Visual inspection device for outer surface crack of bridge pier

Abstract

The invention relates to the technical field of building structure quality detection, and discloses a visual detection device for outer surface cracks of a bridge pier. The bridge pier outer surface crack visual detection device comprises a trolley shell, a bandage and a remote controller shell, wheel shafts which are symmetrically distributed up and down and extend to the left side and the right side of the trolley shell are rotationally connected in the trolley shell, and the device has the advantages that detection personnel do not need to climb up for detection, operation is easy, the crack position can be marked, and the like. The problems that in bridge pier outer surface crack detection in the prior art, detection personnel are lifted along a bridge pier through an undercarriage mostly, then the outer surface of the bridge pier is observed and detected, or an unmanned aerial vehicle is controlled to be provided with a high-definition camera for observation and detection, the detection personnel take the undercarriage, and the bridge pier is too high; the detection method has certain dangerousness, the unmanned aerial vehicle needs certain operation means to control the unmanned aerial vehicle, and a detector needs to have the skill of controlling the unmanned aerial vehicle or carry a professional unmanned aerial vehicle operator.

Description

Technical Field

[0001] The invention relates to the technical field of building structure quality detection, and in particular to a device for visually detecting cracks on the outer surface of a pier. Background Art

[0002] Detection of cracks on the outer surface of bridge piers is usually an important structural health monitoring task, which aims to ensure the safety and durability of bridges.

[0003] In the prior art, crack detection on the outer surface of piers is mostly carried out by lifting inspectors along the piers with landing gear, and then observing and inspecting the outer surface of the piers, or by operating drones equipped with high-definition cameras for observation and inspection. Inspectors ride on the landing gear. Since the piers are relatively high, this detection method has certain risks. The drones require certain operating means to operate them, and the inspectors are required to have the skills to operate drones or bring professional drone operators. Therefore, a visual detection device for cracks on the outer surface of piers is proposed to solve the above problems. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a visual detection device for cracks on the outer surface of a pier, which has the advantages of no need for detection personnel to climb high for detection, simple operation, and the ability to mark cracks. It solves the problem that in the prior art, detection of cracks on the outer surface of a pier is mostly carried out by lifting the detection personnel along the pier through a landing gear, and then observing and inspecting the outer surface of the pier, or operating a drone equipped with a high-definition camera for observation and inspection, with the detection personnel riding on the landing gear. Due to the high piers, this detection method is somewhat dangerous, and the drone requires certain operating means to operate it, and the detection personnel are required to have the skills to operate the drone or bring professional drone operators.

[0006] (II) Technical solution

[0007] The technical solution of the present invention to solve the above technical problems is as follows: a visual detection device for cracks on the outer surface of a pier, comprising a trolley shell, a strap and a remote control shell, characterized in that: the interior of the trolley shell is rotatably connected to a wheel axle which is symmetrically distributed up and down and extends to the left and right sides thereof, the outer side of the wheel axle is fixedly connected to a first cone wheel located in the trolley shell, the rear wall of the inner cavity of the trolley shell is provided with a driving component which is transmission-connected to the first cone wheel, the rear side of the trolley shell is embedded with a marking nozzle which is connected to the interior thereof, the interior of the trolley shell is provided with a spraying component which is connected to the marking nozzle and extends to the right side thereof, the interior of the trolley shell is provided with a power supply module, a control module and a first remote communication module which are electrically connected to each other, the top of the trolley shell is provided with a camera module which is electrically connected to the first remote communication module, and the front side of the trolley shell is provided with a positioning component which is adapted to the strap;

[0008] One end of the binding strap is fixedly connected to an L-shaped plate, one side of the L-shaped plate is rotatably connected to an auxiliary roller, one side of the L-shaped plate is provided with a tightening assembly adapted to both the auxiliary roller and the binding strap, and the other end of the binding strap is fixedly connected to a latch adapted to the tightening assembly;

[0009] A touch panel is embedded on the surface of the remote control housing, and a second remote communication module adapted to the first remote communication module is disposed on the top of the remote control housing.

