaped connecting groove 25 are connected to the installation bevel groove 24 and the connecting groove 23. The connection between the arc-shaped connecting groove 25 and the installation bevel groove 24 and the connecting groove 23 is smoothly transitioned. The connection between the arc-shaped connecting groove 25 and the connecting groove 23 is located between the two internal threads in the connecting groove 23. A long strip-shaped setting groove 26 is fixedly provided on the top surface of the connecting sleeve 22, and a circular positioning circular groove 27 is provided on the top surface of the connecting sleeve 22 at the center of the setting groove 26. A vertical threaded circular groove 210 is provided at the bottom of the setting groove 26, and the threaded circular groove 210 extends downward to communicate with the top surface of the arc-shaped connecting groove 25. A fixing column 211 is fixedly provided in the threaded circular groove 210, and the fixing column 211 is provided along the horizontal plane direction, and the setting direction of the fixing column 211 is perpendicular to the extending direction of the setting groove 26.

[0034] The fastening structure 3 can be positioned and arranged in the installation inclined groove 24 and the arc-shaped connecting groove 25. The fastening structure 3 includes an arc-shaped flexible strip 31. The flexible strip 31 has elastic properties, and the shape of the flexible strip 31 is adapted to the shape of the installation inclined groove 24. A plurality of raised abutting round teeth 32 are fixedly connected to the arc-shaped inner ring wall of the flexible strip 31. A raised disassembly column 34 is fixedly arranged on the outer surface of one end of the flexible strip 31. A reinforcement threaded hole 33 is opened on the upper and lower surfaces of the flexible strip 31. The reinforcement threaded hole 33 is located at the end of the flexible strip 31 away from the disassembly column 34.

[0035] When the fixing screw 1 passes through the two mounting walls 5 for connection, the connecting structure 2 is sleeved on the threaded surface of the fixing screw 1 for fixing. The bottom surface of the fixing nut 21 is in close contact with the mounting wall 5, and the fixing nut 21 reinforces the fixing screw 1 and the mounting wall 5. Then the fastening structure 3 is arranged inside the connecting structure 2, and the flexible strip 31 of the fastening structure 3 extends from the mounting bevel groove 24, and one end of the flexible strip 31 with the reinforcing threaded hole 33 extends into the arc-shaped connecting groove 25. One end of the flexible strip 31 extends into the connecting groove 23 through the arc-shaped connecting groove 25, and the flexible strip 31 is located in the gap between the two threads on the surface of the fixing screw 1. The several interfering round teeth 32 on the inner side of the flexible strip 31 are engaged and fixed with the thread of the fixing screw 1 to prevent the fixing screw 1 from rotating under the action of external force, thereby reinforcing it. When the flexible strip 31 extends into the arc-shaped connecting groove 25, the disassembly column 34 on one side of the flexible strip 31 moves to the side of the mounting bevel groove 24 for engagement, so that the flexible strip 31 moves to the limit position. At this time, the bottom end of the reinforcing bolt 28 is inserted into the setting groove 26, and the bottom end of the reinforcing bolt 28 passes through the threaded circular groove 210 and extends into the arc-shaped connecting groove 25. The bottom end of the reinforcing bolt 28 is threadedly connected with the reinforcing threaded hole 33 on the top surface of the flexible strip 31, so that the flexible strip 31 is fixed in the arc-shaped connecting groove 25. The positioning circular groove 27 inside the setting groove 26 provides a positioning installation position for the reinforcing bolt 28, so that the reinforcing bolt 28 can fix the flexible strip 31 when the flexible strip 31 moves to the limit position.

[0036] The installation of the flexible strip 31 inside the connection structure 2 needs to be installed with the aid of the processing device 4. The processing device 4 includes a positioning disk 41, and a circular positioning cavity 415 is provided at the bottom of the positioning disk 41. The shape of the positioning cavity 415 is adapted to the shape of the connecting sleeve 22. A connecting disk 42 is fixedly provided on the top surface of the positioning disk 41, and a transmission ring 43 is rotatably provided on the circumferential surface of the connecting plate. The transmission ring 43 is located so as to be able to be aligned with the top surface of the positioning disk 41. A first connecting plate is fixedly connected to the circumferential side surface of the transmission ring 43. The shape of the first connecting plate is L-shaped, and one end of the first connecting plate extends to the bottom of the positioning disk 41. A disassembly plate 45 is fixedly connected to the side of the first connecting disk 42 close to the positioning disk 41. A limiting groove 46 is provided on the side of the disassembly plate 45 close to the positioning disk 41, and two sliding plates 47 are slidably connected in the limiting groove 46. A double-headed screw 49 is rotatably provided in the limiting groove 46, and the threads on both sides of the double-headed screw 49 are in opposite directions. The double-headed screw 49 is threadedly connected with the sliding plates 47 on both sides, and a rotating nut 410 is arranged outside the disassembly plate 45, and the rotating nut 410 is coaxially fixedly connected with the double-headed screw 49. A clamping plate 48 is slidably arranged on one side of the two sliding plates 47 close to the positioning plate 41. A second connecting rod 411 is fixedly connected to the circumferential side surface of the connecting plate 42, and the shape of the second connecting rod 411 is L-shaped. A resistance rod 412 is slidably arranged at the vertical end of the second connecting rod 411, and a toggle plate is fixedly connected to the end of the resistance rod 412 away from the positioning plate 41. A reset spring 414 is arranged between the toggle plate and the second connecting rod 411, and the reset spring 414 is sleeved on the circumferential surface of the resistance rod 412.

