A special sleeve head for thread passability detection and its use method

Abstract

The present invention provides a special sleeve head for thread passability detection and a method of using the same, belonging to the technical field of detection tools. The invention solves the problem of thread passability detection on a body assembly / sub-assembly after welding. The sleeve head comprises a matching nut or matching screw, an output end, a magnet, a magnet frame and an input end. A central channel is provided at the central axis of the input end and the output end. The output end is sleeved on the front end of the input end. The central channel of the input end is connected to the central channel of the output end. The output end and the input end are positioned by an anti-slip structure. A magnet frame is sleeved on the input end. The rear end face of the output end is against the front end face of the magnet frame. The output end, the magnet frame and the input end are all coaxially arranged. A plurality of magnet installation through holes are evenly provided between the front and rear end faces of the magnet frame. A magnet is provided in each magnet installation through hole. Both the input end and the output end are magnetic conductive components. The present invention is used for thread passability detection on a body assembly / sub-assembly after welding.

Description

Technical Field

[0001] The invention belongs to the technical field of detection tools, and in particular relates to a special sleeve head for thread passability detection and a detection method thereof. Background Art

[0002] There are thousands of standard threaded parts welded on the automobile body assembly. During the preparation stage of project production, there is a lot of welding spatter during the body manufacturing. The welding spatter is easy to adhere to the thread surface. If it is not removed in advance, it is very likely to damage the thread during subsequent assembly. However, it is impossible to identify all the welding spatters adhered to the thread by naked eye observation. In order to prevent damage to the thread, the existing detection method is to use nuts / bolts matching the threads to be inspected after the assembly is welded, and manually screw in and out to inspect the welded assembly and deal with the problematic threads. This detection method is inefficient.

[0003] In the prior art, a thread detection device is suitable for detecting a single thread standard part / nut plate assembly before welding, but is not suitable for detecting the passability of threads on a body assembly / sub-assembly after welding. In the prior art, no tool suitable for detecting the passability of threads on a car body has been found. Summary of the invention

[0004] In view of this, the invention aims to provide a special socket head for thread passability detection to solve the problem of thread passability detection on a body assembly / sub-assembly after welding.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0006] A special sleeve head for thread passability detection comprises a matching nut or matching bolt, an output end, a magnet, a magnet frame and an input end, wherein a central channel is provided at the central axis of the input end and the output end, the output end is sleeved on the front end of the input end, the central channel of the input end is connected with the central channel of the output end, the output end and the input end are positioned by an anti-slip structure, a magnet frame is sleeved on the input end, the rear end face of the output end abuts against the front end face of the magnet frame, the rear end face of the magnet frame abuts against the axial shoulder of the input end, the output end, the magnet frame and the input end are all coaxially arranged, a plurality of magnet mounting through holes are evenly provided on the front end face of the magnet frame, a magnet is provided in each magnet mounting through hole, the input end and the output end are both magnetic conductive components, the rear end of the central channel of the input end is a first matching connecting hole for mounting a torque wrench, the front end of the central channel of the output end is a second matching mounting hole for mounting a matching nut or a matching bolt, when the matching nut is installed in the second matching mounting hole of the output end, the front end of the matching nut protrudes from the front end face of the output end.

[0007] Furthermore, the anti-slip structure includes two anti-slip pins and a rubber ring, two mounting holes penetrating the wall of the output end are symmetrically arranged on the outer circumferential surface of the output end, an annular groove is opened on the outer circumferential surface of the input end, an anti-slip pin is matched at each mounting hole, the anti-slip pin passes through the mounting hole to the annular groove of the input end, annular grooves are arranged at the arcs where the outer ends of the two mounting holes are located, and the rubber rings are installed in the annular grooves.

[0008] Furthermore, a limiting shoulder for axially positioning the matching bolt or the matching nut is provided in the second matching connecting hole, the matching nut is an external hexagonal nut, the matching bolt is an external hexagonal bolt, and the shape of the second matching connecting hole is adapted to the matching nut or the matching bolt.

