A verticality measuring device for a top-down construction steel pipe column
By designing the guide installation components and detection components, high-precision verticality and tilt angle measurements of steel pipe columns constructed in reverse are achieved, solving the problem that existing technologies cannot meet the requirements for high-precision measurements and improving construction efficiency and effectiveness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF PETROLEUM (EAST CHINA)
- Filing Date
- 2024-07-01
- Publication Date
- 2026-05-12
AI Technical Summary
Existing verticality measuring devices are insufficient to meet the high-precision verticality measurement requirements of steel pipe columns in reverse construction methods, and cannot detect the tilt orientation and tilt angle of the steel pipe columns, resulting in reduced effectiveness.
A verticality measuring device was designed, comprising a guide installation component, a detection component, a line drawing and measurement component, and a marking component. By using the guide tube, the detection component, and the marking component in combination, the verticality and tilt angle of the steel pipe column can be detected, and the tilt direction can be clearly defined by paint spraying and line drawing, which facilitates subsequent straightening.
It enables high-precision detection of the verticality of steel pipe columns and measurement of their tilt angle, improving the accuracy and efficiency of construction and facilitating the straightening operation of steel pipe columns.
Smart Images

Figure CN118816839B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of verticality measurement technology, and in particular to a verticality measuring device for a steel pipe column constructed using the reverse construction method. Background Technology
[0002] The reverse construction method is a construction technique used in building engineering, primarily for underground structures, especially basements and deep foundation pits in high-rise buildings. Its basic principle is to first construct the superstructure on the ground, then gradually excavate downwards to construct the substructure. During reverse construction, the verticality adjustment of the steel pipe columns is a critical process, having a significant impact on the overall building structure. In engineering construction, the verticality of the steel pipe columns must generally meet the requirement of being less than 1 / 500 or even 1 / 1000. Existing verticality measurement devices typically use total stations. However, since the main structure of the steel pipe columns is below ground level, a 2-3 meter guide tube is usually welded to the upper end of the steel pipe column for verticality measurement and adjustment. The total station measures the verticality of the guide tube and then estimates the verticality of the steel pipe column, making it difficult to meet the high-precision verticality measurement requirements.
[0003] For example, the verticality measurement and adjustment structure of steel pipe columns in the reverse construction method of foundation pit disclosed in the patent with announcement number CN212613846U does not have the function of detecting the tilt direction and tilt angle of the steel pipe columns when detecting the verticality of the steel pipe columns. This leads to the need for staff to use other equipment to detect the tilt direction and tilt angle of the steel pipe columns, which reduces the effectiveness of use. Therefore, it is urgent to design a verticality measurement device for steel pipe columns in the reverse construction method. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a verticality measuring device for steel pipe columns constructed using the reverse construction method.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A verticality measuring device for a steel pipe column constructed using a reverse construction method includes a steel pipe column with four uniformly distributed grooves in a ring on its inner wall, and further includes:
[0007] Guide tube, which is vertically installed above the steel pipe column;
[0008] A guide installation assembly is installed on top of the steel pipe column and is used to connect the guide tube and the steel pipe column.
[0009] The detection component is located above the guide tube and is used to detect the verticality of the steel pipe column.
[0010] The line drawing measurement component is set on the detection component and is used to measure the inclination angle of the steel pipe column.
[0011] The marking component is set on the detection component and is used to mark the tilt direction of the steel pipe column.
[0012] As a further technical solution of the present invention, the guide installation assembly includes: a fixed plate, which is fixedly installed inside the guide tube. The bottom of the fixed plate has four evenly distributed L-shaped plates that are slidably arranged in a ring. The horizontal sides of the L-shaped plates are adapted to the grooves. The bottom of the fixed plate has four evenly distributed first sliding grooves in a ring. Each first sliding groove has a first slider that is slidably installed inside. The top of the vertical sides of the four L-shaped plates is fixedly installed at the bottom of the four first sliders.
[0013] As a further technical solution of the present invention, a disc is rotatably installed at the center of the bottom of the fixed disc, and four evenly distributed rotating rods are rotatably installed in a ring at the bottom of the disc. The ends of the four rotating rods away from the disc are respectively rotatably installed on the inner side of the vertical edge of the four L-shaped plates. A first motor is installed on the top of the fixed disc, and the output shaft of the first motor is installed at the center of the top of the disc.
