Nut welding part feeding position correcting device and correcting method

Abstract

The nut welding part feeding position correcting device comprises a base table, a fixing block and a barrel, the fixing block can move up and down, a motor is fixedly installed on the fixing block, the barrel is fixedly installed at the output end of the motor, the barrel can rotate along the axis of the barrel, and a rod body is slidably connected to the inner wall of the barrel. The upper end of the rod body abuts against a third spring, the upper end of the third spring abuts against the upper wall face of the barrel, an outer barrel is fixedly installed at the bottom of the fixing block, the inner wall of the outer barrel is slidably connected with a sliding sleeve, the sliding sleeve can move up and down, the upper end of the sliding sleeve abuts against a first spring, and the upper end of the first spring abuts against the bottom face of the fixing block. The invention provides a nut welding part feeding position correcting device and method. The consistency of the circumferential position of a nut at the clamping position is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of position correction device equipment, and more specifically, to a feeding position correction device and correction method for nut welded parts. Background Art

[0002] At present, many internal hexagonal nuts need to be welded to stamping parts for automobile seats in order to connect with other components. The welding operation is fully automatic. The nuts are transported to the designated positions by a feeder, and the manipulator grabs the nuts and places them at the welding points of the stamping parts for welding. Since the nuts transported to the designated points have different circumferential positions, it cannot be guaranteed that the manipulator grabs a pair of straight edges each time. When the grabbing position of the manipulator is at the adjacent edge junction of the nut, the grabbing is likely to be unstable, resulting in the nut being prone to position deviation, thus affecting the placement position of the nut during welding. When the nut position deviation is serious, it may even cause the subsequent screw holes to be unable to be installed. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a feeding position correction device and correction method for nut welded parts to ensure the consistency of the circumferential position of the nut at the grabbing position.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A feeding position correction device for nut welded parts, including a base, a fixed block, and a cylinder. The fixed block can move up and down. A motor is fixedly installed on the fixed block, and the output end of the motor is fixedly installed with a cylinder. The cylinder can rotate along its own axis. A rod body is slidably connected to the inner wall of the cylinder. The rod body can move up and down and can rotate with the cylinder. The upper end of the rod body abuts against a third spring, and the upper end of the third spring abuts against the upper wall surface of the cylinder. The bottom of the fixed block is fixedly installed with an outer cylinder. A sliding sleeve is slidably connected to the inner wall of the outer cylinder. The sliding sleeve can move up and down. The upper end of the sliding sleeve abuts against a first spring, and the upper end of the first spring abuts against the bottom surface of the fixed block; The upper end surface of the base can place a nut, and the nut can move and be transported along the upper end surface of the base. The nut can move to the lower part of the sliding sleeve and be coaxial with the sliding sleeve. The nut is provided with a screw hole, and the bottom of the rod body can be screwed into the screw hole. The sliding sleeve is provided with an inner wall, and the cross-sectional dimension of the inner wall matches the cross-sectional dimension of the nut. The sliding sleeve includes a convex platform at the bottom. The inner wall of the convex platform is a cylindrical surface, and the diameter of the cylindrical surface is the same as the outer diameter of the circumscribed circle of the nut. The inner wall of the convex platform can be sleeved on the nut, and the nut can be inserted into the inner wall to limit the rotation of the nut.

[0005] The present invention is further provided that a support body is slidably connected and installed at the bottom of the base. The support body can move left and right. A third cylinder is fixedly installed on the support body. The output end of the third cylinder is installed with a moving block. The moving block can move up and down. The base is provided with a first groove. The moving block can pass through the first groove and be inserted into the screw hole. The left and right movement of the moving block can drive the nut to move so that the nut moves to the lower part of the sliding sleeve.

[0006] The present invention is further configured such that the maximum cross-sectional dimension of the moving block is smaller than the inner diameter of the threaded hole, one side of the moving block is an arc surface, and the radius of the arc surface is the same as the minimum radius of the threaded hole.

[0007] The present invention is further configured to further include a limiting block which can move left and right. When the nut moves to below the sliding sleeve, the limiting block is located on one side in the continuous moving direction of the nut, and the inner wall of the limiting block can abut against the nut to limit the nut. The inner wall of the limiting block is arc-shaped, and the radius of the arc is the same as the radius of the circumscribed circle of the nut.

