Magnetic type auxiliary circuit board jig

Abstract

The utility model relates to the technical field of circuit board processing, and discloses a magnetic type auxiliary circuit board jig which comprises a lower die body, two base plates and an upper die body, the upper die body is arranged on the upper end face of the lower die body, and the base plates are arranged between the lower die body and the upper die body. Rapid adsorption and separation between the lower die body and the upper die body are achieved through the magnetic attraction assembly, the production efficiency is remarkably improved, meanwhile, the buffering assembly can effectively absorb instantaneous impact energy generated when the lower die body and the upper die body are closed, meanwhile, microcracks or displacement deviation caused by rigid collision of a circuit board is avoided, and the product quality is improved. When the upper die body and the lower die body need to be separated, the ejection assembly can eject the upper die by a certain distance, strong magnetic adsorption force can be effectively overcome, die scratching and damage caused by direct manual separation can be avoided, and damage to a circuit board caused by too large force when the upper die body and the lower die body are separated can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of circuit board processing technology, specifically to a magnetic auxiliary circuit board fixture. Background Technology

[0002] Circuit boards are carriers of electronic components composed of insulating substrates and conductive copper layers. Circuit connections are formed through etching. They have high-density interconnection capabilities, stability, and scalability, and are therefore widely used in servers. Magnetic auxiliary circuit board fixtures are precision tools used in the field of electronic manufacturing. They are mainly used to fix, position, and assist in the processing of PCBs. Their core feature is that they can be quickly installed and removed through magnetic adsorption, which significantly improves production efficiency and processing accuracy.

[0003] While existing magnetic clamping fixtures simplify opening and closing operations, the instantaneous impact force generated when the upper and lower mold bodies magnetically close is relatively large, which can easily lead to PCB micro-cracks or component displacement, affecting processing accuracy. Furthermore, manually separating the upper and lower mold bodies requires applying a reverse pulling force, which can easily cause scratches on the fixture or PCB delamination. Therefore, those skilled in the art provide a magnetic clamping auxiliary circuit board fixture to solve the problems mentioned in the background art. Summary of the Invention

[0004] The purpose of this utility model is to provide a magnetic auxiliary circuit board fixture to solve the problems in the background art.

[0005] This utility model provides the following technical solution: a magnetic suction type auxiliary circuit board fixture, including a lower mold body, two pads and an upper mold body, the upper mold body is disposed on the upper end face of the lower mold body, the pads are disposed between the lower mold body and the upper mold body, the lower end of the upper mold body is provided with a magnetic suction assembly for fixing, the magnetic suction assembly is installed with two buffer assemblies, each of the two sets of buffer assemblies is installed with an ejection assembly for lifting the upper mold body, and the lower end of the upper mold body is installed with a positioning assembly.

[0006] As a preferred embodiment of the above technical solution, the magnetic attraction assembly includes two first permanent magnets, two second permanent magnets, two first fixing seats, and two second fixing seats. The two first permanent magnets and two second permanent magnets are symmetrically fixedly connected to the four sides of the lower end face of the upper mold body. The two first fixing seats and two second fixing seats are respectively fixedly connected to the four sides of the upper end of the lower mold body. The two first fixing seats correspond one-to-one with the two first permanent magnets, and the two second fixing seats correspond one-to-one with the two second permanent magnets. A first iron plate is fixedly connected to the upper end face of each of the two first fixing seats, and a second iron plate is fixedly connected to the upper end face of each of the two second fixing seats. Each of the two second iron plates has a central through hole. A lifting groove is correspondingly opened on the upper end of each of the two second fixing seats. The two lifting grooves are located directly below the central through holes of the two second iron plates. The two buffer components are respectively disposed in the two lifting grooves.

[0007] As a preferred embodiment of the above technical solution, the buffer assembly includes multiple buffer pads, multiple springs, a working groove, and a top rod. The buffer pads are slidably connected in the lifting groove. The two ends of the multiple springs are respectively connected to the buffer pads and the bottom wall of the lifting groove. The working groove is opened on one side of the lifting groove. The top rod passes through the second fixed seat and is slidably disposed in the working groove. The side wall of the buffer pad is provided with a wedge-shaped groove.

