Foldable exercise plate
By setting an adjustable connecting shaft and support rod structure on the sports plate, it can be folded, which solves the problem of large space occupancy of the sports plate, realizes the adjustment and stability of multiple sports functions, and improves the space utilization and flexibility of use.
Patent Information
- Application Number
- CN202421319635.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-11
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2034-06-11
AI Technical Summary
The existing sports board cannot be folded and used or stored in folded manner, resulting in a large space and a single function, which cannot meet multiple sports needs.
A foldable motion plate is designed. By setting the first connecting shaft and the second connecting shaft, the main body can be folded, and the angle between the main board is adjusted to be within the range of 0° to 180°. Combined with the support rod, pin, anti-loop removal structures, etc., the adjustment and stability of various motion functions can be achieved.
It reduces storage space usage, improves space utilization, meets various sports needs, and enhances the flexibility and stability of use.
Smart Images

Figure CN223069002U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of sports equipment, in particular to a foldable sports board. Background Art
[0002] At present, there are a variety of sports equipment. When users need to do a variety of different sports, they need to use a variety of different equipment. Since these different equipment are independent of each other, the storage of the equipment is relatively scattered and inconvenient. Therefore, there appears a sports board with multiple equipment functions on the market. Users can do a variety of different sports by using this sports board without using a variety of independent equipment, solving the problem of scattered storage of equipment. However, the existing sports board cannot be folded for use and storage, reducing the possibility of the sports board to achieve more sports functions, and the storage space occupied is relatively large. Content of the Utility Model
[0003] In order to overcome the deficiencies of the prior art, the utility model aims to provide a foldable sports board, which can be folded to reduce the storage space occupied.
[0004] The utility model is realized by adopting the following technical solutions:
[0005] A foldable sports board, comprising: a main body, on which at least one kind of sports equipment is arranged, and the main body includes a first main board and a second main board; and a connection structure, which includes a connecting piece, a first connecting shaft and a second connecting shaft. The first connecting shaft and the second connecting shaft are both arranged on the connecting piece. The first main board is rotatably connected to the first connecting shaft, and the second main board is rotatably connected to the second connecting shaft.
[0006] In one embodiment, a support rod is arranged on the first main board, and at least two mounting positions capable of being detachably connected to the support rod are arranged on the second main board. The positions of the mounting positions are different, and the included angle between the first main board and the second main board can be adjusted by installing the support rod at different mounting positions.
[0007] In one embodiment, one end of the support rod is rotatably arranged on the first main board, and a plug pin is arranged at the other end of the support rod. Each of the mounting positions is a jack adapted to the plug pin.
[0008] In one embodiment, a storage hole adapted to the plug pin is arranged on the first main board. When the support rod is not needed, the plug pin can be detachably installed on the storage hole.
[0009] In one embodiment, two support rods are provided. The two support rods are respectively arranged at the left and right ends of the first main board. At least two mounting positions capable of being detachably connected to the corresponding support rods are arranged on both the left and right sides of the second main board. The support rod arranged on the left side of the first main board corresponds to the mounting position arranged on the left side of the second main board, and the support rod arranged on the right side of the first main board corresponds to the mounting position arranged on the right side of the second main board.
[0010] In one embodiment, a first perimeter edge is provided at the bottom edge of the first main board. The height of the first perimeter edge is greater than the width of the support rod. A second perimeter edge is provided at the bottom edge of the second main board. The height of the second perimeter edge is the same as that of the first perimeter edge.
[0011] In one embodiment, a first through hole for connecting to the first connecting shaft is provided on the first main board, and a second through hole for connecting to the second connecting shaft is provided on the second main board. The connecting structure further includes a first anti - detachment ring and a second anti - detachment ring; when the first connecting shaft is installed in the first through hole, the first anti - detachment ring is installed on the first connecting shaft to prevent the first connecting shaft from detaching from the first through hole, and when the second connecting shaft is installed in the second through hole, the second anti - detachment ring is installed on the second connecting shaft to prevent the second connecting shaft from detaching from the second through hole.
