Detachable pedal of wheelchair

Abstract

The detachable pedal of the wheelchair relates to the technical field of pedals and comprises a supporting rod, a connecting rod and a pedal body, the top end of the supporting rod is in an arc shape, the connecting rod is movably connected to the inner side of the supporting rod, a plurality of limiting grooves are formed in the outer side of the supporting rod and distributed in a circular array mode, and the pedal body is connected with the supporting rod. A limiting mechanism is arranged in the connecting rod and matched with the limiting groove. By means of the limiting mechanism, the connecting rod is inserted into the bottom end of the supporting rod till the connecting rod stops, then the control ring is loosened, the movable rod and the protruding block are reset under the action of the compression spring, and therefore the extending plate abuts against the periphery, and the inserting plate is pushed to move out of the through groove; and the inserting plates are inserted into the limiting grooves correspondingly, at the moment, the connecting rods are fixedly connected to the bottom ends of the supporting rods, mounting and dismounting of the foot pedal can be rapidly achieved, operation is easy and convenient, mounting is firm, and damage is not likely to happen.

Description

Technical Field

[0001] The utility model relates to the technical field of foot pedals, in particular to a detachable foot pedal of a wheelchair. Background Art

[0002] With the progress of society and the development of medical technology, wheelchairs have become an indispensable auxiliary tool in the lives of many people with limited mobility. Wheelchairs not only provide them with basic freedom of movement, but also greatly improve their quality of life. In the design of wheelchairs, the foot pedal plays a key role as an important component supporting the user's feet.

[0003] Common wheelchair footrests are usually fixed or simply foldable, usually fixed and connected with screws, but these designs often have some inconveniences in use. For example, fixed footrests are not easy to disassemble and adjust, and users may feel inconvenienced when they need to transfer or store the wheelchair; and simple foldable footrests are prone to wear during frequent folding and unfolding, resulting in a shortened service life. Therefore, a detachable footrest for a wheelchair is needed to solve the existing deficiencies. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a detachable footrest of a wheelchair, and to solve the problem that a simple foldable footrest is easily worn out during frequent folding and unfolding, resulting in a shortened service life, by providing a limiting mechanism and a positioning mechanism.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A detachable foot pedal for a wheelchair comprises a support rod, a connecting rod and a footboard, the top end of the support rod is arc-shaped, the connecting rod is movably connected to the inner side of the support rod, the outer side of the support rod is provided with a plurality of limit grooves, and the plurality of limit grooves are distributed in a circular array, a limit mechanism is arranged inside the connecting rod, the limit mechanism cooperates with the limit groove, a control ring is movably connected to the outer side of the connecting rod, and the control ring is fixedly connected to one end of the limit mechanism, the bottom end of the connecting rod is fixedly connected to a support block, a positioning mechanism is arranged on the inner side of the support block, and one side of the positioning mechanism is fixedly connected to the footboard.

[0007] As mentioned above, the limiting mechanism includes a connecting plate, an insert plate and an extension plate. The connecting plate, the insert plate and the extension plate are a group and are distributed in a circular array. Each group of extension plates is symmetrically arranged. The extension plates are respectively fixedly connected to the two ends of the connecting plate, and one end of the insert plate is fixedly connected to one end of the connecting plate.

[0008] As mentioned above, a plurality of through slots are opened on the outer side of the connecting rod, and the through slots are distributed in a circular array. The plug plates respectively pass through the through slots, and the plug plates are movably connected to the through slots. The plug plates are respectively movably connected to the limiting slots, and the through slots are respectively communicated with the limiting slots.

[0009] As mentioned above, the limiting mechanism also includes a fixing rod and a return spring, and the fixing rod and the return spring are symmetrically arranged in multiple groups, and the fixing rod and the return spring are distributed in a circular array, and the return springs are respectively sleeved on the outside of the fixing rod, and the fixing rod passes through the extension plate respectively, and the fixing rod is movably connected to the extension plate.

