A support fixture for longitudinal seam welding of tower

Abstract

This invention discloses a longitudinal seam welding support fixture for wind turbine towers, relating to the field of offshore wind power technology. It includes a bracket, a drive wheel, a motor mechanism for driving the drive wheel, two driven wheels (I and II) linked to the drive wheel, and a lifting mechanism I for supporting the driven wheel I. The bracket has a U-shaped structure with a base frame hinged to the lower end of one outer wall. The lifting mechanism II connects the base frame to the lower end of the other outer wall of the bracket. Two drive wheels, two driven wheels (I and II), are symmetrically arranged front and rear, each perpendicularly penetrating both sides of the bracket. Two guide wheels that contact and cooperate with the tower are symmetrically installed on both sides of the bracket. This invention addresses the longitudinal seam welding requirements of both circular and conical tower structures of different diameters, significantly improving welding stability and safety, and enhancing the tower's load-bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power generation technology, and more specifically, to a welding support fixture for longitudinal seams of towers. Background Technology

[0002] Wind turbine towers are generally composed of multiple tower sections with a radial length of 4-7 meters. The welding quality of these sections directly affects the performance of the wind turbine tower; and the welding of the inner and outer longitudinal seams is an indispensable part of the tower welding process. Currently, welding robots are mostly used in conjunction with support fixtures such as tower roller frames for longitudinal seam welding. However, during longitudinal seam welding, especially the inner longitudinal seam welding, the tower often deforms under its own weight. Furthermore, the diameter of the tower varies depending on the environmental requirements, and the same support fixture cannot be applied to towers of different diameters.

[0003] Currently, there are longitudinal seam welding support fixtures that can provide anti-deformation support for large-diameter towers during longitudinal seam welding and are applicable to towers of different diameters. However, these support fixtures are only suitable for towers with circular structures and cannot be used for longitudinal seam welding of conical towers. For example, Chinese patent publication number CN109531035A discloses a hydraulically adjustable anti-deformation longitudinal seam welding roller frame. The paper states that "corresponding roller frames are fixedly connected to both sides of the base, and supporting rollers are rotatably installed on the roller frames through corresponding bearings. One of the supporting rollers is connected to the drive mechanism. The adjustable anti-deformation mechanism includes corresponding crossbeams hinged to both ends of the base. Corresponding anti-deformation support rods are hinged to the middle positions of the crossbeams. Corresponding drive hydraulic cylinders are installed between the middle position of the anti-deformation support rods and the outer side of the crossbeams. The piston column of the drive hydraulic cylinders is hinged to the middle position of the anti-deformation support rods. The top of the anti-deformation support rods is provided with corresponding receiving grooves. Corresponding positioning rods are movably installed in the receiving grooves. Corresponding positioning rollers are rotatably installed inward at the end of the positioning rods that are not installed in the receiving grooves."

[0004] While this existing technology, through the coordinated arrangement of support rollers, positioning rollers, a drive mechanism, and an adjustable anti-deformation mechanism, provides rolling support for large-diameter towers and anti-deformation support for towers of different diameters, it is only suitable for circular towers. When welding the outer longitudinal seam of a conical tower, the tower needs to be rolled until the longitudinal seam is at the top, at which point the entire longitudinal seam is tilted downwards, making welding inconvenient. Therefore, this existing technology still has the problem of not being suitable for longitudinal seam welding, especially outer longitudinal seam welding, on conical towers. Furthermore, axial movement is highly likely to occur when welding longitudinal seams on conical towers, affecting the stability and safety of the weld. Additionally, this existing technology only has two support rollers and two positioning rollers, resulting in a generally limited overall load-bearing capacity.

