Anti-countercurrent junction box

Abstract

The utility model relates to the field of junction boxes, in particular to an anti-countercurrent junction box which comprises a box body, an anti-countercurrent module and a heat dissipation module are arranged on the box body, the anti-countercurrent module comprises a chip, a jumper wire and a wiring copper sheet, the chip, the jumper wire and the wiring copper sheet are all installed in the box body, the chip is connected with the jumper wire, and the heat dissipation module is connected with the heat dissipation module. The wiring copper sheet is used for communicating the chip and the jumper wire with an external cable, the heat dissipation module is used for dissipating heat of the anti-backflow module, the box body is further filled with sealant, an upper cover is further installed at the upper end of the box body, and the upper cover is used for covering the sealant. The problem that the service life of an anti-reflux device in a traditional mode is short is solved, and the effect of prolonging the service life of the anti-reflux junction box can be achieved.

Description

Technical Field

[0001] This application relates to the field of junction boxes, and more particularly to a backflow prevention junction box. Background Technology

[0002] In photovoltaic (PV) systems, if a module or string malfunctions (such as due to shading or damage), current may flow backward into the faulty module, causing energy loss and equipment damage. To address this, PV systems are typically equipped with anti-reverse current junction boxes, usually installed at the output end of the PV system. These boxes block this reverse current, ensuring that current flows only from the PV system to the inverter or load, thus protecting the PV system and system safety and preventing efficiency losses or equipment damage caused by reverse current.

[0003] The anti-backflow devices used in the existing technology usually fix the cable terminals to the outside of the junction box, that is, external anti-backflow devices. This fixing method will cause the cable terminals to come into direct contact with the air, which cannot meet the basic requirements of waterproof and dustproof, and is prone to safety hazards and product failure, thus resulting in a short service life of the junction box. Utility Model Content

[0004] To improve the service life of the anti-backflow device, this application provides an anti-backflow junction box.

[0005] This application provides a backflow prevention junction box, which adopts the following technical solution:

[0006] A backflow prevention junction box includes a box body, an backflow prevention module and a heat dissipation module on the box body. The backflow prevention module includes a chip, jumpers and copper contacts, all of which are installed in the box body. The chip and jumpers are connected, and the copper contacts are used to connect the chip and jumpers to external cables. The heat dissipation module is used to dissipate heat from the backflow prevention module. The box body is also filled with sealant, and a top cover is installed on the upper end of the box body to cover the sealant.

[0007] By adopting the above technical solution, the chip, jumper wire, and copper connector are all placed inside the box. After connecting the cable to the copper connector in the anti-backflow module, sealant is injected into the box to seal the anti-backflow module and the connection between the anti-backflow module and the cable. This reduces the exposure of the connection between the anti-backflow module and the cable to the air. The box is sealed by the top cover to keep the components inside the box sealed. A heat dissipation module is installed at the bottom of the box to dissipate heat from the anti-backflow module, thereby improving the service life of the anti-backflow junction box.

[0008] In one specific implementation, the anti-backflow module further includes an insulating plate located inside the housing, which is connected to the chip, jumper wires, and copper wiring contacts, and is used to conduct heat to the heat dissipation module.

[0009] By adopting the above technical solution and setting up an insulating plate, the heat dissipated by the chip, jumper wires and copper wires during operation is transferred to the heat dissipation module, thereby facilitating the maintenance of the anti-backflow module within a suitable operating temperature range and reducing the probability of failure of the anti-backflow module.

[0010] In one specific implementation, the heat dissipation module includes a heat dissipation aluminum fin, which is installed at the bottom of the box and connected to an insulating plate in the anti-backflow module. The heat dissipation aluminum fin is also provided with an upper fin on the periphery of the box and a lower fin on the side away from the box.

[0011] By adopting the above technical solution, by setting up heat dissipation aluminum fins, the heat dissipation aluminum fins are made to contact the anti-backflow module, thereby absorbing the heat in the anti-backflow module, and transferring it to the air through the upper and lower fins, thus facilitating the heat dissipation of the anti-backflow module.

[0012] In one specific implementation, the housing is further provided with a positioning component, which includes a positioning bolt for positioning the anti-backflow module on the heat dissipation module.