[0008] The present invention is further configured such that an inner groove I is provided on the inner wall of the cylinder body, a protrusion corresponding to the inner groove I is provided on the outer wall of the rod body, and the protrusion of the rod body is inserted into the inner groove I.

[0009] The present invention is further configured such that an inner groove II is provided on the inner wall of the outer cylinder, and the sliding sleeve is provided with a convex body which is inserted into the inner groove II.

[0010] The present invention is further configured such that a fixing plate is installed on the sliding sleeve, a sliding rod is slidably connected to the fixing plate, a pressing block is installed at the bottom of the sliding rod, the bottom of the pressing block can abut against the nut, a second spring is sleeved on the sliding rod, the upper end of the second spring abuts against the fixing plate, and the lower end of the second spring abuts against the pressing block.

[0011] The present invention is further configured such that when the nut is sleeved into the inner wall of the convex platform, the bottom of the pressing block abuts against the nut and the second spring is compressed.

[0012] The present invention also adopts the following technical solution: a correction method for a feeding position correction device of a nut welding part, including the following steps:

[0013] ① The moving block is inserted into the threaded hole and pushes the nut to move to below the sliding sleeve, and the nut abuts against the inner wall of the limiting block so that the sliding sleeve and the nut are coaxial;

[0014] ② The outer cylinder moves downward so that the convex platform is sleeved on the nut, the bottom of the pressing block abuts against the top of the nut. When there is no circumferential misalignment between the inner wall and the nut, the inner wall is directly sleeved on the nut; when there is circumferential misalignment between the inner wall and the nut, the inner wall cannot be directly sleeved on the nut. At this time, as the outer cylinder continues to move downward until it abuts against the base, after the bottom of the rod body abuts against the nut, as the cylinder body moves downward, the third spring is compressed;

[0015] ③ The cylinder body rotates and drives the rod body to rotate. When there is circumferential misalignment between the inner wall and the nut, at the initial stage when the rod body is screwed into the threaded hole, the rotation of the rod body will drive the nut to rotate so that the inner wall can be sleeved on the nut. After the inner wall can be sleeved on the nut, the inner wall forms circumferential limitation on the nut to facilitate the screwing in of the rod body;

[0016] ④ The cylinder body rotates reversely to screw out of the threaded hole, and the outer cylinder disengages from the nut upward.

[0017] In summary, the present invention has the following beneficial effects:

[0018] By adjusting the position of the nut, after the nut is inserted into the inner wall, since the circumferential position of the inner wall remains fixed, the circumferential position of the nut is adjusted to be consistent with the inner wall after adjustment, so as to achieve the purpose of keeping the circumferential position of the nut clamped by the manipulator unified, and prevent the situation that when the clamping position of the manipulator is at the adjacent edge junction of the nut, the clamping is likely to be unstable and the nut is likely to have a position deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional schematic view of the embodiment;

[0020] Figure 2 is Figure 1 the enlarged view of part A in

[0021] Figure 3 It is a top view conveying schematic view of the nut in the embodiment;

[0022] Figure 4 It is a cross-sectional schematic view of the moving block and the nut in the embodiment Figure 1 ;

[0023] Figure 5 It is a cross-sectional schematic view of the moving block and the nut in the embodiment Figure 2 ;

[0024] Figure 6 It is a cross-sectional schematic view of the limiting block and the nut in the embodiment;

[0025] Figure 7 It is a cross-sectional schematic view of the sliding sleeve in the embodiment;

[0026] Figure 8 It is a cross-sectional schematic view of the convex platform in the embodiment;

[0027] Figure 9 It is a partial action schematic view in the embodiment Figure 1 ;

[0028] Figure 10 It is a partial action schematic view in the embodiment Figure 2 .

[0029] Reference numerals: base 1, first groove body 11, slide rail 12, first cylinder 13, limiting block 131, baffle 14, nut 2, screw hole 21, support body 3, second cylinder 31, third cylinder 32, moving block 321, connecting seat 4, fixed block 41, motor 42, cylinder body 43, first inner groove 431, bottom support 44, rod body 45, outer cylinder 46, second inner groove 461, sliding sleeve 47, convex body 471, inner wall 472, convex platform 473, first spring 48, fixing plate 5, sliding rod 51, pressing block 52, second spring 53, third spring 6. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figures 1 - 10 shown, this embodiment discloses a feeding position correction device for a nut welding part, including a base 1. The base 1 is provided with a first groove 11, and the first groove 11 penetrates through the base 1 up and down. A nut 2 is conveyed on the upper end surface of the base 1. The nut 2 is an external hexagonal nut. The left side of the upper end surface of the base 1 is connected to the conveying track of the nut 2. Combining Figure 1 and Figure 3 , as the nut 2 is continuously conveyed to the upper end surface of the base 1, the nut 2 on the right side is pushed by the nut 2 on the left side and moves on the upper end surface of the base 1.

