Foldable wheelchair

Abstract

The foldable wheelchair comprises a chassis, a seat assembly with a seat rod and a back rod, and a support assembly with upper and lower front support rods and a rear support rod. The back rod is rotatably connected with the seat rod and extends downward from the connection to form an extension. The upper front support rod is rotatably connected with the middle part of the seat rod and the middle part of the lower front support rod at both ends, respectively. The lower front support rod is rotatably connected with the middle part of the extension and the front part of the chassis at both ends, respectively. The rear support rod is rotatably connected with the lower end of the extension and the rear end of the chassis at both ends, respectively. The two four-link mechanisms between the seat rod and the chassis can be linked, the operation is convenient, the comfort is good, the height of the seat rod when unfolded can be changed by adjusting the length of each rod, the adaptability is good, the chassis does not participate in folding, the safety is good, the lower front and rear support rods are sequentially arranged with the upper front support rod and the extension in the left-right direction, the support is formed by the lower front support rod against the rear support rod and / or the seat rod when unfolded, the one-way self-locking is realized, and the structure is simple.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, specifically relating to a foldable wheelchair. Background Technology

[0002] A wheelchair is a medical device used to assist patients in treatment and rehabilitation. It typically includes a seat, backrest, and wheel assembly for moving the wheelchair. Traditional wheelchairs are mostly non-foldable and take up a lot of space. To solve this problem, foldable wheelchairs have appeared on the market. Their folding mainly involves the folding of the seat and backrest and the lowering of the seat height. Conventional foldable wheelchairs do not have a linkage between these two actions, which need to be performed separately, making them inconvenient to operate. There are also foldable wheelchairs that can achieve linkage, but these wheelchairs mostly achieve linkage through the relative rotation of the front wheel bracket and the rear wheel bracket. Because the front and rear wheel brackets need to be set in a forked configuration, the size of the seat cannot be too large, resulting in poor comfort. Furthermore, the degree of change in seat height is limited by the degree of change in the folding of the seat and backrest, making it difficult to adjust according to the actual needs of seat height. When folded, the front and rear wheels will also come together, which can easily crush or squeeze the feet and other parts of the body, resulting in poor safety. When unfolded, they are not stable and require an additional locking mechanism for locking, making the structure complex. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a foldable wheelchair that is easy to operate, comfortable, adaptable, safe, and simple in structure.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is a foldable wheelchair, comprising: A chassis, the bottom of which is connected to a wheel assembly; A seat assembly, the seat assembly including a seat rod and a backrest rod, the seat rod being located above the chassis, the backrest rod being rotatably connected to the seat rod, and the backrest rod extending downward from the rotatable connection point between the backrest rod and the seat rod to form an extension; A support assembly includes an upper front support rod, a lower front support rod, and a rear support rod. The upper end of the upper front support rod is rotatably connected to the middle of the seat rod, the lower end of the upper front support rod is rotatably connected to the middle of the lower front support rod, the lower end of the lower front support rod is rotatably connected to the front of the chassis, the upper end of the rear support rod is rotatably connected to the lower end of the extension, and the lower end of the rear support rod is rotatably connected to the rear end of the chassis. The upper end of the lower front support rod is rotatably connected to the middle of the extension, so that the first four-bar linkage consisting of the extension, the seat rod, the upper front support rod, and the lower front support rod is linked with the second four-bar linkage consisting of the rear support rod, the extension, the lower front support rod, and the chassis. The lower front support rod and the rear support rod are located on a first plane, and the upper front support rod and the extension are located on a second plane. The first plane and the second plane are arranged sequentially in the left-right direction. When the backrest rod flips backward to unfold the seat assembly, the linkage can cause the lower front support rod to press against the rear support rod and / or the seat rod to form support, preventing the backrest rod from continuing to flip backward and achieving one-way self-locking. When the backrest rod flips forward to fold the seat assembly, the linkage can cause the backrest rod, the seat rod, the lower front support rod, and the rear support rod to sequentially move towards the chassis and fold, and the upper front support rod and the lower front support rod to fold alternately.