[0014] As a further technical solution of the present invention, the detection component includes: a U-shaped frame, the U-shaped frame is set on the ground, a horizontal plate is set below the horizontal side of the U-shaped frame, two symmetrically arranged electric telescopic rods are installed on the top of the horizontal side of the U-shaped frame, the telescopic ends of the two electric telescopic rods are installed on the top of the horizontal plate, a turntable is horizontally rotatably installed at the bottom center of the horizontal plate, a second motor is installed at the top center of the horizontal plate, and the output shaft of the second motor is installed at the top center of the turntable.
[0015] As a further technical solution of the present invention, a second slide groove is provided at the bottom of the turntable, a second slider is slidably installed inside the second slide groove, a second spring rod is horizontally fixedly installed at the inner end of the second slide groove, the telescopic end of the second spring rod is installed on the side of the second slider, and a first spring rod is vertically fixedly installed at the bottom of the second slider, the bottom of the telescopic end of the first spring rod is tapered.
[0016] As a further technical solution of the present invention, the line drawing and measuring component includes: a second collar, which is fixedly sleeved on the fixed end surface of the first spring rod, and a mounting plate is fixedly installed on the side of the second collar. A three-grip chuck is installed on the side of the mounting plate, and a marker pen is fixed on the three-grip chuck.
[0017] As a further technical solution of the present invention, a fixing plate is provided below the turntable, and a connecting plate is vertically fixedly installed on the top of the fixing plate. The top of the connecting plate is fixedly installed at the bottom of the turntable. A cardboard is glued to the side of the fixing plate near the marker pen. The cardboard may have scales, and the end of the marker pen abuts against the cardboard.
[0018] As a further technical solution of the present invention, the marking component includes: a paint bucket, which is vertically arranged below the turntable, with two upright plates fixedly installed on the top of the paint bucket, the tops of the two upright plates being fixedly installed on the bottom of the turntable, a spray pipe being installed at the bottom of the paint bucket, and a feed inlet being provided on the side of the paint bucket, with a feed cover provided at the feed inlet.
[0019] As a further technical solution of the present invention, a piston disc is slidably arranged inside the paint bucket, and a reciprocating screw is vertically rotatably installed at the center of the paint bucket. The surface of the reciprocating screw is threaded into the inside of the piston disc. A one-way bearing is rotatably installed at the center of the top of the paint bucket, and a connecting shaft is fixedly installed between the inner ring of the one-way bearing and the reciprocating screw.
[0020] As a further technical solution of the present invention, a toothed ring is fixedly sleeved on the outer ring of the one-way bearing, a first collar is fixedly sleeved on the fixed end surface of the first spring rod, an L-shaped connecting plate is fixedly installed on the surface of the first collar, and a rack is horizontally fixedly installed on the end of the L-shaped connecting plate away from the first collar, and the rack and the toothed ring mesh.
[0021] The beneficial effects of this invention are as follows:
[0022] Firstly, by setting up detection and marking components, this invention can not only detect the verticality of steel pipe columns, but also drive the paint bucket to spray pigments from the inclined steel pipe columns and guide pipes, so that the pigments are sprayed out from the spray pipe and placed on the top of the guide pipe, so as to clearly and intuitively understand the inclination direction of the steel pipe columns and guide pipes, which facilitates the subsequent straightening of the steel pipe columns and thus improves the effectiveness of the equipment.
[0023] Secondly, by setting up the detection component and the line drawing measurement component, this invention can not only detect the verticality of the steel pipe column, but also make the tilted steel pipe column and guide tube drive the marker pen to move, so that the marker pen draws a line on the cardboard. Then, a right triangle is drawn according to the length of the guide tube and the steel pipe column, so as to obtain the tilt angle of the steel pipe column and the guide tube, which facilitates the staff to make precise adjustments. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the verticality measuring device for a reverse-construction steel pipe column proposed in this invention.
[0025] Figure 2 This is a schematic diagram of the guide tube and the cross-sectional structure of the steel pipe column for measuring the verticality of a reverse-construction steel pipe column proposed in this invention.