[0013] By adopting the above technical solution and setting positioning bolts, the anti-backflow module can be installed on the heat dissipation module, thereby facilitating the stability of the connection between the anti-backflow module and the heat dissipation module.

[0014] In one specific implementation, the bottom of the housing is also coated with adhesive, which is used to adhere the housing to the heat dissipation module.

[0015] By adopting the above technical solution and using adhesive, the box body and the heat dissipation module can be connected more tightly, and the sealing of the connection between the box body and the heat dissipation module can be further improved.

[0016] In one specific implementation, the heat dissipation aluminum fin is further provided with positioning holes, and the heat dissipation aluminum fin is installed on the outside of the photovoltaic device through the positioning holes.

[0017] By adopting the above technical solution and setting positioning holes, the junction box can be easily installed on the outside of the photovoltaic equipment.

[0018] In one specific implementation, a connection module is installed on the heat dissipation module. The connection module includes a connecting sleeve, a connecting component, and a clamping component. The connecting sleeve is used to be installed on the heat dissipation aluminum fin. The connecting component is installed on the connecting sleeve and is also connected to the heat dissipation aluminum fin. The clamping component is installed on the connecting sleeve and is used to clamp onto an external photovoltaic device.

[0019] By adopting the above technical solution, when there is no flat surface for installing heat dissipation aluminum fins in the photovoltaic equipment, a connection module is set up to connect the heat dissipation aluminum fins to the connection sleeve through the connection component. Then, the clamping component is used to clamp the parts of the photovoltaic equipment with protrusions or ridges, or to directly clamp the photovoltaic equipment, so that the junction box can adapt to different installation environments.

[0020] In one specific implementation, the clamping assembly includes a mounting block, a first clamping plate, a second clamping plate, and a clamping screw. The mounting block is mounted on a connecting sleeve, and the clamping screw is mounted in the mounting block. An adjusting handwheel is also mounted at the end of the clamping screw, and the portion of the clamping screw located inside the mounting block is provided with a positive thread and a negative thread. The first clamping plate and the second clamping plate are both slidably mounted on the mounting block, and the first clamping plate is connected to the positive thread on the clamping screw, while the second clamping plate is connected to the negative thread on the clamping screw.

[0021] By adopting the above technical solution, the clamping screw is rotated to drive the first clamping plate and the second clamping plate to move, thereby facilitating the clamping of the photovoltaic equipment through the first clamping plate and the second clamping plate, and thus facilitating the installation of the junction box.

[0022] In summary, this application includes at least one of the following beneficial effects:

[0023] 1. This application integrates the anti-backflow module entirely within the junction box. After the anti-backflow module is connected to the cable, sealant is injected into the junction box to seal the anti-backflow module and the connection point between the anti-backflow module and the cable. This improves the sealing performance of the junction box, reduces the impact of moisture and dust in the air on the anti-backflow module and the connection point between the anti-backflow module and the cable, and thus extends the service life of the anti-backflow junction box.

[0024] 2. By setting up a connection module, this application enables the junction box to be installed on photovoltaic equipment with different external structures, thereby facilitating the universality of the anti-reverse current junction box installation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the anti-backflow junction box of this application.

[0026] Figure 2This is an exploded view of the junction box in Embodiment 1 of this application.

[0027] Figure 3 This is a top view of the anti-backflow module installed inside the box in Embodiment 1 of this application.

[0028] Figure 4 This is a schematic diagram of the installation of the connection module in Embodiment 2 of this application.

[0029] Figure 5 This is an exploded view of the connection module in Embodiment 2 of this application.

[0030] Figure 6 This is a schematic diagram of the installation of the clamping assembly in Embodiment 2 of this application.

[0031] Figure 7 This is a schematic diagram of the anti-loosening component in Embodiment 2 of this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Housing; 11. Positioning rod; 12. Pressure block; 13. Top cover; 2. Anti-backflow module; 21. Chip; 22. Jumper wire; 23. Wiring copper plate; 24. Insulating plate; 3. Positioning bolt; 4. Heat dissipation module; 41. Heat dissipation aluminum fin; 42. Upper fin; 43. Lower fin; 44. Folding plate; 45. Positioning hole; 5. Sealant; 6. Connecting module; 61. Connecting sleeve; 611. Slot; 612. Unlocking slot; 62. Connecting assembly; 621. Connecting rod; 621 1. Baffle; 622. Connecting spring; 623. Connecting block; 63. Clamping assembly; 631. Mounting block; 6311. Adjusting groove; 632. First clamping plate; 633. Second clamping plate; 634. Clamping screw; 6341. Positive thread; 6342. Negative thread; 6343. Limiting hole; 635. Adjusting handwheel; 6351. Locking tooth; 636. Anti-detachment plate; 637. Anti-loosening component; 6371. Fastening ring; 6372. Fastening tooth; 6373. Positioning pin. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the accompanying drawings.

