Bolt limiting equipment

Abstract

The utility model discloses a bolt limiting device, which comprises a positioning sleeve, a limiting block and a limiting block, the clamping component comprises a plurality of clamping blocks arranged in the positioning sleeve and used for abutting against the nut, and a first elastic unit is arranged between each clamping block and the inner wall of the positioning sleeve and used for driving the corresponding clamping block to move towards the interior of the sleeve; the pushing part is arranged on the face, away from the nut, of the positioning sleeve, one end of the pushing part is inserted into the positioning sleeve in a sliding mode, and the pushing part pushes the clamping blocks to clamp the corresponding side faces of the nut; the restraining plate is arranged on the positioning sleeve in a sleeving mode and used for filling the space around the nut; according to the tensioning wheel dismounting device, the pushing component and the clamping component are matched to enable the nut to be clamped in the polygonal groove, the connecting mode is simple, the space around the nut is filled with the restraining plate to enable the restraining plate not to move, the bolt is restrained to rotate through the positioning sleeve, dismounting operation of the tensioning wheel is facilitated, and dismounting efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of maintenance tools, in particular to a bolt limiting device. Background Art

[0002] The tensioner, also known as the adjusting wheel or the tensioning wheel, is a part widely used in mechanical equipment. Its main function is to tension the transmission belt or chain to ensure the normal operation of the transmission system.

[0003] When removing the tension wheel, the bolt used to fix the tension wheel sometimes rotates with the tension wheel in the straight slot, and the bolt cannot be constrained. At this time, the tension wheel is difficult to remove from the bolt. The common solution is that the staff first constrains the nut with a disassembly tool such as a wrench, and then disassembles the tension wheel. However, when the space around the bolt is relatively narrow, it is not easy for a disassembly tool such as a wrench to constrain the nut, which reduces the disassembly efficiency. Therefore, the present application specifically proposes a bolt limit device that is convenient for constraining the tension wheel bolt in a narrow space. Utility Model Content

[0004] The main purpose of the utility model is to provide a bolt limiting device which is convenient for restraining the bolts of a tensioning wheel in a narrow space.

[0005] In order to achieve the above object, the utility model provides a bolt limiting device, comprising:

[0006] A positioning sleeve, one side of which is provided with a polygonal groove corresponding to the nut on the bolt, and the positioning sleeve is used to position the nut on the bolt;

[0007] A clamping component, comprising a plurality of clamping blocks slidably inserted in the positioning sleeve, one end of each clamping block extending into the polygonal groove, and the extending end of each clamping block corresponding to each side surface of the nut one by one, when the bolt needs to be fixed, each clamping block is used to abut against the side surface of the corresponding nut and apply a thrust to the nut toward the center direction of the positioning sleeve, and a first elastic unit is further provided between each clamping block and the inner wall of the positioning sleeve, and the first elastic unit is used to drive the corresponding clamping block to move toward the inside of the sleeve;

[0008] A pushing component is arranged on a side of the positioning sleeve away from the nut, the pushing component is arranged along the bolt installation direction, and one end of the pushing component is slidably inserted in the positioning sleeve, the pushing component moves toward the bolt direction and pushes each clamping block, so that each clamping block clamps the corresponding side surface of the nut;

[0009] A constraint plate is rectangular and sleeved on the outer wall of the positioning sleeve. The constraint plate is used to fill the space around the nut to prevent the bolt from rotating with the tensioning wheel when the tensioning wheel is disassembled.

[0010] Furthermore, the two side surfaces, the top surface and the bottom surface of the constraint plate are respectively provided with straight slots arranged along the direction of the corresponding surfaces;

[0011] The constraint plate is provided with an unfolding component, and the unfolding component includes a sliding plate slidably arranged in each of the straight slots, and each of the sliding plates reciprocates in the corresponding straight slot toward or away from the center direction of the positioning sleeve, and the sliding plate is "L"-shaped, one end of the sliding plate is inserted in the positioning sleeve and abuts against the pushing component, and the short side of the sliding plate is arranged in the positioning sleeve, and a plurality of second elastic units are evenly distributed between each of the straight slots and the corresponding sliding plate, and the second elastic unit is used to drive the corresponding sliding plate to move toward the inside of the constraint plate.