[0005] Therefore, a new technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a longitudinal seam welding support fixture for towers, in order to solve the technical problems of the existing adjustable and deformation-resistant longitudinal seam welding support fixtures for large-diameter towers mentioned in the background art. These fixtures are only suitable for towers with circular structures and cannot be used for longitudinal seam welding, especially for external longitudinal seams, on conical towers. Furthermore, axial movement is very likely to occur when longitudinal seams are welded on the towers, which affects the stability and safety of the welding. At the same time, the overall load-bearing capacity is also generally poor.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A support fixture for longitudinal seam welding of a tower includes a bracket, a drive wheel, a motor mechanism for driving the drive wheel, a driven wheel I and a driven wheel II linked to the drive wheel via the tower, a lifting mechanism I for supporting the driven wheel I, and a positioning mechanism that cooperates with the bracket. The bracket has a U-shaped structure and a base frame is hinged to the lower end of one outer wall. The base frame has a horizontally arranged closed rectangular frame structure. The lifting mechanism II is connected between the base frame and the lower end of the other outer wall of the bracket. Two drive wheels, two driven wheels I, and two driven wheels II are symmetrically arranged front and back and simultaneously penetrate vertically through both side walls of the bracket. The drive wheels, two driven wheels II, and three driven wheels I at the same end are arranged sequentially from the inside to the outside and from low to high. Two wheels that contact the tower are symmetrically installed through both side walls of the bracket. The bracket includes a base plate and two wall plates vertically fixed to both sides of the upper surface of the base plate. The base plate has a closed rectangular frame structure, and both wall plates have a trapezoidal structure with an arc-shaped groove at the top center. The motor mechanism is configured to cooperate with the drive wheel. The lifting mechanism II is connected between the lower end of the outer wall of one wall plate and the outer wall of the base frame on the same side. A rotating mechanism is connected between the lower end of the outer wall of the other wall plate and the outer wall of the base frame on the other side. Two rotating mechanisms and two lifting mechanisms II are symmetrically arranged front and back. The two ends of each driven wheel I are connected to two lifting mechanisms I. The lifting mechanisms I are installed on the inner wall of the wall plate. The two lifting mechanisms I on the inner wall of the same wall plate are symmetrically arranged front and back.

[0009] Furthermore, each of the lifting mechanisms I includes an upwardly inclined hydraulic cylinder I, an upper hydraulic cylinder support hinged to the upper end of the hydraulic cylinder I, and two lower hydraulic cylinder supports symmetrically hinged to the lower ends of the hydraulic cylinder I. The lower hydraulic cylinder supports are all vertically fixed to the inner wall of the wall panel. Each driven wheel I includes a wheel body I and two axle heads I connected to both ends of the wheel body I. A slider is fitted onto the end of the axle head I furthest from the wheel body I. The upper hydraulic cylinder support is fixed to the side of the slider closest to the wheel body I and located below the axle head I. Two slider guide plates are symmetrically fixed to both sides of the slider. The wall panel has openings that match the slider. The inclined slide groove is combined, with two slider guide plates on one side located on the outer wall of the wall panel and two slider guide plates on the other side located on the inner wall of the wall panel. The rotating mechanism includes a lower rotating ear plate and two upper rotating ear plates symmetrically hinged to both sides of the lower rotating ear plate. The lifting mechanism II includes a hydraulic cylinder II, two upper hydraulic cylinder ear plates symmetrically hinged to both sides of the upper end of the hydraulic cylinder II, and two lower hydraulic cylinder ear plates symmetrically hinged to both sides of the lower end of the hydraulic cylinder II. The upper rotating ear plates and the upper hydraulic cylinder ear plates are respectively vertically fixed to the outer wall of the wall panel, and the lower rotating ear plates and the lower hydraulic cylinder ear plates are respectively vertically fixed to the outer wall of the base frame.

