Chip mounting device for semiconductor chip processing

Abstract

The invention discloses a surface mounting device for semiconductor chip processing, and relates to the technical field of chip processing. A PCB is placed on a placement rack, threaded rods rotate to drive clamping plates to clamp the upper side and the lower side of the PCB, and after clamping is completed, a paste brushing plate moves back and forth so that the surface of the PCB can be covered with solder paste; when the paste brushing plate moves, the scraper knife is driven to move, the scraper knife firstly moves backwards, the scraper knife moves backwards to scrape impurities on the surface of the PCB, the PCB may be contaminated with dust, chippings and other impurities in the production process, the impurities can be effectively removed by using the scraper knife for cleaning, and solder paste is coated and leveled when the scraper knife moves forwards. The scraper knife can scrape the uneven position of the surface of the PCB to be flat, the situation that the thickness of solder paste is inconsistent is avoided, the stirring rod rotates when the solder paste tank moves, air in the solder paste can be exhausted, volatilization of solder resist is reduced, and the solder ball problem caused by air condensation is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of chip processing, in particular to a chip placement device for processing semiconductor chips. Background Art

[0002] The chip placement device for semiconductor chip processing, also known as a chip mounter, is one of the key equipment in the semiconductor manufacturing process. Its main function is to accurately place tiny electronic components on a printed circuit board (PCB) or other substrate. The development of this equipment stems from the semiconductor industry's demand for high precision, high efficiency and high reliability.

[0003] Patent announcement number CN222214133U relates to the field of chip processing technology and discloses a patch device for semiconductor chip processing, comprising a base, a patch assembly disposed on the surface of the base, the patch assembly comprising a column fixedly connected to the surface of the base, a slide groove formed in the sidewall of the column, a beam slidably connected to the interior of the slide groove, a patch head fixedly connected to the bottom surface of the beam, two symmetrical groups of beams, the two groups of beams being threadedly connected by a bidirectional threaded rod, an air pump fixedly connected to the surface of the beam, and nozzles fixedly connected to the output end of the air pump via a hose. In this patent, a motor drives the bidirectional threaded rod to rotate, causing the two groups of beams to move toward each other and drive the two groups of patch heads to adhere to the bottom and surface of the semiconductor chip, thereby processing both sides of the semiconductor chip simultaneously and improving work efficiency.

[0004] In the above patent, both sides of the semiconductor chip are processed simultaneously to improve work efficiency. However, the current equipment has the following problems: before the PCB board is coated with glue, dust will inevitably adhere to the surface, which will affect the gluing effect of the circuit board, and the thickness of the solder paste coating may be inconsistent. This will result in insufficient tin in some solder joints and excessive tin in some solder joints during the welding process. The solder joints with insufficient tin may cause loose welding. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a chip placement device for semiconductor chip processing, which solves the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A chip placement device for semiconductor chip processing, comprising a base frame, a surface of which is provided with a cylinder for placing chips on a PCB board, comprising: A fixing bracket, the fixing bracket being fixedly mounted on an output end of the cylinder; A solder paste tank, the solder paste tank being slidably mounted on the surface of the fixing frame; An eccentric rod is rotatably mounted on a surface of a fixed frame; A connecting rod, one side of which is rotatably mounted on the surface of the eccentric rod, and the other side of which is rotatably mounted on the circumferential surface of the solder paste tank; A paste brushing board, the paste brushing board is fixedly installed at the bottom of the solder paste tank; A gear rod frame, wherein the gear rod frame is fixedly mounted on the inner wall of the fixed frame; A gear, the gear being rotatably mounted on the top of the solder paste tank and meshing with the gear rack; A stirring rod, the stirring rod is fixedly mounted on the bottom of the gear; A placement rack, the placement rack being rotatably mounted on the surface of the base frame; A threaded rod, the threaded rod being rotatably mounted on the inner wall of the placement rack; The clamping plate is threadedly mounted on the circumferential surface of the threaded rod. By placing the PCB board on the placement rack, the threaded rod is rotated to drive the clamping plate to clamp the upper and lower sides of the PCB board.