[0009] Furthermore, the magnet is a regularly shaped magnet, and the magnet frame is processed with 2-8 magnet mounting holes, the aperture of the magnet mounting holes is 0.2mm-0.5mm larger than the diameter of the magnet, and the length of the magnet mounting holes is 0.5mm larger than the length of the magnet; the assembly direction of the magnet is in the form of alternating N poles and S poles.

[0010] Furthermore, the minimum diameter of the central channel after the output end and the input end are matched is larger than the thread diameter of the bolt to be inspected, and the available length of the central channel after the output end and the input end are matched is larger than the length of the longest bolt to be inspected of the same specification.

[0011] Furthermore, the maximum outer diameters of the output end, the magnet frame and the input end are consistent, and a knurled area for manual screwing in / out and a colored area for slipping identification are provided at intervals at the maximum outer diameter of the output end.

[0012] Furthermore, the length of the first matching connection hole is not less than the length of the square head of the torque wrench, and a 3 mm empty knife groove is left inwardly of the first matching connection hole.

[0013] Furthermore, after the matching nut is installed into the input end, the front end surface of the matching nut protrudes from the front end surface of the output end by 0.2 mm-0.5 mm.

[0014] Furthermore, a chamfer is machined on the outer diameter of the mounting matching nut at the output end to facilitate observation.

[0015] Another purpose of the invention is to provide a method for using a special sleeve head for thread passability detection, comprising:

[0016] When using, first confirm whether the thread specifications of the matching nut or matching bolt are consistent with the thread to be inspected. After confirming that they are consistent, install the input end of the socket head on the torque wrench, align the output end of the socket head with the thread to be inspected, and then press the switch of the torque wrench to implement the inspection. After visually observing that the inspection is in place, change the reverse switch to exit. When encountering resistance and slipping, manually rotate the output end in the opposite direction to bring out the matching nut or matching bolt, clean off the welding spatter on the thread, and then inspect the passability of the thread again.

[0017] Compared with the prior art, the invention provides the following beneficial effects:

[0018] (1) The special socket head for thread passability detection created by the present invention is a special socket head with an overload protection function, which does not damage the thread during the detection process; when used in conjunction with a low-speed, low-torque torque wrench, it can effectively improve the work efficiency of thread detection; the detection process is consistent with the assembly action during automobile manufacturing, and can almost meet the thread passability detection of all positions of the automobile body or its subassembly; the present invention has a wide range of applications and can be used for thread passability detection on various mechanical assemblies.

[0019] (2) The present invention creates a special socket head for thread passability detection, which is used in conjunction with a torque wrench and rotates forward and reversely with the torque wrench. The input and output of the socket head transmit torque by friction, and there is positive pressure between the output end and the output end, thereby generating friction for transmitting torque, and the positive pressure is generated by a magnet. When the thread screwing resistance is greater than the maximum friction force that the socket head can provide, the input and output ends of the socket head slip, the transmission fails, and the thread is prevented from being damaged.

[0020] (3) The socket head is specially designed for thread detection. First, the torque is transmitted between the input and output ends of the socket head by friction, and the friction comes from the magnet. Second, it has unique universal applicability. When used in conjunction with a torque wrench, it can realize rapid detection of the full range of thread passability on the overall welding component assembly of the automobile body, and is not limited to the automobile body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0022] Figure 1 A schematic diagram of the structure of a special sleeve head (matching nut) for thread passability detection according to an embodiment of the present invention;

[0023] Figure 2 An exploded view of a special sleeve head (matching nut) for thread passability detection according to an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of the structure of a special sleeve head (matching bolt) for thread passability detection according to an embodiment of the present invention;

[0025] Figure 4 An exploded view of a special sleeve head (matching bolt) for thread passability detection according to an embodiment of the present invention;

[0026] Figure 5 A schematic diagram of a knurled area and a colored area at the maximum outer diameter of the output end of a special sleeve head for thread passability detection described in an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 1. Matching nuts;

