Speed reducer for hoisting mechanical equipment

Abstract

The invention discloses a speed reducer for hoisting mechanical equipment, which relates to the technical field of speed reduction equipment and comprises a shell, an input shaft is movably connected to the inner side of the shell, a first speed reduction gear is slidably arranged on the outer side of the input shaft, and a second speed reduction gear is mounted on the side surface of the first speed reduction gear. A third reduction gear is installed on the side, away from the first reduction gear, of the second reduction gear, a first rotating rod is rotationally connected to the inner side of the shell, a fourth reduction gear and a fifth reduction gear are installed on the outer side of the first rotating rod, and the second reduction gear, the third reduction gear and the first rotating rod are all meshed with the fifth reduction gear. A first output shaft is rotationally connected to the inner side of the shell, the first reduction gear, the second reduction gear and the third reduction gear are replaced through the control assembly to be meshed with the fifth reduction gear so that the reduction ratio can be accurately and stably adjusted, and the situation that the stability and reliability of speed reduction work are affected due to motor load changes is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of deceleration equipment, and particularly to a speed reducer for hoisting machinery equipment. Background Art

[0002] Hoisting machinery refers to electromechanical equipment used for vertical lifting or vertical lifting and horizontal movement of heavy objects, and the speed reducer is an important component in hoisting machinery. Hoisting machinery requires a speed reducer to ensure the smooth operation of the equipment, improve operation efficiency and safety by reducing the rotational speed and increasing the torque. A speed reducer is a relatively precise machine, and its working principle is to use the meshing transmission of gears at all levels to achieve the purpose of speed reduction. When the driving shaft rotates at a certain rotational speed, through the meshing transmission of the gear set, the driven shaft will rotate at a lower rotational speed, thereby achieving the effect of speed reduction. In this process, the speed reducer will convert the input power with high rotational speed and low torque into output power with low rotational speed and high torque.

[0003] After retrieval, the invention patent with the Chinese patent number CN115370732A discloses a gear speed reducer. Compared with the prior art, the invention patent with the Chinese patent number CN115370732A can cooperate with the groove and the conveying pipe through the extrusion mechanism arranged inside the housing to make the lubricating oil that does not contact the gears flow to the upper layer of the lubricating oil at the lower side inside the housing, increasing the fluidity of the lubricating oil and avoiding the insufficient fluidity of the lubricating oil inside the housing and the inability to evenly contact the gears, resulting in different degrees of aging of the lubricating oil in different regions.

[0004] In the actual application process, the gear speed reducer disclosed in the above patent has obvious limitations. On the one hand, it is difficult for this speed reducer to flexibly adjust the reduction ratio to accurately adapt to the strict requirements of a specific application scenario for the reduction ratio. Although adjusting the rotational speed of the driving device can also affect the output speed to a certain extent, its overload capacity is relatively limited. When the load suddenly increases beyond the rated load of the motor, the motor may experience overheating, overload protection actions, etc., and the reliability is often greatly reduced. And when the load suddenly increases or decreases, the motor may need to adjust the output torque and rotational speed to maintain a stable reduction ratio, which may lead to short-term fluctuations or instability. On the other hand, the number of output ports of this speed reducer is limited, and this design greatly limits its ability to drive multiple loads and cannot meet some complex application scenarios that require driving multiple devices or components simultaneously. Therefore, a speed reducer for hoisting machinery equipment is proposed. Summary of the Invention