[0035] Example 1:

[0036] This application discloses an anti-backflow junction box, referring to... Figure 1 and Figure 2 It includes a housing 1, an anti-backflow module 2 installed inside the housing 1, and a heat dissipation module 4 installed outside the housing 1. The anti-backflow module 2 is connected to an external cable and is connected to the heat dissipation module 4 through a positioning component. The heat dissipation module 4 is used to dissipate heat from the anti-backflow module 2 inside the housing 1.

[0037] Reference Figure 2and Figure 3 The anti-backflow module 2 includes a chip 21, a jumper 22, copper contact plates 23, and an insulating plate 24. Two copper contact plates 23 are provided. The chip 21 is placed between the two copper contact plates 23, and the jumper 22 is placed between the chip 21 and one of the copper contact plates 23. The copper contact plates 23, chip 21, and jumper 22 are then soldered together. The insulating plate 24 is made of ceramic material. The soldered copper contact plates 23, chip 21, jumper 22, and insulating plate 24 are molded together with the insulating plate 24 using a molding process. During molding, adhesive is injected, so that the copper contact plates 23, chip 21, jumper 22, insulating plate 24, and injected adhesive ultimately form the anti-backflow module 2 after molding. The chip 21 and jumper 22 are existing technologies in the field and will not be described in detail here.

[0038] Reference Figure 2 A positioning rod 11 is fixedly installed vertically on the inner wall of the box 1. The anti-backflow module 2 has a plug-in hole, and the anti-backflow module 2 is installed on the positioning rod 11 inside the box 1 through the plug-in hole. One end of an external cable is passed through the side wall of one end of the box 1 and soldered to one of the copper contact plates 23 inside the box 1. The end of another external cable is passed through the side wall of the other end of the box 1 and soldered to another copper contact plate 23 inside the box 1, thus completing the connection between the anti-backflow module 2 and the external cables. Pressure blocks 12 are welded to both ends of the box 1, and the pressure blocks 12 are used to cover the connection points between the external cables and the box 1.

[0039] Reference Figure 2 The heat dissipation module 4 includes a heat dissipation aluminum fin 41. The top wall of the heat dissipation aluminum fin 41 has several upper fins 42. A receiving groove for accommodating the housing 1 is left between the upper fins 42. The housing 1 is placed in the receiving groove and positioned and connected to the heat dissipation aluminum fin 41 by a positioning component. The positioning component includes a positioning bolt 3, which passes through the anti-backflow module 2 inside the housing 1 and is threadedly connected to the inner bottom wall of the receiving groove of the heat dissipation aluminum fin 41. A threaded blind hole for the positioning bolt 3 is provided on the inner bottom wall of the receiving groove of the heat dissipation aluminum fin 41. At this time, the insulating plate 24 in the anti-backflow module 2 is in close contact with the heat dissipation aluminum fin 41.

[0040] Reference Figure 2 The bottom wall of the heat dissipation aluminum fin 41 is provided with a lower fin 43, and the end of the heat dissipation aluminum fin 41 is provided with an L-shaped folding plate 44. The vertical section of the folding plate 44 is fixedly connected to the end of the heat dissipation aluminum fin 41, and the horizontal section of the folding plate 44 extends away from the heat dissipation aluminum fin 41. The bottom wall of the horizontal section of the folding plate 44 is also provided with a positioning hole 45, and the heat dissipation aluminum fin 41 can be installed on the outside of the photovoltaic device through the positioning hole 45.

[0041] The connection between the box body 1 and the heat dissipation aluminum fin 41 is also coated with adhesive (not shown in the figure). The adhesive is existing technology in this field and will not be described in detail here. The adhesive improves the firmness of the connection between the box body 1 and the heat dissipation aluminum fin 41 and reduces the amount of water vapor entering the box body 1 through the gap between the box body 1 and the heat dissipation aluminum fin 41.