[0010] As mentioned above, one end of the fixing rod is fixedly connected to the inside of the connecting rod, one end of the return spring is fixedly connected to the inner side of the connecting rod, and the other end of the return spring is fixedly connected to one side of the extension plate.

[0011] As mentioned above, the limiting mechanism also includes a protrusion, a moving rod and a compression spring, the protrusion and the compression spring are symmetrically arranged, the moving rod passes through the protrusion, and the moving rod is fixedly connected to the protrusion, the compression spring is sleeved on the outside of the moving rod, one end of the compression spring is fixedly connected to the inside of the connecting rod, and the other end of the compression spring is fixedly connected to the protrusion.

[0012] As mentioned above, the movable rod is movably connected to the inside of the connecting rod, and one end of the movable rod is fixedly connected to the inner side of the control ring, the extension plate is in a "X" shape, the axial section of the protrusion is elliptical, and the outer side of the protrusion is movably connected to the concave side of the extension plate.

[0013] As mentioned above, the positioning mechanism includes a connecting block, a rotating rod, a pair of teeth one and a pair of teeth two, the rotating rod passes through the connecting block, and the rotating rod is fixedly connected to the connecting block, the pair of teeth one is meshed with the pair of teeth two, and the pair of teeth one is fixedly connected to one side of the rotating rod.

[0014] As mentioned above, the positioning mechanism also includes a return spring and a spacer block. The return spring is sleeved on the outside of the rotating rod, one end of the return spring is fixedly connected to the inside of the support block, and the other end of the return spring is fixedly connected to one end of the spacer block. The rotating rod passes through the spacer block, and the rotating rod is movably connected to the spacer block, and the other end of the spacer block is in contact with the back side of the opposite tooth.

[0015] As mentioned above, one end of the connecting block is fixedly connected to one side of the footboard, the connecting block is movably connected to the inside of the supporting block through a rotating rod, the pair of teeth 1 and the spacer block are both movably connected to the inside of the supporting block, and the pair of teeth 2 is fixedly connected to the inside of the supporting block.

[0016] Compared with the prior art, the utility model has at least the following beneficial effects:

[0017] 1. The utility model provides a limiting mechanism, and the connecting rod is inserted into the bottom end of the supporting rod until the connecting rod stops. Then, the control ring is loosened, and the moving rod and the protrusion are reset under the action of the compression spring, so that the extension plate is abutted against each other on all sides, so as to push the plug plate out of the through groove, and the plug plates are respectively inserted into the limiting grooves. At this time, the connecting rod is fixedly connected to the bottom end of the supporting rod, so that the footboard can be quickly installed and disassembled, and the operation is simple, the installation is firm, and it is not easy to be damaged.

[0018] Second, the utility model uses a positioning mechanism to flip the footboard inward, drive the rotating rod to rotate until the footboard is in a vertical position, release the footboard, and under the action of the return spring, push the spacer block to move, thereby pushing the first tooth and the second tooth to re-engage, thereby keeping the position of the footboard fixed, and through the engagement of the first tooth and the second tooth, the footboard can be kept stopped at any angle to prevent the footboard from rotating to a horizontal position again under the action of external force, and the operation is simple, so that the user can store and use it at any time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0020] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0021] Figure 2 It is a schematic diagram of the limit mechanism and the connecting rod structure of the utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the limiting mechanism of the utility model;

[0023] Figure 4 This is a schematic diagram of the positioning mechanism structure of the utility model;

[0024] Figure 5 For this utility model Figure 3 Schematic diagram of the enlarged structure at point A in the middle.

[0025] In the figure: 1. support rod; 2. connecting rod; 3. footboard; 4. limiting groove; 5. limiting mechanism; 501. connecting plate; 502. plug plate; 503. extension plate; 504. fixing rod; 505. reset spring; 506. bump; 507. moving rod; 508. compression spring; 6. control ring; 7. support block; 8. positioning mechanism; 801. connecting block; 802. rotating rod; 803. tooth one; 804. tooth two; 805. return spring; 806. spacer block; 9. through groove.

