CN117696689A - A high-precision straight plate bending machine - Google Patents

Abstract

The invention discloses a high-precision straight plate bending machine, which relates to the field of bending equipment. It includes a bending machine body. The bending machine body is provided with a pressing plate for bending plates. The lower end of the bending machine body There is a support platform fixedly connected. The upper end of the support platform is provided with a positioning mold for limiting the position of the plate. One end of the pressure plate along the length direction is fixedly connected with a connecting block. The height of the connecting block is less than the height of the pressure plate. The connecting block is located directly above the support platform. , the lower end of the connecting block is equipped with a pressure knife adapted to the positioning mold. This application has the effect of improving the convenience of bending machine processing.

Description

A high-precision straight plate bending machine

Technical field

The invention relates to the field of bending equipment, and in particular to a high-precision straight plate bending machine.

Background technique

A bending machine is a machine that can bend plates. It can use special or general molds to bend cold metal plates into workpieces of various geometric cross-section shapes. It is mainly used in cold-rolled sheet metal processing design. sheet forming process.

For related technology, please refer to the Chinese patent with announcement number CN217798225U, which discloses a bending machine, including a machine body. The side wall of the machine body is provided with a bending opening. A workbench is provided at the bending opening. The workbench can be raised and lowered with a downward pressure. The lower mold is provided with a first molding groove and a second molding groove. An upper mold can be lifted and lowered on the workbench. The upper mold and the lower mold are arranged oppositely, and the upper mold faces the lower mold. One side of the body is provided with a press knife for cooperating with the first forming groove and the second forming groove, and the body is provided with a driving die to separate from the workbench so that the first forming groove and the second forming groove are All driving components can cooperate with the press knife and bend the metal sheet. When bending the plate, the driving assembly drives the first forming groove or the second forming groove to cooperate with the press knife to bend the metal plate, so that the bending angle of the metal plate changes, without replacing the lower die. It saves manpower and time and achieves the effect of improving bending efficiency.

Regarding the above-mentioned related technologies, during the production process of some workpieces, the same plate needs to be bent twice to form a "凵"-shaped structure. When processing this part, it is necessary to bend the plate once so that the plate forms two mutually perpendicular short sides, one long and one short. However, when the long side is bent twice, the long side is easily moved during the bending process. The folded short side is pressed upward or the press knife is close to it. When the length of the short side is long, it is used to collide with the bending machine, resulting in inconvenience when processing the workpiece. Therefore, there is an urgent need for a bending method that is convenient for processing the above workpiece. equipment.

Contents of the invention

In order to facilitate processing of the above workpieces, this application provides a high-precision straight plate bending machine.

This application provides a high-precision straight plate bending machine, which adopts the following technical solution:

A high-precision straight plate bending machine includes a bending machine body. The bending machine body is provided with a pressing plate for bending the plate. The lower end of the bending machine body is fixedly connected to a support table, and the upper end of the support table is provided with a For the positioning mold that limits the position of the plate, one end of the pressure plate along the length direction is fixedly connected with a connecting block. The height of the connecting block is smaller than the height of the pressure plate. The connecting block is located directly above the support platform. The lower end of the connecting block is equipped with a connection block that is adapted to the positioning mold. The pressure knife.

By adopting the above technical solution, the bending machine body supports the positioning mold through the support table, places the plate that has been bent once on the positioning mold, and makes the long side of the plate conflict with the positioning mold, and the bending machine body is driven and connected by the pressure plate The block is pressed down so that the connecting block bends the long side of the plate through the pressure knife and the positioning die. During the bending process of the long side, the short side formed by one bending is driven to extend above the connecting block. When the short side conflicts with the connecting block , the long side reaches the required bending angle, and the connecting block is not easy to interfere with the movement of the short side, which is beneficial to improving the convenience of the bending machine body when processing "凵"-shaped workpieces.

Optionally, the upper end of the pressure knife is fixedly connected to a connecting plate, and the connecting block is provided with an installation slot along the length direction that is adapted to the connecting plate. The connecting plate is slidably connected to the connecting block along the length direction of the installation slot, and the connecting plate is provided with a connecting plate. Bolts, connecting bolts pass through the connecting plate and are threadedly connected to the connecting block.

