Multi-angle wind speed self-adjusting device for environmental test

Abstract

The invention discloses a multi-angle wind speed self-adjusting device for an environmental test, which comprises a fixed base, a lifting platform is fixedly connected to the top of the fixed base close to the center, a sliding groove is formed in the outer surface of the front side of the lifting platform, and a balance block is fixedly connected to the top of the lifting platform close to the center through a screw. A stepping motor is controlled through a display controller, so that the stepping motor drives a speed reducer to rotate, the rotating speed can be adjusted in a differential mode, a threaded rod is rotated and adjusted, the effect of accurately adjusting lifting can be achieved, a moving block moves up and down in a sliding groove under the lifting condition, and the lifting effect is improved. Through fixing of a fixing plate, an annular clamping hook can be conveniently and effectively fixed, an electric control rotating shaft is controlled to rotate through a display controller, so that comparison is conducted through precise scales, rotation can be conducted under the precise effect, and therefore equipment can be more precise and stable during rotation.

Description

Technical Field

[0001] The invention relates to the field of wind speed self-regulating devices, in particular to a multi-angle wind speed self-regulating device for environmental testing. Background Art

[0002] With the global emphasis on renewable energy, wind power generation has developed rapidly. Performance optimization of wind turbines is of vital importance. Wind speed self-regulating devices can effectively improve the power generation efficiency of wind turbines. In the process of wind power generation, wind speed is an unstable factor and it often changes. When the wind speed is too high, it may cause damage to the blades and other components of the wind turbine; and when the wind speed is too low, the wind energy cannot be fully utilized for power generation. For example, in some coastal wind farms, the wind speed in the monsoon season may far exceed the rated wind speed of the equipment, and the wind speed in the non-monsoon season is lower. The wind speed self-regulating device can automatically adjust the pitch angle of the blades or the working status of other key components according to the changes in wind speed, so that the wind turbine can operate efficiently and safely under different wind speed conditions;

[0003] Traditional wind power generation equipment usually does not have an efficient wind speed adaptive adjustment mechanism. Most early wind turbines used fixed-pitch blades, which cannot be adjusted according to changes in wind speed. When the wind speed is too high, the generator may overload, overheat, and even damage the generator components due to the high speed. For example, some old-fashioned small wind turbines, when encountering strong winds, may break their blades due to excessive pressure due to the lack of self-adjustment devices, causing equipment failure.

[0004] In addition, in some industrial ventilation systems, traditional ventilation equipment cannot automatically adjust according to actual ventilation needs and external wind speed conditions. For example, in mine ventilation, if the underground ventilation system cannot automatically adjust the ventilation volume according to the wind speed at the wellhead, it may lead to poor air quality underground, safety hazards, and energy waste.

[0005] In the prior art, when using a device for self-adjusting wind speed, traditional devices generally adjust the direction of wind by simply moving the device. However, in different environments, different angles are required for use. The existing equipment is not easy to adjust, and the adjustment effect of the existing equipment is not accurate enough. The degree of adjustment is relatively large, which will have a greater impact on the experimental environment, making it difficult to effectively control the device. The existing equipment is not easy to effectively control the wind speed, so that the wind speed at different positions is different, which will also affect the effect of the experiment, thereby reducing the use effect of the device.