[0042] Reference Figure 2 The box body 1 is also filled with sealant 5, which is used to waterproof and seal the anti-backflow module 2, reducing the contact between the metal parts inside the box body 1 and the air. The sealant 5 is existing technology in this field and will not be described in detail here. The box body 1 is also provided with a top cover 13, which is fastened to the top of the box body 1, and the top cover 13 further achieves the effect of waterproofing and dustproofing.

[0043] The working principle of this embodiment is as follows: The two copper terminals 23, chip 21, and jumper 22 in the anti-backflow module 2 are welded together to form a single unit. Then, the welded copper terminals 23, chip 21, and jumper 22 are molded together with the insulating board 24, and glue is injected during the molding process to ultimately form the anti-backflow module 2. The anti-backflow module 2 is then installed into the housing 1. The end of the cable is passed through the housing 1 and welded to the copper terminals 23 in the anti-backflow module 2. Finally, the pressure block 12 is welded to both ends of the housing 1 to cover the cable, completing the wiring.

[0044] After wiring, the box 1 is placed on the heat sink 41. The anti-backflow module 2 is connected to the heat sink 41 by the positioning bolt 3, so that the insulating plate 24 is in close contact with the heat sink 41, thereby improving the heat dissipation effect. Adhesive is applied to the connection between the box 1 and the heat sink 41 to make the connection between the box 1 and the heat sink 41 more secure and reduce the seepage of moisture from the connection between the box 1 and the heat sink 41.

[0045] Then, sealant 5 is injected into the box body 1, and the top cover 13 is fastened to the upper end of the box body 1, thereby completing the assembly of the junction box and further achieving the effect of waterproofing and dustproofing. Finally, the junction box is installed in the external photovoltaic equipment through the positioning holes 45 on the heat sink aluminum fin 41.

[0046] Example 2:

[0047] Reference Figure 4 and Figure 5The difference between this embodiment and Embodiment 1 is that a connection module 6 for connecting to a photovoltaic device is also installed on the heat sink aluminum fin 41. The connection module 6 includes a connecting sleeve 61, a connecting component 62, and a clamping component 63. The connecting sleeve 61 has a slot 611 for inserting the folding plate 44 on the heat sink aluminum fin 41. The connecting component 62 includes a connecting rod 621, a connecting spring 622, and a connecting block 623. The connecting rod 621 is slidably installed on the connecting sleeve 61 in a direction perpendicular to the top wall of the connecting sleeve 61, and the connecting rod 621 passes through the connecting sleeve 61. The connecting rod 621 is used to insert into the positioning hole 45 on the heat sink aluminum fin 41. A baffle 6211 is fixedly installed on the side wall of the part of the connecting rod 621 above the connecting sleeve 61. The connecting spring 622 is sleeved on the connecting rod 621, and one end of the connecting spring 622 abuts against the top wall of the connecting sleeve 61, and the other end abuts against the bottom wall of the baffle 6211. (Refer to...) Figure 5 and Figure 6 The connecting block 623 is fixedly installed on the side wall of the connecting rod 621 at the end away from the baffle 6211, and the top wall of the connecting block 623 is used to abut against the bottom wall of the connecting sleeve 61. The bottom wall of the connecting sleeve 61 is provided with an unlocking groove 612 for the connecting block 623 to pass through. A marking block (not shown in the figure) is provided at the upper end of the connecting rod 621. The marking block is located above the baffle 6211, and the marking block and the connecting block 623 are located in the same vertical plane.

[0048] Reference Figure 5 and Figure 6 By placing the connecting sleeve 61 onto the folded plate 44 of the heat sink aluminum fin 41, aligning the connecting rod 621 on the connecting sleeve 61 with the positioning hole 45 on the heat sink aluminum fin 41, and then rotating the connecting rod 621, causing the connecting rod 621 to drive the marking block to rotate, so that the marking block of the connecting rod 621 rotates to be in the same vertical plane as the unlocking groove 612, and then pressing the connecting rod 621 downward, so that the connecting spring 622 is compressed, and the connecting rod 621 drives the connecting block 623 to pass through the positioning hole 45 on the heat sink aluminum fin 41 and out of the unlocking groove 612 on the bottom wall of the connecting sleeve 61. Then rotate the connecting rod 621 again, so that the connecting block 623 is misaligned with the unlocking groove 612, and then release the connecting rod 621. Under the action of the connecting spring 622, the connecting rod 621 tends to move upward, so that the connecting rod 621 drives the connecting block 623 to abut against the bottom wall of the connecting sleeve 61, thereby completing the purpose of positioning the connecting sleeve 61 on the heat sink aluminum fin 41.