[0005] Preferably, when the lower front support rod abuts against the rear support rod, the lower front support rod is perpendicular to the rear support rod.

[0006] Preferably, when the lower front support rod abuts against the seat rod, the lower front support rod is perpendicular to the upper front support rod.

[0007] Preferably, when the seat assembly is unfolded, the backrest rod extends backward and upward at an angle of 10-20° to the vertical direction.

[0008] Preferably, when the seat assembly is deployed, the seat post is higher at the front and lower at the back, and parallel to the chassis.

[0009] Preferably, the chassis is provided with a connecting seat for rotatably connecting the lower front support rod and the rear support rod.

[0010] More preferably, the connecting seat is located outside the first plane.

[0011] Preferably, a rotatable armrest is connected to the middle of the backrest rod.

[0012] More preferably, the chassis has a frame structure, and the projection of the chassis in the vertical direction is square-shaped, with the wheel assembly connected to the four corners of the bottom of the chassis.

[0013] More preferably, the wheel assembly includes an electric wheel assembly.

[0014] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The foldable wheelchair provided by this invention includes a chassis, a seat assembly with a seat rod and a backrest rod, and a support assembly with upper and lower front support rods and a rear support rod. The seat rod is located above the chassis. The backrest rod is rotatably connected to the seat rod and extends downward from the connection point to form an extension. The two ends of the upper front support rod are rotatably connected to the middle of the seat rod and the middle of the lower front support rod, respectively. The lower end of the lower front support rod is rotatably connected to the front of the chassis. The upper and lower ends of the rear support rod are rotatably connected to the lower end of the extension and the rear end of the chassis, respectively. By rotatably connecting the upper end of the lower front support rod to the middle of the extension, a first four-bar linkage mechanism consisting of the extension, seat rod, upper front support rod, and lower front support rod is connected to the rear support rod, extension, and lower support rod. The second four-bar linkage, consisting of the front support rod and the chassis, forms a linkage that is easy to operate. The size of the seat rod does not affect the folding process, and a larger seat rod can be selected for better comfort. The height of the seat rod when unfolded can be changed by adjusting the length of each link in the two four-bar linkages, providing good adaptability. The chassis does not participate in the folding process, and the wheel assembly does not move, ensuring good safety. By arranging the lower front support rod and the rear support rod in sequence with the upper front support rod and the extension in the left-right direction, when the backrest rod flips backward to unfold the seat assembly, the linkage can cause the lower front support rod to press against the rear support rod and / or the seat rod to form support, preventing the backrest rod from continuing to flip backward, achieving one-way self-locking, good stability, and a simple structure. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of a preferred embodiment of the present invention.

[0016] Figure 2 , Figure 3 , Figure 4 yes Figure 1 A left-view diagram, in which, Figure 2 In the unfolded state, Figure 4 It is in a folded state. Figure 3 It is in an intermediate state during the unfolding and folding transformation process.

[0017] Wherein: 10. Chassis; 11. Wheel assembly; 12. Connecting seat; 20. Seat assembly; 21. Seat rod; 22. Backrest rod; 221. Extension; 23. Armrest rod; 30. Support assembly; 31. Upper front support rod; 32. Lower front support rod; 33. Rear support rod; 34. First four-bar linkage; 35. Second four-bar linkage. Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0019] The front-back, left-right, and up-down directions described in this invention are based on the front-back, left-right, and up-down directions as observed by a passenger while riding in the foldable wheelchair provided by this invention.