[0006] Therefore, we proposed a multi-angle wind speed self-adjusting device for environmental testing in order to solve the above-mentioned problems. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-angle wind speed self-adjusting device for environmental testing, so as to solve the problem that the traditional devices proposed in the above background technology generally adjust the direction of the wind by simply moving the equipment. However, in different environments, different angles are required for use. The existing equipment is not convenient for adjustment, and the adjustment effect of the existing equipment is not accurate enough. The degree of adjustment is relatively large, which will have a greater impact on the experimental environment, making it difficult for the device to be effectively controlled. The existing equipment is not convenient for effectively controlling the wind speed, so that the wind speed at different positions is different, which will also affect the effect of the experiment, thereby reducing the use effect of the device.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a multi-angle wind speed self-adjusting device for environmental testing, comprising a fixed base, a lifting platform is fixedly connected to the top of the fixed base near the center, a sliding groove is provided on the front outer surface of the lifting platform, a balancing block is fixedly connected to the top of the lifting platform near the center by a screw, a reducer is fixedly installed on the top of the balancing block near the center, a stepper motor is fixedly installed on the top of the reducer, and the output end of the stepper motor is fixedly connected to the input end of the reducer, a threaded rod is fixedly connected to the output end of the reducer, and the bottom end of the threaded rod extends to the bottom surface of the sliding groove and is rotatably connected via a bearing, and a shift sleeve is provided on the outer surface of the threaded sleeve The movable block is slidably connected inside the sliding groove, the front outer surface of the movable block is fixedly connected to the fixed plate, the front outer surface of the fixed plate is fixedly installed with an annular hook, the front outer surface of the annular hook is fixedly connected with a precision rotating sleeve, the front outer surface of the precision rotating sleeve is rotatably connected with an electrically controlled rotating shaft near the center, the front outer surface of the precision rotating sleeve is provided with a plurality of precision scale marks equidistantly along the circumferential direction near the edge, and the precision scale marks are correspondingly connected to the electrically controlled rotating shaft, the front end of the electrically controlled rotating shaft is fixedly connected with a U-shaped frame, the outer surfaces of the opposite sides of the U-shaped frame are rotatably connected with a rotating rod, and the outer surface of the rotating rod is fixedly sleeved with a duct machine near the center.

[0009] Preferably, grooves are provided on the front outer surface of the fixing plate near the four corners, and buffer springs are fixedly welded to the inner surface walls of one side of the four grooves.

[0010] Preferably, one end of the four buffer springs is fixedly connected to a sliding block, and the outer surface of the sliding block is slidably connected to the inside of the groove, and one side outer surface of the four sliding blocks is fixedly connected to an elastic clamping block.

[0011] Preferably, a first slot is provided at the bottom end of the inner wall of the annular hook, and the first slot is engaged with the elastic block.

[0012] Preferably, air outlets are provided at the top and bottom of the air duct machine, a connecting pipe is fixedly connected to the front outer surface of the air duct machine near the center, a second slot is opened near the center of the top of the connecting pipe, and a folding baffle is slidably installed inside the second slot.

[0013] Preferably, a hair dryer is fixedly connected to the front outer surface of the connecting pipe, and an air outlet is provided near the center of the front outer surface of the hair dryer. A rotating shaft is rotatably connected to the inside of the air outlet, and a plurality of wind control blades are fixedly connected to the outer surface of the rotating shaft at equal intervals along the circumferential direction.

[0014] Preferably, a fixed connecting seat is fixedly installed on the edge of the outer surface of one side of the lifting platform near the top, one end of the fixed connecting seat is fixedly connected to a fixed frame, an embedding groove is opened on the outer surface of one side of the fixed frame, a display controller is fixedly installed inside the embedding groove, and the display controller is electrically connected to the stepping motor, the electric control rotating shaft, the rotating rod, the air duct machine, the folding baffle and the rotating shaft rod respectively.

[0015] Preferably, the bottom of the fixed base is fixedly connected to fixed blocks near the four corners by screws, and the bottom of the four fixed blocks is fixedly installed with universal wheels near the center.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The stepper motor is controlled by the display controller, so that the stepper motor drives the reducer to rotate, so that the speed can be adjusted differentially, and the threaded rod can be rotated and adjusted, so that the lifting effect can be accurately adjusted. In the lifting case, the moving block moves up and down inside the sliding groove, and the annular hook is fixed by the fixing plate to facilitate effective fixing. The electric control rotating shaft is controlled by the display controller to rotate, so that it can be compared with the precision scale mark and rotated under the precise effect, which will make the equipment more accurate and stable when rotating, and improve the use effect of the device;

[0018] 2. Through the elastic tension of the buffer spring inside the groove, the buffer spring is easy to drive the sliding block to pull the elastic card block, and the elastic card block is connected with the card groove on the annular hook. Then, by pushing the sliding block, the sliding block drives the elastic card block to push, so that the annular hook can be opened, which is convenient for disassembly of the equipment and improves the convenience of use of the device;