[0005] The purpose of the present invention is to solve the disadvantages in the prior art that it is not convenient to adjust the reduction ratio to adapt to the precise requirements of a specific application scenario for the reduction ratio, and to propose a speed reducer for hoisting machinery equipment.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A speed reducer for a hoisting mechanical equipment, comprising a housing, an input shaft is movably connected inside the housing, a first reduction gear is slidably arranged on the outer side of the input shaft, a second reduction gear is installed on the side of the first reduction gear, a third reduction gear is installed on the side of the second reduction gear away from the first reduction gear, a first rotating rod is rotatably connected inside the housing, a fourth reduction gear and a fifth reduction gear are respectively installed on the outer side of the first rotating rod, the second reduction gear, the third reduction gear and the first rotating rod are all meshed with the fifth reduction gear, a first output shaft is rotatably connected inside the housing, a sixth reduction gear is installed on the outer side of the first output shaft, and the sixth reduction gear is meshed with the fourth reduction gear; A control component for the first reduction gear, the second reduction gear and the third reduction gear is jointly arranged on the housing and the input shaft. The control component includes a push plate symmetrically slidably connected to the housing and a first threaded rod movably connected to the input shaft. The push plate and the first threaded rod are respectively used to realize the switching use of the first reduction gear, the second reduction gear and the third reduction gear through movement and rotation. The switching of the first reduction gear, the second reduction gear and the third reduction gear is respectively meshed with the fifth reduction gear to adjust the reduction ratio. An output component is arranged on the housing. The output component includes second output shafts symmetrically movably connected to the housing. Both of the second output shafts realize self-rotation output through the self-rotation of the sixth reduction gear. An output end is movably connected to the end of the second output shaft. The output end moves in a direction close to or away from the second output shaft to adjust the load length of the output end. First protective shells are movably connected to both sides of the housing. First square grooves are opened on both sides of the housing. A fixing rod is installed on the outer side of the first protective shell. The fixing rod is movably connected to the first protective shell. The size of the opening of the first square groove is adapted to the size of the fixing rod.

[0007] The above technical solutions further include: A second sliding groove is opened on the outer side of the input shaft. A first sliding block is slidably arranged inside the second sliding groove. The first sliding block is fixedly connected to the first reduction gear. The first threaded rod is rotatably connected inside the second sliding groove. The first threaded rod is threadedly connected to the first sliding block.

[0008] Third sliding grooves are opened on both sides of the housing. A second sliding block and a third sliding block are respectively installed on the outer side of the input shaft. The second sliding block and the third sliding block are both slidably arranged inside the third sliding groove. Baffles are symmetrically installed on the outer sides of the second sliding block and the third sliding block. The baffles are slidably connected to the third sliding groove.

[0009] Both of the two pushing plates are installed on the side of the second sliding block away from the housing. A second protective housing is installed on the side of the housing close to the pushing plates. The two pushing plates are slidably arranged inside the second protective housing. A second threaded rod is rotatably connected inside the second protective housing. Both of the two pushing plates are threadedly connected to the second threaded rod. By replacing the first reduction gear, the second reduction gear, the third reduction gear and the fifth reduction gear to engage with each other, the reduction ratio can be precisely adjusted to meet the precise requirements of the reduction ratio for specific application scenarios.

[0010] A second rotating rod is rotatably connected inside the housing. A first bevel gear is installed on the outer side of the second rotating rod. A transmission belt is sleeved together between the second rotating rod and the first output shaft. Both of the two second output shafts are rotatably connected to the housing. Second bevel gears are installed at one ends of the two second output shafts close to the second rotating rod. The second bevel gears are meshed with the first bevel gear. By using the first output shaft and the two second output shafts in cooperation, multiple loads can be driven simultaneously, thereby improving the production efficiency.

[0011] The number of the fixing grooves is multiple groups and they are horizontally and evenly distributed on the upper part of the square rod. The size of the opening of the fixing groove is adapted to the size of the fixing bolt. The length state of the second output shaft can be switched according to whether it is used or not.

[0012] First square grooves are formed on both sides of the housing. A fixing rod is installed on the outer side of the first protective housing. The fixing rod is movably connected to the first protective housing. The size of the opening of the first square groove is adapted to the size of the fixing rod.

[0013] A second square groove is formed on the outer side of the fixing rod. A spring is installed inside the second square groove. A telescopic block is installed at the end of the spring. The telescopic block is slidably arranged inside the second square groove. A third square groove is formed inside the first square groove. The size of the opening of the third square groove is adapted to the size of the telescopic block. The cross section of the telescopic block is trapezoidal.

[0014] A first sliding groove is formed on the outer side of the fixing rod. The first sliding groove communicates with the second square groove. A sliding rod is installed on one side of the telescopic block close to the first protective housing. The sliding rod is slidably arranged inside the first sliding groove.

