A servo-driven force-controlled polishing device

Abstract

This utility model relates to a servo-driven force-controlled polishing device, including a robotic arm and a drive box fixedly installed at the free end of the robotic arm. A support plate is slidably installed on the inner wall of the drive box. A force sensor base plate and a three-dimensional force sensor are fixedly installed on the top of the support plate. A mounting platform for easy installation of polishing components is fixedly installed on the top of the three-dimensional force sensor. A force control component for controlling the force is provided at the bottom of the drive box. The force control component includes two symmetrically arranged L-shaped mounting plates fixedly installed on the bottom inner wall of the drive box. A ball screw rotatably passes between the two L-shaped mounting plates. A motor mounting plate is fixedly installed on the bottom inner wall of the drive box. A servo motor is fixedly installed on one side of the motor mounting plate. Synchronous pulleys are fixedly sleeved on the outer walls of the servo motor output shaft and the ball screw. Synchronous belts are driven by the outer walls of the two synchronous pulleys. This device solves the problems of inaccurate force control, slow response, and inconvenient tool disassembly and assembly in traditional equipment, and is suitable for applications requiring high-precision polishing.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical processing and relates to a servo-driven force-controlled polishing device. Background Technology

[0002] In modern manufacturing, polishing is a common and crucial process, widely used in the surface treatment of metallic and non-metallic materials. It aims to improve the roughness, smoothness, and finish of workpiece surfaces, thereby enhancing the appearance and performance of products. With continuous technological advancements and the increasing demands for precision and efficiency in industrial production, more stringent standards are being placed on the performance of polishing equipment.

[0003] Traditional polishing devices have several shortcomings in force control. Firstly, the force control precision is low, making it difficult to accurately control the force during the polishing process. Secondly, due to the instability of the force, uneven machining marks, over-polishing, or under-polishing can easily occur on the workpiece surface, severely affecting the workpiece's processing quality and consistency, and failing to meet the demands of high-precision machining.

[0004] On the other hand, traditional polishing equipment has a slow dynamic response speed. When processing conditions change or processing parameters need to be adjusted, the equipment cannot react quickly, resulting in delays in the processing and affecting processing efficiency and product quality. This slow response defect is particularly prominent in applications requiring high processing speed and precision.

[0005] Furthermore, existing polishing equipment presents inconveniences in terms of tool assembly and disassembly. Tool installation and removal typically require specialized tools, and the procedures are cumbersome and time-consuming. This not only increases the labor intensity of workers and reduces production efficiency, but also, with frequent tool changes, improper operation can easily lead to tool damage or insecure installation, affecting normal processing. Utility Model Content

[0006] In view of this, in order to solve the problems of low force control accuracy, difficulty in accurately controlling the force during the polishing process, and slow dynamic response speed of existing polishing devices, this utility model provides a servo-driven force control polishing device.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A servo-driven force-controlled polishing device, comprising:

[0009] The robotic arm has a connecting seat I fixedly installed at one end. A drive box is fixedly installed on the top of the connecting seat I. A support plate is slidably installed on the bottom inner wall of the drive box. A force sensor base plate is fixedly installed on the top of the support plate. A three-dimensional force sensor is fixedly installed on the top of the force sensor base plate. A mounting platform is fixedly installed on the top of the three-dimensional force sensor. A force control component for controlling the force is set inside the drive box.

[0010] A mounting box is fixedly installed on the top of the mounting platform. The inside of the mounting box has a circular cavity. A strip hole II is opened on one side of the mounting box. The strip hole II is located below the circular cavity and is connected to the circular cavity. A polishing component for polishing is installed inside the circular cavity.

[0011] A support arc plate is inserted inside the strip hole II, and a fixing component for fixing the polishing assembly is provided on the top of the support arc plate.

[0012] Furthermore, the force control component includes two symmetrically arranged L-shaped mounting plates fixedly installed on the inner wall of the bottom of the drive box. The same ball screw rotates between the two L-shaped mounting plates. A motor mounting plate is fixedly installed on the inner wall of the bottom of the drive box. A servo motor is fixedly installed on one side of the motor mounting plate. Synchronous pulleys are fixedly sleeved on the output shaft of the servo motor and the outer wall of the ball screw. The same synchronous belt is driven by the outer wall of the two synchronous pulleys.