[0026] Figure 3 This is a schematic diagram of the fixed plate structure of the verticality measuring device for a reverse-construction steel pipe column proposed in this invention, viewed from below.
[0027] Figure 4This is a schematic diagram of the horizontal plate and turntable structure of the verticality measuring device for a reverse-construction steel pipe column proposed in this invention, viewed from below.
[0028] Figure 5 For this Figure 4 An enlarged schematic diagram of part A in the middle;
[0029] Figure 6 This is a schematic cross-sectional view of the paint bucket structure of the verticality measuring device for a reverse-construction steel pipe column proposed in this invention.
[0030] Figure 7 for Figure 6 Enlarged schematic diagram of part B in the middle;
[0031] Figure 8 This is a schematic diagram of the verticality measuring device for a reverse-construction steel pipe column proposed in this invention after removing the paint bucket.
[0032] In the diagram: 1. U-shaped frame; 2. Steel pipe column; 3. Guide tube; 4. Horizontal plate; 5. Electric telescopic rod; 6. L-shaped plate; 7. Groove; 8. Turntable; 9. First spring rod; 10. Paint bucket; 11. Spray pipe; 12. Fixed plate; 13. First motor; 14. First slide groove; 15. First slider; 16. Disc; 17. Rotating rod; 18. First collar; 19. Second collar; 20. Rack; 21. Second slide groove; 22. Second slider; 23. Second spring rod; 24. Three-grip chuck; 25. Marker pen; 26. Fixed plate; 27. Cardboard; 28. One-way bearing; 29. Gear ring; 30. Piston disc; 31. Reciprocating screw; 32. Feed cover. Detailed Implementation
[0033] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0034] Please see the appendix Figure 1 -Appendix Figure 8 A verticality measuring device for a steel pipe column constructed using a reverse construction method includes a steel pipe column 2. The inner wall of the steel pipe column 2 has four evenly distributed annular grooves 7. The device also includes a guide pipe 3, a guide installation assembly, a detection assembly, a line drawing and measurement assembly, and a marking assembly. The guide pipe 3 is vertically positioned above the steel pipe column 2. The guide installation assembly is positioned at the top of the steel pipe column 2 and is used to connect the guide pipe 3 and the steel pipe column 2. The detection assembly is positioned above the guide pipe 3 and is used to detect the verticality of the steel pipe column 2. The line drawing and measurement assembly is positioned on the detection assembly and is used to measure the tilt angle of the steel pipe column 2. The marking assembly is positioned on the detection assembly and is used to mark the tilt direction of the steel pipe column 2.
[0035] As mentioned above, lines can be drawn on the cardboard 27 and sprayed on the guide tube 3 to facilitate quick adjustment and straightening of the steel pipe column 2.
[0036] Please see the appendix Figure 1 -Appendix Figure 4 In a preferred embodiment, the guide mounting assembly includes: a fixed disk 12, which is fixedly mounted inside the guide tube 3. The bottom of the fixed disk 12 has four evenly distributed L-shaped plates 6 arranged in a ring shape. The horizontal sides of the L-shaped plates 6 are adapted to the grooves 7. The bottom of the fixed disk 12 has four evenly distributed first sliding grooves 14 arranged in a ring shape. Each first sliding groove 14 has a first slider 15 slidably mounted inside it. The tops of the vertical sides of the four L-shaped plates 6 are fixedly mounted to the bottom of the four first sliders 15. A disc 16 is rotatably mounted at the center of the bottom of the fixed disk 12. The bottom of the disc 16 has four evenly distributed rotating rods 17 rotatably mounted in a ring shape. The ends of the four rotating rods 17 away from the disc 16 are rotatably mounted to the inner sides of the vertical sides of the four L-shaped plates 6. A first motor 13 is mounted on the top of the fixed disk 12. The output shaft of the first motor 13 is mounted at the center of the top of the disc 16.
[0037] Specifically, the horizontal edge of the L-shaped plate 6 and the groove 7 can be separated, thereby disconnecting the steel pipe column 2 and the guide tube 3, which facilitates quick disassembly and repeated use of the guide tube 3.