[0026] As shown in the figure, in order to clearly implement the structure of the embodiment of the utility model, specific structures and devices are marked in the figure, but this is only for illustrative purposes and is not intended to limit the utility model to the specific structure, device and environment. According to specific needs, ordinary technicians in this field can adjust or modify these devices and environments, and the adjustments or modifications made are still included in the scope of the attached claims. DETAILED DESCRIPTION

[0027] The following is a detailed description of a detachable footrest for a wheelchair provided by the utility model in combination with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the utility model.

[0028] It should be noted that the references to "one embodiment", "embodiment", "exemplary embodiments", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0029] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0030] like Figure 1-5 As shown, the utility model provides a technical solution: a detachable foot pedal for a wheelchair, comprising a support rod 1, a connecting rod 2 and a footboard 3, the top end of the support rod 1 is arc-shaped, the connecting rod 2 is movably connected to the inner side of the support rod 1, a plurality of limiting grooves 4 are provided on the outer side of the support rod 1, and the plurality of limiting grooves 4 are distributed in a circular array, a limiting mechanism 5 is arranged inside the connecting rod 2, the limiting mechanism 5 cooperates with the limiting groove 4, a control ring 6 is movably connected to the outer side of the connecting rod 2, and the control ring 6 is fixedly connected to one end of the limiting mechanism 5, the bottom end of the connecting rod 2 is fixedly connected to a support block 7, a positioning mechanism 8 is arranged on the inner side of the support block 7, and one side of the positioning mechanism 8 is fixedly connected to the footboard 3.

[0031] First, the control ring 6 is pushed downward to drive the moving rod 507 to move downward, thereby driving the protrusion 506 to move downward synchronously, and the edge of the protrusion 506 contacts the inner side of the extension plate 503 until the edge of the protrusion 506 moves to the inner groove of the extension plate 503. In this process, the compression spring 508 is deformed, and under the action of the reset spring 505, the extension plate 503 is pushed to move closer to each other along the fixed rod 504, so that the connecting plates 501 are close to each other, and the plug plate 502 is retracted inward until the plug plate 502 is completely retracted to the inside of the through groove 9. Subsequently, the connecting rod 2 is inserted into the bottom end of the support rod 1 until the connecting rod 2 stops. Subsequently, the control ring 6 is released, and under the action of the compression spring 508, the moving rod 507 and the protrusion 506 are reset, thereby 03 contacts each other on all sides, thereby pushing the insert plate 502 out of the through slot 9, and the insert plates 502 are respectively inserted into the limiting slots 4. At this time, the connecting rod 2 is fixedly connected to the bottom end of the support rod 1; by moving the footboard 3 backward, the connecting block 801 is driven to move backward synchronously, so that the rotating rod 802 moves backward synchronously on the inner side of the support block 7, so that the tooth 1 803 and the tooth 2 804 are separated, and the tooth 1 803 squeezes the spacer block 806, so that the return spring 805 is compressed and shortened, and then the footboard 3 is flipped inward, driving the rotating rod 802 to rotate until the footboard 3 is in a vertical position, and the footboard 3 is released. Under the action of the return spring 805, the spacer block 806 is pushed to move, thereby pushing the tooth 1 803 and the tooth 2 804 to re-engage, thereby keeping the position of the footboard 3 fixed.