[0019] 3. The display controller drives the rotating rod to rotate, and the rotating rod drives the duct machine to rotate, so that effective rotation adjustment can be performed in the vertical direction, and the duct machine can be controlled to start effectively, so that the air outlet absorbs air to convert energy and circulates inside the connecting pipe. By sliding and setting a folding baffle inside the card slot, the folding baffle is moved by the display controller to effectively limit the size of the pipe through which the connecting pipe circulates, so that the equipment can effectively control the air volume and improve the effect of the device to control the wind speed;

[0020] 4. Fixing it with a hair dryer will make the air outlet of the air duct convenient for effective air outlet. The display controller will drive the rotating shaft to rotate, so that the rotating shaft will drive the wind control blade to rotate, thereby improving the use effect of the device;

[0021] 5. Through the rolling of the universal wheels, the equipment is easy to move and can be effectively adjusted in direction, which improves the device's ability to be adjusted at multiple angles, thereby improving the use effect of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front perspective view of a multi-angle wind speed self-adjusting device for environmental testing of the present invention;

[0023] Figure 2 A side perspective view of a multi-angle wind speed self-adjusting device for environmental testing according to the present invention;

[0024] Figure 3 A top perspective view of a multi-angle wind speed self-adjusting device for environmental testing according to the present invention;

[0025] Figure 4 This is a bottom-up stereogram of a multi-angle wind speed self-adjusting device for environmental testing of the present invention;

[0026] Figure 5 It is a schematic diagram of the structure of a lifting platform of a multi-angle wind speed self-adjusting device for environmental testing of the present invention;

[0027] Figure 6 The invention is a multi-angle wind speed self-adjusting device for environmental testing Figure 1 Schematic diagram of the structure at A in the middle;

[0028] Figure 7 The invention is a multi-angle wind speed self-adjusting device for environmental testing Figure 2 Schematic diagram of the structure at B in the middle;

[0029] Figure 8 The invention is a multi-angle wind speed self-adjusting device for environmental testing Figure 4Schematic diagram of the structure at point C in the middle.

[0030] In the figure:

[0031] 1. Fixed base; 2. Lifting platform; 3. Sliding slot; 4. Balance block; 5. Reducer; 6. Stepper motor; 7. Threaded rod; 8. Moving block; 9. Fixed plate; 10. Groove; 11. Buffer spring; 12. Sliding block; 13. Elastic block; 14. Annular hook; 15. First slot; 16. Precision rotating sleeve; 17. Electric control rotating shaft; 18. Precision scale mark; 19. U-shaped frame; 20. Rotating rod; 21. Duct machine; 22. Air outlet; 23. Connecting pipe; 24. Second slot; 25. Folding baffle; 26. Hair dryer; 27. Air outlet; 28. Rotating shaft rod; 29. ​​Wind control blade; 30. Fixed connecting seat; 31. Fixed frame; 32. Embedded slot; 33. Display controller; 34. Fixed block; 35. Universal wheel. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1-7The present invention provides a technical solution: a multi-angle wind speed self-adjusting device for environmental testing, comprising a fixed base 1, a lifting platform 2 is fixedly connected to the top of the fixed base 1 near the center, a sliding groove 3 is provided on the front outer surface of the lifting platform 2, a balancing block 4 is fixedly connected to the top of the lifting platform 2 near the center by a screw, a reducer 5 is fixedly installed on the top of the balancing block 4 near the center, a stepper motor 6 is fixedly installed on the top of the reducer 5, and the output end of the stepper motor 6 is fixedly connected to the input end of the reducer 5, a threaded rod 7 is fixedly connected to the output end of the reducer 5, and the bottom end of the threaded rod 7 extends to the bottom surface of the sliding groove 3 and is rotatably connected through a bearing, a moving block 8 is threadedly sleeved on the outer surface of the threaded rod 7, and the moving block 8 is in the sliding The interior of the movable groove 3 is slidably connected, the front outer surface of the movable block 8 is fixedly connected to the fixed plate 9, the front outer surface of the fixed plate 9 is fixedly installed with an annular hook 14, the front outer surface of the annular hook 14 is fixedly connected with a precision rotating sleeve 16, the front outer surface of the precision rotating sleeve 16 is rotatably connected with an electric control rotating shaft 17 near the center, the front outer surface of the precision rotating sleeve 16 is equidistantly provided with a plurality of precision scale marks 18 along the circumferential direction near the edge, and the precision scale marks 18 are correspondingly connected to the electric control rotating shaft 17, the front end of the electric control rotating shaft 17 is fixedly connected with a U-shaped frame 19, the outer surfaces of the opposite sides of the U-shaped frame 19 are rotatably connected with a rotating rod 20, and the outer surface of the rotating rod 20 is fixedly sleeved with a duct machine 21 near the center , the stepper motor 6 is controlled by the display controller 33, so that the stepper motor 6 drives the reducer 5 to rotate, so that the speed can be adjusted differentially, so that the threaded rod 7 is rotated and adjusted, so that the lifting effect can be accurately adjusted. In the lifting case, the moving block 8 moves up and down inside the sliding groove 3, and the annular hook 14 is fixed by the fixing plate 9, so that the annular hook 14 is easy to be effectively fixed. The display controller 33 is used to control the electric control rotating shaft 17 to rotate, so that it can be compared with the precision scale mark 18, and it can be rotated under the precise effect, so that the device will be more accurate and stable when rotating, and the use effect of the device is improved. The elastic tension of the buffer spring 11 inside the groove 10 makes the buffer spring The spring 11 is convenient for driving the sliding block 12 to pull the elastic block 13, and the elastic block 13 is engaged with the first slot 15 on the annular hook 14 to be connected, and then the sliding block 12 is pushed, so that the sliding block 12 drives the elastic block 13 to be pushed, so that the annular hook 14 can be opened, so that the equipment can be disassembled easily, and the use convenience of the device is improved. The display controller 33 is further used to drive the rotating rod 20 to rotate, and the rotating rod 20 drives the duct machine 21 to rotate, so that effective rotation adjustment can be performed in the vertical direction, and the duct machine 21 can be controlled to be effectively started, so that the air outlet 22 can absorb air to convert energy and circulate inside the connecting pipe 23.

[0034] The front outer surface of the fixed plate 9 is provided with grooves 10 near the four corners, and a buffer spring 11 is fixedly welded to the inner surface wall of one side of the four grooves 10. One end of the four buffer springs 11 is fixedly connected to a sliding block 12, and the outer surface of the sliding block 12 is slidably connected to the inside of the groove 10. The outer surface of one side of the four sliding blocks 12 is fixedly connected to an elastic block 13. The bottom end of the inner wall of the annular hook 14 is provided with a first groove 15, and the first groove 15 is engaged with the elastic block 13. Through the elastic tension of the buffer spring 11 inside the groove 10, the buffer spring 11 can easily drive the sliding block 12 to pull the elastic block 13, and the elastic block 13 is engaged with the first groove 15 on the annular hook 14. Then, by pushing the sliding block 12, the sliding block 12 drives the elastic block 13 to be pushed, so that the annular hook 14 can be opened, which is convenient for the equipment to be disassembled, thereby improving the convenience of use of the device.

[0035] The top and bottom of the duct machine 21 are both provided with air outlets 22. A connecting pipe 23 is fixedly connected to the front outer surface of the duct machine 21 near the center. A second slot 24 is provided near the center of the top of the connecting pipe 23. A folding baffle 25 is slidably installed inside the second slot 24. A hair dryer 26 is fixedly connected to the front outer surface of the connecting pipe 23. An air outlet 27 is provided near the center of the front outer surface of the hair dryer 26. A rotating shaft 28 is rotatably connected to the inside of the air outlet 27. The outer surface of the rotating shaft 28 is fixedly connected to multiple rotating shafts 28 at equal intervals along the circumferential direction. The wind control blade 29 is moved by the electronically controlled folding baffle 25 through the display controller 33, so that the size of the pipe through which the connecting pipe 23 flows can be effectively limited, so that the device can effectively control the air volume and improve the effect of the device in controlling the wind speed. The hair dryer 26 is used to fix it, so that the air outlet 27 can be easily discharged effectively. The display controller 33 is used to drive the rotating shaft 28 to rotate, so that the rotating shaft 28 drives the wind control blade 29 to rotate, thereby improving the use effect of the device.