[0038] Please see the appendix Figure 1 -Appendix Figure 8 In a preferred embodiment, the detection component includes: a U-shaped frame 1, which is set on the ground. A horizontal plate 4 is horizontally arranged below the horizontal side of the U-shaped frame 1. Two symmetrically arranged electric telescopic rods 5 are installed on the top of the horizontal side of the U-shaped frame 1. The telescopic ends of the two electric telescopic rods 5 are installed on the top of the horizontal plate 4. A turntable 8 is horizontally rotatably installed at the bottom center of the horizontal plate 4. A second motor is installed at the top center of the horizontal plate 4. The output shaft of the second motor is installed at the top center of the turntable 8. A second slide groove 21 is opened at the bottom of the turntable 8. A second slider 22 is slidably installed inside the second slide groove 21. A second spring rod 23 is horizontally fixedly installed at the inner end of the second slide groove 21. The telescopic end of the second spring rod 23 is installed on the side of the second slider 22. A first spring rod 9 is vertically fixedly installed at the bottom of the second slider 22. The bottom of the telescopic end of the first spring rod 9 is tapered.
[0039] Preferably, if the first spring rod 9 moves horizontally, the surface steel pipe column 2 is tilted; otherwise, it indicates that the steel pipe column 2 is vertical.
[0040] Please see the appendix Figure 1 -Appendix Figure 8In a preferred embodiment, the line drawing and measuring assembly includes: a second collar 19, which is fixedly sleeved on the fixed end surface of the first spring rod 9; a mounting plate is fixedly installed on the side of the second collar 19; a three-jaw chuck 24 is installed on the side of the mounting plate; a marker pen 25 is fixed on the three-jaw chuck 24; a fixing plate 26 is provided below the turntable 8; a connecting plate is vertically fixedly installed on the top of the fixing plate 26; the top of the connecting plate is fixedly installed on the bottom of the turntable 8; a cardboard 27 is glued to the side of the fixing plate 26 near the marker pen 25; the cardboard 27 may have scales; and the end of the marker pen 25 abuts against the cardboard 27.
[0041] Furthermore, the marker 25 moves to draw a line on the cardboard 27, and the length of the line is known according to the scale on the cardboard 27. Then, according to the length of the steel pipe column 2 and the guide tube 3, a right triangle is drawn with the length of the line as the base and the length of the guide tube 3 and the steel pipe column 2 as the height. The angle formed by the hypotenuse and the base of the right triangle is the angle of inclination.
[0042] Please see the appendix Figure 1 -Appendix Figure 8 In a preferred embodiment, the marking assembly includes: a paint bucket 10, which is vertically positioned below the turntable 8. Two upright plates are fixedly mounted on the top of the paint bucket 10, with the tops of both plates fixedly mounted to the bottom of the turntable 8. A spray pipe 11 is connected to the bottom of the paint bucket 10. A feed inlet is provided on the side of the paint bucket 10, and a feed cover 32 is provided at the feed inlet. A piston disc 30 is slidably disposed inside the paint bucket 10. A reciprocating screw 31 is vertically rotatably mounted at the center of the paint bucket 10. The screw 31 is threadedly installed inside the piston disc 30. A one-way bearing 28 is rotatably installed at the top center of the paint bucket 10. A connecting shaft is fixedly installed between the inner ring of the one-way bearing 28 and the reciprocating screw 31. A toothed ring 29 is fixedly sleeved on the outer ring of the one-way bearing 28. A first collar 18 is fixedly sleeved on the fixed end surface of the first spring rod 9. An L-shaped connecting plate is fixedly installed on the surface of the first collar 18. A rack 20 is horizontally fixedly installed on the end of the L-shaped connecting plate away from the first collar 18. The rack 20 and the toothed ring 29 mesh.
[0043] Preferably, the reciprocating screw 31 rotates to drive the piston disc 30 to move, so that the pigment in the paint bucket 10 can be sprayed out from the spray nozzle 11 and sprayed on the top of the guide tube 3. The direction of the paint is the direction in which the steel pipe column 2 is tilted.
[0044] From the above description, it can be seen that the above-mentioned examples of the present invention achieve the following technical effects: First, the U-shaped frame 1 is installed and fixed in a suitable position. During testing, the electric telescopic rod 5 drives the horizontal plate 4 to move upward, and the horizontal plate 4 moves downward, driving the components on it to move upward together. When the first spring rod 9 moves downward, two situations will occur.