[0032] like Figure 1-3 and Figure 5As shown, the limiting mechanism 5 includes a connecting plate 501, a plug plate 502 and an extension plate 503. The connecting plate 501, the plug plate 502 and the extension plate 503 are a group and are all distributed in a circular array. Each group of extension plates 503 is symmetrically arranged. The extension plates 503 are respectively fixedly connected to the two ends of the connecting plate 501, and one end of the plug plate 502 is fixedly connected to one end of the connecting plate 501. A plurality of through grooves 9 are opened on the outer side of the connecting rod 2. The through grooves 9 are distributed in a circular array. The plug plates 502 respectively penetrate the through grooves 9, and The plug plate 502 is movably connected to the through slot 9, and the plug plate 502 is movably connected to the limit slot 4 respectively, and the through slot 9 is communicated with the limit slot 4 respectively. The limit mechanism 5 also includes a fixed rod 504 and a return spring 505, and the fixed rod 504 and the return spring 505 are symmetrically arranged in multiple groups, and the fixed rod 504 and the return spring 505 are distributed in a circular array, and the return spring 505 is respectively sleeved on the outer side of the fixed rod 504, and the fixed rod 504 passes through the extension plate 503 respectively, and the fixed rod 504 and the extension plate 503 are connected. The extension plate 503 is movably connected, one end of the fixed rod 504 is fixedly connected to the inside of the connecting rod 2, one end of the return spring 505 is fixedly connected to the inner side of the connecting rod 2, and the other end of the return spring 505 is fixedly connected to one side of the extension plate 503, the limiting mechanism 5 also includes a protrusion 506, a moving rod 507 and a compression spring 508, the protrusion 506 and the compression spring 508 are symmetrically arranged, the moving rod 507 passes through the protrusion 506, and the moving rod 507 is fixed to the protrusion 506. Fixed connection, the compression spring 508 is sleeved on the outside of the moving rod 507, one end of the compression spring 508 is fixedly connected to the inside of the connecting rod 2, and the other end of the compression spring 508 is fixedly connected to the protrusion 506, the moving rod 507 is movably connected to the inside of the connecting rod 2, and one end of the moving rod 507 is fixedly connected to the inner side of the control ring 6, the extension plate 503 is in a "J" shape, the axial section of the protrusion 506 is elliptical, and the outer side of the protrusion 506 is movably connected to the concave side of the extension plate 503.

[0033] The control ring 6 is pushed downward, driving the moving rod 507 to move downward, thereby driving the protrusion 506 to move downward synchronously, and the edge of the protrusion 506 contacts the inner side of the extension plate 503 until the edge of the protrusion 506 moves to the inside of the inner groove of the extension plate 503. In this process, the compression spring 508 is deformed, and under the action of the return spring 505, the extension plates 503 are pushed closer to each other along the fixing rod 504, so that the connecting plates 501 are brought closer to each other, and the plug plate 502 is retracted inward until the plug plate 502 is completely retracted to the through groove. 9, then, insert the connecting rod 2 into the bottom end of the supporting rod 1 until the connecting rod 2 stops, then, release the control ring 6, under the action of the compression spring 508, the moving rod 507 and the protrusion 506 are reset, so that the extension plate 503 is abutted against each other on all sides, thereby pushing the plug plate 502 out of the through groove 9, and the plug plates 502 are respectively inserted into the limiting grooves 4. At this time, the connecting rod 2 is fixedly connected to the bottom end of the supporting rod 1, and the footboard 3 can be quickly installed and disassembled. The operation is simple, the installation is firm, and it is not easy to be damaged.

[0034] like Figure 1 and Figure 4 As shown, the positioning mechanism 8 includes a connecting block 801, a rotating rod 802, a first tooth 803 and a second tooth 804, the rotating rod 802 passes through the connecting block 801, and the rotating rod 802 is fixedly connected to the connecting block 801, the first tooth 803 is meshed with the second tooth 804, and the first tooth 803 is fixedly connected to one side of the rotating rod 802, the positioning mechanism 8 also includes a return spring 805 and a spacer block 806, the return spring 805 is sleeved on the outer side of the rotating rod 802, one end of the return spring 805 is fixedly connected to the inside of the support block 7, and the return spring 805 is fixedly connected to the inner side of the support block 7. The other end of the spring 805 is fixedly connected to one end of the spacer block 806, the rotary rod 802 passes through the spacer block 806, and the rotary rod 802 is movably connected to the spacer block 806, the other end of the spacer block 806 is in contact with the back side of the tooth 1 803, one end of the connecting block 801 is fixedly connected to one side of the footboard 3, the connecting block 801 is movably connected to the inside of the support block 7 through the rotary rod 802, the tooth 1 803 and the spacer block 806 are both movably connected to the inside of the support block 7, and the tooth 2 804 is fixedly connected to the inside of the support block 7.