[0007] According to the above technical solution, the paste brush plate is connected to the solder paste tank, and a brush is provided at the bottom of the paste brush plate. The eccentric rod is driven by a motor to rotate to drive the connecting rod to rotate. The rotation of the connecting rod causes the solder paste tank to slide back and forth. The sliding of the solder paste tank drives the paste brush plate to move. By injecting solder paste into the paste brush plate, the solder paste adheres to the brush, and the surface of the PCB board is covered with solder paste by moving back and forth.

[0008] According to the above technical solution, the coating device further includes a scraper and a rotating rod, wherein the scraper is fixedly mounted on the rear side of the paste brushing board, and the rotating rod is rotatably mounted on the inner wall of the base frame, and the rotating rod is connected to the placement rack through a No. 1 belt, so that the scraper moves while the paste brushing board moves; Among them, the top of the base frame is provided with a patch device for patching the bottom of the PCB board and a loading device for automatically loading the patches.

[0009] According to the above technical solution, the patch device includes a positioning rod and a positioning plate. The positioning rod is fixedly installed on the circumferential surface of the rotating rod, and the positioning plate is fixedly installed on the surface of the positioning rod. The inner wall of the positioning plate is provided with a rubber pad. When placing the PCB board, the position of the PCB board is centered by making it contact with the positioning plate.

[0010] According to the above technical solution, the patch device also includes an electric push rod and a patch board. The fixed end of the electric push rod is fixedly installed on the top of the base frame, and the patch board is fixedly installed on the output end of the electric push rod, with the coated surface at the bottom. At this time, the patch board is driven by the output end of the electric push rod to move upward after loading is completed to perform patching on the bottom of the PCB board.

[0011] According to the above technical solution, the patch device also includes an elastic telescopic rod, a support plate and a brake rod. The fixed end of the elastic telescopic rod is fixedly installed on the top of the base frame, the support plate is fixedly installed on the movable end of the elastic telescopic rod, and the brake rod is fixedly installed on the movable end of the elastic telescopic rod. When the PCB board rotates, the support plate is driven to move downward so that the output end of the elastic telescopic rod is compressed, and the output end of the elastic telescopic rod causes the brake rod to move. In this way, self-adaptation of the support mechanism is achieved.

[0012] According to the above technical solution, the loading device includes a component box, a push plate and a connecting rod. The component box is fixedly installed on the top of the base frame, the push plate is slidably installed on the surface of the component box, one side of the connecting rod is rotatably installed on the surface of the brake rod, and the other side of the connecting rod is rotatably installed on the surface of the push plate. By adding components into the component box, the connecting rod moves downward by moving the brake rod, and the movement of the connecting rod causes the push plate to move forward.

[0013] According to the above technical solution, the loading device also includes an electric cylinder, a driving wheel, a receiving gear rod 1, a receiving gear rod 2 and a buffer button. The fixed end of the electric cylinder is fixedly mounted on the surface of the push plate close to the component box. The movement of the push plate drives the electric cylinder to move, and at the same time drives the receiving gear rod 1 to move. The receiving gear rod 1 contacts the driving wheel so that the receiving gear rod 2 moves backward. After reaching the specified position, the component is pushed toward the position of the patch board through the output end of the electric cylinder. The driving wheel is rotatably mounted on the surface of the component box, the receiving gear rod 1 is slidably mounted on the inner wall of the component box, the receiving gear rod 2 is slidably mounted on the inner wall of the component box, the receiving gear rod 1 is meshed with the driving wheel, and the receiving gear rod 2 is meshed with the driving wheel. The buffer button is rotatably mounted on the inner wall of the component box. The next component loses the support of the receiving gear rod 2 and falls to the top of the receiving gear rod 1 for support. When the component falls, it is buffered by the buffer button. A No. 1 spring is provided between the buffer button and the component box, and the buffer button is reset by the provided No. 1 spring.