[0029] 2. Rubber ring;

[0030] 3. Output terminal;

[0031] 4. Prevent out-of-stock;

[0032] 5. Magnet;

[0033] 6. Magnet frame;

[0034] 7. Input terminal;

[0035] 8. Torque wrench;

[0036] 9. Matching bolts;

[0037] A. Knurling area;

[0038] B. Coloring area. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0042] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] like Figure 1-5 As shown, a special socket head for thread passability detection includes a matching nut 1 or a matching bolt 9, an output end 3, a magnet 5, a magnet frame 6 and an input end 7, wherein a central channel is provided at the central axis of the input end 7 and the output end 3, the output end 3 is sleeved on the front end of the input end 7, the central channel of the input end 7 is connected with the central channel of the output end 3, the output end 3 and the input end 7 are positioned by an anti-slip structure, a magnet frame 6 is sleeved on the input end 7, the rear end face of the output end 3 abuts against the front end face of the magnet frame 6, the rear end face of the magnet frame 6 abuts against the axial shoulder of the input end 7, and the The output end 3, the magnet frame 6 and the input end 7 are all coaxially arranged, and a plurality of magnet mounting through holes are evenly provided on the front end surface of the magnet frame 6, and a magnet 5 is provided in each magnet mounting through hole. The input end 7 and the output end 3 are both magnetic conductive components, and are made of magnetic materials (carbon steel, etc.); the rear end of the central channel of the input end 7 is a first matching connecting hole for installing a torque wrench 8, and the front end of the central channel of the output end 3 is a second matching mounting hole for installing a matching nut 1 or a matching bolt 9. When the matching nut 1 is installed in the second matching mounting hole of the output end 3, the front end of the matching nut 1 protrudes from the front end surface of the output end 3.

[0044] The anti-slip structure includes two anti-slip pins 4 and a rubber ring 2. Two mounting holes penetrating the wall of the output end 3 are symmetrically arranged on the outer circumference of the output end 3. An annular groove is provided on the outer circumference of the input end 7. An anti-slip pin 4 is matched at each mounting hole. The anti-slip pin 4 passes through the mounting hole and extends into the annular groove of the input end. An annular groove is provided at the arc where the outer ends of the two mounting holes are located, and the rubber ring 2 is installed in the annular groove. This structure restricts the output end from detaching from the output end, but does not restrict the relative rotation between the output end and the input end, that is, slipping is allowed.

[0045] The second matching connection hole is provided with a limiting shoulder for axial positioning of the matching bolt 9 or the matching nut 1. The matching nut 1 is an external hexagonal nut, and the matching bolt 9 is an external hexagonal bolt. The shape of the second matching connection hole is adapted to the matching nut 1 or the matching bolt 9.

[0046] The magnet is a magnet of regular shape, and the magnet frame 6 is processed with 2-8 magnet mounting through holes, the aperture of the magnet mounting through hole is 0.2mm-0.5mm larger than the diameter of the magnet 5, and the length of the magnet mounting through hole is 0.5mm larger than the length of the magnet 5; the assembly direction of the magnet 5 adopts the method of alternating N poles and S poles;

[0047] Taking the magnet 5 as a cylindrical magnet as an example, four magnet mounting through holes are processed on the front end surface of the magnet frame 6, the aperture of the magnet mounting through hole is 0.5 mm larger than the diameter of the magnet 5, and the length of the magnet mounting through hole is 0.5 mm larger than the length of the magnet 5; the assembly direction of the four magnets 5 is in the form of alternating N poles and S poles.

[0048] The minimum diameter of the central channel after the output end 3 and the input end 7 are matched is larger than the thread diameter of the bolt to be inspected, and the available length of the central channel after the output end 3 and the input end 7 are matched is larger than the length of the longest bolt to be inspected of the same specification, that is, after the output end 3 and the input end 7 are assembled, after removing the length occupied by the torque wrench head, the remaining length of the central channel is larger than the length of the longest bolt to be inspected of the same specification.

