Bolt and nut dismounting device and using method

Abstract

The invention relates to a bolt and nut dismounting device and a use method, and the bolt and nut dismounting device is characterized by comprising a main workbench (4), a rotary workbench (3), a rotating mechanism (5), a lifting mechanism (6), an L-shaped connecting plate (7) and a slip collecting mechanism (8); wherein the rotating table (3) is fixedly connected to the main table (4) through screws, the L-shaped connecting plate (7) is fixedly connected to the main table (4) through screws, and the lifting mechanism (6) is fixedly connected to the L-shaped connecting plate (7) through two rows of screws on the back of the lifting mechanism (6); the device is ingenious in structure, easy to operate, safe and reliable, workers are liberated from heavy work, the working effect is greatly improved, and the difficulty in production is solved.

Description

Technical Field

[0001] The present invention relates to a bolt and nut loosening device and a method for using the device. Specifically, a lifting mechanism 6 drives a rotating mechanism 5 to perform up and down linear motion. The rotating mechanism 5 automatically separates the bolts 21 and nuts 22 in a bolt and nut combination workpiece 2 by rotating. A rotary table 3 rotates the loosened bolt and nut combination workpiece 2 to a sliding collection structure 8 for sliding, and the collection is completed after the workpiece falls off the equipment. The present invention belongs to the field of mechanical assembly. Background Art

[0002] Bolts and nuts are essential connection structures in the product assembly process in the fields of aerospace, shipbuilding, etc. With the increasing types and quantities of products, the demand for bolts and nuts has increased significantly. In the assembly process, in order to ensure the integrity of the bolts and nuts, the bolts and nuts are often combined into one piece before assembly. In this state, it is often necessary to manually separate the bolts and nuts before assembly.

[0003] In this type of loosening process, bolts and nuts are manually separated, and a set of fixing devices and corresponding wrench tools, or two sets of wrench tools are needed to complete the loosening process of bolts and nuts. The tightening force of each set of bolt and nut combination workpiece is different, and the loosening force is different. A certain amount of manpower is required to complete this work in the pre-assembly process. Due to the large number of bolts and nuts required by the product, the time consumed is gradually increasing. That is, in the pre-installation preparation process, a certain amount of manpower and time are required to complete this pre-assembly auxiliary work, which is not conducive to the rapid and efficient production of product assembly.

[0004] Therefore, it is necessary to design a bolt loosening device to replace part of the manual work and complete the loosening and separation of bolts and nuts, so as to reduce human resource costs, reduce the time consumed before installation, and improve the overall efficiency of product assembly. Summary of the invention

[0005] In order to solve the above problems, the patent of the present invention is a bolt and nut loosening device and a method of use, which is used for loosening and separating bolts and nuts before assembly work.

[0006] A bolt and nut loosening device, characterized in that it comprises a main workbench 4, a rotary workbench 3, a rotating mechanism 5, a lifting mechanism 6, an L-shaped connecting plate 7 and a sliding collection mechanism 8;

[0007] The rotary table 3 is fixed to the main table 4 by screw connection, the L-shaped connecting plate 7 is fixed to the main table 4 by screw connection, the lifting mechanism 6 is fixed to the L-shaped connecting plate 7 by two rows of screws on its back, the rotating mechanism 5 is fixed to the double-mechanism transfer linear motion plate 62 in the lifting mechanism 6 by screws, and the sliding collection structure 8 is in the shape of an inclined groove and is arranged on the edge of the main table 4; the transparent skin 1 wraps the rotary table 3, the rotating mechanism 5, the lifting mechanism 6 and the L-shaped connecting plate 7 to prevent safety hazards caused by human contact;

[0008] A control device is installed in the main workbench 4 to control the movement of the rotary workbench 3, the rotating mechanism 5 and the lifting mechanism 6; the control room is provided with an interlocking protection function to prevent damage caused by logical errors in the movement of equipment and products.