[0010] The beneficial effects of the present invention are:

[0011] 1) The visual inspection device for cracks on the outer surface of the pier passes the straps through the positioning components on the top of several trolley shells in sequence, surrounds the pier with the pin at one end of the straps inserted into the tightening component, tightens the straps by rotating the tightening component, and makes the trolley shells distributed in a circular array on the outside of the pier, with the wheel axles all in contact with the outside of the pier, thereby limiting the position of the trolley shells by rotating the tightening component, filling the spraying component with paint, and making the driving component drive the wheel axles to rotate synchronously through the touch panel, so that the trolley shells all move upward along the outside of the pier at the same time. In this process, the image captured by the camera module can be observed through the touch panel to observe the cracks on the outside of the pier, which has the advantages of no need for inspection personnel to climb high for inspection and simple operation.

[0012] 2) The visual detection device for cracks on the outer surface of the pier, when cracks are observed through the touch panel, stops the climbing of the trolley shell through the touch panel, so that the spray component sprays the paint through the marking nozzle to the vicinity of the shooting position of the corresponding camera module, which has the advantage of being able to mark the cracks and facilitate the workers' later repairs.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, the driving assembly includes a double-shaft motor and a second cone wheel. The rear wall of the inner cavity of the trolley shell is provided with a double-shaft motor electrically connected to the control module. The output ends of the double-shaft motor are fixedly connected to the second cone wheel meshing with the first cone wheel.

[0015] The beneficial effect of adopting the above further scheme is that the electrical signal is transmitted to the first remote communication module through the touch panel and the second remote communication module, and the control module then enables the dual-output shaft motor to drive the second bevel wheel to move synchronously. Since the second bevel wheel is meshed with the first bevel wheel, it can drive the wheel axle to rotate synchronously.

[0016] Furthermore, the spray assembly includes a cylinder body, a delivery pipe, an electric push rod, a piston, an injection pipe and a sealing cover. The cylinder body is fixedly connected to the rear wall of the inner cavity of the trolley shell, and the bottom of the cylinder body is fixedly connected to the delivery pipe connected thereto and connected to the marking nozzle. The right wall of the inner cavity of the trolley shell is provided with an electric push rod electrically connected to the control module, and the output end of the electric push rod is fixedly connected to a piston adapted to the cylinder body. The right side of the cylinder body is fixedly connected to an injection pipe extending to the right side of the trolley shell and connected thereto, and the right end of the injection pipe is threadedly connected to a sealing cover.

[0017] The beneficial effect of adopting the above further scheme is that the sealing cover is opened, the paint is injected into the cylinder through the injection pipe, the sealing cover is tightened, and the control module causes the output end of the electric push rod to drive the piston to move downward, and then the paint in the cylinder flows through the delivery pipe to the marking nozzle and is sprayed out in a mist form.

[0018] Furthermore, a retaining ring located outside the marking nozzle is fixedly connected to the rear side of the trolley shell, and a wool strip is pasted to the rear side of the retaining ring.

[0019] The beneficial effect of adopting the above further scheme is that the marking nozzle sprays the paint in a mist form onto the surface of the bridge pier, and the retaining ring and the wool strip block the spray to prevent the paint spray from falling onto the surface of the camera module due to air flow disturbance, resulting in unclear shooting.

[0020] Furthermore, the tightening assembly includes a first spoke plate, a second spoke plate, a winding roller, a worm wheel, a worm and a slot, one side of the L-shaped plate is fixedly connected to the first spoke plate and the second spoke plate which are symmetrically distributed, the first spoke plate and the second spoke plate are rotatably connected to the winding roller on the opposite side, the outer side of the winding roller is fixedly connected to the worm wheel located in the first spoke plate, the inside of the first spoke plate is rotatably connected to the worm extending to the outside and meshing with the worm wheel, and the outer side of the winding roller is provided with a slot adapted to the latch.

[0021] The beneficial effect of adopting the above further scheme is that the strap is wrapped around the bridge pier and one end of it is passed through the auxiliary roller, and the pin of one end of the strap is inserted into the slot. By rotating the worm, the worm and the worm wheel are engaged, which in turn drives the winding roller to rotate, so that the strap is wound around the outside of the winding roller, and the strap can be tightened.