[0036] A fixed connecting seat 30 is fixedly installed on the edge of the outer surface of one side of the lifting platform 2 near the top, and one end of the fixed connecting seat 30 is fixedly connected to a fixed frame 31. An embedding groove 32 is opened on the outer surface of one side of the fixed frame 31. A display controller 33 is fixedly installed inside the embedding groove 32, and the display controller 33 is electrically connected to the stepping motor 6, the electric control rotating shaft 17, the rotating rod 20, the air duct machine 21, the folding baffle 25 and the rotating shaft rod 28 respectively. The display controller 33 is embedded and installed inside the embedding groove 32 for stable installation, which will make the use of the display controller 33 better.

[0037] The bottom of the fixed base 1 is fixedly connected to a fixed block 34 near the four corners by screws, and the bottom of the four fixed blocks 34 is fixedly installed with a universal wheel 35 near the center. The rolling of the universal wheel 35 makes it easy to move the device and to effectively adjust the direction, thereby improving the device's convenience in adjusting at multiple angles and thus improving the use effect of the device.

[0038] The working principle of this embodiment is as follows: when the device is used, the stepper motor 6 is first controlled by the display controller 33, so that the stepper motor 6 drives the reducer 5 to rotate, so that the speed can be differentially adjusted, so that the threaded rod 7 is rotated and adjusted, so that the lifting effect can be accurately adjusted. In the lifting state, the moving block 8 moves up and down inside the sliding groove 3, and the annular hook 14 is fixed by the fixing plate 9, so that the annular hook 14 is easy to be effectively fixed, and the display controller 33 is used to control the electric control rotating shaft 17 to rotate, so as to compare with the precision scale mark 18. The device can be rotated with a precise effect, so that the device will be more precise and stable when rotating, and the use effect of the device is improved. Through the elastic tension of the buffer spring 11 inside the groove 10, the buffer spring 11 is easy to drive the sliding block 12 to pull the elastic card block 13, and the elastic card block 13 is engaged with the first card groove 15 on the annular hook 14. Then, by pushing the sliding block 12, the sliding block 12 drives the elastic card block 13 to push, so that the annular hook 14 can be opened, so that the device is easy to disassemble, and the use convenience of the device is improved. The display controller 33 further drives the rotating rod 20 to rotate, and the rotating rod 20 drives the duct machine 21 to rotate, so that effective rotation adjustment can be performed in the vertical direction, and the duct machine 21 can be controlled to be effectively started, so that the air outlet 22 absorbs air to convert energy and circulates inside the connecting pipe 23. The folding baffle 25 is slidably set inside the second card slot 24, and the folding baffle 25 is electronically controlled by the display controller 33 to move, so that the size of the pipe flowing through the connecting pipe 23 can be effectively limited, so that the device can be convenient for effectively controlling the air volume, and the effect of the device being convenient for controlling the wind speed is improved. The hair dryer 26 is fixed, so that the air outlet 27 is convenient for effective air discharge, and the display controller 33 drives the rotating shaft 28 to rotate, so that the rotating shaft 28 drives the wind control blade 29 to rotate, and the use effect of the device is improved. The rolling of the universal wheel 35 makes the device easy to move, and it is also convenient to effectively adjust the direction, and the device is convenient for multi-angle adjustment, thereby improving the use effect of the device.

[0039] In this technical solution, the display controller 33, the stepping motor 6, the electric control rotating shaft 17, the rotating rod 20, the air duct machine 21, the folding baffle 25 and the rotating shaft 28 are all existing technologies and will not be elaborated in detail here.