By adopting the above technical solution, the connecting block limits the connecting plate through the installation groove. Under the connection action of the connecting bolt, the connecting block drives the connecting plate to move when it moves. By removing the connecting bolt, it is beneficial to improve the convenience when replacing the pressure knife.

Optionally, the support platform is provided with a support block. The support block has a chute along the transverse direction. The lower end of the positioning mold is fixedly connected with an inserting plate that is adapted to the chute. The inserting plate is located in the chute and conflicts with the supporting block. The support platform is provided with a limiting component for positioning the support block.

By adopting the above technical solution, under the action of the limiting component, the supporting block is in a stationary state. When the inserting plate is slidingly connected in the chute, the supporting block limits the positioning mold through the cooperation between the chute and the inserting plate. The mold and support block are detachable, which is helpful to improve the convenience when replacing the positioning mold.

Optionally, the limiting assembly includes two sets of support plates, a number of threaded rods and two clamping blocks. The two sets of support plates are located on both sides of the support platform, and all support plates are fixedly connected to the support platform. The threaded rods Positioned one by one with the support plates, the threaded rod passes through the corresponding support plate in the axial direction and is threadedly connected to the support plate. The two clamping blocks are located between the two sets of support plates. The support block is located between the two clamping blocks. One side of the tight block is in contact with the threaded rod, and the other side is in contact with the support block.

By adopting the above technical solution, the support platform positions the threaded rods through the support plate, so that all the threaded rods cooperate to limit the corresponding clamping blocks. Under the abutting action of the threaded rods, the two clamping blocks clamp the support block. Tight positioning. When the threaded rod is rotated, the threaded rod drives the support block to move through the clamping block, thereby facilitating the adjustment of the position of the support block and the positioning mold.

Optionally, a buffer pad is connected to the upper end of the connecting block, and the buffer pad is located on the side of the connecting block close to the workpiece.

By adopting the above technical solution, the short side of the workpiece conflicts with the buffer pad when it approaches the connecting block, and the buffer pad helps reduce the probability of the connecting block damaging the workpiece.

Optionally, a horizontal plate is fixedly connected to one side of the support platform, and a bearing plate is provided at the upper end of the horizontal plate. The horizontal plate limits the bearing plate so that the bearing plate moves along the length direction, and a positioning plate is provided at the upper end of the bearing plate. The load-bearing plate is provided with an adjusting rod for positioning the positioning plate. When the load-bearing plate moves, the positioning plate is driven toward or away from the workpiece. An abutment plate is provided at one end of the positioning plate close to the support platform.

By adopting the above technical solution, in the initial state, the load-bearing plate is located at the end of the horizontal plate away from the support table. After completing the bending process of the workpiece, the load-bearing plate is moved in the direction close to the support table. When the load-bearing plate moves, the positioning is driven by the adjusting rod. The plate moves. When the load-bearing plate moves to the maximum displacement, the abutting plate conflicts with the workpiece. At this time, the short side formed by the secondary bending of the workpiece reaches the required angle, which is beneficial to improving the accuracy of bending the workpiece.

Optionally, a vertical plate is vertically fixed on the side of the load-bearing plate away from the support platform. The adjusting rod passes through the vertical plate in the horizontal direction and is connected to the vertical plate by rotation. The adjusting rod is fixedly connected to a rotating handle on the side facing away from the supporting platform. The handle is in contact with the side of the vertical plate away from the support platform, and the end of the adjustment rod close to the support platform is provided with external threads and is threadedly connected to the positioning plate.

By adopting the above technical solution, the load-bearing plate limits the position of the adjusting rod through the cooperation of the vertical plate and the rotating handle, so that when the load-bearing plate moves, the adjusting rod drives the positioning plate to move. When the adjusting rod is rotated through the rotating handle, the adjusting rod drives the positioning plate to move. Move closer to or away from the support table to fine-tune the position of the positioning plate, thereby facilitating the positioning of bending workpieces at different angles.

Optionally, a mounting plate is fixedly connected to the side of the abutting plate close to the positioning plate. The positioning plate is provided with a supporting plate that is adapted to the mounting plate. The mounting plate is located above the supporting plate and is in contact with the supporting plate. The mounting plate is provided with There are two fixing bolts, which pass through the mounting plate and are threadedly connected to the supporting plate.