[0013] Furthermore, a nut seat is slidably connected to the bottom inner wall of the drive box, and a ball screw thread passes through the nut seat. A force sensor front plate is fixedly installed on one side of the bottom of the force sensor base plate. Two symmetrically arranged guide pillars slide through the inside of the nut seat. The same force sensor rear plate is fixedly installed at one end of the two guide pillars. Two symmetrically arranged tension sensors are arranged between the force sensor rear plate and the force sensor front plate. An adjusting nut is threaded on the outer wall of the guide pillar. Compression spring I is provided between the adjusting nut and the nut seat, and between the force sensor rear plate and the nut seat. A gyroscope is fixedly installed on one side of the bottom inner wall of the drive box.

[0014] Furthermore, the polishing assembly includes a U-shaped plate, a polishing machine is fixedly installed on the top of the U-shaped plate, a polishing disc is fixedly connected to the output shaft of the polishing machine, a round rod is fixedly installed on the bottom of the U-shaped plate, a round plate is fixedly installed on the bottom of the round rod, multiple positioning grooves are opened on the top of the round plate, and multiple positioning blocks are fixedly installed on the top inner wall of the round cavity, and the positioning blocks engage with the positioning grooves.

[0015] Furthermore, the fixing component includes a rectangular block fixedly installed on the top of the supporting arc plate, a limiting plate fixedly installed on one side of the rectangular block, a notch opened on one side of the circular plate, the notch being used in conjunction with the rectangular block, the circular rod being used in conjunction with the limiting plate, and a strip hole I opened on one side of the top of the fixing box, the strip hole I being connected to the circular cavity, and the strip hole I being used in conjunction with the circular rod.

[0016] Furthermore, a groove is provided on the top of the rectangular block, and two symmetrically arranged sliding plates are slidably connected inside the groove. A compression spring III is provided between one side of the sliding plate and one side of the inner wall of the groove. A workpiece clamping plate is fixedly installed on the top of the sliding plate, and the workpiece clamping plate is used to clamp the round rod.

[0017] Furthermore, L-shaped pull plates are slidably connected to both sides of the supporting arc plate, and the same compression spring II is fixedly installed between the two L-shaped pull plates. Slots that engage with the L-shaped pull plates are opened on the inner walls of both sides of the strip hole II.

[0018] The same elliptical slide plate is slidably connected between the inner walls of the two sides of the strip hole I. The elliptical slide plate is used in conjunction with the L-shaped pull plate and the workpiece clamping plate.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. The servo-driven force-controlled polishing device disclosed in this utility model adopts a servo motor drive. The servo motor features a fast dynamic response speed, enabling it to quickly react to control commands and achieve rapid and precise motion adjustments. It inherently utilizes position information detected by a grating reading head to characterize the force magnitude. This detection method results in extremely high force control accuracy, allowing for more accurate control of the force during the polishing process compared to traditional methods, meeting the demands of high-precision machining. Equipped with a gyroscope for angle detection, it achieves gravity compensation, while an accelerometer enables inertial force compensation. During the polishing process, these compensation functions effectively eliminate interference from gravity and inertial forces on force detection and control, further improving the accuracy of force control and ensuring stable and reliable polishing force.

[0021] 2. The servo-driven force-controlled polishing device disclosed in this utility model detects frictional force in real time through tension and compression sensors and a three-dimensional force sensor. Simultaneously, the three-dimensional force sensor can also detect the force on the mounting platform in real time. This comprehensive force detection mechanism can monitor various force conditions during the polishing process in real time, providing rich data support for precise control of the polishing force, which helps optimize the polishing process and improve processing quality.