[0010] Furthermore, each of the motor mechanisms includes a geared motor and a gear I mounted on the output end of the geared motor. The geared motor is fixed to the outer wall of the wall panel. Each of the driving wheel and the driven wheel II includes a wheel body II and two shaft heads II respectively connected to both ends of the wheel body II. The shaft heads II at both ends of the driving wheel and the driven wheel II are respectively mounted through the two wall panels. A gear II is mounted on the shaft head II of the driving wheel near the corresponding geared motor end. The gear II meshes with the gear I. Each of the guide wheels includes a positioning shaft, a wheel body III mounted on the positioning shaft, a bearing disposed between the wheel body III and the positioning shaft, and two bearing baffles that cooperate with the bearing. The two bearing baffles are mounted on the positioning shaft and are respectively fixed to the top and bottom of the wheel body III. The positioning shaft is fixed to the outer wall of the wall panel. The wall panel has mounting holes for the wheel body III, the bearing, and the bearing baffles to pass through. Two positioning mechanisms are symmetrically arranged front and back, each including a positioning tube. The two ends of the positioning tube are respectively vertically mounted through the two wall panels.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1. This invention utilizes a motor mechanism and a lifting mechanism I to achieve rolling support and anti-deformation support for the tower cylinder by the driving wheel, driven wheel I, and driven wheel II, applicable to tower cylinders of different diameters. Furthermore, it employs a U-shaped bracket with a base frame hinged to the lower end of one outer wall. A lifting mechanism II connects the base frame to the lower end of the other outer wall of the bracket. Through the synergistic action of the base frame, bracket, and lifting mechanism II, when one side of the bracket is connected to the base frame, the other side is raised relative to the base frame under the action of the lifting mechanism II. This adjusts the driving wheel, driven wheel I, and driven wheel II on the bracket to be inclined upwards, thus addressing the issue of inclined longitudinal seams during welding of the outer longitudinal seams of conical tower cylinders. The problem of the downward-sloping state was ultimately solved, which also met the longitudinal seam welding requirements of conical tower structures with different diameters. On this basis, by having the active wheel, passive wheel I, and passive wheel II all perpendicularly penetrate the two side walls of the bracket, and by symmetrically installing two guide wheels that contact and cooperate with the tower on both side walls of the bracket, the load-bearing support capacity of the tower is improved. At the same time, the synergistic effect of the four guide wheels and the bracket effectively prevents the axial movement of the tower, greatly improving the stability and safety of the welding, thereby improving the welding efficiency and welding effect. Meanwhile, the symmetrical arrangement of two active wheels, two passive wheels I, and two passive wheels II further enhances the load-bearing support capacity of the tower.

[0013] 2. In this invention, the lifting mechanism I consists of a hydraulic cylinder I, an upper hydraulic cylinder support, and a lower hydraulic cylinder support. The driven wheel I consists of a wheel body I, an axle head I, and a slider. The bracket consists of a base plate and two wall plates vertically fixed to both sides of the upper surface of the base plate. The upper hydraulic cylinder support is fixed to the side of the slider near the wheel body I and located below the axle head I. The lower hydraulic cylinder support is vertically fixed to the inner wall of the wall plate. The wall plate has an inclined groove that cooperates with the slider, so that the slider, driven by the hydraulic cylinder I and guided by the slider guide plate, moves along the inclined groove. The sliding mechanism allows the passive wheel I to adjust its height relative to the base plate under the action of the lifting mechanism I. With the active wheel, passive wheel I, and passive wheel II all installed between the two wall panels, they work together to powerfully support the tower. Ultimately, while meeting the longitudinal seam welding requirements of towers with different diameters, this design, compared to the traditional method where the active wheel, passive wheel I, and passive wheel II support the tower independently, further prevents tower deformation, enhances the tower's load-bearing capacity, and improves the stability and safety of tower welding.

[0014] 3. The support wheels in this invention are composed of a positioning shaft, wheel body III, bearing, and bearing baffle. They are fixed to the outer wall of the wall panel by the positioning shaft. The wall panel is provided with mounting holes for the wheel body III, bearing, and bearing baffle to pass through. After the wheel body III passes through the wall panel, it achieves stable positioning of the tower end inside the wall panel, thereby effectively preventing axial movement of the tower and ensuring the stability and safety of the tower welding.

[0015] 4. The positioning mechanism in this invention has two symmetrically arranged front and rear, each including a positioning tube. The positioning tubes are installed vertically through the two wall panels at both ends, which effectively ensures the stability and reliability of the connection between the two wall panels, thereby further improving the overall load-bearing capacity of the bracket for the tower. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the working principle of the present invention (with the passive wheel II omitted).

