Laser tube cutting machine

Abstract

The present invention relates to a laser pipe cutting machine, comprising a machine body, a feeding mechanism, a clamping mechanism, a mounting plate rotatably connected to the machine body, a first motor provided on the machine body for driving the mounting plate to rotate, a sliding seat slidably connected to the mounting plate, a laser cutting head provided on the sliding seat, the clamping mechanism comprising a mounting frame provided on the frame, a slider slidably connected to the mounting frame, two clamping assemblies respectively provided on two sliders for clamping pipes, a first driving part for driving the two sliders to move, a first connecting block provided on the sliding seat, a second connecting block provided on one of the sliders, an arc-shaped slide groove provided on the second connecting block, the first connecting block and the arc-shaped slide groove slidingly cooperate, and a limiting assembly for limiting the sliding of the sliding seat provided on the machine body. The present invention only needs to adjust the movement trajectory of the slider so that the two clamping assemblies can clamp the pipe, so that the laser cutting head can cut the pipe.

Description

Technical Field

[0001] The invention relates to the field of pipe cutting machines, in particular to a laser pipe cutting machine. Background Art

[0002] Before processing pipe fittings, a pipe cutting machine is needed to cut a long pipe into sections of raw materials as required.

[0003] The Chinese patent with the announcement number CN106041323B discloses a laser cutting machine for cutting pipes, including a bed and a cutting mechanism for cutting pipes, the bed is equipped with a tube pneumatic clamping device and an adjustable limit mechanism for limiting the position of the pipe. The cutting mechanism includes a second first motor, a chuck, a laser cutting head and a servo first motor.

[0004] When the pipe to be cut by the above equipment is changed, the operator must readjust the clamping diameter of the pneumatic clamping device so that the pneumatic clamping device can effectively clamp the pipe, and then adjust the position of the laser cutting head on the chuck through the servo first motor so that the laser cutting head can cut the pipe. Therefore, the preparation work for pipe cutting is relatively cumbersome. Summary of the invention

[0005] The present application provides a laser tube cutting machine, which can enable the laser cutting head to cut the tube by simply adjusting the movement trajectory of the slider so that the two clamping components can clamp the tube.

[0006] The laser tube cutting machine provided in this application adopts the following technical solution:

[0007] A laser pipe cutting machine comprises a body, a feeding mechanism arranged on the body for pushing pipes, a clamping mechanism for clamping pipes, a mounting plate rotatably connected to the body and located between the clamping mechanism and the feeding mechanism, a first motor arranged on the body, the first motor and the mounting plate are connected by gear transmission, the mounting plate is slidably connected to a sliding seat, the sliding seat is provided with a laser cutting head, the movement direction of the sliding seat is the same as the movement direction of the slider, the clamping mechanism comprises a mounting frame arranged on the frame, a slider slidably connected to the mounting frame, two clamping assemblies respectively arranged on two sliders for clamping pipes, a first driving part for driving the two sliders to move, a first connecting block is provided on the sliding seat, one of the sliders is provided with a second connecting block, a surface of the second connecting block facing the mounting plate is provided with an arc groove, the first connecting block slides in cooperation with the arc groove, and the body is also provided with a limiting assembly for limiting the sliding of the sliding seat.

[0008] By adopting the above technical solution, before the pipe is cut, the moving paths of the two sliders are adjusted by the driving unit so that the two clamping assemblies can clamp the pipe. Then the pipe is fixed to the feeding mechanism, and the feeding mechanism will pass the pipe through the mounting plate and send it between the two clamping assemblies. Then the driving unit drives the two sliders to move closer to each other, so that the two clamping assemblies move closer to each other and finally clamp the pipe. When the two sliders move closer to each other, the second connecting block on one of the sliders will drive the sliding seat to move through the first connecting block so that the laser cutting head moves closer to the pipe, and finally the laser cutting head can cut the pipe. Then the limiting assembly limits the movement of the sliding seat, and then the first motor drives the mounting plate to rotate one circle. When the mounting plate rotates, it will drive the sliding seat and the laser cutting head to rotate so that the laser cutting head rotates and cuts the pipe. When the sliding seat rotates, the arc-shaped slide groove and the arc-shaped connecting block will be separated first, and then after the mounting plate rotates one circle, the arc-shaped connecting block will slide back into the arc-shaped slide groove. After the installation disk rotates one circle, the pipe is also cut. The cut pipe will be clamped by the two clamping components. At the same time, after the installation disk rotates one circle, the restriction of the sliding seat movement by the limiting component will be released. After the pipe is cut, the operator manually holds the cut pipe and uses the drive unit to move the two sliders to reset, so that the two clamping components no longer clamp the cut pipe, so that the cut pipe can be taken down. When the slider moves to reset, it will also drive the sliding seat to reset through the second connecting block and the first connecting block. When cutting pipes of different diameters, this equipment can adjust the movement trajectory of the slider so that the two clamping components can clamp the pipe, and at the same time adjust the position of the laser cutting head so that the laser cutting head can cut the pipe, simplifying the preparation work for pipe cutting.

