A wind power blade web positioning detection tool

Abstract

The utility model relates to a kind of wind power blade web positioning detection tool, it includes horizontal pole and vertical fixed length adjustable vertical pole at its both ends, two vertical pole outside is respectively provided with one for length measurement measuring mechanism, the length measurement direction of the measuring mechanism is parallel with the length direction of horizontal pole each other;Horizontal pole is provided with horizontal detection mechanism, and one measuring mechanism below is hinged with support seat.The wind power blade web positioning detection tool is convenient to fold and store, to detect vice beam web, measurement data is accurate, can effectively guarantee the accuracy and stability of blade web structure positioning.

Description

Technical Field

[0001] This utility model relates to the field of wind turbine blade technology, specifically to a tooling for positioning and testing the web of a wind turbine blade. Background Technology

[0002] The web is the main structural component of a wind turbine blade and serves as its primary load-bearing member. During the manufacturing process of wind turbine blades, the web needs to be positioned using positioning and measuring tools. With the rapid development of wind power technology, wind turbine blade structures are becoming increasingly complex, and the load-bearing capacity of the blades is increasing, making web positioning difficult and prone to displacement during shell forming.

[0003] To ensure the accuracy of the web position during blade shell molding, multiple chordal positions of the blade are inspected and measured during production. Traditional web positioning fixtures use a ruler for positioning, which is inefficient, cannot effectively control the detection accuracy, and cannot achieve chordal positioning detection of the sub-spar web in a three-single-web structure. Therefore, it is necessary to design a wind turbine blade web positioning and detection fixture to inspect the sub-spar web, effectively ensuring the accuracy and stability of the blade web structure positioning. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a wind turbine blade web positioning and testing fixture that is easy to store and fold, and is used to test the sub-beam web, which can effectively ensure the accuracy and stability of the blade web structure positioning.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows: A positioning and testing fixture for the web of a wind turbine blade includes a horizontal bar and vertically fixed at both ends with adjustable lengths. A measuring mechanism for length measurement is respectively provided on the outer side of the two vertical bars, and the length measurement direction of the measuring mechanism is parallel to the length direction of the horizontal bar. A horizontal detection mechanism is provided on the horizontal bar, and a support seat is hinged below one of the measuring mechanisms.

[0006] In one embodiment of this utility model, the measuring mechanism includes a first measuring mechanism and a second measuring mechanism respectively connected to the outside of two vertical rods. The first measuring mechanism is a linear displacement sensor, and the second measuring mechanism is a retractable measuring ruler.

[0007] In one embodiment of this utility model, the linear displacement sensor is a rod-type displacement sensor, and a pressure sensor is provided at the outer end of the rod.

[0008] In one embodiment of this utility model, the measuring ruler includes a measuring sleeve and a measuring rod inserted therein, the inner end of the measuring sleeve being connected to the lower end of the vertical rod; the outer surface of the measuring sleeve is provided with a scale with the scale value increasing sequentially from the inside to the outside, and the outer surface of the measuring rod is provided with a scale with the scale value decreasing sequentially from the inside to the outside.

[0009] In one embodiment of this utility model, a pulley mechanism is provided between the measuring sleeve and the measuring rod. The pulley mechanism includes a slide rail symmetrically arranged on the inner wall of the measuring sleeve and a pulley arranged on the measuring rod that is adapted to the slide rail.

[0010] In one embodiment of this utility model, the inner end of the measuring mechanism is hinged to the lower end of the vertical rod, and a limiting mechanism is provided between them. This limiting mechanism ensures that the length measuring direction of the measuring mechanism is parallel to the length direction of the horizontal rod, or... The inner end of the measuring mechanism is fixedly connected to the lower end of the vertical rod.

[0011] As one embodiment of this utility model, the limiting mechanism includes a through hole disposed at the inner end of the linear displacement sensor and the measuring sleeve, and a limiting hole disposed at the lower end of the vertical rod corresponding to the through hole. When the linear displacement sensor and the measuring sleeve are perpendicular to each other with the vertical rod, the through holes on the linear displacement sensor and the measuring sleeve coincide with the axis of the limiting hole on the corresponding vertical rod, and the corresponding through holes and limiting holes are detachably connected together by a pin.