[0014] The present invention provides a chip placement device for semiconductor chip processing. It has the following beneficial effects: (1) The invention, through the setting of the coating device, places the PCB board on the placement rack, and drives the clamping plate to clamp the upper and lower sides of the PCB board by rotating the threaded rod. After the clamping is completed, the surface of the PCB board is covered with solder paste by moving the paste brush plate back and forth. The paste brush plate moves while driving the scraper to move. The scraper will first move backward. The backward movement of the scraper will scrape off the impurities on the surface of the PCB board. The PCB board may be contaminated with dust, debris and other impurities during the production process. Using the scraper to clean can effectively remove these impurities, and the solder paste is applied and flattened when moving forward. The scraper can flatten the uneven surface of the PCB board to avoid the situation of inconsistent solder paste thickness, thereby improving the consistency and reliability of welding. When the solder paste tank moves, the stirring rod rotates, which can discharge the air inside the solder paste, reduce the volatilization of the solder resist, and avoid the problem of solder balls caused by air condensation.

[0015] (2) This invention, through the arrangement of the patch device, when placing the PCB board, makes it contact with the positioning plate so that the position of the PCB board is centered, making it easier to operate in the subsequent patch process. After the PCB board is rotated, it is centered again by the positioning rod. At this time, the coating surface is at the bottom. At this time, the patch board is driven by the output end of the electric push rod to move upward after loading and patch the bottom of the PCB board. When the PCB board is coated, the bottom of the PCB board is supported by the support plate, making the coating and patch process more stable. When the PCB board rotates, the support plate is driven to move downward so that the output end of the elastic telescopic rod is compressed, and the output end of the elastic telescopic rod causes the brake rod to move. In this way, the support mechanism is self-adapted.

[0016] (3) This invention, through the setting of the loading device, adds components to the component box. In the initial state, there is a component on the top of the receiving gear rod 2. After the push plate reaches the specified position, the component is pushed toward the position of the patch board through the output end of the electric cylinder, so that the component is pushed to the inner wall of the patch board. The automatic loading system can ensure the accurate placement of the PCB board, avoiding the deviation and damage that may occur during manual loading, thereby improving the quality and consistency of the product. At this time, the next component loses the support of the receiving gear rod 2 and falls to the top of the receiving gear rod 1 for support. When the component falls, it is buffered by the buffer button to prevent physical damage to the component. If there is no buffer, directly hitting the hard surface may cause cracks and breakage on the PCB board, or damage the components on the board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the position structure of the rotating rod and the placement rack of the present invention; Figure 3This is a schematic diagram of the position structure of the clamping mechanism and the coating device of the present invention; Figure 4 For the present invention Figure 3 A schematic diagram of the structure of part A in the middle; Figure 5 This is a schematic diagram of the position structure of the connecting rod and the solder paste tank of the present invention; Figure 6 This is a schematic diagram of the position structure of the positioning plate and the support plate of the present invention; Figure 7 This is a schematic diagram of the position structure of the connecting rod and the brake rod of the present invention; Figure 8 This is a schematic diagram of the push plate and drive wheel position structure of the present invention.

[0018] In the figure: 1. Base frame; 2. Fixed frame; 3. Solder paste can; 4. Eccentric rod; 5. Connecting rod; 6. Paste brush board; 7. Shovel; 8. Gear rod rack; 9. Gear; 10. Stirring rod; 11. Placement rack; 12. Threaded rod; 13. Clamping plate; 14. Rotating rod; 20. Positioning rod; 21. Positioning plate; 22. Electric push rod; 23. SMD board; 24. Elastic telescopic rod; 25. Support plate; 26. Brake rod; 30. Component box; 31. Push plate; 32. Connecting rod; 33. Electric cylinder; 34. Driving wheel; 35. Connecting gear rod 1; 36. Connecting gear rod 2; 37. Buffer button. DETAILED DESCRIPTION

[0019] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] See also Figures 1-6 One embodiment of the present invention is a chip placement device for semiconductor chip processing, comprising a base frame 1, a surface of which is provided with a cylinder for performing chip placement on a PCB board, comprising: Fixed bracket 2, fixedly mounted on the output end of the cylinder; A solder paste tank 3 is slidably mounted on the surface of the fixing frame 2; An eccentric rod 4 is rotatably mounted on the surface of the fixed frame 2; A connecting rod 5, one side of the connecting rod 5 is rotatably mounted on the surface of the eccentric rod 4, and the other side of the connecting rod 5 is rotatably mounted on the circumferential surface of the solder paste tank 3; A paste brushing board 6 is fixedly mounted on the bottom of the solder paste tank 3; The gear rod frame 8 is fixedly mounted on the inner wall of the fixed frame 2; Gear 9 is rotatably mounted on the top of the solder paste tank 3 and is engaged with the gear rack 8; The stirring rod 10 is fixedly mounted at the bottom of the gear 9. The stirring rod 10 can discharge the air inside the solder paste during the stirring process, thereby reducing the volatilization of the solder resist and avoiding the problem of solder balls caused by air condensation. A placement rack 11, the placement rack 11 is rotatably mounted on the surface of the base frame 1; A threaded rod 12 is rotatably mounted on the inner wall of the placement rack 11; The clamping plate 13 is threadedly mounted on the circumferential surface of the threaded rod 12 .