[0009] Preferably, the limiting assembly includes a sliding groove provided on a side of the sliding seat facing the mounting plate, a limit block slidingly connected in the sliding groove, and a power assembly for driving the limit block to slide and make the limit block contact with the mounting plate.

[0010] By adopting the above technical solution, after the sliding seat moves and resets to the predetermined position so that the laser cutting head can cut the pipe, the power component drives the limit block to slide so that the limit block conflicts with the mounting disk. In this way, the friction between the limit block and the mounting disk can achieve the effect of limiting the movement of the sliding seat during the rotation of the mounting disk.

[0011] Preferably, the power assembly includes a first screw rod rotatably connected to a sliding seat, a gear disposed on the first screw rod, a first rack and a second rack disposed on opposite side walls of an arc-shaped sliding groove, one end of the first screw rod extends into the sliding groove, the other end of the first screw rod extends into the arc-shaped sliding groove, the limit block is threadedly connected to the first screw rod, the gear is located in the arc-shaped sliding groove, the first rack is used to mesh with the gear and drive the gear to rotate positively, the second rack is used to mesh with the gear and drive the gear to rotate negatively, and in an initial state, the gear is meshed with the first rack.

[0012] By adopting the above technical solution, when the mounting plate rotates, the gear will rotate forward under the action of the first rack and bring the first screw rod to rotate forward. When the first screw rod rotates forward, the limit block will slide toward the mounting plate. Finally, when the first rack and the gear separate from each other, the limit block and the mounting plate conflict with each other to achieve the effect of limiting the movement of the sliding seat. When the mounting plate is about to rotate one circle, the first connecting block first slides into the arc-shaped slide groove, and then the second rack engages with the gear. As the mounting plate continues to rotate, under the action of the second rack, the gear will rotate in the opposite direction and bring the first screw rod to rotate in the opposite direction. When the first screw rod rotates in the opposite direction, the limit block will move away from the mounting plate, thereby canceling the movement restriction of the sliding seat. Finally, when the mounting plate rotates one circle, the gear will mesh with the first rack again.

[0013] Preferably, a T-shaped slide groove is provided on the mounting plate, the sliding seat is a T-shaped block, the sliding seat is slidably connected in the T-shaped slide groove, a first avoidance hole for the pipe to pass through is provided in the middle of the mounting plate, the T-shaped slide groove is connected to the first avoidance hole, the first connecting block is located on one end of the sliding seat away from the first avoidance hole, and the laser cutting head is located on one end of the sliding seat close to the first avoidance hole.

[0014] By adopting the above technical solution, when the limit block and the mounting plate conflict with each other, the sliding seat will generate a force moving away from the mounting plate under the influence of the limit block. This force will make the sliding seat and the side wall of the T-shaped slide groove tightly attached, so that the friction between the sliding seat and the T-shaped slide groove becomes larger, so that the limit block has a better anti-displacement effect on the sliding seat.

[0015] Preferably, guide slopes are provided on the ends of both side walls of the arc-shaped slide groove, and a guide cavity is formed between the two guide slopes on the same side, and the guide cavity is used to enable the first connecting block to slide smoothly into the arc-shaped slide groove.

[0016] By adopting the above technical solution, the first connecting block can slide into the arc-shaped sliding groove more accurately during the rotation of the mounting plate.

[0017] Preferably, the clamping assembly includes a clamping head arranged on the slider and a mounting portion for mounting the clamping head on the slider, and a clamping space for fixing the pipe is formed between the two clamps.