[0022] Furthermore, the positioning assembly includes a return plate, an adjusting screw and a convex plate. The front side of the trolley shell is fixedly connected with the return plate that is adapted to the strap. The front side of the return plate is threadedly connected with an adjusting screw extending to its rear side. The rear end of the adjusting screw is rotatably connected with a convex plate that is located between the return plate and the trolley shell and is adapted to the strap.

[0023] The beneficial effect of adopting the above further scheme is that the straps are passed through the return plates on the top of several trolley shells in turn, and during the tightening of the straps, the distance between adjacent trolley shells is adjusted so that the trolley shells are distributed in a circular array on the outside of the bridge pier. When the straps are tightened, the wheel axles are in contact with the outside of the pier, so that by rotating the adjusting screw, the thread rotates to make the raised point plate move to the opposite side, and the straps are clamped between the raised point plate and the trolley shell, so that the distance between adjacent trolley shells can be limited, thereby preventing the trolley shell from running off during the climbing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure used in the present invention;

[0025] Figure 2 This is a cross-sectional view of the housing structure of the trolley of the present invention;

[0026] Figure 3 It is a rear view of the housing structure of the trolley of the present invention;

[0027] Figure 4 It is a right view of the housing structure of the trolley of the present invention;

[0028] Figure 5 It is a schematic diagram of the structure of the tightening assembly of the present invention;

[0029] Figure 6 This is an enlarged schematic diagram of the structure at a of the present invention;

[0030] Figure 7 It is a schematic diagram of the structure of the remote control housing of the present invention.

[0031] In the figure: 1. trolley housing; 2. strap; 3. remote control housing; 4. axle; 5. first cone wheel; 6. drive assembly; 601. double-shaft motor; 602. second cone wheel; 7. marking nozzle; 8. spray assembly; 801. cylinder; 802. delivery pipe; 803. electric push rod; 804. piston; 805. injection pipe; 806. sealing cover; 9. power module; 10. control module; 11. first remote communication module; 12. Camera module; 13. Positioning assembly; 131. Return plate; 132. Adjusting screw; 133. Bump plate; 14. L-shaped plate; 15. Auxiliary roller; 16. Tightening assembly; 161. First spoke plate; 162. Second spoke plate; 163. Winding roller; 164. Worm gear; 165. Worm; 166. Slot; 17. Latch; 18. Touch panel; 19. Second remote communication module; 20. Retaining ring; 21. Wool strip. DETAILED DESCRIPTION

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

[0033] Embodiment 1, by Figure 1-7 A visual detection device for cracks on the outer surface of a pier is provided. The present invention comprises a trolley shell 1, a strap 2 and a remote control shell 3, and is characterized in that: the interior of the trolley shell 1 is rotatably connected to a wheel axle 4 which is symmetrically distributed up and down and extends to the left and right sides thereof, the outer side of the wheel axle 4 is fixedly connected to a first cone wheel 5 located in the trolley shell 1, the rear wall of the inner cavity of the trolley shell 1 is provided with a driving assembly 6 which is transmission-connected to the first cone wheel 5, the rear side of the trolley shell 1 is embedded with a marking nozzle 7 which is connected to the interior thereof, the interior of the trolley shell 1 is provided with a spraying assembly 8 which is connected to the marking nozzle 7 and extends to the right side thereof, the interior of the trolley shell 1 is provided with a power supply module 9, a control module 10 and a first remote communication module 11 which are electrically connected to each other, the top of the trolley shell 1 is provided with a camera module 12 which is electrically connected to the first remote communication module 11, and the front side of the trolley shell 1 is provided with a positioning assembly 13 which is adapted to the strap 2;

[0034] One end of the strap 2 is fixedly connected to an L-shaped plate 14, one side of the L-shaped plate 14 is rotatably connected to an auxiliary roller 15, one side of the L-shaped plate 14 is provided with a tightening assembly 16 adapted to both the auxiliary roller 15 and the strap 2, and the other end of the strap 2 is fixedly connected to a latch 17 adapted to the tightening assembly 16;

[0035] A touch panel 18 is embedded on the surface of the remote control housing 3, and a second remote communication module 19 adapted to the first remote communication module 11 is disposed on the top of the remote control housing 3;

[0036] The driving assembly 6 includes a double-shaft motor 601 and a second cone wheel 602. The rear wall of the inner cavity of the trolley housing 1 is provided with a double-shaft motor 601 electrically connected to the control module 10. The output ends of the double-shaft motor 601 are fixedly connected to the second cone wheel 602 meshing with the first cone wheel 5.