By adopting the above technical solution, the positioning plate supports the installation plate through the supporting plate. Under the connection of the fixing bolts, when the positioning plate moves, the mounting plate drives the abutment plate to move. The abutment plate can be detachably installed, thereby facilitating the alignment of the abutment plate. Remove and replace the adapter plate.

To sum up, this application includes at least one of the following beneficial technical effects:

1. The bending machine body supports the positioning mold through the support table. Place the plate that has been bent once on the positioning mold, and make the long side of the plate conflict with the positioning mold. The bending machine body drives the connecting block to press down through the pressure plate. The connecting block is used to bend the long side of the plate through the pressure knife and the positioning die. During the bending process of the long side, the short side formed by one bending is driven to extend above the connecting block. When the short side conflicts with the connecting block, the long side reaches At the required bending angle, the connecting block will not easily interfere with the movement of the short side, which will help improve the convenience of the bending machine body when processing "凵"-shaped workpieces;

2. The connecting block limits the connecting plate through the installation groove. Under the connection action of the connecting bolt, the connecting block drives the connecting plate to move when it moves. By removing the connecting bolt, it is helpful to improve the convenience when replacing the pressure knife;

3. In the initial state, the load-bearing plate is located at the end of the horizontal plate away from the support table. After completing the bending process of the workpiece, move the load-bearing plate closer to the support table. When the load-bearing plate moves, the positioning plate is driven by the adjusting rod to move. When the load-bearing plate moves to the maximum displacement, the abutting plate conflicts with the workpiece. At this time, the short side formed by the second bending of the workpiece reaches the required angle, which is beneficial to improving the accuracy of the workpiece bending.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of the embodiment.

Figure 2 is a partial schematic diagram intended to highlight the cooperation between the pressing knife and the positioning die.

Figure 3 is a schematic diagram intended to highlight the location of the positioning plate.

Explanation of reference signs: 1. Bending machine body; 11. Pressing plate; 21. Connecting block; 211. Installation slot; 212. Cushion pad; 22. Pressing knife; 221. Connecting plate; 222. Connecting bolts; 3. Supporting platform ; 31. Positioning mold; 311. Plug-in plate; 32. Support block; 321. Chute; 4. Limiting component; 41. Support plate; 42. Threaded rod; 43. Clamping block; 5. Horizontal plate; 51. Bearing plate; 511, vertical plate; 512, adjusting rod; 513, rotating handle; 52, positioning plate; 521, supporting plate; 53, abutting plate; 531, mounting plate; 532, fixing bolts.

Detailed ways

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

The embodiment of the present application discloses a high-precision straight plate bending machine.

Example:

Referring to Figures 1 and 2, a high-precision straight plate bending machine includes a bending machine body 1. The upper end of the bending machine body 1 is provided with a pressing plate 11. The pressing plate 11 is arranged vertically. The bending machine body 1 is equipped with a A driving member that drives the pressure plate 11 to move vertically. One end of the pressing plate 11 along the length direction is fixedly connected with a connecting block 21. When the pressing plate 11 moves, the connecting block 21 is driven to move.

Referring to Figures 1 and 2, a pressing knife 22 is provided at the lower end of the connecting block 21. A connecting plate 221 is fixed on one end of the pressing knife 22 close to the connecting block 21. The connecting block 21 is provided with a mounting slot 211, and the connecting plate 221 is located in the mounting slot 211. And it fits the inner wall of the installation groove 211 . The connecting plate 221 is provided with two connecting bolts 222 , and both of the two connecting bolts 222 pass through the connecting plate 221 and are threadedly connected to the connecting block 21 . The connecting block 21 cooperates with the connecting bolt 222 to position the connecting plate 221, so that when the connecting block 21 moves, the connecting plate 221 drives the pressing knife 22 to move. The connecting block 21 limits the connecting plate 221 through the mounting groove 211, thereby improving the connection stability between the connecting block 21 and the connecting plate 221.