[0017] Figure 2 This is a longitudinal cross-sectional schematic diagram of the present invention (with the base frame omitted);

[0018] Figure 3 This is a schematic diagram of the transverse cross-section of the present invention (without the base frame);

[0019] Figure 4 This is a schematic diagram of the longitudinal cross-section of the base frame of the present invention;

[0020] Figure 5 This is a schematic diagram of the transverse cross-section of the base frame of the present invention;

[0021] Figure 6 This is a schematic diagram of the longitudinal section of the bracket of the present invention;

[0022] Figure 7 This is a schematic diagram of the transverse cross-section of the bracket of the present invention;

[0023] Figure 8 This is a cross-sectional schematic diagram of the rotating mechanism of the present invention;

[0024] Figure 9 This is a cross-sectional schematic diagram of the lifting mechanism I of the present invention;

[0025] Figure 10 This is a cross-sectional schematic diagram of the passive wheel I of the present invention;

[0026] Figure 11 This is a cross-sectional schematic diagram of the passive wheel II of the present invention;

[0027] Figure 12 This is a cross-sectional schematic diagram of the drive wheel of the present invention;

[0028] Figure 13 This is a cross-sectional schematic diagram of the motor mechanism of the present invention;

[0029] Figure 14 This is a cross-sectional schematic diagram of the positioning mechanism of the present invention;

[0030] Figure 15 This is a schematic diagram of the longitudinal section of the wheel of the present invention;

[0031] Figure 16 This is a schematic diagram of the transverse cross-section of the wheel of the present invention;

[0032] In the diagram: 1. Base frame, 2. Hydraulic cylinder I, 3. Upper support of hydraulic cylinder, 4. Lower support of hydraulic cylinder, 5. Bracket, 51. Wall panel, 511. Inclined slide groove, 512. Mounting hole, 513. Arc-shaped groove, 52. Base plate, 6. Driven wheel I, 7. Shaft head I, 8. Wheel body I, 9. Slider, 10. Slider guide plate, 11. Rotating upper ear plate, 12. Rotating lower ear plate, 13. Hydraulic cylinder II, 14. Upper ear plate of hydraulic cylinder, 15. Lower ear plate of hydraulic cylinder, 16. Gear motor, 17. Gear I, 18. Drive wheel, 19. Driven wheel II, 20. Wheel body II, 21. Shaft head II, 22. Gear II, 23. Support wheel, 231. Positioning shaft, 232. Wheel body III, 233. Bearing, 234. Bearing baffle, 24. Positioning tube. Detailed Implementation

[0033] The following examples are used to further illustrate the content of the present invention and do not limit the application of the present invention.

[0034] like Figures 1 to 8 and Figure 14As shown, a support fixture for longitudinal seam welding of a tower includes two driving wheels 18, two driven wheels I 6, two driven wheels II 19, two positioning tubes 24, a horizontally arranged base frame 1, and a U-shaped bracket 5. The bracket 5 consists of a base plate 52 and two wall plates 51 with an isosceles trapezoidal structure and an arc-shaped groove 513 formed at the center of the top. The two wall plates 51 are vertically welded to both sides of the upper surface of the base plate 52. Two guide wheels 23 are symmetrically installed through each wall plate 51. The positioning tubes 24 are also shown. 4. The base frame 1 and the base plate 52 are both closed rectangular frame structures (the basic components such as rectangular tubes, reinforcing plates and partitions of the existing rectangular frame structure are not specifically described here, but should not limit their functionality). The driving wheel 18, the driven wheel I 6 and the driven wheel II 19 are all symmetrically arranged front and back and all penetrate through the two wall panels 51. The driven wheel I 6, the driven wheel II 19 and the driving wheel 18 at the same end are arranged from the outside to the inside and from high to low.