[0009] The rotary table 3 includes a plane adapter plate 32, a fixed plate 35 and a rotating disk 34; the plane adapter plate 32 is fixedly connected to the main table 4 by screws; the fixed plate 35 is installed on the plane adapter plate 32 by multiple screws, a rotary table drive motor 33 is provided at the center of the fixed plate 35, and the rotating disk 34 is fixed to the main shaft of the rotary table drive motor 33 by transverse screws, and the rotary table drive motor 33 supplies power to the rotating disk 34, so that it performs intermittent rotating motion around the central axis of the rotary table drive motor 33; the plane adapter plate 32 is provided with a cable through hole 31, and the cable through hole 31 is used for the passage of equipment control cables and power supply cables; a plurality of bolt and nut assembly workpiece placement positions 36 are provided on the rotating disk 34, which are used to place a plurality of bolt and nut assembly workpieces 2 to be loosened and separated; wherein the bolt and nut assembly workpiece placement position 36 can clamp the end of the bolt 21 of the bolt and nut assembly workpiece 2 to be separated;

[0010] The rotating mechanism 5 includes a rotating mechanism driving motor 51, a rotating mechanism T-shaped connecting plate 52 and a nut loosening sleeve 53; the rotating mechanism driving motor 51 is fixed to the upper surface of the rotating mechanism T-shaped connecting plate 52 by screw connection, and the nut loosening sleeve 53 is fixedly connected to the rotating mechanism driving motor 51. The rotating mechanism driving motor 51 supplies power to the nut loosening sleeve 53, so that the nut loosening sleeve 53 can perform a rotational motion around the central axis of the rotating mechanism driving motor 51;

[0011] The lifting mechanism 6 includes a lifting mechanism drive motor 61, a double mechanism transfer linear motion plate 62, a lifting mechanism door-type connecting plate 63 and a guide rail 64; the lifting mechanism drive motor 61 is fixed to the upper surface of the lifting mechanism door-type connecting plate 63 by multiple long bolts, the guide rail 64 is installed on the side of the lifting mechanism door-type connecting plate 63, and the double mechanism transfer linear motion plate 62 can slide on the guide rail 64; wherein the main shaft of the lifting mechanism drive motor 61 is a worm 65, the worm 65 passes through the center of the double mechanism transfer linear motion plate 62 and is rotationally connected to the double mechanism transfer linear motion plate 62, the double mechanism transfer linear motion plate 62 is restricted by the guide rail 64 and the worm 65 at the same time, the double mechanism transfer linear motion plate 62 and the guide rail 64 form a single-degree-of-freedom linear motion pair, and the lifting mechanism drive motor 61 supplies power to the double mechanism transfer linear motion plate 62, so that it can reciprocate linearly up and down;

[0012] The connecting plate 7 is provided with bolts penetrating through the connecting holes 72 to be fixed to the main workbench 4, and two rows of screws on the back of the lifting mechanism 6 penetrate through the connecting grooves 71 on the connecting plate 7. The vertical distance between the lifting mechanism 6 and the rotary workbench 3 can be adjusted through the connecting grooves 71 to be suitable for bolt and nut assembly workpieces 2 of different lengths;

[0013] A sliding collection structure 8 is provided on the main workbench 4, and the top of the sliding collection structure 8 is a hollow structure. After the bolt and nut combination workpiece placement position 36 moves thereafter, the bolt and nut combination workpiece 2 slides due to gravity, and the loosened bolts 21 and nuts 22 can be collected.

[0014] The rotating disk 34 is provided with eight bolt and nut assembly workpiece placement positions 36 .

[0015] The rotary workbench 3 is fixed to the main workbench 4 by at least four screws.

[0016] The connecting plate 7 is fixed to the main workbench 4 by at least two screws.

[0017] A method for using a bolt and nut loosening device, the characteristics of which are as follows:

[0018] Step 1, place a plurality of bolt-nut assembly workpieces 2 in a vertical position with the nuts 22 on top and the bolts 21 on the bottom, respectively, in the bolt-nut assembly workpiece placement positions 36, so that the ends of the bolts 21 of the bolt-nut assembly workpieces 2 are stuck in the bolt-nut assembly workpiece placement positions 36;

[0019] Step 2: Start the equipment switch, the rotary table driving motor 33 drives the rotating disk 34 to rotate, and the first bolt and nut assembly workpiece 2 is driven by the rotating disk 34 to the bottom of the nut loosening sleeve 53;

[0020] Step 3: The lifting mechanism 6 and the lifting mechanism driving motor 61 drive the dual-mechanism transfer linear motion plate 62 to move linearly downward, and at the same time drive the rotating mechanism 5 to move downward until the nut loosening sleeve 53 is sleeved on the nut 22, and the lower bottom surface of the nut loosening sleeve 53 is completely lower than the lower bottom surface of the nut 22, and then stop;

[0021] Step 4: The interior of the bolt loosening sleeve 53 is a stepped hexagonal shape, which forms a clearance fit with the nut 2; the rotating mechanism driving motor 51 drives the nut loosening sleeve 53 to rotate, and the number of rotations is determined by the technical conditions of the bolt 21 and the nut 22, and the rotation stops when the last thread distance between the bolt 21 and the nut 22 remains.