[0012] In one embodiment, a foot - hooking frame for sit - ups is provided on the first main board, and a suction cup capable of fixing the second main board on the floor is provided on the second main board.
[0013] In one embodiment, the foot - hooking frame is foldably arranged on the first main board.
[0014] In one embodiment, a first push - up handle is provided on the first main board, and a second push - up handle is provided on the second main board; and / or, a first tension rope structure is provided on the first main board, and a second tension rope structure is provided on the second main board.
[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows: By providing the first connecting shaft and the second connecting shaft, the main body of the foldable exercise board of the present utility model can be folded, that is, the included angle between the first main board and the second main board can be changed, and the included angle between the first main board and the second main board can be smoothly adjusted within the range of 0° to 180°. In this way, when storing, the included angle between the first main board and the second main board can be adjusted according to the actual situation, reducing the storage space occupied by the foldable exercise board of the present utility model and improving the space utilization rate. In addition, when a user uses the foldable exercise board of the present utility model for exercise, the included angle between the first main board and the second main board can be adjusted according to actual needs to realize more possibilities of exercise functions. Brief Description of the Drawings
[0016] Figure 1 It is a split schematic diagram of the connection structure in the foldable exercise board in an embodiment of the present utility model;
[0017] Figure 2 It is a rear schematic diagram of the foldable exercise board in an incomplete folding state in an embodiment of the present utility model;
[0018] Figure 3 It is a front schematic diagram of the foldable exercise board in an incomplete folding state in an embodiment of the present utility model;
[0019] Figure 4 It is a schematic diagram of using the ankle hook in the foldable exercise board after it is laid flat in an embodiment of the present utility model;
[0020] Figure 5 It is a schematic diagram of the foldable exercise board after being completely folded in an embodiment of the present utility model;
[0021] Figure 6 It is a first state schematic diagram of using the first push-up handle and the second push-up handle in the foldable exercise board after it is laid flat in an embodiment of the present utility model;
[0022] Figure 7 It is a second state schematic diagram of using the first push-up handle and the second push-up handle in the foldable exercise board after it is laid flat in an embodiment of the present utility model;
[0023] Figure 8 It is a schematic diagram of using the first tension rope structure and the second tension rope structure in the foldable exercise board after it is laid flat in an embodiment of the present utility model;
[0024] Figure 9 It is a split schematic diagram of the knob pressing structure in the foldable exercise board in an embodiment of the present utility model;
[0025] Figure 10 It is a schematic diagram of the rotating part in an embodiment of the present utility model;
[0026] Figure 11 It is a schematic diagram of the pressing part in an embodiment of the present utility model.
[0027] Reference numerals: 1, main body; 2, sports equipment; 3, first main board; 4, second main board; 5, connection structure; 6, connecting piece; 7, first connecting shaft; 8, second connecting shaft; 9, support rod; 10, installation position; 11, pin; 12, storage hole; 13, first surrounding edge; 14, second surrounding edge; 15, first through hole; 16, second through hole; 17, first anti - detachment ring; 18, second anti - detachment ring; 19, hook foot frame; 20, suction cup; 21, first push - up handle; 22, second push - up handle; 23, first front end; 24, first middle part; 25, first rear end; 26, second front end; 27, second middle part; 28, second rear end; 29, first installation structure; 30, second installation structure; 31, first tension rope structure; 32, second tension rope structure; 33, knob pressing structure; 34, rotating part; 35, pressing part; 36, first protrusion; 37, second protrusion; 38, low end part; 39, high end part; 40, pressing part; 41, connecting part; 42, supporting plane. Detailed implementation manners
[0028] This part will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but it cannot be understood as a limitation on the protection scope of the present utility model.
[0029] In the description of the present utility model, it should be understood that for the orientation description, such as up, down, front, back, left, right, etc., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the present utility model.
[0030] In the description of the present utility model, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, exceeding, etc. are understood as not including the original number, above, below, within, etc. are understood as including the original number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.
[0031] In the description of the present utility model, unless otherwise clearly defined, words such as set, install, connect, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meaning of the above words in the present utility model in combination with the specific content of the technical solution.