[0032] As Figure 1 shown, a slide rail 12 is fixedly installed at the bottom of the base 1. The slide rail 12 is slidably connected to a support body 3. A second cylinder 31 is also fixedly installed at the bottom of the base 1. The output end of the second cylinder 31 is connected to the support body 3, and the support body 3 moves left and right under the action of the second cylinder 31. A third cylinder 32 is fixedly installed on the support body 3. A moving block 321 is installed at the output end of the third cylinder 32, and the moving block 321 can move up and down under the action of the third cylinder 32. The nut 2 is provided with a screw hole 21, and the screw hole 21 is a threaded hole. Under the combined action of the second cylinder 31 and the third cylinder 32, the moving block 321 is inserted into the screw hole 21 and pushes the nut 2 to move to the right.

[0033] As Figure 4 and Figure 5 shown, one side of the moving block 321 is an arc surface, and the radius of this arc surface is the same as the minimum radius of the screw hole 21. This arc surface on this side is used to abut against the inner wall of the screw hole 21 to push the nut 2.

[0034] As Figure 1 and Figure 3 shown, a baffle 14 is slidably connected to the base 1, and the baffle 14 is driven by a cylinder to move. When the baffle 14 moves towards the side close to the first groove 11, it can limit the nut 2.

[0035] Since the circumferential positions of the nuts 2 conveyed to the upper end surface of the base 1 are different ( Figure 3 shown), as Figure 4 and Figure 5 shown, by setting the maximum cross-sectional dimension of the moving block 321 to be smaller than the inner diameter of the screw hole 21, it can be ensured that the moving block 321 is inserted into the screw hole 21.

[0036] As Figure 1 and Figure 2As shown, the base 1 is also equipped with a first cylinder 13. The output end of the first cylinder 13 is fixedly connected with a limiting block 131, and the limiting block 131 can move left and right under the drive of the first cylinder 13. The limiting block 131 is located on one side (i.e., the right side) of the moving direction of the nut 2, and the inner wall of the limiting block 131 can abut against the nut 2 to limit the nut 2. Specifically, as Figure 6 shown, the inner wall of the limiting block 131 is arc-shaped and semi-circular, and the radius of the arc is the same as the radius of the circumscribed circle of the nut 2. When the limiting block 131 is in the left extreme position, the nut 2 moves to abut against the inner wall of the limiting block 131. Since the radius of the arc of the inner wall of the limiting block 131 is the same as the radius of the circumscribed circle of the nut 2, after each nut 2 abuts against the inner wall of the limiting block 131, the central position of the nut 2 remains the same.

[0037] As Figure 1 、 Figure 2 shown, the nut welding part feeding position correction device further includes a connecting seat 4. The connecting seat 4 moves up and down through the top connecting cylinder. A fixing block 41 is fixedly installed at the bottom of the connecting seat 4, and a motor 42 is fixedly installed at the top of the fixing block 41. The output end of the motor 42 extends downward through the connecting seat 4 and a cylinder body 43 is fixedly installed at the bottom. The cylinder body 43 can rotate along its own axis under the drive of the motor 42. The cylinder body 43 is inserted into the fixing block 41, and the cylinder body 43 is of a cylindrical structure. A rod body 45 is slidably connected to the inner wall of the cylinder body 43. An inner groove 431 is provided on the inner wall of the cylinder body 43, and a protrusion corresponding to the inner groove 431 is provided on the outer wall of the rod body 45. The protrusion of the rod body 45 is inserted into the inner groove 431, and the rod body 45 can move up and down and can rotate with the cylinder body 43. The upper end of the rod body 45 abuts against a third spring 6, and the upper end of the third spring 6 abuts against the upper wall surface of the cylinder body 43. A bottom support 44 is installed at the bottom of the cylinder body 43, and the bottom support 44 can limit the protrusion of the rod body 45 at the lower end to prevent the rod body 45 from sliding out of the bottom of the cylinder body 43. The lower end of the rod body 45 extends out of the bottom of the cylinder body 43 and passes through the bottom support 44. The outer wall of the bottom of the rod body 45 is provided with a thread and can be screwed into the screw hole 21 to detect whether the screw hole 21 is unobstructed. And the detection step is before the nut 2 is welded to the welded part, preventing the situation that the operator discovers that the size of the screw hole 21 is defective or the thread is damaged only after the nut 2 is welded, and reducing subsequent rework.