[0049] The maximum outer diameters of the output end 3, the magnet frame 6 and the input end 7 are consistent, and a knurled area A for manual screwing in / out and a colored area B for slip identification are provided at intervals at the maximum outer diameter of the output end 3.

[0050] The length of the first matching connection hole is not less than the length of the square head of the torque wrench 8, and a 3mm empty knife groove is left inwardly of the first matching connection hole. After the matching nut 1 is installed into the input end 7, the front end surface of the matching nut 1 protrudes from the front end surface of the output end 3 by 0.5mm.

[0051] The outer diameter of the mounting nut 1 at the output end 3 is processed into a chamfer that is convenient for observation.

[0052] The rear axis of the input end of the sleeve head is provided with a matching connection hole for a torque wrench. The magnet frame and the output end are installed on the front, and the radial directions of the input end, the magnet frame and the output end are matched with the axis and hole clearance to ensure the coaxiality of the three parts and allow the output end to rotate relative to the input end. The input end, the magnet frame and the output end have axial contact surfaces, allowing positive pressure to be applied. The friction between the input end and the input end of the sleeve head comes from the positive pressure between the input end and the output end, and the positive pressure comes from the magnet. The material, shape, size and quantity of the magnet are selected according to the required positive pressure. When using a cylindrical magnet, the number is preferably 2, 4, 6 or 8, and the positive and negative poles are installed at intervals. Other shapes of magnets such as rings and sheets can also be used. The magnet of the sleeve head is installed in the magnet frame. The front axis of the output end of the sleeve head is provided with a matching installation hole for a matching nut / bolt. The inner side of the matching connection hole has an axial positioning stop for the nut / bolt. The axis of the socket head is a front and rear through hole, the minimum diameter of the through hole is larger than the diameter of the bolt to be reduced, and a safety distance is left. After the socket head and the torque wrench are installed, the remaining length of the through hole is larger than the length of the longest bolt to be inspected of the same specification.

[0053] There is an axial contact surface between the input end 7 and the magnet frame 6 and the output end 3; the radial direction of the input end 7 and the magnet frame 6 and the output end 3 is an axial hole clearance fit; there is a positive pressure on the axial contact surface between the input end 7 and the magnet frame 6 and the output end 3, and the positive pressure is provided by the magnet 5 installed in the magnet frame 6; the size of the positive pressure is designed as needed when the socket head is developed, and is achieved by selecting the material, size and quantity of the magnet 5; when the thread passability is poor, the output end 3 can slip unlimitedly relative to the input end 7; overload slippage will not damage the special socket head, the torque wrench, and the inspected thread; the appearance of the socket head output end 3 adopts shape spacing features and coloring that are conducive to slippage identification; the matching nut 1 and the matching bolt 9 are standard parts.

[0054] The output end 3, magnet frame 6, and input end 7 are friction force transmission components, which have requirements such as coaxiality, parallelism, verticality, hardness, roughness, wear resistance, and fit. The magnet frame 6 is manufactured according to the shape and quantity of the magnet 5; after the magnet 5 is assembled, the axial height needs to be slightly lower than the surface of the magnet frame to ensure a good fit of the axial contact surface between the input end and the output end of the sleeve head. The front head outer diameter of the output end 3 is as small as possible to facilitate the observation of the thread position to be inspected during operation. The installation depth of the inspection nut should be slightly less than the thickness of the nut to ensure that the root of the bolt can be detected. Weight reduction is performed while ensuring the function.