[0040] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-angle wind speed self-adjusting device for environmental testing, comprising a fixed base (1), characterized in that: A lifting platform (2) is fixedly connected to the top of the fixed base (1) near the center, a sliding groove (3) is provided on the front outer surface of the lifting platform (2), a balancing block (4) is fixedly connected to the top of the lifting platform (2) near the center by screws, a reducer (5) is fixedly installed on the top of the balancing block (4) near the center, a stepper motor (6) is fixedly installed on the top of the reducer (5), and the output end of the stepper motor (6) is fixedly connected to the input end of the reducer (5), the output end of the reducer (5) is fixedly connected to a threaded rod (7), and the bottom end of the threaded rod (7) extends to the bottom surface of the sliding groove (3) and is rotatably connected via a bearing, a moving block (8) is threadedly sleeved on the outer surface of the threaded rod (7), and the moving block (8) is slidably connected inside the sliding groove (3), and the moving block (6) is fixedly installed on the top of the reducer (5). The front outer surface of the fixing plate (8) is fixedly connected to the fixing plate (9), the front outer surface of the fixing plate (9) is fixedly installed with an annular hook (14), the front outer surface of the annular hook (14) is fixedly connected to a precision rotating sleeve (16), the front outer surface of the precision rotating sleeve (16) is rotatably connected to an electric control rotating shaft (17) near the center, the front outer surface of the precision rotating sleeve (16) is equidistantly provided with a plurality of precision scale marks (18) along the circumferential direction near the edge, and the precision scale marks (18) are correspondingly connected to the electric control rotating shaft (17), the front end of the electric control rotating shaft (17) is fixedly connected to a U-shaped frame (19), the outer surfaces of the opposite sides of the U-shaped frame (19) are rotatably connected with a rotating rod (20), and the outer surface of the rotating rod (20) is fixedly sleeved with a duct machine (21) near the center.

2. The multi-angle wind speed self-adjusting device for environmental testing according to claim 1, characterized in that: The front outer surface of the fixing plate (9) is provided with grooves (10) near the four corners, and a buffer spring (11) is fixedly welded to the inner surface wall of one side of the four grooves (10).

3. The multi-angle wind speed self-adjusting device for environmental testing according to claim 2, characterized in that: One end of each of the four buffer springs (11) is fixedly connected to a sliding block (12), and the outer surface of the sliding block (12) is slidably connected to the inside of the groove (10), and one side outer surface of each of the four sliding blocks (12) is fixedly connected to an elastic clamping block (13).

4. The multi-angle wind speed self-adjusting device for environmental testing according to claim 3, characterized in that: A first clamping groove (15) is provided at the bottom end of the inner wall of the annular clamping hook (14), and the first clamping groove (15) is clamped and connected with the elastic clamping block (13).

5. The multi-angle wind speed self-adjusting device for environmental testing according to claim 1, characterized in that: The top and bottom of the duct machine (21) are both provided with air outlets (22); a connecting pipe (23) is fixedly connected to the front outer surface of the duct machine (21) near the center; a second slot (24) is provided at the top of the connecting pipe (23) near the center; a folding baffle (25) is slidably mounted inside the second slot (24).

6. The multi-angle wind speed self-adjusting device for environmental testing according to claim 5, characterized in that: A hair dryer (26) is fixedly connected to the front outer surface of the connecting pipe (23); an air outlet (27) is provided near the center of the front outer surface of the hair dryer (26); a rotating shaft (28) is rotatably connected inside the air outlet (27); and a plurality of wind control blades (29) are fixedly connected to the outer surface of the rotating shaft (28) at equal intervals along the circumferential direction.

7. The multi-angle wind speed self-adjusting device for environmental testing according to claim 6, characterized in that: A fixed connection seat (30) is fixedly installed on the edge of the outer surface of one side of the lifting platform (2) near the top, and one end of the fixed connection seat (30) is fixedly connected to a fixed frame (31). An embedding groove (32) is opened on the outer surface of one side of the fixed frame (31), and a display controller (33) is fixedly installed inside the embedding groove (32). The display controller (33) is electrically connected to the stepping motor (6), the electric control rotating shaft (17), the rotating rod (20), the air duct machine (21), the folding baffle (25) and the rotating shaft (28) respectively.

8. The multi-angle wind speed self-adjusting device for environmental testing according to claim 1, characterized in that: The bottom of the fixed base (1) is fixedly connected to a fixing block (34) near the four corners by screws, and the bottom of the four fixing blocks (34) is fixedly installed with a universal wheel (35) near the center.

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