[0037] The electrical signal is transmitted to the first remote communication module 11 through the touch panel 18 and the second remote communication module 19, and the control module 10 then causes the double-output shaft motor 601 to drive the second cone wheel 602 to move synchronously. Since the second cone wheel 602 is meshed with the first cone wheel 5, the wheel shaft 4 can be driven to rotate synchronously.

[0038] The tightening assembly 16 includes a first spoke 161, a second spoke 162, a winding roller 163, a worm wheel 164, a worm 165 and a slot 166. The first spoke 161 and the second spoke 162 are symmetrically distributed and fixedly connected to one side of the L-shaped plate 14. The winding roller 163 is rotatably connected to the opposite side of the first spoke 161 and the second spoke 162. The outer side of the winding roller 163 is fixedly connected to the worm wheel 164 located in the first spoke 161. The inside of the first spoke 161 is rotatably connected to the worm 165 extending to the outer side thereof and meshing with the worm wheel 164. The outer side of the winding roller 163 is provided with a slot 166 adapted to the latch 17.

[0039] The strap 2 is wrapped around the bridge pier and one end of the strap is passed through the auxiliary roller 15, and the latch 17 of one section of the strap 2 is inserted into the slot 166. The worm 165 is rotated, and the worm 165 is meshed with the worm wheel 164, which in turn drives the winding roller 163 to rotate, so that the strap 2 is wound around the outside of the winding roller 163, and the strap 2 can be tightened.

[0040] The positioning assembly 13 includes a return plate 131, an adjusting screw 132 and a convex plate 133. The front side of the trolley housing 1 is fixedly connected with the return plate 131 adapted to the strap 2. The front side of the return plate 131 is threadedly connected with the adjusting screw 132 extending to the rear side thereof. The rear end of the adjusting screw 132 is rotatably connected with the convex plate 133 located between the return plate 131 and the trolley housing 1 and adapted to the strap 2.

[0041] The straps 2 are passed through the return plates 131 on the tops of several trolley shells 1 in sequence. During the tightening process of the straps 2, the distance between adjacent trolley shells 1 is adjusted so that the trolley shells 1 are distributed in a circular array on the outside of the bridge pier. When the straps 2 are tightened, the wheel axles 4 are all in contact with the outside of the bridge pier. Therefore, by rotating the adjusting screw 132, the threaded rotation causes the convex plate 133 to move to the opposite side, and the straps 2 are clamped between the convex plate 133 and the trolley shell 1. This can limit the distance between adjacent trolley shells 1 and prevent the trolley shell 1 from running off during the climbing process.

[0042] Embodiment 2, on the basis of embodiment 1, the spray assembly 8 includes a cylinder 801, a delivery pipe 802, an electric push rod 803, a piston 804, an injection pipe 805 and a sealing cover 806, the rear wall of the inner cavity of the trolley housing 1 is fixedly connected with the cylinder 801, the bottom of the cylinder 801 is fixedly connected with the delivery pipe 802 which is connected thereto and connected with the marking nozzle 7, the right wall of the inner cavity of the trolley housing 1 is provided with an electric push rod 803 which is electrically connected to the control module 10, the output end of the electric push rod 803 is fixedly connected with the piston 804 which is adapted to the cylinder 801, the right side of the cylinder 801 is fixedly connected with the injection pipe 805 which extends to the right side of the trolley housing 1 and is connected thereto, and the right end of the injection pipe 805 is threadedly connected with the sealing cover 806;

[0043] Open the sealing cover 806, inject the paint into the cylinder 801 through the injection pipe 805, tighten the sealing cover 806, and the control module 10 causes the output end of the electric push rod 803 to drive the piston 804 to move downward, and then the paint in the cylinder 801 flows through the delivery pipe 802 to the marking nozzle 7 and is sprayed out in a mist form;

[0044] A retaining ring 20 located outside the marking nozzle 7 is fixedly connected to the rear side of the trolley housing 1, and a wool strip 21 is pasted to the rear side of the retaining ring 20;

[0045] The marking nozzle 7 sprays the paint in the form of mist onto the surface of the bridge pier, and the retaining ring 20 and the wool strip 21 block the spray to prevent the paint spray from falling onto the surface of the camera module 12 due to air flow disturbance, resulting in unclear shooting.