[0008] As a preferred embodiment of the above technical solution, the ejection assembly includes a spur gear, a rack, a threaded rod, and a top plate. The spur gear is rotatably connected to the top wall of the working groove, the rack is fixedly connected to the side wall of the ejector rod, the rack slides through the second fixed seat, and the rack and the spur gear mesh with each other. The upper end of the threaded rod is fixedly connected to the lower end of the spur gear, and the lower end of the threaded rod is rotatably connected to the bottom wall of the working groove. The top plate is slidably connected within the working groove and the lifting groove, the threaded rod passes through one side of the top plate, and the threaded rod is threadedly connected to the external top plate.

[0009] As a preferred embodiment of the above technical solution, the positioning component includes four positioning rods and four positioning holes. The positioning rods are fixedly connected to the four corners of the lower end of the upper mold body. The four positioning rods are arranged in a rectangular array. The four positioning holes are all opened at the upper end of the lower mold body. The four positioning rods and the four positioning holes correspond one-to-one.

[0010] As a preferred embodiment of the above technical solution, multiple guide rods are fixedly connected to both sides of the lower end of the two pads, and multiple guide grooves are opened on the upper end of the lower mold body, with each of the multiple guide rods corresponding to one of the multiple guide grooves.

[0011] As a preferred embodiment of the above technical solution, the side wall of the second fixed seat is provided with a telescopic rod, the fixed end of the telescopic rod is connected to the side wall of the second fixed seat, and the telescopic end of the telescopic rod is fixedly connected to the side wall of the top rod.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. By cooperating with the lower mold body, the pad, and the upper mold body, the material floating and deformation of large circuit board materials are prevented from causing material misalignment. At the same time, the magnetic suction component enables rapid adsorption and separation between the lower mold body and the upper mold body, significantly improving production efficiency. When the lower mold body and the upper mold body are closed, the buffer component can effectively absorb the instantaneous impact energy when the lower mold body and the upper mold body close, reduce the peak mechanical stress at the moment of contact, extend the life of the device, and avoid micro-cracks or displacement deviations of the circuit board caused by rigid collision, thereby ensuring processing accuracy.

[0014] 2. After processing, the upper mold body and the lower mold body need to be separated. At this time, the ejection component can eject the upper mold a certain distance, which can effectively overcome the strong magnetic attraction force and avoid mold scratches and damage caused by direct manual separation. This ensures that the mold is separated quickly and without damage. At the same time, it can eliminate the risk of the circuit board sticking due to the residual magnetic attraction force, ensuring that the workpiece is demolded without damage. It can also avoid damage to the circuit board caused by excessive force when separating the upper mold body and the lower mold body. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a magnetic auxiliary circuit board fixture.

[0016] Figure 2 This is a schematic diagram of the unfolded structure of a magnetic auxiliary circuit board fixture.

[0017] Figure 3 A schematic diagram of the magnetic suction component and positioning component of a magnetic auxiliary circuit board fixture;

[0018] Figure 4 A schematic diagram of the telescopic rod structure of a magnetic auxiliary circuit board fixture;

[0019] Figure 5 A schematic diagram of the buffer assembly structure of a magnetic auxiliary circuit board fixture;

[0020] Figure 6 This is a schematic diagram of the structure of a magnetic auxiliary circuit board fixture after the top plate is raised.

[0021] Figure 7 This is a schematic diagram of the structure of a magnetic auxiliary circuit board fixture after the top plate is lowered.

[0022] 1. Lower mold body; 2. Pad plate; 3. Upper mold body; 4. Magnetic suction assembly; 401. First permanent magnet; 402. Second permanent magnet; 403. First fixed seat; 404. Second fixed seat; 405. First iron sheet; 406. Second iron sheet; 407. Lifting groove; 5. Buffer assembly; 501. Buffer pad; 502. Spring; 503. Working groove; 504. Ejector rod; 505. Wedge-shaped slot; 6. Ejection assembly; 601. Spur gear; 602. Rack; 603. Threaded rod; 604. Top plate; 7. Positioning assembly; 701. Positioning rod; 702. Positioning hole; 8. Guide rod; 9. Guide groove; 10. Telescopic rod. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0024] Please see Figures 1-7 As shown, this utility model provides a technical solution: a magnetic suction type auxiliary circuit board fixture, including a lower mold body 1, two pads 2 and an upper mold body 3. The upper mold body 3 is disposed on the upper end face of the lower mold body 1, the pads 2 are disposed between the lower mold body 1 and the upper mold body 3, the lower end of the upper mold body 3 is provided with a magnetic suction component 4 for fixing, two buffer components 5 are installed in the magnetic suction component 4, and each of the two sets of buffer components 5 is installed with an ejection component 6 for lifting the upper mold body 3, and a positioning component 7 is installed at the lower end of the upper mold body 3.