Referring to Figures 1 and 2, a support platform 3 is fixedly connected to the lower end of the bending machine body 1. The support platform 3 is located directly below the connecting block 21. When the connecting block 21 moves, it drives the pressure knife 22 to move closer to or away from the support platform 3. The upper end of the support platform 3 is provided with a positioning mold 31. The upper end of the positioning mold 31 is provided with a triangular groove. The angle of the triangular groove is adapted to the required bending angle of the workpiece. There is a support block 32 between the support platform 3 and the positioning mold 31. The upper end of the support block 32 is provided with a chute 321 along the length direction. The lower end of the positioning mold 31 is fixedly connected with an inserting plate 311 adapted to the chute 321. The inserting plate 311 It is inserted into the chute 321 and conflicts with the support block 32. The support block 32 limits the positioning mold 31 through the chute 321. When the support block 32 moves, it drives the positioning mold 31 to move.

Referring to Figures 1 and 2, the support platform 3 is provided with a limiting assembly 4. The limiting assembly 4 includes two sets of support plates 41, a number of threaded rods 42 and two clamping blocks 43. Two sets of support plates 41 are respectively located on both sides of the support platform 3 along the width direction, and the support plates 41 are vertically fixed to the support platform 3. In this embodiment, the number of the support plates 41 is four.

Referring to Figures 1 and 2, the threaded rod 42 corresponds to the support plate 41 one-to-one. The threaded rod 42 passes through the corresponding support plate 41 and is threadedly connected to the support plate 41. When the threaded rod 42 is rotated, the threaded rod 42 moves along the axial direction. The two clamping blocks 43 are between the two threaded rods 42 located on the same axis. The support block 32 is located between the two clamping blocks 43. Rotate the threaded rod 42 so that the threaded rod 42 pushes the clamping block 43 toward the support block. 32 approaches, when both clamping blocks 43 collide with the support block 32, the clamping block 43 limits the position of the support block 32 under the push of the threaded rod 42. At this time, the positioning die 31 is located directly below the blade.

Referring to Figures 1 and 2, by rotating the threaded rod 42, the threaded rod 42 pushes the clamping block 43 to move, so that the clamping block 43 drives the positioning mold 31 to move through the support block 32, thereby facilitating the adjustment of the position of the positioning mold 31. The workpiece that has been bent once is placed on the positioning mold 31 so that the long side of the workpiece conflicts with the positioning mold 31 and is located between the pressing knife 22 and the positioning mold 31 .

Referring to Figures 1 and 3, a horizontal plate 5 is fixedly connected to one side of the support platform 3. The horizontal plate 5 is arranged in the horizontal direction. The upper end of the horizontal plate 5 is slidingly connected to a load-bearing plate 51, and the lower end of the load-bearing plate 51 is fixedly connected to a trapezoidal block. , a trapezoidal groove is provided on the upper end surface of the horizontal plate 5 along the direction in which the horizontal plate 5 points to the support platform 3. The trapezoidal block is located in the trapezoidal groove and is slidingly connected to the horizontal plate 5 along the length direction of the trapezoidal groove.

Referring to FIGS. 1 and 3 , the horizontal plate 5 limits the bearing plate 51 so that the bearing plate 51 slides toward or away from the support platform 3 . A positioning plate 52 is provided above the bearing plate 51 , and the lower end of the positioning plate 52 conflicts with the bearing plate 51 . A vertical plate 511 is fixedly connected to the side of the bearing plate 51 away from the support platform 3. The bearing plate 51 is provided with an adjusting rod 512 corresponding to the positioning plate 52. The adjusting rod 512 passes through the vertical plate 511 and is rotationally connected to the vertical plate 511. A rotating handle 513 is coaxially fixed on the end of the adjusting rod 512 away from the support platform 3. When the rotating handle 513 rotates, the adjusting rod 512 is rotated. The diameter of the rotating handle 513 is larger than the diameter of the adjusting rod 512. The end of the rotating handle 513 close to the supporting platform 3 is in contact with the vertical plate. 511 conflict.

Referring to Figures 1 and 3, one end of the adjusting rod 512 close to the support platform 3 is provided with external threads and is threadedly connected to the positioning plate 52. Under the limiting action of the vertical plate 511, the adjusting rod 512 limits the positioning plate 52. When the bearing plate 51 moves, the positioning plate 52 is driven by the adjusting rod 512 to move. When the adjusting rod 512 is rotated, the adjusting rod 512 drives the positioning plate 52 away from or close to the vertical plate 511 .