[0049] Reference Figure 5 and Figure 6The clamping assembly 63 includes a mounting block 631, a first clamping plate 632, a second clamping plate 633, a clamping screw 634, and an anti-loosening component 637. The mounting block 631 is rotatably mounted on the bottom wall of the connecting sleeve 61. An adjustment groove 6311 is also provided on the bottom wall of the mounting block 631, which is arranged along the length direction of the mounting block 631. The clamping screw 634 is rotatably mounted in the adjustment groove 6311 of the mounting block 631 along the length direction of the mounting block 631. The clamping screw 634 is provided with two sections of threads with opposite directions of rotation, i.e., positive and negative threads. The threads 6341 and 6342 are respectively located on both sides of the middle part of the clamping screw 634. The upper ends of the first clamping plate 632 and the second clamping plate 633 are slidably installed in the adjusting groove 6311, and the upper ends of the first clamping plate 632 and the second clamping plate 633 are threadedly connected to the clamping screw 634. The upper end of the first clamping plate 632 is located at the positive thread 6341 of the clamping screw 634, and the upper end of the second clamping plate 633 is located at the reverse thread 6342 of the clamping screw 634.

[0050] Reference Figure 6 and Figure 7 The clamping screw 634 has smooth ends that both pass through the sidewall of the mounting block 631. The end of the clamping screw 634 is slidably connected to the sidewall of the end of the mounting block 631, and an adjusting handwheel 635 is coaxially mounted on one end of the clamping screw 634. The anti-loosening component 637 includes a fastening ring 6371 and a positioning pin 6373. The fastening ring 6371 is fixedly mounted on the sidewall of the mounting block 631 near the end of the adjusting handwheel 635, and the fastening ring 6371 is sleeved on the clamping screw 634. Several fastening teeth 6372 are fixedly mounted on the sidewall of the fastening ring 6371 near the adjusting handwheel 635. Several locking teeth 6351 are fixedly mounted on the sidewall of the adjusting handwheel 635 near the fastening ring 6371. The locking teeth 6351 are used to engage with the fastening teeth 6372. A limiting hole 6343 is provided on the side wall of the end of the clamping screw 634 away from the adjusting handwheel 635. The axis of the limiting hole 6343 is perpendicular to the axis of the clamping screw 634 and passes through the clamping screw 634. The positioning pin 6373 is used to be inserted into the limiting hole 6343 of the clamping screw 634. When the side wall of the positioning pin 6373 is used to abut against the side wall of the mounting block 631, the fastening ring 6371 engages with the locking tooth 6351.

[0051] Reference Figure 6 An anti-detachment plate 636 is also fixedly installed at the end of the clamping screw 634 away from the adjusting handwheel 635. The anti-detachment plate 636 is used to abut against the side wall of the mounting block 631, and the limiting hole 6343 is located between the anti-detachment plate 636 and the adjusting handwheel 635.

[0052] The working principle of this embodiment is as follows: When the surface of the external photovoltaic device has protruding edges and does not have a flat mounting surface, the connecting sleeve 61 is placed on the folded plate 44 of the heat sink aluminum fin 41, and then the connecting assembly 62 positions the connecting sleeve 61 on the heat sink aluminum fin 41. Then, the adjusting handwheel 635 is pulled, causing the adjusting handwheel 635 to drive the clamping screw 634 to move, thereby separating the locking teeth 6351 and the fastening teeth 6372 on the adjusting handwheel 635. Then, the adjusting handwheel 635 is rotated, causing the adjusting handwheel 635 to drive the clamping screw 634 to rotate, thereby driving the first clamping plate 632 to move through the positive thread 6341 on the clamping screw 634, and driving the second clamping plate 633 to move through the negative thread 6342 on the clamping screw 634, thereby shortening the distance between the first clamping plate 632 and the second clamping plate 633 until the first clamping plate 632 and the second clamping plate 633 clamp the protruding edges on the surface of the photovoltaic device. Then, push the mounting block 631, causing the mounting block 631 to move the fastening ring 6371 towards the adjusting handwheel 635. This causes the clamping screw 634, the first clamping block, and the second clamping block to move relative to the mounting block 631, making the fastening teeth 6372 on the fastening ring 6371 engage with the locking teeth 6351. At this time, the limiting hole 6343 at the end of the clamping screw 634 away from the adjusting handwheel 635 moves from inside the mounting block 631 to outside the mounting block 631. Finally, insert the positioning pin 6373 into the limiting hole 6343, thereby limiting the clamping screw 634 to its current position. This keeps the fastening teeth 6372 engaged with the locking teeth 6351, reducing the possibility of the clamping screw 634 becoming loose. This makes it easier to keep the first clamping plate 632 and the second clamping plate 633 clamping the protrusions on the photovoltaic equipment for a long time, thus ensuring the stable installation of the junction box.