[0038] As Figure 2 shown, an outer cylinder 46 is fixedly installed at the bottom of the fixing block 41. A sliding sleeve 47 is slidably connected to the inner wall of the outer cylinder 46, and the sliding sleeve 47 can move up and down. Convex bodies 471 are provided on both sides of the outer wall of the top of the sliding sleeve 47. An inner groove 461 matching the convex bodies 471 is provided on the inner wall of the outer cylinder 46. The upper end of the inner groove 461 penetrates through the top of the outer cylinder 46, and the lower end does not penetrate through the bottom of the outer cylinder 46. The convex bodies 471 are inserted into the inner groove 461 and can move up and down along the inner groove 461, and at the same time, the convex bodies 471 will not extend downward out of the outer cylinder 46. When the limiting block 131 is in the left extreme position, the sliding sleeve 47 is coaxial with the limiting block 131.

[0039] As Figure 2 shown, a first spring 48 abuts against the upper end of the sliding sleeve 47, and the upper end of the first spring 48 abuts against the bottom surface of the fixing block 41. A through hole penetrating up and down is provided in the center of the sliding sleeve 47, and the rod body 45 can pass through the through hole of the sliding sleeve 47. The nut 2 can be moved below the sliding sleeve 47 under the push of the moving block 321. Through the arrangement of the limiting block 131, the nut 2 and the sliding sleeve 47 are coaxial.

[0040] Combined with Figure 2 、 Figure 7 、 Figure 8 As shown, the sliding sleeve 47 is provided with an inner wall 472, the cross-sectional dimension of the inner wall 472 matches the cross-sectional dimension of the nut 2, and the inner wall 472 is a regular hexagon. The sliding sleeve 47 includes a boss 473 at the bottom, the inner wall of the boss 473 is a cylindrical surface, and the diameter of the cylindrical surface is the same as the diameter of the circumscribed circle of the nut 2. The inner wall of the boss 473 can fit over the nut 2, and the nut 2 can be inserted into the inner wall 472 to limit the rotation of the nut 2.

[0041] Since the circumferential positions of the nuts 2 conveyed to the upper end surface of the base 1 are different ( Figure 3 shown), after the nut 2 is pushed to the right, in order to ensure that when the manipulator grabs the nut 2 at this position, it can grab a pair of straight sides of the nut 2, the circumferential position of the nut 2 must be kept unified when it is grabbed by the manipulator. Therefore, by adjusting the position of the nut 2, after the nut 2 is inserted into the inner wall 472, since the circumferential position of the inner wall 472 remains fixed, the circumferential position of the nut 2 after adjustment is consistent with the inner wall 472, so that the circumferential positions of the nuts 2 grabbed by the manipulator are kept unified.

[0042] As Figure 2 shown, a fixing plate 5 is installed at the top of the sliding sleeve 47, the rod body 45 passes through the fixing plate 5, the fixing plate 5 is slidably connected with a sliding rod 51, the sliding rod 51 can move up and down, the sliding rods 51 are located on both sides of the fixing plate 5, the sliding rods 51 are inserted into the sliding sleeve 47, a pressing block 52 is installed at the bottom of the sliding rod 51, a second spring 53 is sleeved on the sliding rod 51, the bottom of the second spring 53 abuts against the upper end of the pressing block 52, and the top of the second spring 53 abuts against the fixing plate 5.

[0043] The correction method of the correction device is as follows:

[0044] ①As Figure 1 、 Figure 2 shown, the limiting block 131 moves to the left extreme position, the moving block 321 cooperates with the cylinder two 31 and the cylinder three 32 to insert into the screw hole 21 and push the nut 2 to move below the sliding sleeve 47, and the nut 2 abuts against the inner wall of the limiting block 131 to make the sliding sleeve 47 and the nut 2 coaxial.