Referring to Figures 1 and 3, an abutment plate 53 is provided at one end of the positioning plate 52 close to the support platform 3. A supporting plate 521 is fixedly connected to the end of the positioning plate 52 close to the supporting platform 3. The upper end surface of the supporting plate 521 is connected to the upper end surface of the positioning plate 52. There is a certain distance between them, and when the positioning plate 52 moves, it drives the supporting plate 521 to move. A mounting plate 531 is fixedly connected to one end of the abutting plate 53 close to the supporting plate 521. The lower end of the mounting plate 531 conflicts with the upper end of the supporting plate 521. Two fixing bolts 532 are provided above the mounting plate 531, and the fixing bolts 532 pass through the mounting plate 531. Threaded connection with supporting plate 521.

Referring to FIGS. 1 and 3 , under the connection between the supporting plate 521 and the mounting plate 531 , when the positioning plate 52 moves, the abutting plate 53 is driven to move. In the initial state, the bearing plate 51 is located away from the support platform 3 . When placing the workpiece, the end of the long side of the workpiece is brought into contact with the abutment plate 53. At this time, the length of the long side on the side of the press knife 22 is limited, thereby limiting the position of the workpiece, which is beneficial to improving the workpiece during secondary bending. positioning accuracy.

Referring to Figures 1 and 3, the bending machine body 1 drives the pressure plate 11 to move downward, so that the pressure plate 11 drives the pressure knife 22 to approach the long side of the workpiece through the connecting block 21. The pressure knife 22 cooperates with the positioning die 31 to align the long side of the workpiece. During the bending process, the long side of the workpiece is bent and deformed, driving the short side formed by the first bending to approach the connecting block 21 , and causing the end of the short side to extend above the connecting block 21 .

Referring to Figures 1 and 3, a buffer pad 212 is engaged with the upper end of the connecting block 21. When the lower end surface of the short side conflicts with the buffer pad 212, the angle between the long side of the workpiece and the pressing knife 22 reaches the required angle. The buffer pad 212 is helpful to reduce the probability of the connecting block 21 damaging the workpiece. At this time, the load-bearing plate 51 is moved toward the support platform 3. When the load-bearing plate 51 is at the end closest to the support platform 3, the abutment plate 53 conflicts with the short side formed by the second bending of the workpiece. At this time, the short side of the second bending The angle between the edge and the pressing knife 22 reaches the required angle, which is beneficial to improving the accuracy when bending the "凵"-shaped workpiece. When bending the workpiece, the connecting block 21 will not easily interfere with the deformation of the workpiece, making it more convenient to process the workpiece.

Referring to Figures 1 and 3, both the pressing knife 22 and the positioning die 31 are detachable, thereby facilitating the processing of different types of workpieces. When the long sides of the workpiece have different lengths, the adjusting rod 512 is rotated, and the adjusting rod 512 drives the positioning plate 52 to move closer to or away from the workpiece, thereby adjusting the horizontal distance between the abutting plate 53 and the pressing knife 22, so that the abutting plate 53 and the pressing knife 22 are Adapts to long sides of different lengths.

The implementation principle of a high-precision straight plate bending machine in the embodiment of the present application is as follows: place the workpiece that has been bent once on the positioning mold 31 so that one end of the long side of the workpiece conflicts with the abutment plate 53 . The bending machine body 1 drives the pressing plate 11 to move in the direction close to the support table 3. When the pressing plate 11 moves, the connecting block 21 drives the pressing knife 22 to approach the workpiece. The pressing knife 22 cooperates with the positioning die 31 to bend the long side of the workpiece. During the bending and deformation process of the long side of the workpiece, the short side formed by one bending is brought closer to the connecting block 21, and the end of the short side away from the long side extends above the connecting block 21. The connecting block 21 is not likely to interfere with the workpiece. A buffer pad 212 is provided at the upper end of the connecting block 21. When the lower end surface of the short side of the workpiece collides with the buffer pad 212, the bending machine body 1 is controlled to stop bending. At this time, the load-bearing plate 51 is pushed to move toward the workpiece, so that the load-bearing plate 51 drives the abutment plate 53 through the positioning plate 52 to conflict with the short side formed by the secondary bending of the workpiece. At this time, the workpiece reaches the required bending angle, which is beneficial to improving processing. Convenience when working with "凵" shaped workpieces.

The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application shall be covered by the scope of protection of the present application. Inside.