[0021] The paste brushing board 6 is connected to the solder paste tank 3. A brush is provided at the bottom of the paste brushing board 6. By injecting solder paste into the paste brushing board 6, the solder paste adheres to the brush.

[0022] The coating device also includes a scraper 7 and a rotating rod 14. The scraper 7 is fixedly installed on the rear side of the paste brushing board 6, and the rotating rod 14 is rotatably installed on the inner wall of the base frame 1. The rotating rod 14 is connected to the placement rack 11 through a No. 1 belt. The solder paste is applied and flattened when moving forward. The scraper 7 can scrape the uneven surface of the PCB board to ensure that the solder paste can be evenly coated on the pad, avoiding inconsistent solder paste thickness, thereby improving the consistency and reliability of welding.

[0023] When this embodiment is working, the PCB board is placed on the placement rack 11, and the threaded rod 12 rotates to drive the clamping plate 13 to clamp its upper and lower sides. After clamping, the fixed frame 2 is driven to descend through the output end of the cylinder. When it reaches the specified position, the eccentric rod 4 is driven by the motor to rotate to drive the connecting rod 5 to rotate. The rotation of the connecting rod 5 causes the solder paste tank 3 to slide back and forth. The sliding of the solder paste tank 3 drives the paste brush plate 6 to move. By injecting solder paste into the paste brush plate 6, the solder paste adheres to the brush and is covered with solder paste by moving back and forth. The movement of the paste brush plate 6 drives the scraper 7 to move at the same time. The scraper 7 will first move backward. The backward movement of the scraper 7 will scrape off impurities on the surface of the PCB board. The PCB board may be contaminated with dust, debris and other impurities during the production process. Using the scraper 7 to clean can effectively remove these impurities. The scraper 7 can scrape the uneven parts of the PCB board surface flat to ensure that the solder paste can be evenly coated on the pad, avoiding the situation of inconsistent solder paste thickness, thereby improving the consistency and reliability of welding. When the solder paste tank 3 moves, it drives the gear 9 to move. The movement of the gear 9 will contact the rack 8 to make the gear 9 rotate. The rotation of the gear 9 makes the stirring rod 10 rotate. The stirring rod 10 can discharge the air inside the solder paste during the stirring process, reduce the volatilization of the solder resist, and avoid the problem of solder balls caused by air condensation. After one side of the PCB board is coated, the placement rack 11 is driven by the motor to rotate to drive the PCB board to rotate so that the other side is coated. While the placement rack 11 rotates, the No. 1 belt is driven to drive the rotating rod 14 to rotate.

[0024] See also Figures 1-8 On the basis of the above embodiment, in another embodiment of the present invention, a patch device for patching the bottom of the PCB board and a loading device for automatically loading the patch are provided on the top of the base frame 1. The patch device includes a positioning rod 20 and a positioning plate 21. The positioning rod 20 is fixedly mounted on the circumferential surface of the rotating rod 14, and the positioning plate 21 is fixedly mounted on the surface of the positioning rod 20. The inner wall of the positioning plate 21 is provided with a rubber pad, so that the position of the PCB board is centered, making it easier to operate in the subsequent patch process.

[0025] The patch device also includes an electric push rod 22 and a patch board 23. The fixed end of the electric push rod 22 is fixedly installed on the top of the base frame 1, and the patch board 23 is fixedly installed on the output end of the electric push rod 22 to patch the bottom of the PCB board.