[0046] In this embodiment: the model selected by the electrical appliance proposed in the text is added separately.

[0047] Working principle:

[0048] The first step to implement the innovation point:

[0049] Step 1: Pass the strap 2 through the return plates 131 on the top of the trolley housing 1 in sequence, so that the strap 2 surrounds the bridge pier and passes one end of the strap 2 through the auxiliary roller 15, and insert the latch 17 of one section of the strap 2 into the card slot 166, and rotate the worm 165. Since the worm 165 is engaged with the worm wheel 164, the winding roller 163 is driven to rotate, so that the strap 2 is wound around the outside of the winding roller 163, and the strap 2 can be tightened;

[0050] Step 2: During the tightening of the strap 2, the distance between adjacent trolley shells 1 is adjusted so that the trolley shells 1 are distributed in a circular array outside the bridge pier. When the strap 2 is tightened, the wheel axles 4 are all in contact with the outside of the bridge pier. Thus, by rotating the adjusting screw 132, the screw rotates to move the convex plate 133 to the opposite side, and the strap 2 is clamped between the convex plate 133 and the trolley shell 1. This can limit the distance between adjacent trolley shells 1 to prevent the trolley shell 1 from running off during the climbing process. Open the sealing cover 806, inject the paint into the cylinder 801 through the injection pipe 805, and tighten the sealing cover 806.

[0051] Step 3: The electrical signal is transmitted to the first remote communication module 11 through the touch panel 18 and the second remote communication module 19. The control module 10 then enables the dual-shaft motor 601 to drive the second cone wheel 602 to move synchronously. Since the second cone wheel 602 is meshed with the first cone wheel 5, the wheel axle 4 can be driven to rotate synchronously, so that the trolley shell 1 moves upward along the outside of the pier at the same time. In this process, the picture captured by the camera module 12 is observed through the touch panel 18, so as to observe and detect cracks on the outside of the pier.

[0052] The second innovation point implementation steps:

[0053] Step 1: The trolley housing 1 moves upward along the outside of the pier at the same time, and the image captured by the camera module 12 is observed through the touch panel 18. When a crack is observed, an electrical signal is transmitted to the first remote communication module 11 through the touch panel 18 and the second remote communication module 19, and the control module 10 then stops the rotation of the dual-output shaft motor 601;

[0054] Step 2: Since the dual-output shaft motor 601 has a self-locking brake, the trolley housing 1 can be parked near the crack, and the control module 10 transmits an electrical signal to the electric push rod 803 through the touch panel 18. The control module 10 causes the output end of the electric push rod 803 to drive the piston 804 to move downward, and then the paint in the cylinder 801 flows through the delivery pipe 802 to the marking nozzle 7 and is sprayed out in a mist form;

[0055] Step 3: The marking nozzle 7 sprays the paint in a mist form to the vicinity of the shooting position of the corresponding camera module 12, which is convenient for workers to repair later. The retaining ring 20 and the wool strip 21 block the spray to prevent the paint spray from falling onto the surface of the camera module 12 due to air flow disturbance, resulting in unclear shooting.