[0018] By adopting the above technical solution, the clamping head can be disassembled, which allows the appropriate clamping head to be installed on the connecting column when cutting pipes of different diameters, so that the two clamping heads can clamp the pipes well. At the same time, the replaceable design of the clamping head also allows the machine to clamp special-shaped pipes such as Q-shaped pipes, so that the machine can also complete the cutting of special-shaped pipes.

[0019] Preferably, the mounting portion includes a countersunk hole formed on the chuck, a countersunk bolt provided on the slider, and a threaded hole formed on the connecting column and matched with the countersunk bolt.

[0020] By adopting the above technical solution, the connection method of the countersunk bolt and the threaded hole makes the connection and disassembly of the chuck very simple.

[0021] Preferably, the first driving part includes a second screw rod rotatably connected to the mounting frame, a second motor for driving the two second screw rods to rotate respectively, and a guide rod fixedly connected to the mounting frame, the second screw rod is provided with two first thread segments and a second thread end with opposite thread directions, one end of the two sliding blocks are slidably connected to the guide rod, and the other ends of the two sliding blocks are respectively threadedly connected to the first thread segment and the second thread segment.

[0022] By adopting the above technical solution, the second motor will rotate forward with the second screw rod, and when the second screw rod rotates forward, the two sliders will move closer to each other so that the two chucks can clamp the pipe. When the second motor rotates reversely with the second screw rod, the two sliders will move away from each other, so that the two chucks no longer clamp the pipe, and the cut pipe can be taken off the machine body.

[0023] The technical effects of the present invention are mainly reflected in the following aspects:

[0024] 1. The present invention only needs to adjust the motion trajectory of the slider so that the two clamping components can clamp the pipe and the laser cutting head can cut the pipe;

[0025] 2. When the mounting plate rotates, the first screw rod can be rotated forward and backward by the cooperation of the first rack, the second rack and the gear, thereby controlling the sliding of the limit block, so that the limit block and the mounting plate conflict with each other, thereby limiting the movement of the sliding seat;

[0026] 3. The detachable design of the chuck of the present invention allows the appropriate chuck to be installed on the connecting column when cutting pipes of different diameters, so that the two chucks can clamp the pipes well. At the same time, the replaceable design of the chuck also allows the machine to clamp special-shaped pipes such as Q-shaped pipes, so that the machine can also complete the cutting of special-shaped pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the laser tube cutting machine of the present application.

[0028] Figure 2 This is a schematic diagram of the structure of the laser tube cutting machine of the present application from another angle.

[0029] Figure 3 yes Figure 1 Schematic diagram of the structure of the clamping mechanism.

[0030] Figure 4 It is a structural schematic diagram of the slider and clamping assembly.

[0031] Figure 5 yes Figure 2 Structural diagram of the middle machine body, mounting plate, first motor, second connecting block, sliding seat, power assembly and other components.

[0032] Figure 6 yes Figure 5 Cross-sectional view of each component along line AA.

[0033] Figure 7 yes Figure 3 A partial enlarged view of point B in the middle.

[0034] Figure 8 yes Figure 6 A partial enlarged view of point C in the middle.

[0035] Figure numerals: 1, body; 11, mounting plate; 111, T-shaped slide; 112, first avoidance hole; 12, first motor; 2, feeding mechanism; 21, linear motor; 22, base; 23, clamp; 24, support frame; 3, clamping mechanism; 31, mounting frame; 32, slider; 33, clamping assembly; 331, chuck; 4, sliding seat; 41, laser cutting head; 42, first connecting block; 5, second connecting block; 51, arc-shaped slide; 52, Guide slope; 53, guide cavity; 6, limiting assembly; 61, sliding groove; 62, limit block; 63, power assembly; 631, first screw rod; 632, gear; 633, first rack; 634, second rack; 7, mounting portion; 71, countersunk hole; 72, countersunk bolt; 73, threaded hole; 8, first driving portion; 81, second screw rod; 82, second motor; 83, guide rod; 84, first threaded section; 85, second threaded end; 9, pipe. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings to make the technical solution of the present application easier to understand and grasp.