[0032] Refer to Figures 1 to 11, A preferred embodiment of the foldable exercise board in the present utility model includes: a main body 1, on which at least one exercise equipment 2 is provided, and the main body 1 includes a first main board 3 and a second main board 4; and a connection structure 5, which includes a connecting member 6, a first connecting shaft 7 and a second connecting shaft 8. Both the first connecting shaft 7 and the second connecting shaft 8 are provided on the connecting member 6. The first main board 3 is rotatably connected to the first connecting shaft 7, and the second main board 4 is rotatably connected to the second connecting shaft 8.
[0033] Due to the provision of the first connecting shaft 7 and the second connecting shaft 8 in the foldable exercise board of the present utility model, the main body 1 can be folded, that is, the included angle between the first main board 3 and the second main board 4 can be changed, and it can be smoothly adjusted within the range of 0° to 180°. In this way, when storing, the included angle between the first main board 3 and the second main board 4 can be adjusted according to the actual situation, reducing the storage space occupied by the foldable exercise board of the present utility model and improving the space utilization rate. In addition, when the user uses the foldable exercise board of the present utility model for exercise, the included angle between the first main board 3 and the second main board 4 can be adjusted according to the actual needs to realize more possibilities of exercise functions.
[0034] As a preferred embodiment of the foldable exercise board in the present utility model, it may also have the following additional technical features:
[0035] Refer to Figure 2 , In one embodiment, a support rod 9 is provided on the first main board 3, and at least two mounting positions 10 that can be detachably connected to the support rod 9 are provided on the second main board 4. The positions of the respective mounting positions 10 are different. By installing the support rod 9 at different mounting positions 10, the included angle between the first main board 3 and the second main board 4 can be adjusted. With the above structure, the user can adjust the included angle between the first main board 3 and the second main board 4 according to the actual needs, and then install the support rod 9 onto the corresponding mounting position 10, thereby playing a role in fixing the included angle between the first main board 3 and the second main board 4 and making the foldable exercise board of the present utility model more stable when in use.
[0036] In one embodiment, one end of the support rod 9 is rotatably provided on the first main board 3, and a plug pin 11 is provided at the other end of the support rod 9. Each mounting position 10 is a jack adapted to the plug pin 11. With the above structure, by swinging the support rod 9, the support rod 9 can be aligned with the corresponding mounting position 10, and the support rod 9 is installed on the second main board 4 through the connection between the plug pin 11 and the jack. When the foldable exercise board of the present utility model needs to be stored after use, the plug pin 11 is removed from the jack, the support rod 9 is retracted, and then the included angle between the first main board 3 and the second main board 4 is adjusted to the required angle, which is easy to store. The above steps are simple to operate and have high installation and disassembly efficiency.
[0037] In one embodiment, a receiving hole 12 adapted to the plug 11 is provided on the first main board 3. When the support rod 9 is not needed, the plug 11 is detachably mounted on the receiving hole 12. Thus, by connecting the plug 11 and the receiving hole 12, the random swinging of the support rod 9 can be prevented. In other embodiments, other suitable receiving structures can be used instead of the receiving hole 12 to receive the support rod 9, and it is not limited thereto.
[0038] In one embodiment, there are two support rods 9, and the two support rods 9 are respectively arranged at the left and right ends of the first main board 3. At least two mounting positions 10 capable of being detachably connected to the corresponding support rods 9 are provided on both the left and right sides of the second main board 4. The support rod 9 arranged on the left side of the first main board 3 corresponds to the mounting position 10 arranged on the left side of the second main board 4, and the support rod 9 arranged on the right side of the first main board 3 corresponds to the mounting position 10 arranged on the right side of the second main board 4. Thus, the included angle between the first main board 3 and the second main board 4 is fixed by the two support rods 9 respectively, and the stability is higher. In other embodiments, the number of the support rods 9 can be set according to actual needs. For example, the number of the support rods 9 can be 1, or the number of the support rods 9 can be 3, or the number of the support rods 9 can be 4, or the number of the support rods 9 can also be other numbers.