[0022] Step 5, the rotating mechanism driving motor 51 stops working, the lifting mechanism driving motor 61 drives the dual-mechanism transfer linear motion plate 62 and the rotating mechanism 5 to move linearly upward, the nut loosening sleeve 53 moves away from the bolt and nut combination workpiece 2, and the loosening work of the first bolt and nut combination workpiece 2 is completed.

[0023] Step six, when the first bolt and nut combination workpiece placement position 36 in the rotating disk 34 rotates to the top of the sliding collection structure 8, the loosened bolts 21 and nuts 22 slide down the slideway in the collection structure 8 under the action of gravity to slide out a bolt and nut loosening device, and a collection container should be provided outside the slideway to complete the overall loosening of the first bolt and nut combination workpiece 2.

[0024] Step 7: Repeat the above steps to complete the loosening of the second and subsequent bolt-nut assembly workpieces 2.

[0025] Beneficial effects:

[0026] The invention is not a difficult job to loosen the bolts and nuts connected together, but in actual production, this work is time-consuming and laborious, and the work efficiency is low under the existing working tools and conditions. For this reason, we invented the invention. The invention has a clever structure, simple operation, safety and reliability, frees workers from heavy work, greatly improves work efficiency, and solves difficulties in production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 , is a schematic diagram of the external structure of the device of the present invention;

[0028] Figure 2 , is a schematic diagram of the internal structure of the device of the present invention after the transparent skin 1 is removed;

[0029] Figure 3 , is a schematic structural diagram of a bolt-nut assembly workpiece 2 of the device of the present invention;

[0030] Figure 4, is a schematic diagram of the rotary table structure of the device of the present invention;

[0031] Figure 5 , is a schematic diagram of the structure of the rotating mechanism of the device of the present invention;

[0032] Figure 6 , is a schematic diagram of the lifting mechanism structure of the device of the present invention;

[0033] Figure 7 , is a schematic diagram of the structure of the connecting plate of the device of the present invention;

[0034] Figure 8 , is a partial enlarged schematic diagram of the sliding collection structure of the device of the present invention.

[0035] Among them, 1 is the transparent skin of the bolt loosening device, 2 is the bolt and nut combination workpiece, 3 is the rotary worktable, 4 is the main worktable, 5 is the rotating mechanism, 6 is the lifting mechanism, 7 is the connecting plate, and 8 is the sliding collection structure.

[0036] Wherein: 21 is a bolt, 22 is a nut;

[0037] 31 is a cable through hole, 32 is a plane adapter plate, 33 is a rotary table drive motor, 34 is a rotating disk, 35 is a fixed plate, and 36 is a bolt and nut assembly workpiece placement position;

[0038] 51 is a rotating mechanism driving motor, 52 is a rotating mechanism T-shaped connecting plate, and 53 is a nut loosening sleeve;

[0039] 61 is the lifting mechanism driving motor, 62 is the double mechanism transfer linear motion plate, 63 is the lifting mechanism door-type connecting plate, 64 is the guide rail, and 65 is the worm;

[0040] 71 is a connection groove and 72 is a connection hole. DETAILED DESCRIPTION

[0041] The invention discloses a bolt and nut loosening device, which mainly comprises a main working table, a rotary working table, a rotating mechanism, a lifting mechanism and a sliding collection mechanism.

[0042] A bolt and nut loosening device can complete the function of loosening the bolt 21 and the nut 22 of the bolt and nut combination workpiece 2. The specific technical scheme is as follows:

[0043] The rotary workbench 3 is fixed to the main workbench 4 by screws at four places, the connecting plate 7 is fixed to the main workbench 4 by screws at two places, the lifting mechanism 6 is fixed to the connecting plate 7 by two rows of screws on the back, the rotating mechanism 5 is fixed to the double-mechanism transfer linear motion plate 62 in the lifting mechanism 6 by screws at four places, a bolt and nut loosening device is also equipped with a sliding collection structure 8, the moving part of the device is wrapped and protected by a transparent skin 1 of the bolt loosening device, and it also has a safety protection function to prevent people from accidentally entering.