[0015] The present invention has the following beneficial effects: 9. In the present invention, by controlling the component to replace the first reduction gear, the second reduction gear, the third reduction gear and the fifth reduction gear to engage with each other, the reduction ratio can be precisely adjusted to meet the precise requirements of the reduction ratio for specific application scenarios, and the influence of load change on the stability and reliability of the reduction work can be avoided.

[0016] 10. In the present invention, by using the first output shaft in cooperation with two second output shafts, multiple loads can be driven simultaneously, thereby improving production efficiency. Moreover, the length of the load can be switched by the second output shaft according to the usage scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a schematic top-sectional structure diagram of a speed reducer for a hoisting mechanical device proposed by the present invention; Figure 2 FIG. is a schematic side-sectional structure diagram of the present invention; Figure 3 FIG. is a schematic rear-sectional structure diagram of the present invention; Figure 4 FIG. is a schematic overall structure diagram of the present invention; Figure 5 is Figure 1 a schematic enlarged structure diagram of part A in Figure 6 is Figure 1 a schematic enlarged structure diagram of part B in Figure 7 is Figure 2 a schematic enlarged structure diagram of part C in Figure 8 is Figure 7 a schematic enlarged structure diagram of part D in Figure 9 is Figure 3 a schematic enlarged structure diagram of part E in

[0018] In the figures: 1, housing; 2, input shaft; 3, first reduction gear; 4, second reduction gear; 5, third reduction gear; 6, first rotating rod; 7, fourth reduction gear; 8, fifth reduction gear; 9, first output shaft; 10, sixth reduction gear; 11, second rotating rod; 12, transmission belt; 13, first bevel gear; 14, second output shaft; 15, second bevel gear; 16, square rod; 17, fixing groove; 18, output end; 19, fixing bolt; 20, first protective shell; 21, fixing rod; 22, first square groove; 23, second square groove; 24, spring; 25, telescopic block; 26, third square groove; 27, first sliding groove; 28, sliding rod; 29, second sliding groove; 30, first sliding block; 31, first threaded rod; 32, third sliding groove; 33, second sliding block; 34, baffle; 35, pushing plate; 36, second protective shell; 37, second threaded rod; 38, third sliding block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1 As Figures 1 - 9 shown, a speed reducer for a hoisting mechanical equipment proposed by the present invention includes a housing 1. An input shaft 2 is movably connected to the inner side of the housing 1. A first reduction gear 3 is slidably arranged on the outer side of the input shaft 2. A second reduction gear 4 is installed on the side of the first reduction gear 3. A third reduction gear 5 is installed on the side of the second reduction gear 4 away from the first reduction gear 3. A first rotating rod 6 is rotatably connected to the inner side of the housing 1. A fourth reduction gear 7 and a fifth reduction gear 8 are respectively installed on the outer side of the first rotating rod 6. The second reduction gear 4, the third reduction gear 5 and the first rotating rod 6 are all meshed with the fifth reduction gear 8. A first output shaft 9 is rotatably connected to the inner side of the housing 1. A sixth reduction gear 10 is installed on the outer side of the first output shaft 9. The sixth reduction gear 10 is meshed with the fourth reduction gear 7. A control assembly for the first reduction gear 3, the second reduction gear 4 and the third reduction gear 5 is jointly provided on the housing 1 and the input shaft 2. The control assembly includes a push plate 35 symmetrically and slidably connected to the housing 1 and a first threaded rod 31 movably connected to the input shaft 2. The push plate 35 and the first threaded rod 31 respectively realize the switching use of the first reduction gear 3, the second reduction gear 4 and the third reduction gear 5 through movement and rotation. The first reduction gear 3, the second reduction gear 4 and the third reduction gear 5 are respectively meshed with the fifth reduction gear 8 to adjust the reduction ratio. An output assembly is provided on the housing 1. The output assembly includes second output shafts 14 symmetrically and movably connected to the housing 1. Both second output shafts 14 realize self-rotation output through the self-rotation of the sixth reduction gear 10. An output end 18 is movably connected to the end of the second output shaft 14. The output end 18 moves in a direction close to or away from the second output shaft 14 to adjust the load length of the output end 18. First protective shells 20 are movably connected to both sides of the housing 1. First square grooves 22 are opened on both sides of the housing 1. A fixing rod 21 is installed on the outer side of the first protective shell 20. The fixing rod 21 is movably connected to the first protective shell 20. The size of the opening of the first square groove 22 is adapted to the size of the fixing rod 21.