[0039] In one embodiment, a first border 13 is provided at the bottom edge of the first main board 3, and the height of the first border 13 is greater than the width of the support rod 9. A second border 14 is provided at the bottom edge of the second main board 4, and the height of the second border 14 is the same as that of the first border 13. With the above structure, when the main body 1 needs to be laid flat for use, that is, the included angle between the first main body 1 and the second main body 1 is 180°, the first border 13 and the second border 14 will directly contact the floor, preventing the support rod 9 from directly contacting the floor. On the one hand, the support rod 9 can be prevented from being damaged when the foldable exercise board of the present invention is used. On the other hand, when the foldable exercise board of the present invention is used, the main body 1 can be placed more stably on the ground.
[0040] Refer to Figure 1, in one embodiment, a first through hole 15 for connecting with a first connecting shaft 7 is provided on the first main board 3, and a second through hole 16 for connecting with a second connecting shaft 8 is provided on the second main board 4. The connecting structure 5 further includes a first anti - detachment ring 17 and a second anti - detachment ring 18. When the first connecting shaft 7 is installed in the first through hole 15, the first anti - detachment ring 17 is installed on the first connecting shaft 7 to prevent the first connecting shaft 7 from detaching from the first through hole 15. When the second connecting shaft 8 is installed in the second through hole 16, the second anti - detachment ring 18 is installed on the second connecting shaft 8 to prevent the second connecting shaft 8 from detaching from the second through hole 16. With the above - mentioned structure, the disassembly and assembly between the first connecting shaft 7 and the first main board 3 are easy. By providing the first anti - detachment ring 17, it can prevent the first connecting shaft 7 from detaching from the first through hole 15 when adjusting the included angle between the first main board 3 and the second main board 4, with higher safety. The disassembly and assembly between the second connecting shaft 8 and the second main board 4 are easy. By providing the second anti - detachment ring 18, it can prevent the second connecting shaft 8 from detaching from the second through hole 16 when adjusting the included angle between the first main board 3 and the second main board 4, with higher safety.
[0041] Refer to Figures 1 to 3 , in one embodiment, a foot - hooking frame 19 for sit - ups is provided on the first main board 3, and a suction cup 20 capable of fixing the second main board 4 on the floor is provided on the second main board 4. In this way, when the user needs to do sit - ups, the suction cup 20 is used to suck the floor to prevent the second main board 4 from moving. The first main board 3 and the second main board 4 are adjusted to a suitable angle so that when the user hooks their feet on the foot - hooking frame 19, the soles of their feet can just be placed on the first main board 3, making the sit - up exercise proceed more smoothly and improving the user experience.
[0042] In one embodiment, the foot - hooking frame 19 is foldably arranged on the first main board 3. In this way, when the foot - hooking frame 19 is not needed, it can be folded up. On the one hand, it can reduce the situation where the foot - hooking frame 19 affects the use of other equipment. On the other hand, when the foldable exercise board of the present utility model is not needed, it is more conducive to the storage of the foldable exercise board of the present utility model.
[0043] Refer to Figure 6 and Figure 7 , in one embodiment, a first push - up handle 21 is provided on the first main board 3, and a second push - up handle 22 is provided on the second main board 4. In this way, the user can use the foldable exercise board of the present utility model to assist in doing push - up exercises, which is more beneficial to the user's exercise. In other embodiments, the first push - up handle 21 and the second push - up handle 22 may not be provided.