[0044] The main workbench 4 stores the control device, which is used to control the movement of the rotary table 3, the rotating mechanism 5 and the lifting mechanism 6. The control room has an interlocking protection function, and the equipment and products will not be damaged due to movement logic errors. In the rotary table 3, the cable through hole 31 is used for the passage of the equipment control cable and the power supply cable, and the flat adapter plate 32 is used to connect the main workbench 4 and the fixed plate 35, both of which are fixed by threaded connection. The rotating disk 34 is fixed to the main shaft of the rotary table drive motor 33 with transverse screws. The rotary table drive motor 33 supplies power to the rotating disk 34, causing it to rotate around the central axis of the rotary table drive motor 33.

[0045] The rotary table 3 is provided with eight bolt and nut assembly workpiece placement positions 36 for placing a plurality of bolt and nut assembly workpieces 2 to be loosened and separated;

[0046] The rotating mechanism driving motor 51 in the rotating mechanism 5 is fixed to the upper surface of the rotating mechanism T-shaped connecting plate 52 by four screws, and the nut loosening sleeve 53 is fixed on the rotating mechanism driving motor 51. The rotating mechanism driving motor 51 supplies power to the nut loosening sleeve 53 to make it rotate around the central axis.

[0047] The lifting mechanism driving motor 61 in the lifting mechanism 6 is fixed to the upper surface of the lifting mechanism door-type connecting plate 63 by four long bolts, wherein the main shaft of the lifting mechanism driving motor 61 is a worm 65 structure, and the double-mechanism transfer linear motion plate 62 is restricted by the guide rail 64 and the worm 65, forming a single-degree-of-freedom linear motion pair with the guide rail 64. The lifting mechanism driving motor 61 supplies power to the double-mechanism transfer linear motion plate 62, so that it can complete linear up and down reciprocating linear motion.

[0048] The connecting plate 7 is fixed to the main workbench 4 by two bolts passing through the connecting holes 72. Two rows of screws on the back of the lifting mechanism 6 pass through the connecting grooves 71 on the connecting plate 7. The upper and lower distances of the lifting mechanism from the rotary workbench 3 can be adjusted through the connecting grooves 71, which is suitable for use with bolt and nut assemblies 2 of different lengths.

[0049] A sliding collection structure 8 is provided on the main workbench 4, and the upper part of the sliding collection structure 8 is a hollow structure. After the bolt and nut combination workpiece placement position 36 moves thereafter, the bolt and nut combination workpiece 2 slides down due to gravity, and the loosened bolts 21 and nuts 22 are collected.

[0050] In order to make the technical solution, use process, effect and function achieved by the present invention easy to understand, the specific configuration and operation method of a bolt and nut loosening device are further explained below.

[0051] A method for using a bolt and nut loosening device and the device operation process are as follows:

[0052] In the first step, a plurality of bolt-nut assembly workpieces 2 are placed in the bolt-nut assembly workpiece placement positions 36 respectively.

[0053] The second step is to start the equipment switch, and the rotary table driving motor 33 drives the rotating disk 34 to rotate, and the first bolt and nut combination workpiece 2 is driven by the rotating disk 34 to the bottom of the nut loosening sleeve 53.

[0054] In the third step, the lifting mechanism driving motor 61 in the lifting mechanism 6 drives the dual-mechanism transfer linear motion plate 62 to move linearly downward, and at the same time drives the rotating mechanism 5 to move downward, and stops after moving until the lower bottom surface of the nut loosening sleeve 53 is completely lower than the lower bottom surface of the nut 22.

[0055] Step 4: The bolt loosening sleeve 53 has a stepped hexagonal shape inside, which forms a clearance fit with the nut 2. The rotating mechanism driving motor 51 drives the nut loosening sleeve 53 to rotate, and the number of revolutions is determined by the technical conditions of the bolt 21 and the nut 22, and the rotation stops when the last thread distance between the bolt 21 and the nut 22 is left.