[0037] When the fastening structure 3 is installed using this processing device 4, the disassembly column 34 on the surface of the flexible strip 31 is set between the clamping plates 48 on both sides. Then, by rotating the rotating nut 410, the double-headed screw 49 is driven to rotate, and the sliding plates 47 on both sides are close to each other so that the connected clamping plates 48 clamp the surface of the disassembly column 34. Then, the positioning plate 41 is placed on the top surface of the fixing nut 21, and the positioning cavity 415 at the bottom of the positioning plate 41 is engaged with the outside of the connecting sleeve 22. At this time, the first connecting rod 44 fixes the flexible strip 31 on the outside of the installation bevel groove 24, and the end of the flexible strip 31 away from the disassembly column 34 is placed in the installation bevel groove 24. At this time, one end of the resistance rod 412 will be extended into the installation bevel groove 24 by the force of the reset spring 414, and one end of the resistance rod 412 drives the flexible strip 31 to the deepest part of the installation bevel groove 24. The abutment rod 412 is located at the connection between the installation bevel groove 24 and the arc-shaped connecting groove 25. At this time, the transmission ring 43 is manually toggled, and the transmission ring 43 drives the clamping plate 48 to rotate through the first connecting plate, and the clamping plate 48 drives the fixedly connected flexible strip 31 to move in the installation bevel groove 24. At this time, the abutment rod 412 always abuts the flexible strip 31 at the connection between the installation bevel groove 24 and the arc-shaped connecting groove 25, so that the flexible strip 31 can smoothly enter the arc-shaped connecting groove 25 during the movement. When the flexible strip 31 moves to the limit position and the disassembly column 34 is located at the edge of the installation bevel groove 24, the rotating nut 410 is rotated to release the fixation of the disassembly column 34. Subsequently, the reinforcing bolts 28 are set in the setting groove 26 and the positioning circular groove 27 on the top surface of the connecting sleeve 22 to fix the flexible strip 31. The processing device 4 can disassemble and assemble the fastening structure 3, and drive the reinforcing bolt 28 to release the fixation of the flexible strip 31 through the mounting hole 29 on the top surface of the reinforcing bolt 28. At this time, the height of the reinforcing bolt 28 is lifted and exposed from the positioning circular groove 27. At this time, part of the bottom end of the reinforcing bolt 28 is still located in the positioning threaded hole of the flexible strip 31. The top end of the lifted reinforcing bolt 28 is moved toward the direction close to the fixing column 211, and the bottom end of the reinforcing bolt 28 pushes the flexible strip 31 out of the arc-shaped connecting groove 25. At this time, there is a gap between the disassembly column 34 on the surface of the flexible strip 31 and the edge of the installation inclined groove 24, providing a placement space for the clamping plate 48. At this time, by shifting the transmission ring 43, the nut 410 is rotated to drive the disassembly shaft to move. By pulling the shifting plate outward, the resistance rod 412 is driven to compress the reset spring 414, so that the flexible strip 31 can be taken out of the arc-shaped connecting groove 25 more quickly. Thereby, the fixation of the fixing screw 1 by the flexible strip 31 is released. Then, the fixing nut 21 is rotated to release the interference with the installation wall 5 , so that the fixing screw 1 can be taken out from the installation wall 5 .