[0025] Furthermore, the lower mold body 1, the pad 2, and the upper mold body 3 work together to prevent large circuit board materials from floating and deforming, thus preventing material misalignment. Simultaneously, the magnetic suction component 4 enables rapid adsorption and separation between the lower mold body 1 and the upper mold body 3, significantly improving production efficiency. When the lower mold body 1 and the upper mold body 3 close, the buffer component 5 effectively absorbs the instantaneous impact energy, reducing the peak mechanical stress at the moment of contact and extending the device's lifespan. It also prevents micro-cracks or displacement deviations in the circuit board caused by rigid collisions, ensuring processing accuracy. After processing, the upper mold body 3 and the lower mold body 1 need to be separated. At this time, the ejection component 6 can eject the upper mold body 3 a certain distance, effectively overcoming strong magnetic adsorption and avoiding mold scratches and damage caused by direct manual separation. This ensures rapid and damage-free mold separation and eliminates the risk of adhesion caused by residual magnetic force on the circuit board, ensuring undamaged demolding of the workpiece. It also avoids damage to the circuit board caused by excessive force when separating the upper mold body 3 and the lower mold body 1.

[0026] As one implementation method in this embodiment, please refer to Figures 1-5As shown, the magnetic attraction assembly 4 includes two first permanent magnets 401, two second permanent magnets 402, two first fixing seats 403, and two second fixing seats 404. The two first permanent magnets 401 and two second permanent magnets 402 are symmetrically fixedly connected to the four sides of the lower end face of the upper mold body 3. The two first fixing seats 403 and two second fixing seats 404 are respectively fixedly connected to the four sides of the upper end of the lower mold body 1. The two first fixing seats 403 correspond one-to-one with the two first permanent magnets 401, and the two second fixing seats 404... Each of the two bases 404 corresponds to one of the two second permanent magnets 402. The upper surfaces of the two first fixed bases 403 are fixedly connected to the first iron plates 405. The upper surfaces of the two second fixed bases 404 are fixedly connected to the second iron plates 406. The two second iron plates 406 have a central through hole. The upper surfaces of the two second fixed bases 404 are respectively provided with lifting grooves 407. The two lifting grooves 407 are located directly below the central through holes of the two second iron plates 406. The two buffer components 5 are respectively set in the two lifting grooves 407.

[0027] Furthermore, align the lower mold body 1 and the upper mold body 3. Then, press down on the upper mold body 3. The first permanent magnet 401 is attracted to the first iron sheet 405, and the second permanent magnet 402 is attracted to the second iron sheet 406. This completes the rapid attraction and separation between the lower mold body 1 and the upper mold body 3, significantly improving production efficiency.

[0028] As one implementation method in this embodiment, please refer to Figure 5 As shown, the buffer assembly 5 includes multiple buffer pads 501, multiple springs 502, a working groove 503, and a top rod 504. The buffer pads 501 are slidably connected in the lifting groove 407. The two ends of the multiple springs 502 are respectively connected to the buffer pads 501 and the bottom wall of the lifting groove 407. The working groove 503 is opened on one side of the lifting groove 407. The top rod 504 passes through the second fixed seat 404 and is slidably disposed in the working groove 503. The side wall of the buffer pads 501 is provided with a wedge-shaped slot 505.