[0056] In the fifth step, the rotating mechanism driving motor 51 stops working, and the lifting mechanism driving motor 61 drives the dual-mechanism transfer linear motion plate 62 and the rotating mechanism 5 to move linearly upward, and the nut loosening sleeve 53 moves away from the bolt and nut combination workpiece 2, completing the loosening work of the first bolt and nut combination workpiece 2.

[0057] The sixth step is to wait for the first bolt and nut combination workpiece placement position 36 in the rotating disk 34 to rotate to the top of the sliding collection structure 8, and the loosened bolts 21 and nuts 22 slide down the slideway in the collection structure 8 under the action of gravity to slide out a bolt and nut loosening device, and a collection container should be provided outside the slideway to complete the overall loosening of the first bolt and nut combination workpiece 2.

[0058] Step 7: Repeat the above steps to complete the loosening of the second and subsequent bolt and nut assembly workpieces 2.

[0059] The above description is the main structural features and usage methods of the present invention. It should be noted that technical personnel in this industry can propose corresponding improvements and changes based on the structural and technical principles of the present invention, but the improvements and changes should also be regarded as the protection scope of the patent of the present invention.

Claims

1. A bolt and nut loosening device, characterized in that: It comprises a main working table (4), a rotary working table (3), a rotating mechanism (5), a lifting mechanism (6), an L-shaped connecting plate (7) and a sliding collection mechanism (8); The rotary table (3) is fixed to the main table (4) by screw connection, the L-shaped connecting plate (7) is fixed to the main table (4) by screw connection, the lifting mechanism (6) is fixed to the L-shaped connecting plate (7) by two rows of screws on its back, the rotating mechanism (5) is fixed to the double-mechanism transfer linear motion plate (62) in the lifting mechanism (6) by screws, and the sliding collection structure (8) is in the shape of an inclined groove and is arranged on the edge of the main table (4); the transparent skin (1) wraps the rotary table (3), the rotating mechanism (5), the lifting mechanism (6) and the L-shaped connecting plate (7) to prevent safety hazards caused by human contact; A control device is installed in the main workbench (4) for controlling the movement of the rotary workbench (3), the rotating mechanism (5) and the lifting mechanism (6); an interlocking protection function is provided in the control room to prevent damage caused by logical errors in the movement of equipment and products; The rotary table (3) comprises a plane adapter plate (32), a fixed plate (35) and a rotating disk (34); the plane adapter plate (32) is fixedly connected to the main table (4) by screws; the fixed plate (35) is installed on the plane adapter plate (32) by multiple screws, a rotary table driving motor (33) is arranged at the center of the fixed plate (35), and the rotating disk (34) is fixed to the main shaft of the rotary table driving motor (33) by transverse screws, and the rotary table driving motor (33) supplies power to the rotating disk (34) so ​​that the rotating disk (34) The rotating table (34) performs intermittent rotational motion around the central axis of the rotating table driving motor (33); the plane adapter plate (32) is provided with a cable through hole (31), and the cable through hole (31) is used for passing the equipment control cable and the power supply cable; the rotating disk (34) is provided with a plurality of bolt and nut assembly workpiece placement positions (36) for placing a plurality of bolt and nut assembly workpieces (2) to be loosened and separated; wherein the bolt and nut assembly workpiece placement positions (36) can clamp the ends of the bolts (21) of the bolt and nut assembly workpieces (2) to be separated; The rotating mechanism (5) comprises a rotating mechanism driving motor (51), a rotating mechanism T-shaped connecting plate (52) and a nut loosening sleeve (53); the rotating mechanism driving motor (51) is fixed to the upper surface of the rotating mechanism T-shaped connecting plate (52) by screw connection, the nut loosening sleeve (53) is fixedly connected to the rotating mechanism driving motor (51), and the rotating mechanism driving motor (51) supplies power to the nut loosening sleeve (53), so that the nut loosening sleeve (53) can perform a rotary motion around the central axis of the rotating mechanism driving motor (51); The lifting mechanism (6) comprises a lifting mechanism driving motor (61), a double-mechanism transfer linear motion plate (62), a lifting mechanism door-shaped connecting plate (63) and a guide rail (64); the lifting mechanism driving motor (61) is fixed to the upper surface of the lifting mechanism door-shaped connecting plate (63) by multiple long bolts, the guide rail (64) is installed on the side of the lifting mechanism door-shaped connecting plate (63), and the double-mechanism transfer linear motion plate (62) can slide on the guide rail (64); wherein the lifting mechanism driving motor (61) is fixed to the upper surface of the lifting mechanism door-shaped connecting plate (63) by multiple long bolts, and ...). ) The main shaft is a worm (65), the worm (65) passes through the center of the double-mechanism transfer linear motion plate (62) and is rotationally connected to the double-mechanism transfer linear motion plate (62), the double-mechanism transfer linear motion plate (62) is restricted by the guide rail (64) and the worm (65) at the same time, the double-mechanism transfer linear motion plate (62) and the guide rail (64) form a single-degree-of-freedom linear motion pair, and the lifting mechanism drive motor (61) supplies power to the double-mechanism transfer linear motion plate (62), so that it can reciprocate linearly up and down; The connecting plate (7) is fixed to the main workbench (4) by bolts passing through connecting holes (72); two rows of screws on the back of the lifting mechanism (6) pass through connecting grooves (71) on the connecting plate (7); and the distance between the lifting mechanism (6) and the rotary workbench (3) can be adjusted by the connecting grooves (71) to adapt to bolt and nut assembly workpieces (2) of different lengths; A sliding collection structure (8) is provided on the main workbench (4), and the upper portion of the sliding collection structure (8) is a hollow structure. After the bolt and nut assembly workpiece placement position (36) moves thereto, the bolt and nut assembly workpiece (2) slides down due to gravity, and the loosened bolts (21) and nuts (22) can be collected.