[0021] A second sliding groove 29 is formed on the outer side of the input shaft 2, and a first sliding block 30 is slidably arranged inside the second sliding groove 29. The first sliding block 30 is fixedly connected to the first reduction gear 3. A first threaded rod 31 is rotatably connected to the inner side of the second sliding groove 29, and the first threaded rod 31 is threadedly connected to the first sliding block 30. Third sliding grooves 32 are formed on both sides of the housing 1. Second sliding blocks 33 and third sliding blocks 38 are respectively installed on the outer side of the input shaft 2. The second sliding blocks 33 and the third sliding blocks 38 are both slidably arranged inside the third sliding grooves 32. Baffles 34 are symmetrically installed on the outer sides of the second sliding blocks 33 and the third sliding blocks 38, and the baffles 34 are slidably connected to the third sliding grooves 32; Two push plates 35 are both installed on the side of the second sliding block 33 away from the housing 1. A second protective housing 36 is installed on the side of the housing 1 close to the push plates 35. The two push plates 35 are slidably arranged inside the second protective housing 36. A second threaded rod 37 is rotatably connected to the inside of the second protective housing 36, and the two push plates 35 are both threadedly connected to the second threaded rod 37.

[0022] In this embodiment, when deceleration work needs to be carried out, first connect an external driving device to the input shaft 2, and then start the driving device, thereby driving the input shaft 2 to rotate. Since the first reduction gear 3 meshes with the fifth reduction gear 8, when the input shaft 2 rotates, the first rotating rod 6 can be driven to rotate through the first reduction gear 3 and the fifth reduction gear 8. Since the fourth reduction gear 7 meshes with the sixth reduction gear 10, when the first rotating rod 6 rotates, the first output shaft 9 can be driven to rotate, so as to achieve the deceleration effect; And if the reduction ratio needs to be adjusted, at this time, the driving device can be turned off, and then the second threaded rod 37 is rotated. The acting force generated by rotating the second threaded rod 37 drives the push plate 35 to move, thereby driving the second sliding block 33 to slide along the third sliding groove 32. At the same time, the third sliding block 38 on the input shaft 2 slides along the third sliding groove 32, and the third sliding groove 32 is always kept sealed by the baffle 34 until the first reduction gear 3 is separated from the fifth reduction gear 8. Then the first threaded rod 31 is rotated, and the acting force generated by rotating the first threaded rod 31 drives the first sliding block 30 to move along the second sliding groove 29 until the second reduction gear 4 and the fifth reduction gear 8 are on the same horizontal plane. Then the second threaded rod 37 is continuously rotated, thereby driving the input shaft 2 to move along the third sliding groove 32 until the second reduction gear 4 is driven to mesh with the fifth reduction gear 8. In this way, the reduction ratio is accurately adjusted by replacing the first reduction gear 3, the second reduction gear 4, and the third reduction gear 5 to mesh with the fifth reduction gear 8, avoiding affecting the stability and reliability of the deceleration work due to load changes.

[0023] Embodiment Two As Figures 1 - 9As shown, based on the first embodiment, a second rotating rod 11 is rotatably connected to the inner side of the housing 1. A first bevel gear 13 is installed on the outer side of the second rotating rod 11. A transmission belt 12 is sleeved between the second rotating rod 11 and the first output shaft 9. Both second output shafts 14 are rotatably connected to the housing 1. Second bevel gears 15 are installed at one ends of the two second output shafts 14 close to the second rotating rod 11. The second bevel gears 15 are meshed with the first bevel gear 13. A square rod 16 is installed at the end of the second output shaft 14 away from the second bevel gear 15. The output end 18 is slidably arranged on the outer side of the square rod 16. A fixing groove 17 is formed in the upper part of the square rod 16. The output end 18 is threadedly connected with a fixing bolt 19. The fixing bolt 19 is movably connected with the fixing groove 17. The number of the fixing grooves 17 is multiple and they are horizontally and evenly distributed on the upper part of the square rod 16. The size of the opening of the fixing groove 17 is adapted to the size of the fixing bolt 19.