[0045] First: ① If the guide tube 3 is tilted and the telescopic end of the first spring rod 9 abuts against the top of the guide tube 3, the second motor drives the turntable 8 to rotate. The rotation of the turntable 8 causes the second slide groove 21, the second slider 22, and the first spring rod 9 to revolve, thereby changing the position of the telescopic end of the first spring rod 9 until the telescopic end of the first spring rod 9 can move downward and is located on the side of the guide tube 3 (when the telescopic end of the first spring rod 9 is in the non-tilted direction). The second motor drives the turntable 8 and the first spring rod 9 to revolve, and the telescopic end of the first spring rod 9 will revolve around the center of the turntable 8. When the telescopic end of the first spring rod 9 rotates and contacts the outer wall of the guide tube 3 in the tilted direction, it will cause the first spring rod 9 to move outward and cause the second spring rod 23 to generate tension. The movement of the first spring rod 9 drives the first collar 18 and the second collar 19 to move. The movement of the first collar 18 drives the rack 20 to move. The movement of the rack 20 drives the gear ring 29 to rotate. The rotation of the gear ring 29 drives the reciprocating motion through the one-way bearing 28. The lead screw 31 rotates (the reciprocating lead screw 31 does not rotate when the rack 20 moves in the opposite direction). The rotation of the reciprocating lead screw 31 drives the piston disc 30 to move, thereby spraying the paint in the paint bucket 10 from the spray nozzle 11 and onto the top of the guide tube 3 (the direction with paint is the direction in which the steel pipe column 2 is tilted). The movement of the second ring 19 drives the three-jaw chuck 24 and the marker pen 25 to move. The movement of the marker pen 25 will draw a line on the cardboard 27, and the length of the line can be determined according to the scale on the cardboard 27. Then, according to the steel pipe... ① Draw a right triangle with the length of the line drawn as the base and the lengths of the guide tube 3 and the steel pipe column 2 as the height. The angle formed by the hypotenuse and the base of this right triangle is the angle of inclination. In summary, this can facilitate the quick adjustment and straightening of the steel pipe column 2. ② If the guide tube 3 is inclined and the telescopic end of the first spring rod 9 does not abut against the top of the guide tube 3, then the telescopic end of the first spring rod 9 is located on the side of the guide tube 3. In summary, lines can be drawn on the cardboard 27 and sprayed on the guide tube 3.
[0046] Second: If the guide tube 3 is not tilted, the telescopic end of the first spring rod 9 will not come into contact with the guide tube 3, and when it moves directly downward, it will be located on the side of the guide tube 3. The marker 25 will not draw lines on the cardboard 27, and the spray nozzle 11 will not spray paint on the guide tube 3.
[0047] When it is necessary to disassemble the guide tube 3, simply drive the disc 16 to rotate via the first motor 13. The rotation of the disc 16 drives the rotating rod 17 to rotate, and the rotation of the rotating rod 17 drives the L-shaped plate 6 to move. This allows the horizontal edge of the L-shaped plate 6 to separate from the groove 7, thereby detaching the steel pipe column 2 and the guide tube 3. This facilitates quick disassembly and repeated use of the guide tube 3.