[0029] Furthermore, when the lower mold body 1 and the upper mold body 3 are closed, the upper mold body 3 will pre-contact the upper end face of the buffer pad 501. Under the buffer of the spring 502, the buffer pad 501 can effectively absorb the instantaneous impact energy when the lower mold body 1 and the upper mold body 3 close, reduce the peak mechanical stress at the moment of contact, avoid damage to the lower mold body 1 and the upper mold body 3 from impact, extend the life of the device, and at the same time avoid micro-cracks or displacement deviations of the circuit board caused by rigid collision, thereby ensuring processing accuracy. After the lower mold body 1 and the upper mold body 3 are in contact, the buffer pad 501 retracts into the lifting groove 407. At this time, the upper end face of the buffer pad 501 and the second iron When the upper surface of piece 406 is on the same plane, the bottom wall of wedge groove 505 and the lower surface of push rod 504 are on the same plane. Pushing push rod 504 will push push rod 504 into wedge groove 505. As push rod 504 is pushed in, push rod 504 contacts the inclined surface of bottom wall of wedge groove 505. At this time, wedge groove 505 will decompose the force, which will cause buffer pad 501 to drop a certain distance. Push rod 504 and wedge groove 505 can limit buffer pad 501, thereby preventing spring 502 from exerting an upward pushing force on upper mold body 3, thereby ensuring the stability of adsorption between lower mold body 1 and upper mold body 3.

[0030] As one implementation method in this embodiment, please refer to Figures 6-7 As shown, the ejector assembly 6 includes a spur gear 601, a rack 602, a threaded rod 603, and a top plate 604. The spur gear 601 is rotatably connected to the top wall of the working groove 503. The rack 602 is fixedly connected to the side wall of the ejector rod 504. The rack 602 slides through the second fixed seat 404. The rack 602 and the spur gear 601 mesh with each other. The upper end of the threaded rod 603 is fixedly connected to the lower end of the spur gear 601. The lower end of the threaded rod 603 is rotatably connected to the bottom wall of the working groove 503. The top plate 604 is slidably connected to the working groove 503 and the lifting groove 407. The threaded rod 603 passes through one side of the top plate 604 and is threadedly connected to the external top plate 604.

[0031] Furthermore, after processing, the upper mold body 3 and the lower mold body 1 need to be separated. Pull the ejector rod 504 to pull it out of the wedge-shaped slot 505. Then, the rack 602 on the ejector rod 504 will contact the spur gear 601, and the threaded rod 603 will rotate, causing the top plate 604 to rise. This will apply an upward pushing force to the buffer pad 501, which will push the upper mold body 3 out a certain distance. This can effectively overcome the strong magnetic attraction force, avoid mold scratches and damage caused by direct manual separation, ensure quick and damage-free mold separation, and eliminate the risk of adhesion of the circuit board caused by the residual magnetic attraction force. This ensures that the workpiece is demolded without damage and avoids damage to the circuit board caused by excessive force when separating the upper mold body 3 and the lower mold body 1.

[0032] It is worth noting that when the user removes the upper mold body 3, the top plate 604 causes the buffer pad 501 to be in the ejected state. At this time, the user pushes the push rod 504, moving it closer to the buffer pad 501. With the cooperation of the rack 602, spur gear 601, and threaded rod 603, the top plate 604 is reset to the lowest end of the working groove 503. At this time, the rack 602 disengages from the meshing area of ​​the spur gear 601, so the top plate 604 will not move. The push rod 504 can still be pushed. However, due to the reset of the spring 502, the buffer pad 501 will not descend. Instead, the buffer pad 501 is in the initial state of extending out of the lifting groove 407. The wedge-shaped slot 505 is not directly facing the push rod 504. When one end of the push rod 504 touches the side wall of the buffer pad 501, the user cannot push the push rod 504. This indicates that the push rod 504 has been pushed in place, and the next circuit board placement operation can be performed.

[0033] As one implementation method in this embodiment, please refer to Figures 2-3 As shown, the positioning component 7 includes four positioning rods 701 and four positioning holes 702. The positioning rods 701 are fixedly connected to the four corners of the lower end of the upper mold body 3. The four positioning rods 701 are distributed in a rectangular array. The four positioning holes 702 are all opened on the upper end of the lower mold body 1. The four positioning rods 701 and the four positioning holes 702 correspond one-to-one.

[0034] Furthermore, the lower mold body 1 and the upper mold body 3 can be aligned using the positioning rod 701 and the positioning hole 702, which makes it easier for the user to assemble the upper mold body 3 and the lower mold body 1, and at the same time can prevent relative displacement between the lower mold body 1 and the upper mold body 3.