[0044] In one embodiment, the first handle 21 of the push-up exercise includes a first front end portion 23, a first middle portion 24, and a first rear end portion 25. The first front end portion 23 can be directly connected to the first rear end portion 25, or the first front end portion 23 can be connected to the first rear end portion 25 through the first middle portion 24. Users can select a suitable connection method according to actual needs, so as to adjust the length of the first handle 21 of the push-up exercise. The second handle 22 of the push-up exercise includes a second front end portion 26, a second middle portion 27, and a second rear end portion 28. The second front end portion 26 can be directly connected to the second rear end portion 28, or the second front end portion 26 can be connected to the second rear end portion 28 through the second middle portion 27. Users can select a suitable connection method according to actual needs, so as to adjust the length of the second handle 22 of the push-up exercise. A plurality of first mounting structures 29 for mounting the first front end portion 23 and the first rear end portion 25 are provided on the first main board 3, and a plurality of second mounting structures 30 for mounting the second front end portion 26 and the second rear end portion 28 are provided on the second main board 4. Users can mount the first front end portion 23 and the first rear end portion 25 on a suitable first mounting structure 29 according to actual needs, and mount the second front end portion 26 and the second rear end portion 28 on a suitable second mounting structure 30, so as to adjust the distance between the first handle 21 and the second handle 22 of the push-up exercise. In other embodiments, the first handle 21 and the second handle 22 of the push-up exercise can adopt other suitable structures to replace the above structures, and are not limited thereto.
[0045] In one embodiment, the structures of the first front end portion 23, the first rear end portion 25, the second front end portion 26, and the second rear end portion 28 are the same, and the structures of the first mounting structure 29 and the second mounting structure 30 are the same. In this way, the first front end portion 23 and the second rear end portion 28 can be mounted on the second mounting structure 30, and the second front end portion 26 and the second rear end portion 28 can be mounted on the first mounting structure 29. Users can select a suitable assembly method according to actual needs.
[0046] Refer to Figure 8 , in one embodiment, a first tension rope structure 31 is provided on the first main board 3, and a second tension rope structure 32 is provided on the second main board 4. In this way, users can use the foldable exercise board of the present utility model to assist in tension exercises, which is more beneficial to users' exercises. In other embodiments, the first tension rope structure 31 and the second tension rope structure 32 can be not provided.
[0047] Refer to Figures 9 to 11, in an embodiment, a knob pressing-down structure 33 is provided on the second main board 4. By rotating the knob pressing-down structure 33, the knob pressing-down structure 33 can push the suction cup 20 to adsorb the floor. By rotating the knob pressing-down structure 33 in the opposite direction, the knob pressing-down structure 33 resets. Through the cooperative setting of the knob pressing-down structure 33 and the suction cup 20, by rotating the knob pressing-down structure 33, the knob pressing-down structure 33 can push the suction cup 20 to adsorb the floor. Thus, when the user performs sit-up exercises, the foldable exercise board of the present utility model will not shift, which is more conducive to the user performing sit-up exercises. After the user finishes exercising, the knob pressing-down structure 33 can be rotated in the opposite direction to reset the knob pressing-down structure 33. At this time, since the suction cup 20 lacks the downward pressure of the knob pressing-down structure 33, the user only needs to use a relatively small force to separate the suction cup 20 from the floor, or the suction cup 20 waits for a period of time in the natural state, and the state of adsorbing the floor will end due to insufficient suction force.
[0048] In an embodiment, the knob pressing-down structure 33 includes a rotating member 34 and a pressing-down member 35, and the pressing-down member 35 is connected to the suction cup 20; a plurality of first protrusions 36 are provided at the bottom of the rotating member 34, and the first protrusions 36 are distributed in an array around the center of the rotating member 34; a plurality of second protrusions 37 are provided at the top of the pressing-down member 35, and the second protrusions 37 are distributed in an array around the center of the pressing-down member 35. Each second protrusion 37 includes a low end portion 38 and a high end portion 39, and the height of the second protrusion 37 gradually increases from the low end portion 38 to the high end portion 39; in the initial state of the rotating member 34, each first protrusion 36 is located on the bottom end portion of the corresponding second protrusion 37. During the process of rotating the rotating member 34, each first protrusion 36 will move along the top of the corresponding second protrusion 37 from the low end portion 38 to the high end portion 39, so that the pressing-down member 35 moves downward to press the suction cup 20. When the rotation of the rotating member 34 is completed, each first protrusion 36 abuts against the high end portion 39 of the corresponding second protrusion 37. With the above structure, the structure is simple and the operation is easy. In other embodiments, the knob pressing-down structure 33 can adopt other suitable structures to replace the above structure.