[0056] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A visual detection device for cracks on the outer surface of a bridge pier, comprising a trolley housing (1), a binding strap (2) and a remote control housing (3), characterized in that: The interior of the trolley shell (1) is rotatably connected to a wheel axle (4) which is symmetrically distributed up and down and extends to the left and right sides thereof; the outer side of the wheel axle (4) is fixedly connected to a first cone wheel (5) located in the trolley shell (1); the rear wall of the inner cavity of the trolley shell (1) is provided with a driving assembly (6) which is transmission-connected to the first cone wheel (5); the rear side of the trolley shell (1) is embedded with a marking nozzle (7) which is in communication with the interior thereof; the interior of the trolley shell (1) is provided with a spraying assembly (8) which is in communication with the marking nozzle (7) and extends to the right side thereof; the interior of the trolley shell (1) is provided with a power supply module (9), a control module (10) and a first remote communication module (11) which are electrically connected to each other; the top of the trolley shell (1) is provided with a camera module (12) which is electrically connected to the first remote communication module (11); the front side of the trolley shell (1) is provided with a positioning assembly (13) which is adapted to the strap (2); One end of the binding belt (2) is fixedly connected to an L-shaped plate (14), one side of the L-shaped plate (14) is rotatably connected to an auxiliary roller (15), one side of the L-shaped plate (14) is provided with a tightening assembly (16) adapted to both the auxiliary roller (15) and the binding belt (2), and the other end of the binding belt (2) is fixedly connected to a latch (17) adapted to the tightening assembly (16); A touch panel (18) is embedded on the surface of the remote control housing (3), and a second remote communication module (19) adapted to the first remote communication module (11) is provided on the top of the remote control housing (3).

2. The visual detection device for cracks on the outer surface of a pier according to claim 1, characterized in that: The driving assembly (6) comprises a double-shaft motor (601) and a second cone wheel (602); the rear wall of the inner cavity of the trolley housing (1) is provided with a double-shaft motor (601) electrically connected to the control module (10); the output ends of the double-shaft motor (601) are fixedly connected to the second cone wheel (602) meshing with the first cone wheel (5).

3. The visual detection device for cracks on the outer surface of a pier according to claim 1, characterized in that: The spraying assembly (8) comprises a cylinder body (801), a delivery pipe (802), an electric push rod (803), a piston (804), an injection pipe (805) and a sealing cover (806); the cylinder body (801) is fixedly connected to the rear wall of the inner cavity of the trolley housing (1); the bottom of the cylinder body (801) is fixedly connected to the delivery pipe (802) which is in communication with the cylinder body and the marking nozzle (7); the right wall of the inner cavity of the trolley housing (1) is provided with an electric push rod (803) which is electrically connected to the control module (10); the output end of the electric push rod (803) is fixedly connected to the piston (804) which is adapted to the cylinder body (801); the right side of the cylinder body (801) is fixedly connected to the injection pipe (805) which extends to the right side of the trolley housing (1) and is in communication with the cylinder body; the right end of the injection pipe (805) is threadedly connected to the sealing cover (806).

4. The visual detection device for cracks on the outer surface of a pier according to claim 1, characterized in that: A retaining ring (20) located outside the marking nozzle (7) is fixedly connected to the rear side of the trolley housing (1), and a wool strip (21) is pasted to the rear side of the retaining ring (20).

5. The visual detection device for cracks on the outer surface of a pier according to claim 1, characterized in that: The positioning assembly (13) comprises a return plate (131), an adjusting screw (132) and a convex plate (133); the front side of the trolley housing (1) is fixedly connected to the return plate (131) adapted to the binding strap (2); the front side of the return plate (131) is threadedly connected to the adjusting screw (132) extending to the rear side thereof; the rear end of the adjusting screw (132) is rotatably connected to the convex plate (133) located between the return plate (131) and the trolley housing (1) and adapted to the binding strap (2).

6. The visual detection device for cracks on the outer surface of a pier according to claim 1, characterized in that: The tightening assembly (16) comprises a first spoke plate (161), a second spoke plate (162), a winding roller (163), a worm wheel (164), a worm (165) and a slot (166); one side of the L-shaped plate (14) is fixedly connected to the first spoke plate (161) and the second spoke plate (162) which are symmetrically distributed; the opposite side of the first spoke plate (161) and the second spoke plate (162) is rotatably connected to the winding roller (163); the outer side of the winding roller (163) is fixedly connected to the worm wheel (164) located in the first spoke plate (161); the inside of the first spoke plate (161) is rotatably connected to the worm wheel (165) extending to the outer side thereof and meshing with the worm wheel (164); and the outer side of the winding roller (163) is provided with a slot (166) adapted to the latch (17).

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