[0037] Reference Figure 1 and Figure 2 A laser tube cutting machine of this embodiment includes a machine body 1 and a feeding mechanism 2 disposed on the machine body 1 for pushing a tube 9. The feeding mechanism 2 includes a linear motor 21 disposed on the machine body 1, a base 22 disposed on the linear motor 21, a clamp 23 fixed on the base 22 for clamping the tube 9, and a plurality of support frames 24 fixed on the machine body 1 for supporting the tube 9.

[0038] Reference Figure 1 and Figure 3 A clamping mechanism 3 for clamping the pipe 9 is also installed at the end of the machine body 1. The clamping mechanism 3 includes a mounting frame 31 mounted on the frame, a slider 32, and a first driving unit 8 for driving the two sliders 32 to move. The first driving unit 8 includes a second screw rod 81 rotatably connected to the mounting frame 31, a second motor 82 for driving the two second screw rods 81 to rotate respectively, and a guide rod 83 fixedly connected to the mounting frame 31. The axial directions of the two second screw rods 81 are perpendicular to the conveying direction of the pipe 9. The two second screw rods 81 are provided with two first thread segments 84 and second thread ends 85 with opposite thread directions. One end of the two sliders 32 is threadedly connected to the first thread segment 84, and the other ends of the two sliders 32 are threadedly connected to the second thread segment.

[0039] Reference Figure 3 and Figure 4 The clamping mechanism 3 also includes two clamping assemblies 33 respectively arranged on the two sliders 32 for clamping the pipe 9. The two clamping assemblies 33 respectively include two clamps 331 installed on the side of the slider 32 close to each other, and two mounting parts 7 for mounting the clamps 331 on the slider 32, and a clamping space for fixing the pipe 9 is formed between the two clamps 331. The mounting part 7 includes a plurality of countersunk holes 71 provided on the clamps 331, a plurality of countersunk bolts 72 provided in the countersunk holes 71, and a plurality of threaded holes 73 provided on the slider 32 for bolting with the countersunk bolts 72.

[0040] Reference Figure 3 and Figure 4 The clamping head can be disassembled, so that when cutting pipes 9 of different diameters, the appropriate clamping head 331 can be installed on the connecting column, so that the two clamping heads 331 can well clamp the pipe 9. At the same time, the replaceable design of the clamping head 331 also allows the machine to clamp special-shaped pipes such as Q-shaped pipes, so that the machine can also complete the cutting of various special-shaped pipes.

[0041] Reference Figure 2 and Figure 5The machine body 1 is also rotatably connected to a mounting plate 11, which is located between the feeding mechanism 2 and the clamping mechanism 3, and is disposed close to the clamping mechanism 3. A first avoidance hole 112 is provided in the middle of the mounting plate 11 for the pipe 9 to pass through. The machine body 1 is also fixed with a first motor 12, which is connected to the mounting plate 11 by a gear 632.

[0042] Reference Figure 2 and Figure 5 , and a T-shaped slide groove 111 is provided on one side of the mounting plate 11 facing the clamping mechanism 3 along a direction perpendicular to the conveying direction of the pipe 9, the T-shaped slide groove 111 is connected to the first avoidance hole 112, and a sliding seat 4 is slidably connected in the T-shaped slide groove 111 along a direction perpendicular to the conveying direction of the pipe 9. A first connecting block 42 is fixed to one end of the sliding seat 4 away from the first avoidance hole 112, and a laser cutting head 41 is fixed to one end of the sliding seat 4 close to the first avoidance hole 112.

[0043] Reference Figure 2 , Figure 5-Figure 7 The first connecting block 42 has an arc shape, and an arc groove 51 is provided on the side of the second connecting block 5 facing the mounting plate 11 along the conveying direction of the pipe 9. The end of the first connecting block 42 away from the sliding seat 4 extends into the arc groove 51 and is slidably connected in the arc groove 51.

[0044] Reference Figure 5-Figure 8 The machine body 1 is also provided with a limiting assembly 6 for limiting the sliding movement of the sliding seat 4. The limiting assembly 6 includes a sliding groove 61 provided on the side of the sliding seat 4 facing the mounting plate 11, a limit block 62 slidably connected in the sliding groove 61 along the conveying direction of the pipe 9, and a power assembly 63 for driving the limit block 62 to slide and make the limit block 62 conflict with the mounting plate 11.