[0045] ②As Figure 2As shown, the outer cylinder 46 moves downward so that the boss 473 is sleeved into the nut 2, and the bottom of the pressing block 52 abuts against the top of the nut 2. When there is no circumferential misalignment between the inner wall 472 and the nut 2, the inner wall 472 is directly sleeved into the nut 2; when there is circumferential misalignment between the inner wall 472 and the nut 2, the inner wall 472 cannot be directly sleeved into the nut 2, as Figure 9 shown. At this time, as the outer cylinder 46 continues to move downward until it abuts against the base 1, during this process, the first spring 48 is compressed, and after the bottom of the rod body 45 abuts against the nut 2, as the cylinder body 43 moves downward, the third spring 6 is compressed. As Figure 10 shown, after the inner wall 472 is sleeved into the nut 2, the second spring 53 is compressed.

[0046] ③ The cylinder body 43 rotates driven by the motor 42 and drives the rod body 45 to rotate. The rod body 45 is screwed into the screw hole 21 under the action of the third spring 6 and rotation. After the bottom of the rod body 45 is screwed out of the screw hole 21, the sensor senses the bottom of the rod body 45 to judge whether the screw hole 21 is qualified. When there is circumferential misalignment between the inner wall 472 and the nut 2, at the stage when the rod body 45 is just screwed into the screw hole 21, since the pressure of the pressing block 52 on the nut 2 is only an auxiliary force and cannot restrict the rotation of the nut 2 in the circumferential direction, the rotation of the rod body 45 will drive the nut 2 to rotate so that the inner wall 472 can be sleeved into the nut 2. After the inner wall 472 can be sleeved into the nut 2, the inner wall 472 forms a circumferential limit on the nut 2 to facilitate the screwing of the rod body 45.

[0047] ④ The cylinder body 43 rotates reversely to screw out the screw hole 21, and the outer cylinder 46 disengages from the nut 2 upward.

[0048] By adjusting the circumferential states of each nut 2 moved to the position below the sliding sleeve 47 to be consistent, it is convenient for the manipulator to accurately clamp a pair of straight edges of the nut 2, making the clamping more stable. And by inspecting each screw hole 21 of each nut 2 again, it is prevented that the screw holes 21 of the nut 2 cannot be used after welding.

[0049] When the whole component disengages from the nut 2 upward, the pressure of the pressing block 52 on the nut 2 prevents the nut 2 from rotating and moving, so as to ensure the stability of its position.

[0050] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A feeding position correction device for nut welding parts, characterized in that: The invention comprises a base (1), a fixed block (41), and a cylinder (43), wherein the fixed block (41) can move up and down, a motor (42) is fixedly mounted on the fixed block (41), the cylinder (43) is fixedly mounted on the output end of the motor (42), the cylinder (43) can rotate along its own axis, the inner wall of the cylinder (43) is slidably connected to a rod (45), the rod (45) can move up and down and can rotate with the cylinder (43) The upper end of the rod body (45) is in contact with a spring three (6), and the upper end of the spring three (6) is in contact with the upper wall of the cylinder body (43); an outer cylinder (46) is fixedly installed at the bottom of the fixed block (41); a sliding sleeve (47) is slidably connected to the inner wall of the outer cylinder (46); the sliding sleeve (47) can move up and down; the upper end of the sliding sleeve (47) is in contact with a spring one (48), and the upper end of the spring one (48) is in contact with the bottom surface of the fixed block (41); A nut (2) can be placed on the upper end surface of the base (1), and the nut (2) can be moved and transported along the upper end surface of the base (1). The nut (2) can be moved to the bottom of the sliding sleeve (47), and the nut (2) can be coaxial with the sliding sleeve (47). The nut (2) is provided with a screw hole (21), and the bottom of the rod body (45) can be screwed into the screw hole (21). The sliding sleeve (47) is provided with an inner wall (472), and the cross-sectional size of the inner wall (472) matches the cross-sectional size of the nut (2). The sliding sleeve (47) includes a boss (473) located at the bottom, and the inner wall of the boss (473) is a cylindrical surface, and the diameter of the cylindrical surface is the same as the diameter of the circumscribed circle of the nut (2). The inner wall of the boss (473) can be inserted into the nut (2), and the nut (2) can be inserted into the inner wall (472) to limit the rotation of the nut (2).