[0012] Furthermore, the pushing component includes a lead screw arranged on a side of the positioning sleeve away from the bolt, and the lead screw is arranged along the bolt installation direction, a linkage component is rotatably inserted into a side of the bolt close to the positioning sleeve, and the linkage component is slidably arranged in the positioning sleeve along the bolt installation direction, the linkage component is abutted and matched with each of the clamping blocks and the sliding plate, and a positioning ring that is threadedly matched with the lead screw is also sleeved on the lead screw, and a plurality of connecting rods for fixing the positioning ring are arranged between the positioning ring and the positioning sleeve, when the bolt needs to be clamped, the lead screw drives the linkage component to move toward the direction close to the bolt through the spiral cooperation between the lead screw and the positioning ring, so that the linkage component abuts against each of the clamping blocks and the sliding plate.

[0013] Furthermore, the linkage component includes a pushing block slidably arranged in the positioning sleeve, the pushing block is rotatably inserted with the lead screw on a side away from the bolt, a plurality of second abutment blocks are circumferentially distributed on an end of the pushing block away from the lead screw, and each of the second abutment blocks corresponds to and abuts with each of the sliding plates one by one. When the pushing block moves toward the direction approaching the bolt, each of the second abutment blocks abuts with the corresponding sliding plates. A pushing ring is also provided on the side of the pushing block away from the lead screw, a plurality of first abutment blocks are circumferentially distributed on the inner ring of the pushing ring, and each of the first abutment blocks corresponds to and abuts with each of the clamping blocks one by one. When the pushing block moves toward the direction approaching the bolt, the pushing block drives each of the first abutment blocks to move toward the direction approaching the bolt through the pushing ring, and makes each of the first abutment blocks abut with the corresponding clamping block.

[0014] Furthermore, a limit plate is provided at the top of each clamping block, and the limit plate is in abutment with the corresponding first abutment block. When the first abutment block moves forward and abuts against the top of the corresponding clamping block, the limit plate is used to prevent the first abutment block from moving forward further.

[0015] Furthermore, a first groove is formed on a side of the push block close to the bolt;

[0016] The push ring is slidably set in the first groove along the bolt installation direction, and a third elastic unit is provided between the push ring and the bottom surface of the first groove. When the sliding plate is not fully unfolded after the nut is clamped, the push block continues to move toward the direction close to the bolt, and the third elastic unit is compressed until the sliding plate is fully unfolded.

[0017] The beneficial effects of the utility model are embodied in:

[0018] The utility model discloses, by pushing the component and the clamping component cooperate with each other, the nut is clamped in the polygonal groove of the positioning sleeve, the connection method is simple and convenient, and then the space around the nut is filled by the constraint plate to make the constraint plate unable to move and the bolt is constrained to rotate by the positioning sleeve, which facilitates the disassembly operation of the tensioning wheel and improves the disassembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional view of the front side of the bolt limiting device of the utility model;

[0020] Figure 2 It is a partial cross-sectional view of the bolt limiting device of the utility model;

[0021] Figure 3 yes Figure 2 Magnified view at A in the middle.

[0022] Description of reference numerals:

[0023] 1. Positioning sleeve; 11. Polygonal groove; 2. Clamping component; 21. Clamping block; 211. Limiting plate; 22. First elastic unit; 3. Pushing component; 31. Screw; 32. Linking member; 321. Pushing block; 3211. First groove; 322. Pushing ring; 323. Second abutting block; 324. First abutting block; 325. Third elastic unit; 33. Positioning ring; 34. Connecting rod; 4. Constraint plate; 41. Straight notch; 5. Expanding component; 51. Sliding plate; 52. Second elastic unit; 6. Bolt; 61. Nut; 7. Tensioning wheel. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0025] See also Figure 1-Figure 3 .