[0035] Among them, such as Figure 2 , Figure 6 , Figure 9 and Figure 10 As shown, the passive wheel I6 consists of a wheel body I8 and two shaft heads I7. The two shaft heads I7 are respectively connected to the two ends of the wheel body I8. A slider 9 is fitted on the end of the shaft head I7 away from the wheel body I8 (a copper sleeve can be set on the inner side of the slider 9, and the oil inlet hole of the copper sleeve oil groove is drilled to match the oil inlet hole of the slider 9). A hydraulic cylinder upper support 3 is welded and fixed on the side of the slider 9 closest to the wheel body I8. The hydraulic cylinder upper support 3 is located below the shaft head I7. A hydraulic cylinder I2 is hinged to the lower end of the hydraulic cylinder upper support 3. The hydraulic cylinder I2 is inclined upward and two hydraulic cylinder lower supports 4 are symmetrically hinged on both sides of its lower end. The hydraulic cylinder lower supports 4 are all vertically fixed to the inner wall of the wall plate 51. Two slider guide plates 10 are symmetrically bolted to both sides of the slider 9. The wall plate 51 is sandwiched between the four slider guide plates 10. An inclined slide groove 511 adapted to the slider 9 is opened on the wall plate 51. Figure 1 and Figures 11-13 As shown, both the driving wheel 18 and the driven wheel II 19 consist of a wheel body II 20 and two shaft heads II 21 connected to both ends of the wheel body II 20 and respectively installed through the two wall plates 51 (the basic structures such as bearings, bearing seats, and bearing pressure plates on the existing shaft heads are not specifically described here, but should not limit their functionality). A gear II 22 is installed on one end of the shaft head II 21 of the driving wheel 18. The gear II 22 meshes with a gear I 17, which is installed on the output shaft of a reduction motor 16. The reduction motor 16 is fixed to the outer wall of the wall plate 51. Figures 6-7 and Figures 15-16As shown, the wheel 23 consists of a positioning shaft 231, a wheel body Ⅲ 232, a bearing 233, and two bearing baffles 234 that cooperate with the bearing. The positioning shaft 231 is bolted to the outer wall of the wall panel 51. The wheel body Ⅲ 232, the bearing 233, and the bearing baffles 234 are all fitted onto the positioning shaft 231. The bearing 233 is located between the positioning shaft 231 and the wheel body Ⅲ 232. The two bearing baffles 234 are bolted to the top and bottom of the wheel body Ⅲ 232, respectively. The wall panel 51 has mounting holes 512 for the wheel body Ⅲ 232, the bearing 233, and the bearing baffles 234 to pass through.

[0036] Furthermore, such as Figure 1 , Figure 4 , Figure 5 and Figure 8 As shown, two rotating lower ear plates 12 are symmetrically and vertically welded to the outer wall of one side of the base frame 1. Two rotating upper ear plates 11 are symmetrically hinged to both sides of each rotating lower ear plate 12. The rotating upper ear plates 11 are all vertically welded to the outer wall of the wall panel 51 on the same side. Two sets of hydraulic cylinder lower ear plates 15 are symmetrically and vertically welded to the outer wall of the other side of the base frame 1. Each set of hydraulic cylinder lower ear plates 15 has two (a reinforcing plate can be welded between the hydraulic cylinder lower ear plate 15 and the outer wall of the base frame 1). A hydraulic cylinder II 13 is hinged between the two hydraulic cylinder lower ear plates 15 in the same set. Two hydraulic cylinder upper ear plates 14 are symmetrically hinged to both sides of the upper end of the hydraulic cylinder II 13. The hydraulic cylinder upper ear plates 14 are all vertically welded to the outer wall of the wall panel 51 on the same side.

[0037] like Figures 1 to 16 As shown, during the welding process, the reduction motor 16 is started, which drives the drive wheel 18 to roll. Since the drive wheel 18, driven wheel I6, and driven wheel II19 are all supported below the tower, the rolling of the drive wheel 18, under the action of the tower, drives the driven wheels I6 and II19 to roll synchronously, achieving rolling support for the tower. At the same time, the guide wheel 23 passes through the wall plate 51 to limit the end of the tower, preventing axial movement of the tower. During this process, the hydraulic cylinder I2 drives the slider 9, which, under the guidance of the slider guide plate 10, slides along the inclined groove 511 of the wall plate 51, thereby driving the driven wheel I6 to roll. The body can be adjusted vertically relative to the base plate 51 of the bracket 5 to achieve anti-deformation support for towers of different diameters by the passive wheel I6. In addition, when it is necessary to weld a conical tower, one side wall plate 51 of the bracket 5 can be lifted upward by the hydraulic cylinder II13, so that one end of the driving wheel 18, the passive wheel I6 and the passive wheel II19 are all lifted upward synchronously with the bracket 5. At this time, the driving wheel 18, the passive wheel I6 and the passive wheel II19 are all adjusted to be inclined upward relative to the base frame 1 to deal with the problem that the longitudinal seam of the conical tower is inclined downward when welding the outer longitudinal seam. Finally, the longitudinal seam of the tower is set horizontally, which facilitates welding.