[0035] As one implementation method in this embodiment, please refer to Figures 2-3 As shown, multiple guide rods 8 are fixedly connected to both sides of the lower end of the two pads 2, and multiple guide grooves 9 are opened on the upper end of the lower mold body 1. The multiple guide rods 8 correspond one-to-one with the multiple guide grooves 9.

[0036] Furthermore, by using the guide rod 8 in conjunction with the guide groove 9, the pad 2 can be placed on the upper end of the lower mold body 1, and then the circuit board can be placed on top of the two pads 2. Finally, the upper mold body 3 can be placed on the upper end of the lower mold body 1, which makes it convenient for the user to place the pad 2. The pad 2 can support and protect the bottom of the circuit board, preventing the circuit board from being damaged by direct contact with the lower mold body 1 during processing, thereby protecting the circuit board.

[0037] As one implementation method in this embodiment, please refer to Figure 4 As shown, the second fixed base 404 has a telescopic rod 10 on its side wall. The fixed end of the telescopic rod 10 is connected to the side wall of the second fixed base 404, and the telescopic end of the telescopic rod 10 is fixedly connected to the side wall of the top rod 504.

[0038] Furthermore, the telescopic rod 10 is used to limit the range of movement of the top rod 504, preventing the top rod 504 from being pulled out of the second fixed seat 404, thereby facilitating user use.

[0039] Working principle: The lower mold body 1 and the upper mold body 3 can be aligned through the positioning rod 701 and the positioning hole 702. At this time, the upper mold body 3 is pressed down, the first permanent magnet 401 is attracted to the first iron sheet 405, and the second permanent magnet 402 is attracted to the second iron sheet 406. This completes the rapid attraction and separation between the lower mold body 1 and the upper mold body 3, significantly improving production efficiency. At the same time, when the lower mold body 1 and the upper mold body 3 are closed, the upper mold body 3 will pre-contact the upper end face of the buffer pad 501. Under the buffer of the spring 502, the buffer pad 501 can effectively absorb the lower mold body 1 and the upper mold body 3. The instantaneous impact energy when the body 3 closes reduces the peak mechanical stress at the moment of contact, avoiding damage from the impact between the lower mold body 1 and the upper mold body 3, extending the life of the device, and preventing micro-cracks or displacement deviations of the circuit board caused by rigid collision, thus ensuring processing accuracy. After the lower mold body 1 and the upper mold body 3 are in contact, the buffer pad 501 retracts into the lifting groove 407. At this time, the upper end face of the buffer pad 501 and the upper end face of the second iron sheet 406 are on the same plane. At this time, the bottom wall of the wedge-shaped groove 505 and the lower end face of the push rod 504 are on the same plane. Pushing the push rod 504 at this time can remove the impact energy. The ejector pin 504 is pushed into the wedge-shaped groove 505. As the ejector pin 504 is gradually pushed in, it contacts the inclined surface of the bottom wall of the wedge-shaped groove 505. At this time, the wedge-shaped groove 505 decomposes the force, allowing the buffer pad 501 to descend a certain distance. The ejector pin 504, in conjunction with the wedge-shaped groove 505, can limit the buffer pad 501, thereby preventing the spring 502 from exerting an upward pushing force on the upper mold body 3, thus ensuring the stability of the adsorption between the lower mold body 1 and the upper mold body 3. After processing, the upper mold body 3 and the lower mold body 1 need to be separated by pulling the ejector pin 504. 4. After being pulled out from the wedge-shaped slot 505, the rack 602 on the ejector rod 504 will contact the spur gear 601, and the threaded rod 603 will rotate, causing the top plate 604 to rise. This will apply an upward pushing force to the buffer pad 501, which will push the upper mold body 3 out a certain distance. This can effectively overcome the strong magnetic attraction force, avoid mold scratches and damage caused by direct manual separation, ensure quick and damage-free mold separation, and eliminate the risk of adhesion of the circuit board caused by the residual magnetic attraction force. This ensures that the workpiece is demolded without damage and avoids damage to the circuit board caused by excessive force when separating the upper mold body 3 and the lower mold body 1.

[0040] The above embodiments are only used to illustrate the technical solution of this utility model, and are not intended to limit it.