[0026] The patch device also includes an elastic telescopic rod 24, a support plate 25 and a brake rod 26. The fixed end of the elastic telescopic rod 24 is fixedly mounted on the top of the base frame 1, the support plate 25 is fixedly mounted on the movable end of the elastic telescopic rod 24, and the brake rod 26 is fixedly mounted on the movable end of the elastic telescopic rod 24. The bottom of the PCB board is supported by the support plate 25, making the coating and patch process more stable.

[0027] The loading device includes a component box 30, a push plate 31 and a connecting rod 32. The component box 30 is fixedly mounted on the top of the base frame 1, and the push plate 31 is slidably mounted on the surface of the component box 30. One side of the connecting rod 32 is rotatably mounted on the surface of the brake rod 26, and the other side of the connecting rod 32 is rotatably mounted on the surface of the push plate 31. The automatic loading system can ensure the accurate placement of components, avoid deviations and damage that may occur during manual loading, and thus improve the quality and consistency of the products.

[0028] The loading device also includes an electric cylinder 33, a driving wheel 34, a connecting gear rod 1 35, a connecting gear rod 2 36 and a buffer button 37. The fixed end of the electric cylinder 33 is fixedly mounted on the surface of the push plate 31 close to the component box 30, the driving wheel 34 is rotatably mounted on the surface of the component box 30, the connecting gear rod 1 35 is slidably mounted on the inner wall of the component box 30, the connecting gear rod 2 36 is slidably mounted on the inner wall of the component box 30, the connecting gear rod 1 35 is engaged with the driving wheel 34, the connecting gear rod 2 36 is engaged with the driving wheel 34, and the buffer button 37 is rotatably mounted on the inner wall of the component box 30. When the component falls, the buffer button 37 is used to buffer it to prevent physical damage to the component. If there is no buffering, directly hitting the hard surface may cause cracks or breakage on the PCB board, or damage the components on the board. A No. 1 spring is provided between the buffer button 37 and the component box 30, and the buffer button 37 is reset by the provided No. 1 spring.

[0029] When the present embodiment is working, when placing the PCB board, the position of the PCB board is centered by making it contact with the positioning plate 21, which makes it easier to operate in the subsequent patch process. When the PCB board rotates, the rotation of the rotating rod 14 drives the positioning rod 20 to rotate. The rotation of the positioning rod 20 drives the positioning plate 21 to disengage the positioning of the PCB board, and after the PCB board rotates, it resets and centers the position again. At this time, the coating surface is at the bottom. At this time, the output end of the electric push rod 22 drives the patch board 23 to move upward after loading to perform patching on the bottom of the PCB board. When the PCB board is coated, the support plate 25 supports the bottom of the PCB board, making the coating and patching process more stable. When the PCB board rotates, the support plate 25 is driven to move downward, so that the output end of the elastic telescopic rod 24 is compressed, and the output end of the elastic telescopic rod 24 causes the brake rod 26 to move. In this way, the support mechanism is self-adapted. By adding components into the component box 30, in the initial state, there is a component on the top of the receiving gear rod 2 36, and the brake rod 26 is moved downward to move the connecting rod 32, and the movement of the connecting rod 32 causes the push plate 31 to move forward, and the movement of the push plate 31 drives the electric cylinder 33 to move, and at the same time drives the receiving gear rod 1 35 to move. The receiving gear rod 1 35 contacts the driving wheel 34 to make the receiving gear rod 2 36 move backward. After reaching the specified position, the output end of the electric cylinder 33 pushes the component toward the position of the patch board 23, so that the component is pushed to the inner wall of the patch board 23. The automatic loading system can ensure the accurate placement of the components, avoid the deviation and damage that may occur during manual loading, thereby improving the quality and consistency of the product. At this time, the next component loses the support of the receiving gear rod 2 36 and falls to the top of the receiving gear rod 1 35 for support. When the component falls, it is buffered by the buffer button 37 to prevent physical damage to the component. If there is no buffer, directly hitting the hard surface may cause cracks and breakage on the PCB board, or damage the components on the board.