[0049] In an embodiment, the pressing-down member 35 includes a pressing-down portion 40 and a connecting portion 41. The connecting portion 41 is respectively connected to the pressing-down portion 40 and the suction cup 20, and the pressing-down portion 40 is located above the connecting portion 41. Thus, the manufacturing of parts is easier and the yield is high. In other embodiments, the pressing-down member 35 may not include the connecting portion 41, and the pressing-down portion 40 is directly connected to the suction cup 20.
[0050] In one embodiment, a support plane 42 for abutting against the corresponding first protrusion 36 is provided at the top of the high-end portion 39 of each of the second protrusions 37. In this way, when the first protrusion 36 abuts against the top of the high-end portion 39 of the second protrusion 37, it is more stable, preventing the first protrusion 36 and the second protrusion 37 from sliding relative to each other during the user's movement on the skateboard, thereby ensuring that the suction cup 20 can stably adsorb to the floor. In other embodiments, other suitable structures may be provided at the top of the high-end portion 39 of each of the second protrusions 37 to replace the support plane 42.
[0051] On the premise that no conflict occurs, those skilled in the art can freely combine and superimpose the above-mentioned additional technical features.
[0052] The above embodiments are only the preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.
Claims
1. A foldable exercise board, characterized in that, Comprising: A main body, on which at least one piece of sports equipment is provided, and the main body includes a first main board and a second main board; And A connection structure, which includes a connecting piece, a first connecting shaft and a second connecting shaft. Both the first connecting shaft and the second connecting shaft are provided on the connecting piece. The first main board is rotatably connected to the first connecting shaft, and the second main board is rotatably connected to the second connecting shaft.
2. The foldable exercise board according to claim 1, wherein, A support rod is provided on the first main board, and at least two mounting positions capable of being detachably connected to the support rod are provided on the second main board. The positions of the mounting positions are different, and by mounting the support rod to different mounting positions, the included angle between the first main board and the second main board can be adjusted.
3. The foldable exercise board according to claim 2, wherein One end of the support rod is rotatably provided on the first main board, and a plug pin is provided at the other end of the support rod. Each of the mounting positions is a jack adapted to the plug pin.
4. The foldable exercise board according to claim 3, wherein A storage hole adapted to the plug pin is provided on the first main board. When the support rod is not needed, the plug pin is detachably mounted to the storage hole.
5. The foldable exercise board according to claim 2, wherein There are two support rods, which are respectively provided at the left and right ends of the first main board. At least two mounting positions capable of being detachably connected to the corresponding support rods are provided on both the left and right sides of the second main board. The support rod provided on the left side of the first main board corresponds to the mounting position provided on the left side of the second main board, and the support rod provided on the right side of the first main board corresponds to the mounting position provided on the right side of the second main board.
6. The foldable exercise board according to claim 3, wherein A first border is provided at the bottom edge of the first main board, and the height of the first border is greater than the width of the support rod. A second border is provided at the bottom edge of the second main board, and the height of the second border is the same as that of the first border.
7. The foldable exercise board according to claim 1, wherein A first through hole for connecting to the first connecting shaft is provided on the first main board, and a second through hole for connecting to the second connecting shaft is provided on the second main board. The connection structure further includes a first anti - detachment ring and a second anti - detachment ring; when the first connecting shaft is installed in the first through hole, the first anti - detachment ring is installed on the first connecting shaft to prevent the first connecting shaft from detaching from the first through hole, and when the second connecting shaft is installed in the second through hole, the second anti - detachment ring is installed on the second connecting shaft to prevent the second connecting shaft from detaching from the second through hole.
8. The foldable exercise board according to claim 1, characterized in that, A foot - hooking frame for sit - ups is provided on the first main board, and a suction cup capable of fixing the second main board on the floor is provided on the second main board.
9. The foldable exercise board according to claim 8, characterized in that, The foot - hooking frame is foldably provided on the first main board.
10. The foldable exercise board according to claim 1, wherein, A first push - up handle is provided on the first main board, and a second push - up handle is provided on the second main board; And / or, a first tension rope structure is provided on the first main board, and a second tension rope structure is provided on the second main board.