[0012] In one embodiment of this utility model, a hinge seat is fixedly provided at the bottom of the outer end of the measuring sleeve. The support seat includes a support rod hinged to the hinge seat and a suction cup fixed at the outer end of the support rod. The length of the support rod is adjustable. The suction cup is made of plastic, is conical, and its axis coincides with the axis of the support rod.

[0013] As one embodiment of this utility model, it also includes a wireless data transmission module, a display and a host, and the detection data of the linear displacement sensor 11 is synchronized to the display through the wireless data transmission module.

[0014] In one embodiment of this utility model, the level detection mechanism is a level instrument set at the top of the crossbar; the crossbar and the two vertical bars are generally U-shaped; the vertical bar includes an adjusting sleeve vertically fixed to the lower end of the crossbar and an adjusting rod inserted into the adjusting sleeve, the adjusting sleeve and the adjusting rod are both square and a height adjustment mechanism is provided between them.

[0015] The beneficial effects of adopting the above technical solution are as follows: The wind turbine blade web positioning and testing fixture provided by this utility model is shaped like a "Z" and can span the intermediate blocking web (tail-edge UD web). The support base is attached to the mold of the blade shell by a suction cup, and a horizontal detection mechanism ensures that the crossbar is horizontal. The second measuring mechanism directly reads the scale at the inner edge of the mold. The first measuring mechanism adjusts the position of the pull rod so that the end of the pull rod abuts against the sub-beam web. The length of the linear displacement sensor housing is fixed and can read the movement distance of the pull rod. The length of the crossbar is fixed. Therefore, by adding the readings of the first measuring mechanism, the second measuring mechanism, the length of the crossbar, and the length of the linear displacement sensor housing, the distance between the sub-beam web and the inner edge of the mold at the current measurement position can be obtained. The testing fixture realizes the fully digital detection of the web positioning process, with a positioning accuracy of ±0.5mm, which is 60% more efficient than traditional methods, effectively ensuring the accuracy and stability of the blade web structure positioning. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the structure of this utility model from another angle.

[0018] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0019] Figure 4 This is a structural schematic diagram of the horizontal and vertical bars in this utility model.

[0020] Figure 5 This is a structural schematic diagram of the support base and the second measuring mechanism in this utility model.

[0021] Figure 6 This is a schematic diagram of the structure of the support base and the measuring sleeve in the second measuring mechanism of this utility model.

[0022] Figure 7 This is a schematic diagram of the measuring rod in the second measuring mechanism of this utility model.

[0023] Figure 8 This is a schematic diagram of the main structure of this utility model.

[0024] Figure 9 yes Figure 8 A magnified view of a portion of point B in the middle.

[0025] Figure 10 This is a schematic diagram of the working state of this utility model.

[0026] Figure 11 This is a schematic diagram of the structure of the wind turbine blade in this utility model.

[0027] The components are as follows: 1. Crossbar, 2. Level, 3. Adjusting sleeve, 301. Adjusting hole, 4. Adjusting rod, 401. Mounting hole, 402. Limiting hole, 5. Mounting sleeve, 6. Adjusting button, 601. Snap ring, 602. Limiting post, 7. Spring, 8. Rotating shaft, 9. First rotating cylinder, 10. Cotter pin, 11. Linear displacement sensor, 12. Through hole, 13. Tie rod, 14. Pressure sensor, 15. Second rotating cylinder, 16. Measuring sleeve, 17. Scale, 18. Slide rail, 19. Hinge seat, 20. Measuring rod, 21. Pulley, 22. Support rod, 23. Suction cup, 24. Pressure surface, 25. Main beam web, 26. Secondary beam web, 27. Rear edge UD web, 28. Suction surface, 29. Mold frustum, 30. Mold cavity. Detailed Implementation

[0028] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be clearly and completely described below in conjunction with specific embodiments.

[0029] like Figure 1 and Figure 2 The invention relates to a wind turbine blade web positioning and testing fixture, which includes a horizontal bar 1 and vertical bars with adjustable lengths fixed at both ends. A measuring mechanism for length measurement is provided on the outer side of each of the two vertical bars, and the length measurement direction of the measuring mechanism is parallel to the length direction of the horizontal bar 1. A horizontal detection mechanism is provided on the horizontal bar 1, and a support base is hinged to the bottom of one of the measuring mechanisms.