[0045] Reference Figure 5-Figure 8 The power assembly 63 includes a first screw rod 631 rotatably connected to the sliding seat 4, a gear 632 fixedly connected to the first screw rod 631, a first rack 633 and a second rack 634 respectively fixed to the opposite side walls of the arc-shaped slide groove 51. One end of the first screw rod 631 extends into the slide groove 61, and the other end of the first screw rod 631 extends into the arc-shaped slide groove 51. The limit block 62 is threadedly connected to the first screw rod 631, and the gear 632 is located in the arc-shaped slide groove 51. The first rack 633 is used to mesh with the gear 632 and drive the gear 632 to rotate in the positive direction, and the second rack 634 is used to mesh with the gear 632 and drive the gear 632 to rotate in the negative direction. In the initial state, the gear 632 is meshed with the first rack 633, and the first rack 633 is located on the side of the second rack 634 away from the ground.

[0046] Reference Figure 1-Figure 8 The specific pipe cutting process of the equipment in this application is as follows:

[0047] According to the diameter of the pipe 9 to be cut, the parameters such as the number of rotations of the output shaft of the second motor 82 are set, thereby controlling the number of rotations of the second screw rod 81 to achieve the effect of controlling the movement of the two sliders 32, so that the two chucks 331 can smoothly clamp the pipe 9.

[0048] After the parameters of the second motor 82 are set, the pipe 9 is fixed on the fixture, and the linear motor is started to move the base and the fixture, so that the pipe 9 passes through the first avoidance hole 112 and extends between the two clamps 331.

[0049] Then, when the second motor 82 rotates forward and drives the screw rod forward, the screw rod rotates forward, and the two sliders 32 move closer to each other, and when the two sliders 32 move closer to each other, the two clamps 331 move closer to each other and finally clamp the pipe 9. At the same time, when the slider 32 moves, the second connecting block 5 drives the sliding seat 4 to move through the first connecting block 42, so that the laser cutting head 41 moves closer to the pipe 9, and finally the laser cutting head 41 can cut the pipe 9.

[0050] Then the first motor 12 drives the mounting plate 11 to rotate one circle. When the mounting plate 11 rotates, it will drive the sliding seat 4 and the laser cutting head 41 to rotate, so that the laser cutting head 41 rotates and cuts the pipe 9. When the mounting plate 11 rotates, under the action of the first rack 633, the gear 632 will rotate forward and drive the first screw rod 631 to rotate forward. When the first screw rod 631 rotates forward, the limit block 62 will slide toward the mounting plate 11. Finally, when the first rack 633 and the gear 632 separate from each other, the limit block 62 and the mounting plate 11 conflict with each other to limit the movement of the sliding seat 4.

[0051] When the limit block 62 and the mounting plate 11 conflict with each other, the sliding seat 4 will generate a force moving away from the mounting plate 11 under the influence of the limit block 62. This force will make the sliding seat 4 and the side wall of the T-shaped slide groove 111 tightly attached, so that the friction between the sliding seat 4 and the T-shaped slide groove 111 becomes larger, further enhancing the effect of the limit block 62 on limiting the movement of the sliding seat 4.

[0052] When the mounting plate 11 is about to rotate one circle, the first connecting block 42 first slides into the arc-shaped sliding groove 51, and then the second rack 634 meshes with the gear 632. As the mounting plate 11 continues to rotate, under the action of the second rack 634, the gear 632 will rotate in the opposite direction and bring the first screw rod 631 to rotate in the opposite direction. When the first screw rod 631 rotates in the opposite direction, the limit block 62 will move away from the mounting plate 11, thereby removing the movement restriction on the sliding seat 4. Finally, when the mounting plate 11 rotates one circle, the gear 632 will mesh with the first rack 633 again.

[0053] After the pipe 9 is cut, the operator manually holds the cut pipe 9 and then the second motor 82 is reversed to move the two slide blocks 32 away from each other, so that the two clamps 331 no longer clamp the pipe and the two slide blocks 32 move to reset, so that the cut pipe 9 can be taken down. When the slide block 32 moves to reset, it also drives the sliding seat 4 to move to reset through the second connecting block 5 and the first connecting block 42.

[0054] Of course, the above are only typical examples of the present application. In addition, the present application may have many other specific implementation methods. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present application.