[0022] 3. The servo-driven force-controlled polishing device disclosed in this utility model features a simple and efficient tool disassembly and installation process. Simply press the two L-shaped pull plates to release the braking state of the supporting arc plate, allowing it to be moved out of the slot II. A series of linked actions then cause the workpiece clamping plate to release its grip on the round rod, ultimately allowing the U-shaped plate and polishing assembly to be easily pulled out as a whole. The entire disassembly and assembly process requires no complex tools or cumbersome operating steps, greatly saving time and improving work efficiency, making it particularly suitable for processing scenarios requiring frequent tool changes.

[0023] 4. The servo-driven force-controlled polishing device disclosed in this utility model can be equipped with various custom tools on the mounting platform, which makes the polishing device highly versatile and flexible. It can quickly change the appropriate tools according to different processing needs, realize multiple processing functions, and reduce equipment purchase costs and space occupation.

[0024] 5. The servo-driven force-controlled polishing device disclosed in this utility model achieves high-precision force control and multiple functions while maintaining low cost. Compared with some passive force-controlled devices, it significantly reduces equipment costs while achieving similar or even better performance, resulting in a high cost-performance ratio and facilitating wider application in various fields.

[0025] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 This is a three-dimensional structural diagram of the servo-driven force-controlled polishing device of this utility model;

[0028] Figure 2 This utility model Figure 1 A three-dimensional structural diagram of the drive box and the grinding and polishing machine;

[0029] Figure 3 This utility model Figure 1 Internal structure diagram of the drive box Figure 1 ;

[0030] Figure 4 This utility model Figure 1 Internal structure diagram of the drive box Figure 2 ;

[0031] Figure 5 This utility model Figure 4 A three-dimensional structural diagram of the rear plate of the force sensor and the front plate of the force sensor;

[0032] Figure 6 This utility model Figure 2 A three-dimensional structural diagram of a grinding and polishing machine and grinding discs;

[0033] Figure 7This utility model Figure 6 Exploded view of the middle circular plate and the fixed box;

[0034] Figure 8 This utility model Figure 7 A three-dimensional sectional view of the central fixing box;

[0035] Figure 9 This utility model Figure 7 Exploded view of the workpiece clamping plate and the supporting arc plate;

[0036] Figure 10 This utility model Figure 9 A three-dimensional structural diagram of the supporting arc-shaped plate and rectangular block.

[0037] In the diagram: 1. Robotic arm; 2. Drive box; 3. Grinding and polishing machine; 4. Grinding disc; 5. Connecting seat I; 6. Support plate; 7. Servo motor; 8. Motor mounting plate; 9. Force sensor base plate; 10. Mounting platform; 11. L-shaped mounting plate; 12. Three-dimensional force sensor; 13. Gyroscope; 14. Ball screw; 15. Guide column; 16. Adjusting nut; 17. Tension sensor; 18. Force sensor rear plate; 19. Force sensor front plate; 20. Nut seat; 21. 1. Compression Spring I; 22. Fixing Box; 23. U-shaped Plate; 24. Positioning Groove; 25. Round Rod; 26. Round Plate; 27. Notch; 28. Workpiece Clamping Plate; 29. ​​Compression Spring II; 30. Elliptical Slide Plate; 31. L-shaped Pull Plate; 32. Positioning Block; 33. Strip Hole I; 34. Slot; 35. Rectangular Block; 36. Limiting Plate; 37. Support Arc Plate; 38. Compression Spring III; 39. Sliding Plate; 40. Slide Groove; 41. Strip Hole II; 42. Round Cavity. Detailed Implementation

[0038] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0039] like Figure 1 The servo-driven force-controlled polishing device shown mainly consists of a robotic arm 1, a drive box 2, a force control component, a mounting platform 10, a fixing box 22, a polishing component, and a fixing component.

[0040] like Figure 2As shown, a connecting seat I5 is fixedly installed at one end of the robotic arm 1, and a drive box 2 is fixedly installed on the top of the connecting seat I5. A support plate 6 is slidably installed on the bottom inner wall of the drive box 2. A force sensor base plate 9 is fixed on the top of the support plate 6, and a three-dimensional force sensor 12 is fixed on the force sensor base plate 9. A mounting platform 10 is fixed on the top of the three-dimensional force sensor 12. The mounting platform 10 can be equipped with various custom tools according to actual processing needs to achieve flexible expansion of functions.