[0030] In this embodiment, the measuring mechanism includes a first measuring mechanism and a second measuring mechanism respectively connected to the outside of the two vertical rods. The first measuring mechanism is a linear displacement sensor 11, and the second measuring mechanism is a retractable measuring ruler.

[0031] Specifically, the linear displacement sensor 11 is a KTC-1000mm tie rod type displacement sensor, with a pressure sensor 14 installed at the outer end of its tie rod 13. The pressure sensor 14 ensures that there is no gap between the end of the tie rod 13 and the web plate 26 of the sub-beam. The tie rod type displacement sensor is externally equipped with a wireless transmission module and a battery, and the wireless transmission module is used to transmit the length of the tie rod type displacement sensor and the pressure value of the pressure sensor 14 in real time.

[0032] like Figures 5-7As shown, the measuring ruler includes a measuring sleeve 16 and a measuring rod 20 inserted inside it. The inner end of the measuring sleeve 16 is connected to the lower end of the vertical rod. The outer surface of the measuring sleeve 16 is provided with a scale 17, and the scale values ​​increase sequentially from the inside to the outside. The 0 mark on the measuring sleeve 16 is flush with the end of the horizontal rod 1. The outer surface of the measuring rod 20 is provided with a scale 17, and the scale values ​​decrease sequentially from the inside to the outside. That is, when the measuring rod 20 is completely retracted into the measuring sleeve 16, the 0 mark value at the right end of the measuring rod 20 coincides with the maximum scale value at the outer end of the measuring sleeve 16. The maximum scale value of the measuring sleeve 16 is 500mm-1000mm, and the maximum scale value of the measuring rod 20 is also 500mm-1000mm, and the maximum scale value on the measuring rod 20 is not greater than the maximum scale value on the measuring sleeve 16. The measuring range of the measuring ruler is 0mm-Lmm, where L is the sum of the maximum scale value of the measuring sleeve 16 and the maximum scale value of the measuring rod 20.

[0033] The wind turbine blade consists of a blade shell pressure surface 24, a suction surface 28, and a main beam web 25, a secondary beam web 26, and a trailing edge UD web 27 located between them. Due to the curved structure of the wind turbine blade, the position of the inner edge of the mold is variable. In actual use, the lower part of the outer end of the measuring sleeve 16 is connected to the blade mold via a support base. When the support base is located outside the inner edge of the mold (inner edge of the mold frustum 29), the suction cup 23 is adsorbed on the upper surface of the mold frustum 29. After adjusting the crossbar 1 to keep it horizontal, the data can be read directly through the scale 17 on the measuring sleeve 16. When the support base is located inside the inner edge of the mold, the suction cup 23 is adsorbed on the surface of the pressure surface 24 (PS surface) of the blade shell inside the mold cavity 30. After adjusting the crossbar 1 to keep it horizontal, the measuring rod 20 is pulled out from the measuring sleeve 16 so that the 0 scale on the right end of the measuring rod 20 is aligned with the inner edge of the mold, and the reading can be read directly. The data is read by adding the maximum scale value of the measuring sleeve 16 to the reading of the measuring rod 20. The scale 17 is located on the side or top of the measuring ruler. The length of the housing of the linear displacement sensor 11 is 600mm-1000mm, and the length of the crossbar 1 is 300mm-700mm.

[0034] like Figure 6 and Figure 7 As shown, as a further optimization, a pulley mechanism is provided between the measuring sleeve 16 and the measuring rod 20. The pulley mechanism includes a slide rail 18 symmetrically arranged on the inner wall of the measuring sleeve 16 and a pulley 21 arranged on the measuring rod 20 and adapted to the slide rail 18. Both the measuring sleeve 16 and the measuring rod 20 are square hollow rods. The slide rail 18 includes two L-shaped limiting plates arranged vertically opposite each other. The pulley 21 is rotatably arranged on the side wall of the measuring sleeve 20 and is engaged between the two limiting plates.

[0035] like Figure 3As shown, the inner end of the measuring mechanism is hinged to the lower end of the vertical rod, and a limit mechanism is provided between them. The limit mechanism enables the length measuring direction of the measuring mechanism to be parallel to the length direction of the horizontal rod 1. That is, when the length direction of the measuring mechanism is perpendicular to the vertical rod, it is locked by the limit mechanism.