[0055] A specific example is given below: taking the passability test of a stud / bolt with a length of 30 mm as an example, the special socket head is composed of a matching nut 1, a rubber ring 2, an output end 3, an anti-drop pin 4, a magnet 5, a magnet frame 6, and an input end 7. Among them, the matching nut 1, rubber ring 2, anti-dropout pin 4, and magnet 5 are standard parts, and the output end 3, magnet frame 6, and input end 7 are non-standard manufactured parts; the assembly of each component is easy to disassemble; the matching nut 1 is an external hexagonal nut; the matching mounting hole on the output end 3 and the matching nut 1 is provided with an axial limit shoulder, and after the matching nut is installed, the outer side protrudes from the front end surface of the output end 3 by 0.2mm; the outer diameter of the matching nut 1 installed at the output end 3 is processed into a chamfer that is conducive to observation; a mounting hole for the anti-dropout pin 4 is processed on the output end 3, and two anti-dropout pins are symmetrically distributed, and an annular groove for installing the rubber ring is processed outside the anti-dropout pin mounting hole; the magnet 5 is a columnar magnet; a magnet mounting through hole for the magnet 5 is processed in the magnet frame 6, and the number of the magnet mounting through holes is 4, the hole diameter is larger than the diameter of the magnet by 0.2mm, and the length of the hole is larger than the length of the magnet 5 by 0.5mm. The assembly direction of the magnet is in the form of alternating N poles and S poles; the length of the matching connection hole between the input terminal 7 and the torque wrench is not less than the length of the square head of the wrench, and a 3mm empty knife groove is left inward of the matching connection hole; after the socket head is assembled, the outer side of the output terminal 3 is 35mm away from the torque wrench head inside the output terminal 7, ensuring a safety distance of 5mm for the longest bolt, and is suitable for thread passability detection of bolts / studs with a length of 30mm and below; the maximum outer diameters of the output terminal 3, the magnet frame 6, and the input terminal 7 are consistent, and the cylindrical surface at the maximum outer diameter of the output terminal of the socket head is knurled; the axial contact surface and radial contact surface of the output terminal 3, the magnet frame 6, and the input terminal 7 are all mating surfaces; the output terminal 3, the magnet frame 6, and the input terminal 7 are made of carbon steel, and the axial and radial contact surfaces are ground after quenching to ensure the coaxiality and verticality of each surface.

[0056] A method for using a special sleeve head for thread passability detection, comprising:

[0057] When using, first confirm whether the thread specifications of the matching nut 1 or the matching bolt 9 are consistent with the thread to be inspected. After confirming that they are consistent, install the input end 7 of the socket head on the torque wrench 8, align the matching nut 1 or the matching bolt 9 on the socket head with the thread to be inspected, and then press the switch of the torque wrench 8 to implement the inspection. After visually observing that the inspection is in place, change the reverse switch to exit. When encountering resistance and slipping, manually rotate the output end 3 in the opposite direction to bring out the matching nut 1 or the matching bolt 9, clean off the welding spatter on the thread, and then inspect the passability of the thread again.

[0058] The working principle of the present application is as follows: the socket head is used in conjunction with a torque wrench, and rotates forward and reversely with the torque wrench; the torque is transmitted between the input and output of the socket head by friction, and there is a positive pressure between the output end 3 and the input end 7, thereby generating friction for transmitting torque, and the positive pressure is generated by the magnet 5. When the thread screwing resistance is greater than the maximum friction force that the socket head can provide, the input end 7 and the output end 3 of the socket head slip, and the transmission fails, which plays a role in preventing thread damage.

[0059] The embodiments of the invention disclosed above are only used to help illustrate the invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the invention, so that those skilled in the art can understand and use the invention well.