[0024] A second square groove 23 is formed in the outer side of the fixing rod 21. A spring 24 is installed inside the second square groove 23. A telescopic block 25 is installed at the end of the spring 24. The telescopic block 25 is slidably arranged inside the second square groove 23. A third square groove 26 is formed in the inner side of the first square groove 22. The size of the opening of the third square groove 26 is adapted to the size of the telescopic block 25. The cross section of the telescopic block 25 is trapezoidal. A first sliding groove 27 is formed in the outer side of the fixing rod 21. The first sliding groove 27 communicates with the second square groove 23. A sliding rod 28 is installed on the side of the telescopic block 25 close to the first protective shell 20. The sliding rod 28 is slidably arranged inside the first sliding groove 27.

[0025] In this embodiment, when the first output shaft 9 rotates to output power, the second rotating rod 11 can be driven to rotate by the transmission belt 12 at this time, and the first bevel gear 13 is driven to rotate at the same time. Since the first bevel gear 13 meshes with the second bevel gear 15, the second output shaft 14 can be driven to rotate by the first bevel gear 13 and the second bevel gear 15 when the second rotating rod 11 rotates, so that the housing 1 is provided with multiple output ports. When the second output shaft 14 is not needed, it can be protected by the first protective housing 20. When the second output shaft 14 is needed, the sliding rod 28 can be pressed in the direction close to the first protective housing 20 at this time, so that the sliding rod 28 moves along the first sliding groove 27, and at the same time drives the telescopic block 25 to separate from the third square groove 26, so that the telescopic block 25 retracts into the second square groove 23. At this time, the spring 24 contracts, and then the fixing rod 21 can be separated from the first square groove 22, so as to disassemble the first protective housing 20. Then rotate the fixing bolt 19 to separate the fixing bolt 19 from the fixing groove 17 until the output end 18 slides in the direction away from the second output shaft 14 to extend the output end 18. Finally, rotate the fixing bolt 19 and insert the fixing bolt 19 into the fixing groove 17 at the corresponding position. The load length of the output end 18 can be adjusted according to the use scenario. At this time, the output can be carried out through the output end 18 on the second output shaft 14, so that multiple loads can be driven at the same time, thereby improving the production efficiency.

[0026] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A speed reducer for a lifting machinery, comprising a housing (1), characterized in that: The inner side of the housing (1) is movably connected to an input shaft (2); the outer side of the input shaft (2) is slidably provided with a first reduction gear (3); a second reduction gear (4) is mounted on the side of the first reduction gear (3); a third reduction gear (5) is mounted on the side of the second reduction gear (4) away from the first reduction gear (3); the inner side of the housing (1) is rotatably connected to a first rotating rod (6); a fourth reduction gear (7) and a fifth reduction gear (8) are mounted on the outer side of the first rotating rod (6); the second reduction gear (4), the third reduction gear (5) and the fourth reduction gear (7) are all meshed with the fifth reduction gear (8); the inner side of the housing (1) is rotatably connected to a first output shaft (9); a sixth reduction gear (10) is mounted on the outer side of the first output shaft (9); the sixth reduction gear (10) is meshed with the fourth reduction gear (7); The housing (1) and the input shaft (2) are jointly provided with a control assembly for the first reduction gear (3), the second reduction gear (4) and the third reduction gear (5), the control assembly comprising a push plate (35) symmetrically slidably connected to the housing (1) and a first threaded rod (31) movably connected to the input shaft (2), the push plate (35) and the first threaded rod (31) being respectively used to realize the switching of the first reduction gear (3), the second reduction gear (4) and the third reduction gear (5) by moving and rotating, respectively, and the first reduction gear (3), the second reduction gear (4) and the third reduction gear (5) are respectively meshed with the fifth reduction gear (8) to adjust the reduction ratio, and the housing (1) is provided with an output assembly, the output assembly comprising the housing (1) The second output shafts (14) are symmetrically and movably connected to each other, and the two second output shafts (14) realize self-rotation output through the self-rotation of the sixth reduction gear (10). The ends of the second output shafts (14) are movably connected to the output ends (18), and the output ends (18) move in a direction close to or away from the second output shafts (14) to adjust the load length of the output ends (18). Both sides of the housing (1) are movably connected to the first protective shell (20), and both sides of the housing (1) are provided with first square grooves (22). A fixing rod (21) is installed on the outer side of the first protective shell (20), and the fixing rod (21) is movably connected to the first protective shell (20). The size of the opening of the first square groove (22) is adapted to the size of the fixing rod (21).