[0041] like Figure 3 , 4 As shown, the force control component is located inside the drive housing 2. Two L-shaped mounting plates 11 are symmetrically fixed to the inner bottom wall of the drive housing 2, and the same ball screw 14 rotates between the two L-shaped mounting plates 11. A motor mounting plate 8 is also fixed to the inner bottom wall of the drive housing 2. A servo motor 7 is fixed to one side of the motor mounting plate 8. Synchronous pulleys are fixedly fitted onto the output shaft of the servo motor 7 and the outer wall of the ball screw 14. The outer walls of the two synchronous pulleys are fitted with the same synchronous belt. When the servo motor 7 starts, it drives the ball screw 14 to rotate through the transmission of the synchronous pulleys and the synchronous belt.

[0042] like Figure 5 As shown, a nut seat 20 is slidably connected to the inner wall of the bottom of the drive box 2, and a ball screw 14 is threaded through the nut seat 20. A force sensor front plate 19 is fixed to one side of the bottom of the force sensor base plate 9. Two symmetrically arranged guide posts 15 slide through the inside of the nut seat 20. One end of each guide post 15 is fixed to the same force sensor rear plate 18. Two symmetrical tension sensors 17 are arranged between the force sensor rear plate 18 and the force sensor front plate 19. An adjusting nut 16 is threaded onto the outer wall of the guide post 15. Compression springs I 21 are installed between the adjusting nut 16 and the nut seat 20, and between the force sensor rear plate 18 and the nut seat 20. A gyroscope 13 is fixedly installed on one side of the inner wall of the bottom of the drive box 2. During processing, the servo motor 7 drives the ball screw 14 to rotate, causing the nut seat 20 to slide on the inner wall of the bottom of the drive box 2. The tension sensor 17 and the three-dimensional force sensor 12 detect the friction force and the force on the mounting platform 10 in real time. Simultaneously, the position information detected by the grating reading head is used to characterize the magnitude of the force, achieving high-precision force control. The gyroscope 13 detects the angle and enables gravity compensation, while the accelerometer provides inertial force compensation, ensuring accurate force control. Furthermore, the servo motor 7 boasts a fast dynamic response, quickly reacting to changes in processing conditions or the need to adjust processing parameters, preventing processing delays and improving processing efficiency and product quality.

[0043] Mounting platform 10 has a fixed box 22 welded to its top. The fixed box 22 has a circular cavity 42 inside. A strip hole II 41 is opened on one side of the fixed box 22. The strip hole II 41 is located below the circular cavity 42 and is connected to the circular cavity 42. A polishing component for polishing is installed inside the circular cavity 42.

[0044] like Figure 6 , 7 As shown, the polishing assembly includes a U-shaped plate 23, with a polishing machine 3 fixed to the top of the U-shaped plate 23. The output shaft of the polishing machine 3 is fixedly connected to a polishing disc 4. A round rod 25 is fixed to the bottom of the U-shaped plate 23, and a round plate 26 is fixed to the bottom of the round rod 25. Multiple positioning grooves 24 are opened on the top of the round plate 26. Multiple positioning blocks 32 are fixed to the inner wall of the top of the round cavity 42. The positioning blocks 32 engage with the positioning grooves 24 to ensure accurate positioning of the polishing assembly in the round cavity 42 and ensure processing stability.

[0045] like Figure 8 , 9 As shown, the fixing assembly is located on the top of the supporting arc plate 37, which is inserted into the slotted hole II 41. A rectangular block 35 is fixed to the top of the supporting arc plate 37, and a limiting plate 36 is fixed to one side of the rectangular block 35. A notch 27 is opened on one side of the circular plate 26, which works in conjunction with the rectangular block 35. The circular rod 25 works in conjunction with the limiting plate 36. A slotted hole I 33 is opened on one side of the top of the fixing box 22. The slotted hole I 33 communicates with the circular cavity 42 and works in conjunction with the circular rod 25, facilitating the installation and removal of the circular rod 25.