Claims (8)

1. A high-precision straight plate bending machine, including a bending machine body (1). The bending machine body (1) is provided with a pressing plate (11) for bending the plate, and is characterized in that: the bending machine The lower end of the body (1) is fixedly connected to a support table (3), the upper end of the support table (3) is provided with a positioning mold (31) for limiting the plate, and one end of the pressure plate (11) along the length direction is fixedly connected to a connection. Block (21), the height of the connecting block (21) is less than the height of the pressure plate (11), the connecting block (21) is located directly above the support platform (3), the lower end of the connecting block (21) is provided with a positioning mold (31) suitable for Comes with pressure knife (22). 2. A high-precision straight plate bending machine according to claim 1, characterized in that: the upper end of the press knife (22) is fixedly connected with a connecting plate (221), and the connecting block (21) is provided with a connecting plate (221) along the length direction. The mounting slot (211) is adapted to the connecting plate (221). The connecting plate (221) is slidably connected to the connecting block (21) along the length of the mounting slot (211). The connecting plate (221) is provided with connecting bolts (222). The connecting bolt (222) passes through the connecting plate (221) and is threadedly connected to the connecting block (21). 3. A high-precision straight plate bending machine according to claim 1, characterized in that: the support platform (3) is provided with a support block (32), and the support block (32) has a chute (321) along the transverse direction. ), the lower end of the positioning mold (31) is fixedly connected with an inserting plate (311) adapted to the chute (321). The inserting plate (311) is located in the chute (321) and conflicts with the supporting block (32). The supporting platform (3) A limiting component (4) is provided for positioning the support block (32). 4. A high-precision straight plate bending machine according to claim 3, characterized in that: the limiting assembly (4) includes two sets of support plates (41), a number of threaded rods (42) and two clamping Block (43), two sets of support plates (41) are located on both sides of the support platform (3), and all support plates (41) are fixedly connected to the support platform (3), and the threaded rod (42) and the support plate (41 ) are positioned one by one, the threaded rod (42) passes through the corresponding support plate (41) in the axial direction and is threadedly connected to the support plate (41). The two clamping blocks (43) are located between the two sets of support plates (41). , the support block (32) is located between the two clamping blocks (43), one side of the clamping block (43) is in contact with the threaded rod (42), and the other side is in contact with the support block (32). 5. A high-precision straight plate bending machine according to claim 1, characterized in that: the upper end of the connecting block (21) is connected with a buffer pad (212), and the buffer pad (212) is located on the connecting block (21) The side closest to the workpiece. 6. A high-precision straight plate bending machine according to claim 1, characterized in that: a horizontal plate (5) is fixedly connected to one side of the support platform (3), and the upper end of the horizontal plate (5) is provided with a The load-bearing plate (51) and the horizontal plate (5) limit the position of the load-bearing plate (51) so that the load-bearing plate (51) moves along the length direction. The upper end of the load-bearing plate (51) is provided with a positioning plate (52). The load-bearing plate (51) 51) is provided with an adjusting rod (512) for positioning the positioning plate (52). When the load-bearing plate (51) moves, the positioning plate (52) is driven toward or away from the workpiece, and the positioning plate (52) is close to the support table (3) One end is provided with abutting plate (53). 7. A high-precision straight plate bending machine according to claim 6, characterized in that: a vertical plate (511) is vertically fixed on the side of the load-bearing plate (51) away from the support platform (3), and an adjusting rod (511) is vertically fixed. 512) passes through the vertical plate (511) in the horizontal direction and is rotationally connected to the vertical plate (511). The side of the adjusting rod (512) facing away from the support platform (3) is fixedly connected with a rotating handle (513), and the rotating handle (513) is connected to the vertical plate (511). The side of the vertical plate (511) facing away from the support platform (3) abuts, and the end of the adjustment rod (512) close to the support platform (3) is provided with external threads and is threadedly connected to the positioning plate (52). 8. A high-precision straight plate bending machine according to claim 6, characterized in that: a mounting plate (531) is fixedly connected to the side of the abutment plate (53) close to the positioning plate (52), and the positioning plate (52) is provided with a supporting plate (521) adapted to the mounting plate (531). The mounting plate (531) is located above the supporting plate (521) and abuts against the supporting plate (521). The mounting plate (531) is provided with two A fixing bolt (532) passes through the mounting plate (531) and is threadedly connected to the supporting plate (521).