[0048] This invention is intended to cover all such substitutions, modifications, and variations falling within the broad scope of the claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A verticality measuring device for a steel pipe column constructed using a reverse method, comprising a steel pipe column (2), wherein the inner wall of the steel pipe column (2) is provided with four uniformly distributed grooves (7) arranged in a ring, characterized in that, Also includes: Guide tube (3), the guide tube (3) is vertically installed above the steel pipe column (2); A guide installation assembly is provided on the top of the steel pipe column (2) and is used to connect the guide tube (3) and the steel pipe column (2). The guide installation assembly includes: a fixing plate (12), which is fixedly installed inside the guide tube (3). The bottom of the fixing plate (12) is provided with four evenly distributed L-shaped plates (6) in a ring shape. The horizontal side of the L-shaped plate (6) is adapted to the groove (7). The bottom of the fixing plate (12) is provided with four evenly distributed first sliding grooves (14) in a ring shape. Each first sliding groove (14) is slidably installed with a first slider (15). The top of the vertical side of the four L-shaped plates (6) is fixedly installed at the bottom of the four first sliders (15). The detection component is set above the guide tube (3) and is used to detect the verticality of the steel pipe column (2). The detection component includes: a U-shaped frame (1), which is set on the ground. A horizontal plate (4) is set below the horizontal side of the U-shaped frame (1). Two symmetrically arranged electric telescopic rods (5) are installed on the top of the horizontal side of the U-shaped frame (1). The telescopic ends of the two electric telescopic rods (5) are installed on the top of the horizontal plate (4). A turntable (8) is installed horizontally at the bottom center of the horizontal plate (4). A second motor is installed at the top center of the horizontal plate (4). The output shaft of the second motor is installed at the top center of the turntable (8). A line drawing measurement component is provided on the detection component and is used to measure the inclination angle of the steel pipe column (2). The line drawing measurement component includes: a second collar (19), which is fixedly sleeved on the fixed end surface of the first spring rod (9). An installation plate is fixedly installed on the side of the second collar (19), and a three-grip chuck (24) is installed on the side of the installation plate. A marker pen (25) is fixed on the three-grip chuck (24). A marking component is provided on the detection component and is used to mark the tilt direction of the steel pipe column (2). The marking component includes: a paint bucket (10), which is vertically arranged below the turntable (8). Two upright plates are fixedly installed on the top of the paint bucket (10), and the tops of the two upright plates are fixedly installed on the bottom of the turntable (8). A spray pipe (11) is connected to the bottom of the paint bucket (10). An inlet is provided on the side of the paint bucket (10), and an inlet cover (32) is provided at the inlet.
2. The verticality measuring device for a steel pipe column constructed using the reverse construction method according to claim 1, characterized in that, A disc (16) is rotatably mounted at the bottom center of the fixed disk (12). Four evenly distributed rotating rods (17) are rotatably mounted in a ring at the bottom of the disc (16). The ends of the four rotating rods (17) away from the disc (16) are rotatably mounted on the inner side of the vertical side of the four L-shaped plates (6). A first motor (13) is mounted on the top of the fixed disk (12). The output shaft of the first motor (13) is mounted at the top center of the disc (16).
3. The verticality measuring device for a steel pipe column constructed using the reverse construction method according to claim 1, characterized in that, The turntable (8) has a second slide groove (21) at the bottom. A second slider (22) is slidably installed inside the second slide groove (21). A second spring rod (23) is horizontally fixed at the inner end of the second slide groove (21). The telescopic end of the second spring rod (23) is installed on the side of the second slider (22). A first spring rod (9) is vertically fixed at the bottom of the second slider (22). The bottom of the telescopic end of the first spring rod (9) is conical.
4. The verticality measuring device for a steel pipe column constructed using the reverse construction method according to claim 1, characterized in that, A fixing plate (26) is provided below the turntable (8). A connecting plate is vertically fixed on the top of the fixing plate (26). The top of the connecting plate is fixedly installed at the bottom of the turntable (8). A cardboard (27) is glued to the side of the fixing plate (26) near the marker (25). The cardboard (27) may have scales. The end of the marker (25) abuts against the cardboard (27).
5. The verticality measuring device for a steel pipe column constructed using the reverse construction method according to claim 1, characterized in that, A piston disc (30) is slidably disposed inside the paint bucket (10). A reciprocating screw (31) is vertically rotatably mounted at the center of the paint bucket (10). The surface of the reciprocating screw (31) is threadedly mounted inside the piston disc (30). A one-way bearing (28) is rotatably mounted at the center of the top of the paint bucket (10). A connecting shaft is fixedly mounted between the inner ring of the one-way bearing (28) and the reciprocating screw (31).
6. The verticality measuring device for a steel pipe column constructed using the reverse construction method according to claim 5, characterized in that, The outer ring of the one-way bearing (28) is fixedly sleeved with a toothed ring (29), and the fixed end surface of the first spring rod (9) is fixedly sleeved with a first collar (18). An L-shaped connecting plate is fixedly installed on the surface of the first collar (18), and a rack (20) is horizontally fixedly installed at the end of the L-shaped connecting plate away from the first collar (18). The rack (20) and the toothed ring (29) mesh.