Claims

1. A special sleeve head for thread passability detection, characterized in that: The invention comprises a matching nut (1) or a matching bolt (9), an output end (3), a magnet (5), a magnet frame (6) and an input end (7), wherein a central channel is provided at the central axis of the input end (7) and the output end (3), the output end (3) is sleeved on the front end of the input end (7), the central channel of the input end (7) is communicated with the central channel of the output end (3), the output end (3) and the input end (7) are positioned by an anti-slip structure, the magnet frame (6) is sleeved on the input end (7), the rear end face of the output end (3) abuts against the front end face of the magnet frame (6), and the rear end face of the magnet frame (6) abuts against the axial shoulder of the input end (7) The output end (3), the magnet frame (6) and the input end (7) are all coaxially arranged, a plurality of magnet mounting through holes are evenly provided on the magnet frame (6), a magnet (5) is provided in each magnet mounting through hole, the input end (7) and the output end (3) are both magnetic conductive components, the rear end of the central channel of the input end (7) is a first matching connection hole for mounting a torque wrench (8), the front end of the central channel of the output end (3) is a second matching mounting hole for mounting a matching nut (1) or a matching bolt (9), and when the matching nut (1) is mounted in the second matching mounting hole of the output end (3), the front end of the matching nut (1) protrudes from the front end surface of the output end (3); The magnet is a magnet of regular shape, and 2-8 magnet mounting through holes are processed on the magnet frame (6), the aperture of the magnet mounting through hole is 0.2mm-0.5mm larger than the diameter of the magnet (5), and the length of the magnet mounting through hole is 0.5mm larger than the length of the magnet (5); the assembly direction of the magnet (5) adopts the method of alternating N poles and S poles.

2. A special sleeve head for thread passability detection according to claim 1, characterized in that: The anti-dropout structure comprises two anti-dropout pins (4) and a rubber ring (2); two mounting holes penetrating the wall of the output end (3) are symmetrically arranged on the outer peripheral surface of the output end (3); an annular groove is provided on the outer peripheral surface of the input end (7); an anti-dropout pin (4) is matched at each mounting hole; the anti-dropout pin (4) passes through the mounting hole and extends into the annular groove of the input end; an annular groove is provided at the arc where the outer ends of the two mounting holes are located, and the rubber ring (2) is installed in the annular groove.

3. A special sleeve head for thread passability detection according to claim 1, characterized in that: A limiting shoulder for axially positioning the matching bolt (9) or the matching nut (1) is provided in the second matching connection hole; the matching nut (1) is an external hexagonal nut, the matching bolt (9) is an external hexagonal bolt, and the shape of the second matching connection hole is adapted to the matching nut (1) or the matching bolt (9).

4. A special sleeve head for thread passability detection according to claim 1, characterized in that: The minimum diameter of the central channel after the output end (3) and the input end (7) are matched is greater than the thread diameter of the bolt to be inspected, and the available length of the central channel after the output end (3) and the input end (7) are matched is greater than the length of the longest bolt to be inspected of the same specification.

5. The special sleeve head for thread passability detection according to claim 1, characterized in that: The maximum outer diameters of the output end (3), the magnet (5) frame and the input end (7) are consistent, and a knurled area (A) for manual screwing in / out and a colored area (B) for slippage identification are provided at intervals at the maximum outer diameter of the output end (3).

6. A special sleeve head for thread passability detection according to claim 1, characterized in that: The length of the first matching connection hole is not less than the length of the square head of the torque wrench (8), and a 3 mm empty knife groove is left inwardly of the first matching connection hole.

7. The special sleeve head for thread passability detection according to claim 1, characterized in that: After the matching nut (1) is installed into the input end (7), the front end surface of the matching nut (1) protrudes from the front end surface of the output end (3) by 0.2-0.5 mm.

8. The special sleeve head for thread passability detection according to claim 1, characterized in that: The outer diameter of the mounting matching nut (1) at the output end (3) is processed to have a chamfer that facilitates observation.

9. A method for using a special socket head for thread passability detection according to any one of claims 1 to 8, characterized in that: include When in use, first confirm whether the thread specifications of the matching nut (1) or matching bolt (9) are consistent with the thread to be inspected. After confirming that they are consistent, the input end (7) of the socket head is installed on the torque wrench (8), the matching nut (1) or matching bolt (9) on the socket head is aligned with the thread to be inspected, and then the switch of the torque wrench (8) is pressed to implement the inspection. After visually observing that the inspection is in place, the reverse switch is switched to exit. When encountering resistance and slipping, the output end (3) is manually rotated in the reverse direction to bring out the matching nut (1) or matching bolt (9), and after cleaning the welding spatter on the thread, the passability of the thread is inspected again.

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