[0026] The utility model discloses a bolt limiting device, comprising:

[0027] A positioning sleeve 1, one side of which is provided with a polygonal groove 11 corresponding to the nut 61 on the bolt 6, and the positioning sleeve 1 is used for positioning the nut 61 on the bolt 6;

[0028] The clamping component 2 includes a plurality of clamping blocks 21 slidably inserted in the positioning sleeve 1, one end of each clamping block 21 extends into the polygonal groove 11, and the extended end of each clamping block 21 corresponds to each side surface of the nut 61 one by one. When the bolt 6 needs to be fixed, each clamping block 21 is used to abut against the side surface of the corresponding nut 61 and apply a thrust to the nut 61 toward the center direction of the positioning sleeve 1. A first elastic unit 22 is also provided between each clamping block 21 and the inner wall of the positioning sleeve 1, and the first elastic unit 22 is used to drive the corresponding clamping block 21 to move toward the inside of the sleeve;

[0029] The pushing component 3 is arranged on a side of the positioning sleeve 1 away from the nut 61. The pushing component 3 is arranged along the installation direction of the bolt 6, and one end of the pushing component 3 is slidably inserted in the positioning sleeve 1. When the bolt 6 needs to be fixed, the pushing component 3 moves toward the direction close to the bolt 6 and pushes each clamping block 21, so that each clamping block 21 clamps the corresponding side of the nut 61;

[0030] The constraint plate 4 is rectangular and sleeved on the outer wall of the positioning sleeve 1. The constraint plate 4 is used to fill the space around the nut 61 to prevent the bolt 6 from rotating with the tensioning wheel 7 when the tensioning wheel 7 is disassembled.

[0031] In specific implementation, when it is necessary to disassemble the tensioning wheel 7 installed in a narrow space, the staff will sleeve the polygonal notch on the positioning sleeve 1 on the nut 61 of the bolt 6. At this time, the constraint plate 4 fills the space around the nut 61. The constraint plate 4 is now stuck in the surrounding environment of the nut 61, and then the pushing component 3 is controlled to make the pushing component 3 slide and move one end inserted in the positioning sleeve 1 toward the direction close to the bolt 6 until the pushing component 3 abuts against each clamping block 21. At this time, the pushing component 3 continues to move toward the direction close to the bolt 6, and the pushing component 3 abuts and squeezes each clamping block 21, so that each clamping block 21 slides toward the center direction of the polygonal groove 11 and abuts and A thrust is provided toward the center of the positioning sleeve 1 to the side corresponding to the nut 61, and each first elastic unit 22 is stretched by the movement of the corresponding clamping block 21. At this time, the bolt 6 is clamped by the clamping component 2, and the staff disassembles the tensioning wheel 7. Since the constraint plate 4 is stuck in the surrounding environment and cannot rotate, the bolt 6 is constrained from rotating by the positioning sleeve 1. When the tensioning wheel 7 is disassembled, the pushing component 3 is operated to make the pushing component 3 slide and insert one end of the positioning sleeve 1 and move away from the bolt 6. Each clamping block 21 loses the constraint of the pushing component 3. At this time, each first elastic unit 22 is reset and drives the corresponding clamping block 21 to reset. At this time, the positioning sleeve 1 is separated from the bolt 6.

[0032] The utility model, through the cooperation between the pushing component 3 and the clamping component 2, the nut 61 is clamped in the polygonal groove 11 of the positioning sleeve 1, the connection method is simple and convenient, and then the space around the nut 61 is filled by the constraint plate 4 to make the constraint plate 4 unable to move and the bolt 6 is constrained to rotate by the positioning sleeve 1, which facilitates the disassembly operation of the tensioning wheel 7 and improves the disassembly efficiency.

[0033] Preferably, the first elastic unit 22 may use a spring in the prior art.

[0034] In one embodiment, the two side surfaces, the top surface and the bottom surface of the restraining plate 4 are respectively provided with straight slots 41 arranged along the direction of the corresponding surfaces;

[0035] The constraint plate 4 is provided with an unfolding component 5, which includes a sliding plate 51 slidably arranged in each straight slot 41, and each sliding plate 51 reciprocates in the corresponding straight slot 41 toward or away from the center direction of the positioning sleeve 1, and the sliding plate 51 is "L"-shaped, one end of the sliding plate 51 is inserted into the positioning sleeve 1 and abuts against the pushing component 3, and the short side of the sliding plate 51 is arranged in the positioning sleeve 1, and a plurality of second elastic units 52 are evenly distributed between each straight slot 41 and the corresponding sliding plate 51, and the second elastic unit 52 is used to drive the corresponding sliding plate 51 to move toward the inside of the constraint plate 4.