[0030] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A chip placement device for semiconductor chip processing, comprising a base frame 1, wherein a cylinder is provided on the surface of the base frame 1, characterized in that: Used for mounting PCB boards, including: A fixing bracket 2, the fixing bracket 2 being fixedly mounted on the output end of the cylinder; A solder paste tank 3, wherein the solder paste tank 3 is slidably mounted on the surface of the fixing frame 2; An eccentric rod 4 is rotatably mounted on the surface of the fixing frame 2; A connecting rod 5, one side of which is rotatably mounted on the surface of the eccentric rod 4, and the other side of which is rotatably mounted on the circumferential surface of the solder paste tank 3; A paste brushing plate 6, which is fixedly mounted on the bottom of the solder paste tank 3; A gear rod frame 8, wherein the gear rod frame 8 is fixedly mounted on the inner wall of the fixed frame 2; Gear 9, the gear 9 is rotatably mounted on the top of the solder paste tank 3, and the gear 9 is engaged with the gear rack 8; A stirring rod 10, wherein the stirring rod 10 is fixedly mounted on the bottom of the gear 9; A placement rack 11 is rotatably mounted on the surface of the base frame 1; A threaded rod 12, the threaded rod 12 being rotatably mounted on the inner wall of the placement rack 11; The clamping plate 13 is threadedly mounted on the circumferential surface of the threaded rod 12 .

2. A chip bonding device for semiconductor chip processing according to claim 1, characterized in that: The paste brushing plate 6 is connected to the solder paste tank 3 , and a brush is provided at the bottom of the paste brushing plate 6 .

3. A chip bonding device for semiconductor chip processing according to claim 2, characterized in that: The coating device also includes a scraper 7 and a rotating rod 14, the scraper 7 is fixedly mounted on the rear side of the paste brushing plate 6, the rotating rod 14 is rotatably mounted on the inner wall of the base frame 1, and the rotating rod 14 is connected to the placement rack 11 through a belt. The top of the base frame 1 is provided with a patch device for patching the bottom of the PCB board and a loading device for automatically loading the patches.

4. A chip bonding device for semiconductor chip processing according to claim 3, characterized in that: The patch device includes a positioning rod 20 and a positioning plate 21. The positioning rod 20 is fixedly mounted on the circumferential surface of the rotating rod 14. The positioning plate 21 is fixedly mounted on the surface of the positioning rod 20. The inner wall of the positioning plate 21 is provided with a rubber pad.

5. The chip bonding device for semiconductor chip processing according to claim 4, characterized in that: The patch device further includes an electric push rod 22 and a patch board 23 . The fixed end of the electric push rod 22 is fixedly mounted on the top of the base frame 1 , and the patch board 23 is fixedly mounted on the output end of the electric push rod 22 .

6. The chip bonding device for semiconductor chip processing according to claim 5, characterized in that: The patch device also includes an elastic telescopic rod 24, a support plate 25 and a brake rod 26. The fixed end of the elastic telescopic rod 24 is fixedly mounted on the top of the base frame 1, the support plate 25 is fixedly mounted on the movable end of the elastic telescopic rod 24, and the brake rod 26 is fixedly mounted on the movable end of the elastic telescopic rod 24.

7. The chip bonding device for semiconductor chip processing according to claim 6, characterized in that: The loading device includes a component box 30, a push plate 31 and a connecting rod 32. The component box 30 is fixedly installed on the top of the base frame 1, the push plate 31 is slidably installed on the surface of the component box 30, one side of the connecting rod 32 is rotatably installed on the surface of the brake rod 26, and the other side of the connecting rod 32 is rotatably installed on the surface of the push plate 31.

8. The chip bonding device for semiconductor chip processing according to claim 7, characterized in that: The loading device also includes an electric cylinder 33, a driving wheel 34, a connecting gear rod 1 35, a connecting gear rod 2 36 and a buffer button 37. The fixed end of the electric cylinder 33 is fixedly mounted on the surface of the push plate 31 close to the component box 30. The driving wheel 34 is rotatably mounted on the surface of the component box 30. The connecting gear rod 1 35 is slidably mounted on the inner wall of the component box 30. The connecting gear rod 2 36 is slidably mounted on the inner wall of the component box 30. The connecting gear rod 1 35 is engaged with the driving wheel 34. The connecting gear rod 2 36 is engaged with the driving wheel 34. The buffer button 37 is rotatably mounted on the inner wall of the component box 30. A spring No. 1 is provided between the buffer button 37 and the component box 30.

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