[0035] By moving the footboard 3 backward, the connecting block 801 is driven to move backward synchronously, so that the rotating rod 802 is moved backward synchronously on the inner side of the supporting block 7, so that the tooth 1 803 and the tooth 2 804 are separated, and the tooth 1 803 squeezes the spacer block 806, so that the return spring 805 is compressed and shortened, and then the footboard 3 is flipped inward, driving the rotating rod 802 to rotate until the footboard 3 is in a vertical position, and the footboard 3 is released. Under the action of the return spring 805, the spacer block 806 is pushed to move, thereby pushing the tooth 1 803 and the tooth 2 804 to re-engage, thereby keeping the position of the footboard 3 fixed, and through the engagement of the tooth 1 803 and the tooth 2 804, the footboard 3 can be kept stopped at any angle to prevent the footboard 3 from rotating to the horizontal position again under the action of external force. The operation is simple and convenient, and the user can store and use it at any time.

[0036] Working principle: When in use, first, push the control ring 6 downward to drive the moving rod 507 to move downward, thereby driving the protrusion 506 to move downward synchronously, and the edge of the protrusion 506 contacts the inner side of the extension plate 503 until the edge of the protrusion 506 moves to the inner groove of the extension plate 503. In this process, the compression spring 508 is deformed, and under the action of the reset spring 505, the extension plate 503 is pushed to approach each other along the fixed rod 504, so that the connecting plates 501 are close to each other, and the plug plate 502 is retracted inward until the plug plate 502 is completely retracted to the inside of the through groove 9. Then, the connecting rod 2 is inserted into the bottom end of the support rod 1 until the connecting rod 2 stops. Then, the control ring 6 is released, and under the action of the compression spring 508, the moving rod 507 and the protrusion 506 are reset, thereby The extension plate 503 contacts each other on all sides, thereby pushing the plug plate 502 out of the through slot 9, and the plug plates 502 are respectively inserted into the limiting slots 4. At this time, the connecting rod 2 is fixedly connected to the bottom end of the support rod 1; by moving the footboard 3 backward, the connecting block 801 is driven to move backward synchronously, so that the rotating rod 802 moves backward synchronously on the inner side of the support block 7, so that the tooth 1 803 and the tooth 2 804 are separated, and the tooth 1 803 squeezes the spacer block 806, so that the return spring 805 is compressed and shortened, and then the footboard 3 is flipped inward, driving the rotating rod 802 to rotate until the footboard 3 is in a vertical position, and the footboard 3 is released. Under the action of the return spring 805, the spacer block 806 is pushed to move, thereby pushing the tooth 1 803 and the tooth 2 804 to re-engage, thereby keeping the position of the footboard 3 fixed.

[0037] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, the specific details are described in detail in the above preferred embodiments of the present invention, and those skilled in the art can fully understand the present invention without the description of these details.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A detachable footrest for a wheelchair, comprising a support rod (1), a connecting rod (2) and a footrest (3), characterized in that: The top end of the support rod (1) is arc-shaped, the connecting rod (2) is movably connected to the inner side of the support rod (1), the outer side of the support rod (1) is provided with a plurality of limit grooves (4), and the plurality of limit grooves (4) are distributed in a circular array, a limit mechanism (5) is arranged inside the connecting rod (2), the limit mechanism (5) cooperates with the limit groove (4), the outer side of the connecting rod (2) is movably connected with a control ring (6), and the control ring (6) is fixedly connected to one end of the limit mechanism (5), the bottom end of the connecting rod (2) is fixedly connected to a support block (7), the inner side of the support block (7) is provided with a positioning mechanism (8), and one side of the positioning mechanism (8) is fixedly connected to the footboard (3).