[0036] When the inner end of the measuring mechanism is hinged to the lower end of the vertical rod, the limiting mechanism includes a through hole 12 at the inner end of the linear displacement sensor 11 and the measuring sleeve 16, and a limiting hole 402 at the lower end of the vertical rod corresponding to the through hole 12. When the linear displacement sensor 11 and the measuring sleeve 16 are perpendicular to the vertical rod, the through holes 12 on the linear displacement sensor 11 and the measuring sleeve 16 are aligned with the axes of the corresponding limiting holes 402 on the vertical rod. The corresponding through holes 12 and limiting holes 402 are detachably connected together by a pin. The support rod 22 is hinged to the measuring sleeve 16. When the measuring mechanism and the vertical rod are detachably hinged together, the entire testing fixture can be easily folded and stored when not in use.

[0037] Specifically, the lower end of the adjusting rod 4 in the vertical rod is provided with a rotating shaft 8. A limiting hole 402 parallel to the axis of the rotating shaft 8 is opened on the side of the adjusting rod 4. The inner end of the linear displacement sensor 11 is rotatably sleeved on the rotating shaft 8 via a first rotating cylinder 9. The through hole 12 is opened on the inner end of the linear displacement sensor 11 or on the first rotating cylinder 9. The inner end of the measuring sleeve 16 is rotatably sleeved on the rotating shaft 8 via a second rotating cylinder 15. The through hole 12 is opened on the second rotating cylinder 15 or on the measuring sleeve 16. A through hole is provided on the outer side of the rotating shaft 8, and a cotter pin 10 is provided in the through hole. The cotter pin 10 limits the first rotating cylinder 9 and the second rotating cylinder 15 on the rotating shaft 8 to prevent them from falling off.

[0038] In addition, as another way of connecting the measuring mechanism and the vertical rod, the measuring mechanism and the vertical rod are directly and perpendicularly fixed together. When this method is used, the measuring mechanism cannot be folded and stored.

[0039] like Figure 5 and Figure 6As shown, a hinge seat 19 is fixedly provided at the bottom of the outer end of the measuring sleeve 16. The support seat includes a support rod 22 hinged to the hinge seat 19 and a suction cup 23 fixed to the outer end of the support rod 22. The support rod 22 is hinged to the hinge seat 19. When the suction cup 23 is adsorbed on the pressure surface 24 of the mold frustum 29 or the blade shell inside the mold cavity 30, it is convenient to adjust the crossbar 1 to be horizontal. In particular, when the suction cup 23 is adsorbed on the pressure surface 24, since the mold cavity 30 and the pressure surface 24 are arc-shaped, the support rod 22 cannot be in a vertical state. The horizontal adjustment of the crossbar 1 can only be achieved by adjusting the relative angle between the support rod 22 and the measuring sleeve 16. The suction cup 23 is made of plastic, is conical, and its axis coincides with the axis of the support rod 22. As a further optimization, the length of the support rod 22 is adjustable.

[0040] The testing fixture also includes a wireless data transmission module, a display, and a host computer. The wireless data transmission module synchronizes the detection data from the linear displacement sensor 11 to the display. The host computer contains a wireless receiving module corresponding to the wireless transmitting module, as well as a data storage card, a data processor, a controller, and other modules, and external input devices such as a keyboard and mouse. The detection data from the linear displacement sensor 11 is transmitted to the display for recording and storage via an industrial bus (wireless or wired). The lengths of the crossbar 1 and the outer shell of the linear displacement sensor 11 are fixed values ​​and are pre-entered into the display system. The data read by the measuring ruler is manually entered into the display system. After the host computer processes the data, the display can show the current measurement data in real time and automatically generate a positioning error map.

[0041] like Figure 8 and Figure 9 As shown, in this embodiment, the level detection mechanism is a level instrument set at the top of the crossbar 1; the crossbar 1 and the two vertical bars are in the shape of a c; the vertical bar includes an adjusting sleeve 3 vertically fixed to the lower end of the crossbar 1 and an adjusting rod 4 inserted in the adjusting sleeve 3. The adjusting rod 4 is also a hollow rod. The adjusting sleeve 3 and the adjusting rod 4 are both square and a height adjustment mechanism is provided between them.