[0038] Working principle of the present invention: A screw anti-loosening fastener and its processing equipment of the present invention, by setting a connecting structure 2 and a fastening structure 3, the fixing nut 21 of the connecting structure 2 is fixed with the fixing screw 1; the surface of the fixing nut 21 is provided with an installation bevel groove 24, and the installation bevel groove 24 and the inner ring of the fixing nut 21 are provided with an arc-shaped connecting groove 25; the flexible strip 31 can enter through the installation bevel groove 24, and one end of the flexible strip 31 enters the inner cavity of the fixing nut 21 through the arc-shaped connecting groove 25; then a plurality of abutting round teeth 32 on the surface of the flexible strip 31 are engaged with the thread gap on the surface of the fixing screw 1, thereby preventing the fixing screw 1 from rotating itself; by setting a reinforcing bolt 28, the reinforcing bolt 28 can be set from the top surface of the connecting sleeve 22, when When the flexible strip 31 moves to the extreme position, the bottom of the reinforcing bolt 28 extends into the reinforcing threaded hole 33 of the flexible strip 31 for connection, thereby further reinforcing the flexible strip 31; by providing a processing device 4, the processing device 4 can fix the flexible strip 31, and the processing device 4 is positioned and installed on the top surface of the connecting structure 2, and then the processing device 4 drives the flexible strip 31 to move in the arc-shaped connecting groove 25 for installation; when disassembling the flexible strip 31, the reinforcing bolt 28 can be pried with the fixing column 211 after disassembly, so that the bottom of the reinforcing bolt 28 can drive the flexible strip 31 to move, so that an installation space for the processing device 4 appears between the disassembly column 34 and the installation inclined groove 24, allowing the processing device 4 to drive the flexible strip 31 to be taken out of the arc-shaped connecting groove 25.

[0039] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A screw anti-loosening fastener, characterized in that: The invention comprises a fixing screw (1), wherein a connection structure (2) is arranged on the surface of the fixing screw (1); a fixing nut (21) of the connection structure (2) is threadedly connected to the surface of the fixing screw (1); a connection sleeve (22) is arranged on the top surface of the fixing nut (21); a connection groove (23) is provided in the center of the fixing nut (21) and the connection sleeve (22); a mounting bevel groove (24) is provided on the surface of the fixing nut (21); an arc-shaped connecting groove (25) is arranged inside the fixing nut (21); two ends of the arc-shaped connecting groove (25) are respectively connected to the mounting bevel groove (24) and the connecting groove (23); a reinforcing bolt (28) is arranged on the top surface of the connecting sleeve (22); the bottom end of the reinforcing bolt (28) extends into the arc-shaped connecting groove (25); A fastening structure (3) is arranged in the installation inclined groove (24) and the arc-shaped connecting groove (25), and a flexible strip (31) of the fastening mechanism slides in the installation inclined groove (24) and the arc-shaped connecting groove (25); a plurality of abutting round teeth (32) are arranged at one end of the flexible strip (31), a reinforcing threaded hole (33) is opened on the top surface of the flexible strip (31), and the bottom end of the reinforcing bolt (28) is threadedly connected to the reinforcing threaded hole (33); and a disassembly column (34) is fixedly connected to the surface of the flexible strip (31).

2. A screw anti-loosening fastener according to claim 1, characterized in that: A setting groove (26) is provided on the top surface of the connecting sleeve (22), a threaded circular groove (210) is provided at the bottom of the setting groove (26), and the bottom end of the threaded circular groove (210) is communicated with the arc-shaped connecting groove (25).

3. A screw anti-loosening fastener and a processing device thereof according to claim 2, characterized in that: A positioning circular groove (27) is provided at the top end of the connecting sleeve (22). The positioning circular groove (27) is located at the center of the setting groove (26). The shape of the positioning circular groove (27) is adapted to the shape of the nut of the reinforcing bolt (28).

4. A processing device for screw anti-loosening fasteners, characterized in that: The processing device (4) comprises a first connecting rod (44) rotatably arranged on one side of a positioning plate (41) of the processing device (4), a disassembly plate (45) is arranged at one end of the first connecting rod (44), and two clamping plates (48) are slidably arranged on the surface of the disassembly plate (45).

5. The processing equipment for screw anti-loosening fasteners according to claim 4, characterized in that: A positioning cavity (415) is formed on the bottom surface of the positioning plate (41).

6. The processing equipment for screw anti-loosening fasteners according to claim 5, characterized in that: The top surface of the positioning disk (41) is fixedly connected to a connecting disk (42), a transmission ring (43) is slidably provided on the surface of the connecting disk (42), and the transmission ring (43) is fixedly connected to a first connecting rod (44).

7. The processing equipment for screw anti-loosening fasteners according to claim 6, characterized in that: A disassembly plate (45) is provided on one side of the first connecting rod (44) close to the positioning plate (41), a limiting groove (46) is provided on the surface of the disassembly plate (45), two sliding plates (47) are slidably connected in the limiting groove (46), and a clamping plate (48) is slidably provided on one side of the two sliding plates (47) close to the positioning plate (41).

8. The processing equipment for screw anti-loosening fasteners according to claim 7, characterized in that: A second connecting rod (411) is fixedly connected to the surface of the connecting disk (42), and an abutting rod (412) is slidably provided on the surface of the second connecting rod (411).

9. The processing equipment for screw anti-loosening fasteners according to claim 8, characterized in that: A toggle plate is arranged at one end of the abutment rod (412) away from the positioning plate (41), a return spring (414) is arranged between the toggle plate and the second connecting rod (411), and the return spring (414) is sleeved on the surface of the abutment rod (412).

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