[0053] The above are preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be included within the scope of protection of this application.

Claims

1. A backflow prevention junction box, comprising a box body (1), characterized in that: The box (1) is provided with an anti-backflow module (2) and a heat dissipation module (4). The anti-backflow module (2) includes a chip (21), a jumper (22) and a copper wire (23). The chip (21), jumper (22) and copper wire (23) are all installed in the box (1). The chip (21) and jumper (22) are connected. The copper wire (23) is used to connect the chip (21) and jumper (22) to external cables. The heat dissipation module (4) is used to dissipate heat from the anti-backflow module (2). The box (1) is also filled with sealant (5). The upper end of the box (1) is also equipped with a top cover (13). The top cover (13) is used to cover the sealant (5).

2. The anti-backflow junction box according to claim 1, characterized in that: The anti-backflow module (2) also includes an insulating plate (24), which is located inside the housing (1) and is connected to the chip (21), jumper (22) and wiring copper plate (23). The insulating plate (24) is used to conduct heat to the heat dissipation module (4).

3. The anti-backflow junction box according to claim 2, characterized in that: The heat dissipation module (4) includes a heat dissipation aluminum fin (41), which is installed at the bottom of the box (1) and is connected to the insulating plate (24) in the anti-backflow module (2). The heat dissipation aluminum fin (41) is also provided with an upper fin (42) on the periphery of the box (1) and a lower fin (43) on the side away from the box (1).

4. The anti-backflow junction box according to claim 1, characterized in that: The box (1) is also provided with a positioning component, which includes a positioning bolt (3) for positioning the anti-backflow module (2) on the heat dissipation module (4).

5. The anti-backflow junction box according to claim 1, characterized in that: The bottom of the box (1) is also coated with adhesive, which is used to adhere the box (1) to the heat dissipation module (4).

6. The anti-backflow junction box according to claim 3, characterized in that: The heat dissipation aluminum fin (41) is also provided with a positioning hole (45), and the heat dissipation aluminum fin (41) is installed on the outside of the photovoltaic device through the positioning hole (45).

7. A backflow prevention junction box according to claim 3, characterized in that: A connection module (6) is installed on the heat dissipation module (4). The connection module (6) includes a connecting sleeve (61), a connecting component (62), and a clamping component (63). The connecting sleeve (61) is used to be installed on the heat dissipation aluminum fin (41). The connecting component (62) is installed on the connecting sleeve (61) and is also connected to the heat dissipation aluminum fin (41). The clamping component (63) is installed on the connecting sleeve (61) and is used to clamp onto an external photovoltaic device.

8. A backflow prevention junction box according to claim 7, characterized in that: The clamping assembly (63) includes a mounting block (631), a first clamping plate (632), a second clamping plate (633), and a clamping screw (634). The mounting block (631) is mounted on the connecting sleeve (61), and the clamping screw (634) is mounted in the mounting block (631). An adjusting handwheel (635) is also mounted on the end of the clamping screw (634). The clamping screw (634) has a positive thread (6341) and a negative thread (6342) on the part of the clamping screw (631) located in the mounting block (631). The first clamping plate (632) and the second clamping plate (633) are both slidably mounted on the mounting block (631). The first clamping plate (632) is connected to the positive thread (6341) on the clamping screw (634), and the second clamping plate (633) is connected to the negative thread (6342) on the clamping screw (634).

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