2. The detachable footrest of a wheelchair according to claim 1, characterized in that: The limiting mechanism (5) comprises a connecting plate (501), an inserting plate (502) and an extending plate (503); the connecting plate (501), the inserting plate (502) and the extending plate (503) form a group and are all distributed in a circular array; each group of the extending plates (503) is symmetrically arranged; the extending plates (503) are respectively fixedly connected to two ends of the connecting plate (501); and one end of the inserting plate (502) is fixedly connected to one end of the connecting plate (501).

3. The detachable footrest of a wheelchair according to claim 2, characterized in that: A plurality of through slots (9) are provided on the outer side of the connecting rod (2), the through slots (9) being distributed in a circular array, the plug plates (502) respectively pass through the through slots (9), and the plug plates (502) are movably connected to the through slots (9), the plug plates (502) are respectively movably connected to the limiting slots (4), and the through slots (9) are respectively connected to the limiting slots (4).

4. The detachable footrest of a wheelchair according to claim 3, characterized in that: The limiting mechanism (5) further comprises a fixing rod (504) and a return spring (505), wherein the fixing rod (504) and the return spring (505) are symmetrically arranged in a plurality of groups, and the fixing rod (504) and the return spring (505) are both distributed in a circular array, and the return spring (505) is respectively sleeved on the outside of the fixing rod (504), and the fixing rod (504) respectively penetrates the extension plate (503), and the fixing rod (504) is movably connected to the extension plate (503).

5. The detachable footrest of a wheelchair according to claim 4, characterized in that: One end of the fixing rod (504) is fixedly connected to the inside of the connecting rod (2), one end of the return spring (505) is fixedly connected to the inner side of the connecting rod (2), and the other end of the return spring (505) is fixedly connected to one side of the extension plate (503).

6. The detachable footrest of a wheelchair according to claim 5, characterized in that: The limiting mechanism (5) further comprises a protrusion (506), a moving rod (507) and a compression spring (508); the protrusion (506) and the compression spring (508) are symmetrically arranged; the moving rod (507) passes through the protrusion (506), and the moving rod (507) is fixedly connected to the protrusion (506); the compression spring (508) is sleeved on the outside of the moving rod (507); one end of the compression spring (508) is fixedly connected to the inside of the connecting rod (2), and the other end of the compression spring (508) is fixedly connected to the protrusion (506).

7. The detachable footrest of a wheelchair according to claim 6, characterized in that: The movable rod (507) is movably connected to the inside of the connecting rod (2), and one end of the movable rod (507) is fixedly connected to the inner side of the control ring (6). The extension plate (503) is in a "F" shape. The axial cross section of the protrusion (506) is in an elliptical shape, and the outer side of the protrusion (506) is movably connected to the inner concave side of the extension plate (503).

8. The detachable footrest of a wheelchair according to claim 1, characterized in that: The positioning mechanism (8) comprises a connecting block (801), a rotating rod (802), a first pair of teeth (803) and a second pair of teeth (804); the rotating rod (802) passes through the connecting block (801), and the rotating rod (802) is fixedly connected to the connecting block (801); the first pair of teeth (803) is meshed with the second pair of teeth (804), and the first pair of teeth (803) is fixedly connected to one side of the rotating rod (802).

9. The detachable footrest of a wheelchair according to claim 8, characterized in that: The positioning mechanism (8) further comprises a return spring (805) and a spacer block (806); the return spring (805) is sleeved on the outside of the rotary rod (802); one end of the return spring (805) is fixedly connected to the inside of the support block (7); and the other end of the return spring (805) is fixedly connected to one end of the spacer block (806); the rotary rod (802) passes through the spacer block (806); the rotary rod (802) and the spacer block (806) are movably connected; and the other end of the spacer block (806) is in contact with the back side of the first tooth (803).

10. The detachable footrest of a wheelchair according to claim 9, characterized in that: One end of the connecting block (801) is fixedly connected to one side of the footboard (3); the connecting block (801) is movably connected to the inside of the supporting block (7) via a rotating rod (802); the pair of teeth (803) and the spacing block (806) are both movably connected to the inside of the supporting block (7); and the pair of teeth (804) is fixedly connected to the inside of the supporting block (7).

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