2. A bolt and nut loosening device according to claim 1, characterized in that: The rotating disk (34) is provided with eight bolt and nut assembly workpiece placement positions (36).

3. A bolt and nut loosening device according to claim 1 or 2, characterized in that: The rotary workbench (3) is fixed on the main workbench (4) by at least four screws.

4. A bolt and nut loosening device according to claim 1 or 2, characterized in that: The connecting plate (7) is fixed on the main workbench (4) by at least two screws.

5. A method for using the bolt and nut loosening device according to claim 1, characterized in that: Step 1: Place a plurality of bolt-nut assembly workpieces (2) in a vertical position with the nuts (22) on top and the bolts (21) on the bottom, respectively, in the bolt-nut assembly workpiece placement positions (36), so that the ends of the bolts (21) of the bolt-nut assembly workpieces (2) are clamped in the bolt-nut assembly workpiece placement positions (36); Step 2: Start the equipment switch, the rotary table driving motor (33) drives the rotating disk (34) to rotate, and the first bolt and nut assembly workpiece (2) is driven by the rotating disk (34) to the bottom of the nut loosening sleeve (53); Step 3: The lifting mechanism (6) and the lifting mechanism driving motor (61) drive the dual-mechanism transfer linear motion plate (62) to perform linear motion downward, and at the same time drive the rotating mechanism (5) to move downward until the nut loosening sleeve (53) is sleeved on the nut (22), and the nut loosening sleeve (53) stops after the lower bottom surface is completely lower than the lower bottom surface of the nut (22); Step 4: The interior of the bolt loosening sleeve (53) is a stepped hexagonal shape, which forms a clearance fit with the nut (2); the rotating mechanism driving motor (51) drives the nut loosening sleeve (53) to rotate, and the number of revolutions is determined by the technical conditions of the bolt (21) and the nut (22), and the sleeve is rotated until the last thread distance between the bolt (21) and the nut (22) remains and stops; Step 5: the rotating mechanism driving motor (51) stops working, the lifting mechanism driving motor (61) drives the dual-mechanism transfer linear motion plate (62) and the rotating mechanism (5) to move linearly upward, and the nut loosening sleeve (53) moves away from the bolt and nut assembly workpiece (2), completing the loosening work of the first bolt and nut assembly workpiece (2); Step 6: When the first bolt-nut assembly workpiece placement position (36) in the rotating disk (34) rotates to the top of the sliding collection structure (8), the loosened bolts (21) and nuts (22) slide down the slideway in the collection structure (8) under the action of gravity to slide out a bolt-nut loosening device, and a collection container should be provided outside the slideway to complete the overall loosening of the first bolt-nut assembly workpiece (2); Step 7: Repeat the above steps to complete the loosening of the second and subsequent bolt-nut assembly workpieces (2).

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