[0046] like Figure 10 As shown, a groove 40 is opened on the top of the rectangular block 35. Two symmetrical sliding plates 39 are slidably connected inside the groove 40. The same compression spring Ⅲ 38 is set between the sliding plate 39 and the inner wall of the groove 40. Two workpiece clamping plates 28 are fixed on the top of the sliding plate 39 respectively. The workpiece clamping plates 28 are used to clamp the round rod 25, which can ensure the stability of the polishing assembly during operation.

[0047] Both sides of the supporting arc plate 37 are slidably connected to L-shaped pull plates 31. A compression spring II 29 is fixed between the two L-shaped pull plates 31. Slots 34 are provided on the inner walls of both sides of the strip hole II 41 to engage with the L-shaped pull plates 31, thereby braking the supporting arc plate 37. An elliptical slide plate 30 is slidably connected between the inner walls of both sides of the strip hole I 33. The elliptical slide plate 30 is used in conjunction with the L-shaped pull plates 31 and the workpiece clamping plate 28.

[0048] When the polishing tool needs to be disassembled, first press the two L-shaped pull plates 31. The L-shaped pull plates 31 compress the compression spring II 29 and move out of the slot 34, releasing the braking state of the supporting arc plate 37. At this time, the supporting arc plate 37 can be moved out of the slot II 41 through the L-shaped pull plates 31. At this time, the rectangular block 35 no longer gets stuck in the notch 27, the limiting plate 36 will not get stuck in the round rod 25, and the compression spring II 29 pushes the elliptical slide plate 30 upward. The elliptical slide plate 30 gets stuck in the two workpiece clamping plates 28. The two workpiece clamping plates 28 drive the two sliding plates 39 away from each other. The sliding plates 39 compress the compression spring III 38, and the two workpiece clamping plates 28 no longer clamp the round rod 25. After the supporting arc plate 37 is pulled out as a whole, the supporting arc plate 37 no longer supports the circular plate 26, and the workpiece clamping plate 28 is no longer between the fixed box 22 and the U-shaped plate 23. As a result, the U-shaped plate 23 no longer supports the U-shaped plate 23. The U-shaped plate 23 drives the circular rod 25 to move down, and the circular rod 25 drives the circular plate 26 to move down. The circular plate 26 moves from the inside of the circular cavity 42 to the inside of the strip hole II 41, and then is pulled out laterally. This releases the braking state of the device and completes the disassembly of the polishing tool.

[0049] The installation of this polishing tool is the reverse of the disassembly process, allowing for quick and convenient installation, which greatly saves time, reduces the labor intensity of workers, and improves production efficiency. At the same time, it avoids problems such as tool damage or insecure installation due to improper operation.

[0050] Through the aforementioned structural design and operating method, this servo-driven force-controlled polishing device achieves high-precision force control, rapid dynamic response, and convenient tool assembly and disassembly, meeting the high requirements of modern manufacturing for polishing processes, improving production efficiency and product quality, and reducing production costs.

[0051] The mounting platform 10 of this invention can be equipped with various custom tools for force control. It is low-cost and driven by a servo motor 7, resulting in fast dynamic response. The position information detected by the grating reading head is used to characterize the force, so the force control accuracy is very high. The angle is detected by the gyroscope 13 to achieve gravity compensation, and an accelerometer is also equipped to achieve inertial force compensation. Friction is detected in real time by tension and compression sensors and a three-dimensional force sensor 12. The three-dimensional force sensor 12 detects the force on the mounting platform 10 in real time. Compared with passive force control devices, this invention has higher accuracy and faster response speed.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A servo-driven force-controlled polishing device, characterized in that, The device includes a robotic arm (1) and a drive box (2) fixedly installed at the free end of the robotic arm (1). A support plate (6) is slidably installed on the inner wall of the drive box (2). A force sensor base plate (9) and a three-dimensional force sensor (12) are fixedly installed on the top of the support plate (6) in sequence. A mounting platform (10) for easy installation of polishing components is fixedly installed on the top of the three-dimensional force sensor (12). A force control component for controlling the force is provided at the bottom of the drive box (2). The force control component includes two symmetrically arranged L-shaped mounting plates (11) fixedly installed on the bottom inner wall of the drive box (2). The same ball screw (14) rotates between the two L-shaped mounting plates (11). A motor mounting plate (8) is fixedly installed on the bottom inner wall of the drive box (2). A servo motor (7) is fixedly installed on one side of the motor mounting plate (8). The output shaft of the servo motor (7) and the outer wall of the ball screw (14) are both fixedly fitted with synchronous pulleys. The outer walls of the two synchronous pulleys are fitted with synchronous belts.