2. A speed reducer for hoisting machinery according to claim 1, characterized in that: A second sliding groove (29) is provided on the outer side of the input shaft (2), a first sliding block (30) is slidably provided inside the second sliding groove (29), the first sliding block (30) is fixedly connected to the first reduction gear (3), the first threaded rod (31) is rotatably connected to the inner side of the second sliding groove (29), and the first threaded rod (31) is threadedly connected to the first sliding block (30).

3. A speed reducer for hoisting machinery according to claim 2, characterized in that: A third sliding groove (32) is provided on both sides of the housing (1); a second sliding block (33) and a third sliding block (38) are respectively installed on the outer side of the input shaft (2); the second sliding block (33) and the third sliding block (38) are both slidably arranged on the inner side of the third sliding groove (32); baffles (34) are symmetrically installed on the outer sides of the second sliding block (33) and the third sliding block (38); the baffles (34) are slidably connected to the third sliding groove (32).

4. A speed reducer for hoisting machinery according to claim 3, characterized in that: The two push plates (35) are both mounted on a side of the second sliding block (33) away from the housing (1); a second protective shell (36) is mounted on a side of the housing (1) close to the push plates (35); the two push plates (35) are slidably arranged on the inner side of the second protective shell (36); a second threaded rod (37) is rotatably connected to the inner side of the second protective shell (36); and the two push plates (35) are both threadedly connected to the second threaded rod (37).

5. A speed reducer for hoisting machinery according to claim 1, characterized in that: A second rotating rod (11) is rotatably connected to the inner side of the housing (1), a first bevel gear (13) is mounted on the outer side of the second rotating rod (11), a transmission belt (12) is sleeved between the second rotating rod (11) and the first output shaft (9), two second output shafts (14) are rotatably connected to the housing (1), and a second bevel gear (15) is mounted on one end of the two second output shafts (14) close to the second rotating rod (11), and the second bevel gear (15) is meshed with the first bevel gear (13).

6. A speed reducer for hoisting machinery according to claim 5, characterized in that: A square rod (16) is mounted on one end of the second output shaft (14) away from the second bevel gear (15); the output end (18) is slidably arranged on the outside of the square rod (16); a fixing groove (17) is provided on the upper portion of the square rod (16); the output end (18) is threadedly connected to a fixing bolt (19); and the fixing bolt (19) is movably connected to the fixing groove (17).

7. A speed reducer for hoisting machinery according to claim 6, characterized in that: The fixing grooves (17) are provided in a plurality of groups and are evenly distributed horizontally on the upper portion of the square rod (16); the size of the opening of the fixing grooves (17) is adapted to the size of the fixing bolts (19).

8. A speed reducer for hoisting machinery according to claim 7, characterized in that: A second square groove (23) is formed on the outer side of the fixing rod (21), a spring (24) is installed on the inner side of the second square groove (23), a telescopic block (25) is installed on the end of the spring (24), the telescopic block (25) is slidably arranged on the inner side of the second square groove (23), a third rectangular groove (26) is formed on the inner side of the first square groove (22), the size of the opening of the third rectangular groove (26) is adapted to the size of the telescopic block (25), and the cross section of the telescopic block (25) is a trapezoid.

9. A speed reducer for hoisting machinery according to claim 8, characterized in that: A first sliding groove (27) is provided on the outer side of the fixing rod (21), the first sliding groove (27) and the second square groove (23) are connected to each other, and a sliding rod (28) is installed on a side of the telescopic block (25) close to the first protective shell (20), and the sliding rod (28) is slidably arranged on the inner side of the first sliding groove (27).

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