Claims

1. A laser tube cutting machine, comprising a machine body (1), a feeding mechanism (2) arranged on the machine body (1) for pushing a tube (9), a clamping mechanism (3) for clamping the tube (9), a mounting plate (11) rotatably connected to the machine body (1) and located between the clamping mechanism (3) and the feeding mechanism (2), and a first motor (12) arranged on the machine body (1), wherein the first motor (12) and the mounting plate (11) are connected by a gear (632) for transmission, the mounting plate (11) is slidably connected to a sliding seat (4), the sliding seat (4) is provided with a laser cutting head (41), the movement direction of the sliding seat (4) is the same as the movement direction of a slider (32), and the characteristics are: The clamping mechanism (3) comprises a mounting frame (31) arranged on a frame, a slider (32) slidably connected to the mounting frame (31), two clamping assemblies (33) respectively arranged on the two sliders (32) for clamping the pipe (9), and a first driving part (8) for driving the two sliders (32) to move, the sliding seat (4) is provided with a first connecting block (42), one of the sliders (32) is provided with a second connecting block (5), and the second connecting block (5) faces An arcuate sliding groove (51) is provided on one surface of the mounting plate (11), the first connecting block (42) is slidably matched with the arcuate sliding groove (51), and the machine body (1) is further provided with a limiting assembly (6) for limiting the sliding movement of the sliding seat (4); the limiting assembly (6) comprises a sliding groove (61) provided on a surface of the sliding seat (4) facing the mounting plate (11), a limiting block (62) slidably connected in the sliding groove (61), and a limiting block (62) for driving the limiting block (62) to slide and make the limiting block (4) The power assembly (63) is configured to contact the mounting plate (11) with the first screw rod (631) rotatably connected to the sliding seat (4), a gear (632) provided on the first screw rod (631), a first rack (633) and a second rack (634) respectively provided on the side walls of the arc-shaped sliding groove (51) on both sides opposite to each other, one end of the first screw rod (631) extending into the sliding groove (61), and the other end of the first screw rod (631) extending into the sliding groove (61). The first rack (633) is used to mesh with the gear (632) and drive the gear (632) to rotate in a positive direction, and the second rack (634) is used to mesh with the gear (632) and drive the gear (632) to rotate in a negative direction. In an initial state, the gear (632) is meshed with the first rack (633).

2. A laser tube cutting machine according to claim 1, characterized in that: A T-shaped slide groove (111) is provided on the mounting plate (11); the sliding seat (4) is a T-shaped block; the sliding seat (4) is slidably connected in the T-shaped slide groove (111); a first avoidance hole (112) for the pipe (9) to pass through is provided in the middle of the mounting plate (11); the T-shaped slide groove (111) is connected to the first avoidance hole (112); the first connection block (42) is located on one end of the sliding seat (4) away from the first avoidance hole (112); and the laser cutting head (41) is located on one end of the sliding seat (4) close to the first avoidance hole (112).

3. The laser tube cutting machine according to claim 1, characterized in that: The ends of the side walls on both sides of the arc-shaped slide groove (51) are provided with guiding inclined surfaces (52), and a guiding cavity (53) is formed between the two guiding inclined surfaces (52) on the same side, and the guiding cavity (53) is used to enable the first connecting block (42) to slide smoothly into the arc-shaped slide groove (51).

4. A laser tube cutting machine according to claim 1, characterized in that: The clamping assembly (33) comprises a clamp (331) provided on the slider (32) and a mounting portion (7) for mounting the clamp (331) on the slider (32), and a clamping space for fixing the pipe (9) is formed between the two clamps (331).

5. A laser tube cutting machine according to claim 4, characterized in that: The mounting portion (7) comprises a countersunk hole (71) formed on the clamp (331), a countersunk bolt (72) provided on the slider (32), and a threaded hole (73) formed on the connecting column and matched with the countersunk bolt (72).

6. The laser tube cutting machine according to claim 1, characterized in that: The first driving part (8) comprises a second screw rod (81) rotatably connected to the mounting frame (31), a second motor (82) for driving the two second screw rods (81) to rotate respectively, and a guide rod (83) fixedly connected to the mounting frame (31); the second screw rod (81) is provided with two first thread segments (84) and second thread ends (85) with opposite thread directions; one end of the two sliding blocks (32) is slidably connected to the guide rod (83), and the other ends of the two sliding blocks (32) are respectively threadedly connected to the first thread segment (84) and the second thread segment.

Images