[0036] With this design, when the constraint plate 4 cannot fill the space around the nut 61, the pushing component 3 is controlled to move toward the direction close to the bolt 6. At this time, the pushing component 3 abuts against each sliding plate 51. As the pushing component 3 continues to move, the short sides of the pushing component 3 and the sliding plates 51 abut against each other. The pushing component 3 applies a thrust away from the center of the bolt 6 to each sliding plate 51. The top end of the long side of each sliding plate 51 extends from the constraint plate 4 and fills the space not filled by the constraint plate 4, thereby increasing the filling area of ​​the constraint plate 4. At this time, each second elastic unit 52 is compressed. When the tensioning wheel 7 is disassembled, the pushing component 3 is controlled to move away from the bolt 6. Each sliding plate 51 loses the thrust provided by the pushing component 3. At this time, each second elastic unit 52 resets and drives the corresponding sliding plate 51 to shrink.

[0037] Preferably, the second elastic unit 52 may use a spring in the prior art.

[0038] In one embodiment, the pushing component 3 includes a lead screw 31 arranged on a side of the positioning sleeve 1 away from the bolt 6, and the lead screw 31 is arranged along the installation direction of the bolt 6. A linkage component 32 is rotatably inserted on a side of the bolt 6 close to the positioning sleeve 1, and the linkage component 32 is slidably arranged in the positioning sleeve 1 along the installation direction of the bolt 6. The linkage component 32 abuts and cooperates with each clamping block 21 and the sliding plate 51. A positioning ring 33 threadedly matched with the lead screw 31 is also sleeved on the lead screw 31. A plurality of connecting rods 34 for fixing the positioning ring 33 are arranged between the positioning ring 33 and the positioning sleeve 1. When the bolt 6 needs to be clamped, the lead screw 31 drives the linkage component 32 to move toward the direction close to the bolt 6 through the spiral cooperation between the lead screw 31 and the positioning ring 33, so that the linkage component 32 abuts against each clamping block 21 and the sliding plate 51. With such a design, when the tensioning wheel 7 needs to be removed, the lead screw 31 is rotated, the lead screw 31 is spirally matched with the positioning ring 33 and moves toward the direction close to the bolt 6, and the linkage member 32 is pushed by the lead screw 31 and moves toward the direction of the bolt 6 until the linkage member 32 abuts against each clamping block 21 and the pushing plate, and each clamping block 21 clamps the nut 61, and each sliding plate 51 extends out of the constraint plate 4, thereby driving the clamping component 2 and the unfolding component 5 to work.

[0039] In one embodiment, the linkage member 32 includes a push block 321 slidably disposed in the positioning sleeve 1, and a lead screw 31 is rotatably inserted into the side of the push block 321 away from the bolt 6. A plurality of second abutment blocks 323 are distributed circumferentially on the end of the push block 321 away from the lead screw 31, and each second abutment block 323 corresponds to and abuts against each sliding plate 51 one by one. When the push block 321 moves toward the direction close to the bolt 6, each second abutment block 323 abuts against the corresponding sliding plate 51. A pushing ring 322 is also provided on the side of the pushing block 321 away from the screw 31, and a plurality of first abutting blocks 324 are distributed on the inner circumference of the pushing ring 322, and each first abutting block 324 corresponds to and abuts against each clamping block 21 one by one. When the pushing block 321 moves toward the direction close to the bolt 6, the pushing block 321 drives each first abutting block 324 to move toward the direction close to the bolt 6 through the pushing ring 322, and makes each first abutting block 324 abut against the corresponding clamping block 21.

[0040] With this design, when the tensioning wheel 7 needs to be removed, the screw 31 drives the pushing block 321 to move toward the direction close to the bolt 6, and the second abutment block 323 moves with the pushing block 321 and abuts against the corresponding sliding plate 51. The pushing block 321 drives each first abutment block 324 to move and abut against the corresponding clamping block 21 through the pushing ring 322. At this time, the pushing block 321 continues to move, and each first abutment block 324 applies pressure to the corresponding clamping block 21 in the direction close to the center of the positioning sleeve 1 until each clamping block 21 tightly clamps the nut 61, and each second abutment block 323 applies a thrust to the corresponding sliding plate 51 in the direction away from the center of the positioning sleeve 1, so that each sliding plate 51 extends out of the constraint plate 4.