Claims

1. A support fixture for longitudinal seam welding of a tower, comprising a bracket, a driving wheel, a motor mechanism for driving the driving wheel, a driven wheel I and a driven wheel II linked to the driving wheel, and a lifting mechanism I for supporting the driven wheel I, characterized in that, The bracket has a U-shaped structure with a base frame hinged to the lower end of one outer wall. The base frame is horizontally positioned. A lifting mechanism II is connected between the base frame and the lower end of the other outer wall of the bracket. The lifting mechanism II is connected between the lower end of the outer wall of one side wall panel and the outer wall of the base frame on the same side. A rotating mechanism is connected between the lower end of the outer wall of the other side wall panel and the other outer wall of the base frame. Two rotating mechanisms and two lifting mechanisms II are symmetrically arranged front and rear. Each rotating mechanism includes a lower rotating ear plate and two upper rotating ear plates symmetrically hinged to both sides of the lower rotating ear plate. Each lifting mechanism II includes a hydraulic cylinder II, two upper hydraulic cylinder ear plates symmetrically hinged to both sides of the upper end of the hydraulic cylinder II, and a hydraulic cylinder upper ear plate symmetrically hinged to the lower rotating ear plate. Two lower lugs on both sides of the lower end of cylinder II are provided. The rotating upper lug and the hydraulic cylinder upper lug are both vertically fixed to the outer wall of the wall panel. The rotating lower lug and the hydraulic cylinder lower lug are both vertically fixed to the outer wall of the base frame. Two driving wheels, driven wheels I and II are symmetrically arranged front and rear, each simultaneously penetrating vertically through both sides of the bracket. Each driving wheel and driven wheel II includes a wheel body II and two shaft heads II connected to both ends of the wheel body II. The shaft heads II at both ends of the driving wheel and driven wheel II are respectively installed through the two wall panels. A gear II meshing with gear I is installed on the shaft head II of the driving wheel near the corresponding reduction motor end. The driven wheel II and driven... Wheel I is linked to the drive wheel via a tower. Each drive wheel and motor mechanism is configured to work in a one-to-one correspondence. Each motor mechanism includes a geared motor and a gear I mounted on the output end of the geared motor. The geared motor is fixed to the outer wall of the wall panel. The drive wheel, driven wheel II, and driven wheel I at the same end are arranged sequentially from the inside out and from low to high. Each driven wheel I has two ends connected to two lifting mechanisms I. Each lifting mechanism I is mounted on the inner wall of the wall panel. Two lifting mechanisms I on the same inner wall panel are symmetrically arranged. Each lifting mechanism I includes an upwardly inclined hydraulic cylinder I, a hydraulic cylinder upper support hinged to the upper end of the hydraulic cylinder I, and symmetrically hinged to... Two hydraulic cylinder lower supports are located on both sides of the lower end of hydraulic cylinder I. The hydraulic cylinder lower supports are vertically fixed to the inner wall of the wall panel. The bracket includes a base plate and two wall panels that are vertically fixed to both sides of the upper surface of the base plate. Two rollers that are symmetrically installed on the side walls of the rollers and are in contact with the tower are installed in front and behind. Each roller includes a positioning shaft, a wheel body III mounted on the positioning shaft, a bearing disposed between the wheel body III and the positioning shaft, and two bearing baffles that cooperate with the bearing. The two bearing baffles are mounted on the positioning shaft and fixed to the top and bottom of the wheel body III, respectively. The positioning shaft is fixed to the outer wall of the wall panel. The wall panel has mounting holes for the wheel body III, the bearing and the bearing baffles to pass through.Each passive wheel I includes a wheel body I and two axle heads I connected to both ends of the wheel body I. A slider is fitted onto the end of each axle head I furthest from the wheel body I. The upper support of the hydraulic cylinder is fixed to the side of the slider closest to the wheel body I and located below the axle head I. An inclined groove that mates with the slider is provided on the wall panel. Two slider guide plates are symmetrically fixed to both sides of the slider, with the two guide plates on one side located on the outer wall of the wall panel and the two guide plates on the other side located on the inner wall of the wall panel.

2. The tower longitudinal seam welding support fixture according to claim 1, characterized in that, The tooling also includes a positioning mechanism, which has two symmetrically arranged front and rear and each includes a positioning tube. The two ends of the positioning tube are respectively vertically installed on the two wall panels. Both wall panels are in the form of an isosceles trapezoidal structure and have an arc-shaped groove at the center of the top. The base plate and the base frame are both in the form of a closed rectangular frame structure.

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