[0042] The height adjustment mechanism includes multiple adjustment holes 301 evenly spaced along the length of the adjustment sleeve 3 and mounting holes 401 on the side of the adjustment rod 4. A cylindrical mounting sleeve 5 is fixed inside the mounting hole 401. An adjustment button 6 is installed inside the mounting sleeve 5. A retaining ring 601 is provided at the inner end of the adjustment button 6. The retaining ring 601 is confined to the inner side of the mounting sleeve 5 by a tapering end. A spring 7 is provided between the retaining ring 601 and the inner wall of the adjustment rod 4 inside the mounting sleeve 5. As a further optimization, to prevent the adjustment button 6 from getting stuck when it is fully inserted into the mounting sleeve 5, a limiting post 602 is coaxially fixed inside the retaining ring 601. When the outer end of the adjustment button 6 is just flush with the outer surface of the adjustment rod 4, the limiting post 602 abuts against the inner wall of the adjustment rod 4.

[0043] For specific usage instructions, please refer to... Figure 10 and Figure 11 : Step 1: Fixing the tooling Open the testing fixture support base, and use the suction cup 23 to attach the fixture support to the blade mold. Place the crossbar 1 on the upper side of the web to keep the whole structure stable.

[0044] Step 2: Height Adjustment The height of the vertical bar is adjusted by the height adjustment mechanism to ensure that the height of the horizontal bar 1 matches the height of the rear edge UD web plate 27, thus solving the problem of physical isolation in the middle.

[0045] Step 3: Level Check The horizontal bar 1 of the inspection fixture is checked using a level 2 to ensure that the horizontal bar 1 remains horizontal during the measurement process and to ensure the accuracy of the measurement.

[0046] Step 4: Adjusting the chord direction The first and second measuring mechanisms are rotated perpendicular to the vertical rod. The scale of the measuring ruler is aligned with the inner edge of the mold. The linear displacement sensor 11 is adjusted so that its end contacts the vertical surface of the sub-beam web 26. The chordal positioning data of the sub-beam web 26 is detected in real time using the data from the scale on the measuring ruler, the measured length of the linear displacement sensor 11, and the lengths of the crossbar 1 and the outer shell of the linear displacement sensor 11. This data is then transmitted to the display for analysis, recording, and storage. The actual measured length is the distance from the sub-beam web 26 to the inner edge of the mold.

[0047] Step 5: Tool Storage After the test is completed, the measuring mechanisms on both sides of the testing fixture are rotated and folded for storage, and the support base is also folded for storage, making it convenient for storage and assembly.

[0048] Specific usage process: When the web plate 26 of the sub-beam is bonded and positioned, one end of the pressure sensor 14 of the testing fixture is placed above the blade housing in the mold cavity 30, and the other end is adsorbed onto the mold by the suction cup 23 at the bottom of the support rod 22 to ensure that the testing fixture does not shift during placement and positioning. Axial positioning is performed by the mold metric mark. The lengths of the first and second measuring mechanisms are adjusted for chordal positioning (positioning tolerance ±10mm). After positioning, the length of the second measuring mechanism remains unchanged.

[0049] After the sub-beam web 26 is properly positioned according to the standard location using the testing fixture, it is transferred to the pressure surface 24 of the blade shell for positioning. The "U"-shaped mechanism (horizontal bar 1 and two vertical bars) of the testing fixture is passed over the trailing edge UD web 27, so that the vertical surface of the sub-beam web 26 abuts against the pressure sensor 14 in the testing fixture, achieving the initial testing and positioning of the sub-beam web 26. To avoid the sub-beam web 26 failing to abut against the pressure sensor 14 or changing the horizontal position of the pressure sensor 14 during placement, the sub-beam web 26 is positioned on the pressure surface 24 of the blade shell. 6. After placement, control the pull rod 13 of the linear displacement sensor 11 to move again until the pressure sensor 14 abuts against the vertical surface of the sub-beam web 26. The measurement data is obtained by adding the scale data on the measuring ruler, the measured length of the linear displacement sensor 11, and the length data of the crossbar 1 and the shell of the linear displacement sensor 11. The measurement data is then displayed on the monitor, thereby realizing the secondary detection of the chordal positioning of the sub-beam web 26, determining whether the position of the sub-beam web 26 has shifted, and adjusting the position of the sub-beam web 26 to the standard position.