[0041] In one embodiment, a limiting plate 211 is provided at the top of each clamping block 21, and the limiting plate 211 is in abutment with the corresponding first abutting block 324. When the first abutting block 324 moves forward and abuts on the top of the corresponding clamping block 21, the limiting plate 211 is used to prevent the first abutting block 324 from continuing to move forward. With this design, when the nut 61 is clamped but the push block 321 still needs to move, the push block 321 continues to drive the first abutting blocks 324 to move through the push ring 322, and each limiting plate 211 is used to prevent the corresponding first abutting block 324 from continuing to move, and prevent the first abutting block 324 from interfering with the first elastic unit 22.

[0042] In one embodiment, a first groove 3211 is formed on a side of the push block 321 close to the bolt 6;

[0043] The push ring 322 is slidably set in the first groove 3211 along the installation direction of the bolt 6, and a third elastic unit 325 is provided between the push ring 322 and the bottom surface of the first groove 3211. When the sliding plate 51 is not fully unfolded after the nut 61 is clamped, the push block 321 continues to move toward the direction close to the bolt 6, and the third elastic unit 325 is compressed until the sliding plate 51 is fully unfolded.

[0044] With this design, when the space around the bolt 6 is large, as the linkage member 32 moves toward the direction close to the bolt 6 until each clamping block 21 completes clamping the nut 61, the sliding plate 51 on the constraint plate 4 has not yet completely filled the space around the bolt 6. At this time, the pushing block 321 continues to move toward the direction close to the bolt 6, and each first abutment block 324 abuts against the corresponding clamping block 21 and cannot move, thereby restricting the movement of the pushing ring 322. At this time, the third elastic unit 325 is compressed, and the pushing ring 322 moves alone toward the direction close to the bolt 6, so that each second abutment block 323 continues to contact the corresponding sliding plate 51 and provide thrust until each sliding plate 51 is fully unfolded.

[0045] It should be noted that when the linkage member 32 moves toward the direction close to the bolt 6, each first abutment block 324 first contacts the corresponding clamping block 21, and each second abutment block 323 then contacts the corresponding sliding plate 51, so as to avoid that when the space around the bolt 6 is small, the sliding plate 51 first fills the space around the bolt 6 and causes the moving block to be unable to move, thereby interfering with the movement of the moving ring.

[0046] It should be noted that the elastic force of the third elastic unit 325 is greater than the reaction force when each first abutting block 324 abuts against the corresponding clamping block 21, and is less than the reaction force when the first abutting block 324 abuts against the corresponding limiting plate 211, thereby avoiding the third elastic unit 325 from being compressed when the first abutting block 324 abuts against the corresponding clamping block 21.

[0047] Preferably, the third elastic unit 325 may use a spring in the prior art.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. In addition, "multiple", "multiple groups", and "several" refer to more than two.

Claims

1. A bolt limiting device, characterized in that: include: A positioning sleeve (1), one side of which is provided with a polygonal groove (11) corresponding to a nut (61) on a bolt (6), and the positioning sleeve (1) is used to position the nut (61) on the bolt (6); The clamping component (2) comprises a plurality of clamping blocks (21) slidably inserted in the positioning sleeve (1), one end of each clamping block (21) protrudes into the polygonal groove (11), and the protruding end of each clamping block (21) corresponds to each side surface of the nut (61) one by one. When the bolt (6) needs to be fixed, each clamping block (21) is used to abut against the side surface of the corresponding nut (61) and apply a thrust to the nut (61) toward the center direction of the positioning sleeve (1). A first elastic unit (22) is also provided between each clamping block (21) and the inner wall of the positioning sleeve (1), and the first elastic unit (22) is used to drive the corresponding clamping block (21) to move toward the inside of the sleeve; A pushing component (3) is arranged on a side of the positioning sleeve (1) away from the nut (61), the pushing component (3) is arranged along the installation direction of the bolt (6), and one end of the pushing component (3) is slidably inserted in the positioning sleeve (1), the pushing component (3) moves toward the direction approaching the bolt (6) and pushes each clamping block (21), so that each clamping block (21) clamps the corresponding side surface of the nut (61); A restraining plate (4) is rectangular and is sleeved on the outer wall of the positioning sleeve (1). The restraining plate (4) is used to fill the space around the nut (61) to prevent the bolt (6) from rotating with the tensioning wheel (7) when the tensioning wheel (7) is disassembled.