2. A nut welding part feeding position correction device according to claim 1, characterized in that: A support body (3) is slidably connected to the bottom of the base (1), and the support body (3) can move left and right. A cylinder three (32) is fixedly installed on the support body (3), and a moving block (321) is installed at the output end of the cylinder three (32). The moving block (321) can move up and down. The base (1) is provided with a groove body one (11), and the moving block (321) can pass through the groove body one (11) and be inserted into the screw hole (21). The moving block (321) can drive the nut (2) to move left and right so that the nut (2) moves to the bottom of the sliding sleeve (47).

3. A nut welding part feeding position correction device according to claim 2, characterized in that: The maximum cross-sectional dimension of the moving block (321) is smaller than the inner diameter of the screw hole (21); one side of the moving block (321) is an arc surface, and the radius of the arc surface is the same as the minimum radius of the screw hole (21).

4. A nut welding part feeding position correction device according to claim 1, characterized in that: The invention also comprises a limit block (131), wherein the limit block (131) can move left and right. When the nut (2) moves to below the sliding sleeve (47), the limit block (131) is located on the side of the direction in which the nut (2) continues to move. The inner wall of the limit block (131) can abut against the nut (2) to limit the position of the nut (2). The inner wall of the limit block (131) is in an arc shape, and the radius of the arc shape is the same as the radius of the circumscribed circle of the nut (2).

5. A nut welding part feeding position correction device according to claim 1, characterized in that: The inner wall of the cylinder (43) is provided with an inner groove (431), the outer wall of the rod body (45) is provided with a protrusion corresponding to the inner groove (431), and the protrusion of the rod body (45) is inserted into the inner groove (431).

6. A nut welding part feeding position correction device according to claim 1, characterized in that: The inner wall of the outer cylinder (46) is provided with an inner groove (461), and the sliding sleeve (47) is provided with a convex body (471), and the convex body (471) is inserted into the inner groove (461).

7. A nut welding part feeding position correction device according to claim 1, characterized in that: The sliding sleeve (47) is installed with a fixed plate (5), and the fixed plate (5) is slidably connected with a sliding rod (51). A pressure block (52) is installed at the bottom of the sliding rod (51), and the bottom of the pressure block (52) can abut against the nut (2). The sliding rod (51) is sleeved with a second spring (53), and the upper end of the second spring (53) abuts against the fixed plate (5), and the lower end of the second spring (53) abuts against the pressure block (52).

8. A method for correcting the feeding position of a nut welding piece according to claim 7, characterized in that: When the inner wall of the boss (473) is inserted into the nut (2), the bottom of the pressing block (52) abuts against the nut (2), and the second spring (53) is compressed.

9. A correction method for a nut welding piece feeding position correction device according to any one of claims 1 to 8, characterized in that: The steps include: ① The moving block (321) is inserted into the screw hole (21) and pushes the nut (2) to move below the sliding sleeve (47), and the nut (2) abuts against the inner wall of the limiting block (131) so that the sliding sleeve (47) and the nut (2) are coaxial; ② The outer cylinder (46) moves downward so that the boss (473) is inserted into the nut 2, and the bottom of the pressure block (52) abuts against the top of the nut (2). When the inner wall (472) and the nut (2) are not misaligned in the circumferential direction, the inner wall (472) is directly inserted into the nut (2); when the inner wall (472) and the nut (2) are misaligned in the circumferential direction, the inner wall (472) cannot be directly inserted into the nut (2). At this time, as the outer cylinder (46) continues to move downward until it abuts against the base (1), the bottom of the rod body (45) abuts against the nut (2), and as the cylinder body (43) moves downward, the spring three (6) is compressed; ③ The cylinder (43) rotates and drives the rod (45) to rotate, and the rod (45) is screwed into the screw hole (21). When the inner wall (472) and the nut (2) are misaligned in the circumferential direction, when the rod (45) is just screwed into the screw hole (21), the rotation of the rod (45) drives the nut (2) to rotate, so that the inner wall (472) can be inserted into the nut (2). After the inner wall (472) can be inserted into the nut 2, the inner wall (472) forms a circumferential limit for the nut (2), so as to facilitate the screwing of the rod (45); ④ The cylinder (43) is rotated in the reverse direction to screw out the screw hole (21), and the outer cylinder (46) is disengaged from the nut (2) upward.

Images