Claims

1. A magnetic auxiliary circuit board fixture, comprising a lower mold body (1), two pads (2) and an upper mold body (3), characterized in that: The upper mold body (3) is disposed on the upper end face of the lower mold body (1), the pad (2) is disposed between the lower mold body (1) and the upper mold body (3), the lower end of the upper mold body (3) is provided with a magnetic suction assembly (4) for fixing, two buffer assemblies (5) are installed in the magnetic suction assembly (4), and both sets of buffer assemblies (5) are provided with an ejection assembly (6) for lifting the upper mold body (3), and a positioning assembly (7) is installed at the lower end of the upper mold body (3).

2. The magnetic auxiliary circuit board jig according to claim 1, characterized in that: The magnetic attraction component (4) includes two first permanent magnets (401), two second permanent magnets (402), two first fixing seats (403), and two second fixing seats (404). The two first permanent magnets (401) and two second permanent magnets (402) are symmetrically fixedly connected to the four sides of the lower end face of the upper mold body (3). The two first fixing seats (403) and two second fixing seats (404) are respectively fixedly connected to the four sides of the upper end of the lower mold body (1). The two first fixing seats (403) correspond one-to-one with the two first permanent magnets (401), and the two second fixing seats (404) are respectively fixedly connected to the four sides of the upper end of the lower mold body (1). 04) Each of the two second permanent magnets (402) corresponds to one of the two first fixed bases (403). The upper end face of each of the two first fixed bases (403) is fixedly connected with a first iron piece (405). The upper end face of each of the two second fixed bases (404) is fixedly connected with a second iron piece (406). Each of the two second iron pieces (406) has a central through hole. Each of the two second fixed bases (404) has a corresponding lifting groove (407) on its upper end. The two lifting grooves (407) are located directly below the central through holes of the two second iron pieces (406). The two buffer components (5) are respectively set in the two lifting grooves (407).

3. The magnetic auxiliary circuit board jig according to claim 2, characterized in that: The buffer assembly (5) includes multiple buffer pads (501), multiple springs (502), a working groove (503), and a top rod (504). The buffer pads (501) are slidably connected in the lifting groove (407). The two ends of the multiple springs (502) are respectively connected to the buffer pads (501) and the bottom wall of the lifting groove (407). The working groove (503) is opened on one side of the lifting groove (407). The top rod (504) passes through the second fixed seat (404) and is slidably set in the working groove (503). The side wall of the buffer pads (501) is provided with a wedge-shaped slot (505).

4. The magnetic auxiliary circuit board fixture according to claim 3, characterized in that: The ejector assembly (6) includes a spur gear (601), a rack (602), a threaded rod (603), and a top plate (604). The spur gear (601) is rotatably connected to the top wall of the working groove (503). The rack (602) is fixedly connected to the side wall of the ejector rod (504). The rack (602) slides through the second fixed seat (404). The rack (602) and the spur gear (601) mesh with each other. The upper end of the threaded rod (603) is fixedly connected to the lower end of the spur gear (601). The lower end of the threaded rod (603) is rotatably connected to the bottom wall of the working groove (503). The top plate (604) is slidably connected to the working groove (503) and the lifting groove (407). The threaded rod (603) passes through one side of the top plate (604), and the threaded rod (603) is threadedly connected to the external top plate (604).

5. A magnetic auxiliary circuit board fixture according to claim 1, characterized in that: The positioning component (7) includes four positioning rods (701) and four positioning holes (702). The positioning rods (701) are fixedly connected to the four corners of the lower end of the upper mold body (3). The four positioning rods (701) are arranged in a rectangular array. The four positioning holes (702) are all opened at the upper end of the lower mold body (1). The four positioning rods (701) and the four positioning holes (702) correspond one-to-one.

6. The magnetic auxiliary circuit board fixture according to claim 1, characterized in that: Multiple guide rods (8) are fixedly connected to both sides of the lower end of the two pads (2), and multiple guide grooves (9) are opened on the upper end of the lower mold body (1). The multiple guide rods (8) correspond one-to-one with the multiple guide grooves (9).

7. A magnetic auxiliary circuit board fixture according to claim 3, characterized in that: The second fixed seat (404) has a telescopic rod (10) on its side wall. The fixed end of the telescopic rod (10) is connected to the side wall of the second fixed seat (404), and the telescopic end of the telescopic rod (10) is fixedly connected to the side wall of the top rod (504).

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