2. The bolt limiting device according to claim 1, characterized in that: The two side surfaces, the top surface and the bottom surface of the restraining plate (4) are respectively provided with straight slots (41) arranged along the direction of the corresponding surfaces; The constraint plate (4) is provided with an unfolding component (5), and the unfolding component (5) includes a sliding plate (51) slidably arranged in each of the straight slots (41), and each of the sliding plates (51) reciprocates in the corresponding straight slot (41) toward or away from the center direction of the positioning sleeve (1), and the sliding plate (51) is "L"-shaped, one end of the sliding plate (51) is inserted into the positioning sleeve (1) and abuts against the pushing component (3), and the short side of the sliding plate (51) is arranged in the positioning sleeve (1), and a plurality of second elastic units (52) are evenly distributed between each of the straight slots (41) and the corresponding sliding plate (51), and the second elastic unit (52) is used to drive the corresponding sliding plate (51) to move toward the inside of the constraint plate (4).

3. The bolt limiting device according to claim 2, characterized in that: The pushing component (3) comprises a lead screw (31) arranged on a side of the positioning sleeve (1) away from the bolt (6), and the lead screw (31) is arranged along the installation direction of the bolt (6), and a linkage component (32) is rotatably inserted on a side of the bolt (6) close to the positioning sleeve (1), and the linkage component (32) is slidably arranged in the positioning sleeve (1) along the installation direction of the bolt (6), and the linkage component (32) is in abutment with each of the clamping blocks (21) and the sliding plate (51), and the lead screw (31) is A positioning ring (33) threadedly engaged with the lead screw (31) is also sleeved thereon, and a plurality of connecting rods (34) for fixing the positioning ring (33) are arranged between the positioning ring (33) and the positioning sleeve (1). When the bolt (6) needs to be clamped, the lead screw (31) drives the linkage member (32) to move toward the bolt (6) through the screw engagement between the lead screw (31) and the positioning ring (33), thereby causing the linkage member (32) to abut against each of the clamping blocks (21) and the sliding plate (51).

4. The bolt limiting device according to claim 3 is characterized in that: The linkage component (32) comprises a pushing block (321) slidably arranged in the positioning sleeve (1); the push block (321) is rotatably inserted with the lead screw (31) on a side away from the bolt (6); a plurality of second abutting blocks (323) are circumferentially distributed on an end of the push block (321) away from the lead screw (31); and each of the second abutting blocks (323) corresponds to and abuts against each of the sliding plates (51) one by one. When the push block (321) moves toward the direction approaching the bolt (6), each of the second abutting blocks (323) abuts against the corresponding sliding plate (51). A pushing ring (322) is also provided on a side of the moving block (321) away from the lead screw (31); a plurality of first abutting blocks (324) are distributed on the inner circumference of the pushing ring (322); and each of the first abutting blocks (324) corresponds to and abuts against each of the clamping blocks (21) one by one. When the pushing block (321) moves toward the direction approaching the bolt (6), the pushing block (321) drives each of the first abutting blocks (324) to move toward the direction approaching the bolt (6) through the pushing ring (322), and makes each of the first abutting blocks (324) abut against the corresponding clamping block (21).

5. The bolt limiting device according to claim 4, characterized in that: A limit plate (211) is provided at the top of each clamping block (21), and the limit plate (211) is in abutment with the corresponding first abutment block (324). When the first abutment block (324) moves forward and abuts against the top of the corresponding clamping block (21), the limit plate (211) is used to prevent the first abutment block (324) from continuing to move forward.

6. The bolt limiting device according to claim 4, characterized in that: A first groove (3211) is formed on a side of the pushing block (321) close to the bolt (6); The pushing ring (322) is slidably arranged in the first groove (3211) along the installation direction of the bolt (6), and a third elastic unit (325) is provided between the pushing ring (322) and the bottom surface of the first groove (3211). When the sliding plate (51) is not fully unfolded after the nut (61) is clamped, the pushing block (321) continues to move toward the direction close to the bolt (6), and the third elastic unit (325) is compressed until the sliding plate (51) is fully unfolded.

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