[0050] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tooling for positioning and detecting the web of a wind turbine blade, characterized in that: It includes a horizontal bar (1) and vertical bars with adjustable lengths fixed at both ends. A measuring mechanism for length measurement is provided on the outer side of each of the two vertical bars. The length measurement direction of the measuring mechanism is parallel to the length direction of the horizontal bar (1). A horizontal detection mechanism is provided on the horizontal bar (1), and a support seat is hinged below one of the measuring mechanisms.

2. The wind turbine blade web positioning and detection fixture according to claim 1, characterized in that: The measuring mechanism includes a first measuring mechanism and a second measuring mechanism respectively connected to the outside of the two vertical rods. The first measuring mechanism is a linear displacement sensor (11), and the second measuring mechanism is a retractable measuring ruler.

3. The wind turbine blade web positioning and detection fixture according to claim 2, characterized in that: The linear displacement sensor (11) is a rod-type displacement sensor, and a pressure sensor (14) is provided at the outer end of its rod (13).

4. The wind turbine blade web positioning and detection fixture according to claim 3, characterized in that: The measuring ruler includes a measuring sleeve (16) and a measuring rod (20) inserted therein. The inner end of the measuring sleeve (16) is connected to the lower end of the vertical rod. The measuring sleeve (16) is provided with a scale (17) on the outside, and the scale value increases from the inside to the outside. The measuring rod (20) is provided with a scale (17) on the outer surface, and the scale value decreases from the inside to the outside.

5. The wind turbine blade web positioning and detection fixture according to claim 4, characterized in that: A pulley mechanism is provided between the measuring sleeve (16) and the measuring rod (20). The pulley mechanism includes a slide rail (18) symmetrically arranged on the inner wall of the measuring sleeve (16) and a pulley (21) arranged on the measuring rod (20) and adapted to the slide rail (18).

6. The wind turbine blade web positioning and detection fixture according to claim 4, characterized in that: The inner end of the measuring mechanism is hinged to the lower end of the vertical rod, and a limit mechanism is provided between them. This limit mechanism ensures that the length measurement direction of the measuring mechanism is parallel to the length direction of the horizontal rod (1), or... The inner end of the measuring mechanism is fixedly connected to the lower end of the vertical rod.

7. The wind turbine blade web positioning and detection fixture according to claim 6, characterized in that: The limiting mechanism includes a through hole (12) provided at the inner end of the linear displacement sensor (11) and the measuring sleeve (16) and a limiting hole (402) provided at the lower end of the vertical rod corresponding to the through hole (12). When the linear displacement sensor (11) and the measuring sleeve (16) are perpendicular to each other with the vertical rod, the through hole (12) on the linear displacement sensor (11) and the measuring sleeve (16) are respectively aligned with the axis of the limiting hole (402) on the corresponding vertical rod. The corresponding through hole (12) and the limiting hole (402) are detachably connected together by a pin.

8. The wind turbine blade web positioning and detection fixture according to claim 4, characterized in that: The measuring sleeve (16) has a hinge seat (19) fixed at the bottom of its outer end. The support seat includes a support rod (22) hinged to the hinge seat (19) and a suction cup (23) fixed at the outer end of the support rod (22). The length of the support rod (22) is adjustable; the suction cup (23) is made of plastic, is conical, and its axis coincides with the axis of the support rod (22).

9. The wind turbine blade web positioning and detection fixture according to claim 2, characterized in that: It also includes a wireless data transmission module, a display and a host, through which the detection data of the linear displacement sensor (11) is synchronized to the display.

10. The wind turbine blade web positioning and detection fixture according to claim 1, characterized in that: The level detection mechanism is a level instrument set at the top of the crossbar (1); the crossbar (1) and the two vertical bars are in the shape of a U; the vertical bar includes an adjusting sleeve (3) vertically fixed below the end of the crossbar (1) and an adjusting rod (4) inserted in the adjusting sleeve (3). The adjusting sleeve (3) and the adjusting rod (4) are both square and a height adjustment mechanism is provided between them.

Images