2. The apparatus according to claim 1, wherein The bottom inner wall of the drive box (2) is slidably connected to a nut seat (20), and the ball screw (14) is threaded through the nut seat (20). A force sensor front plate (19) is fixedly installed on one side of the bottom of the force sensor base plate (9). Two symmetrically arranged guide columns (15) slide through the inside of the nut seat (20). The same force sensor rear plate (18) is fixedly installed on the end of the two guide columns (15) away from the synchronous belt. Two symmetrically arranged tension sensors (17) are arranged between the force sensor rear plate (18) and the force sensor front plate (19). An adjusting nut (16) is threaded on the outer wall of the guide column (15). A compression spring I (21) is provided between the adjusting nut (16) and the nut seat (20) and between the force sensor rear plate (18) and the nut seat (20). A gyroscope (13) is fixedly installed on one side of the bottom inner wall of the drive box (2).

3. The apparatus according to claim 1, wherein The mounting platform (10) is fixedly mounted with a fixing box (22) on top. The fixing box (22) has a circular cavity (42) inside. A strip hole II (41) is opened on one side of the fixing box (22). The strip hole II (41) is located below the circular cavity (42) and is connected to the circular cavity (42). The polishing assembly is installed inside the circular cavity (42).

4. The apparatus according to claim 3, wherein The polishing assembly includes a U-shaped plate (23) and a polishing machine (3) fixedly installed inside the U-shaped plate (23). The output shaft of the polishing machine (3) is fixedly connected to a polishing disc (4). A round rod (25) is fixedly installed at the bottom of the U-shaped plate (23). A round plate (26) is fixedly installed at the bottom of the round rod (25). A plurality of positioning grooves (24) are opened at the top of the round plate (26). A plurality of positioning blocks (32) are fixedly installed on the top inner wall of the round cavity (42). The positioning blocks (32) engage with the positioning grooves (24).

5. The apparatus according to claim 4, wherein A supporting arc plate (37) is inserted inside the strip hole II (41). A fixing component for fixing the polishing assembly is provided on the top of the supporting arc plate (37). The fixing component includes a rectangular block (35) fixedly installed on the top of the supporting arc plate (37). A limiting plate (36) is fixedly installed on one side of the rectangular block (35). A notch (27) is opened on one side of the circular plate (26). The notch (27) is used in conjunction with the rectangular block (35). The circular rod (25) is used in conjunction with the limiting plate (36). A strip hole I (33) is opened on one side of the top of the fixing box (22). The strip hole I (33) is connected to the circular cavity (42). The strip hole I (33) is used in conjunction with the circular rod (25).

6. The apparatus according to claim 5, wherein The rectangular block (35) has a groove (40) at the top. Two symmetrically arranged sliding plates (39) are slidably connected inside the groove (40). A compression spring III (38) is provided between the sliding plate (39) and the inner wall of the groove (40). Two workpiece clamping plates (28) are fixed to the top of the sliding plate (39) respectively. The workpiece clamping plates (28) are used to clamp the round rod (25).

7. The apparatus according to claim 6, wherein The supporting arc plate (37) is slidably connected to both sides of an L-shaped pull plate (31), and the same compression spring II (29) is fixedly installed between the two L-shaped pull plates (31). The inner walls of both sides of the strip hole II (41) are provided with slots (34) that engage with the L-shaped pull plate (31).

8. The apparatus according to claim 7, wherein The same elliptical slide plate (30) is slidably connected between the inner walls of the two sides of the strip hole I (33). The elliptical slide plate (30) is used in conjunction with the L-shaped pull plate (31) and the workpiece clamping plate (28).

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