[0020] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0021] like Figures 1 to 4As shown, the foldable wheelchair provided by the present invention includes: a chassis 10, a seat assembly 20, and a support assembly 30. The chassis 10 has a frame structure, and its projection in the vertical direction is U-shaped. A wheel assembly 11 is connected to the bottom of the chassis 10. Four wheel assemblies 11 are connected to the four corners of the bottom of the chassis 10, and each wheel assembly 11 includes an electric wheel assembly for electric drive. The seat assembly 20 includes a seat post 21 and a backrest post 22. The seat post 21 is located above the chassis 10, and the lower end of the backrest post 22 is rotatably connected to the rear end of the seat post 21. The lower end of the backrest post 22 is connected to the seat post 21. The seat post 21 extends downwards from its rotatable connection to form an extension 221; the support assembly 30 includes an upper front support rod 31, a lower front support rod 32, and a rear support rod 33. The upper end of the upper front support rod 31 is rotatably connected to the middle of the seat post 21, the lower end of the upper front support rod 31 is rotatably connected to the middle of the lower front support rod 32, the upper end of the lower front support rod 32 is rotatably connected to the middle of the extension 221, the lower end of the lower front support rod 32 is rotatably connected to the front of the chassis 10, the upper end of the rear support rod 33 is rotatably connected to the lower end of the extension 221, and the lower end of the rear support rod 33 is rotatably connected to the rear end of the chassis 10, thereby connecting the seat post 21 to the rear of the seat post 21. Two four-bar linkages are formed between the seat assembly 20 and the chassis 10. These two four-bar linkages are a first four-bar linkage 34 consisting of an extension 221, a seat rod 21, an upper front support rod 31, and a lower front support rod 32, and a second four-bar linkage 35 consisting of a rear support rod 33, an extension 221, a lower front support rod 32, and the chassis 10. Since these two four-bar linkages share the lower front support rod 32 and the extension 221, they can be linked together to simultaneously realize the folding of the seat assembly 20 and the lowering of the seat rod 21. This makes operation convenient. During the folding process of the seat assembly 20, the seat rod 21 is in a flat position. The downward movement of the seat post 21 does not interfere with the folding process. In other words, the size of the seat post 21 does not affect the folding process. A larger seat post 21 can be selected to improve the comfort of riding. Furthermore, by adjusting the length and connection position of each link in the two four-bar linkages (such as the connection position between the front support rod 32 and the extension 221), the height of the seat post 21 when unfolded can be changed to adapt to different user needs, thus providing good adaptability. The chassis 10 does not move during the folding process and does not participate in the folding. The relative position of the wheel assembly 11 does not change, so there is no risk of crushing or squeezing people's feet, resulting in better safety.The lower front support rod 32 and the rear support rod 33 are located on the first plane, while the upper front support rod 31 and the extension 221 are located on the second plane. The first and second planes are arranged sequentially in the left-right direction. When the backrest rod 22 flips backward to unfold the seat assembly 20, the lower front support rod 32 can also be linked to the rear support rod 33 to form support, preventing the backrest rod 22 from continuing to flip backward, thus achieving one-way self-locking. After unfolding, the user only needs to sit on the backrest rod and press it backward to lock it, without the need for an additional locking mechanism, making the structure simpler. Of course, to ensure safety, common safety mechanisms can also be set in the two four-bar linkages to ensure that the rods cannot rotate relative to each other when unfolded. When the backrest rod 22 flips forward to fold the seat assembly 20, the backrest rod 22, seat rod 21, lower front support rod 32, and rear support rod 33 can be linked to move towards the chassis 10 in sequence and fold together, with the upper front support rod 31 and lower front support rod 32 folding together alternately, resulting in a better folding effect and less space occupation after folding.

[0022] In this embodiment, to facilitate the user to lean back against the backrest 22, when the seat assembly 20 is unfolded, the backrest 22 extends backward and upward at an angle of 10° with the vertical direction. Of course, the size of this angle can also be changed by adjusting the length and connection position of each link in the two four-bar linkages. To prevent discomfort and overturning hazards caused by excessive backward leaning, in this invention, the adjustment range of this angle is preferably 10-20°.

[0023] To further enhance stability in the unfolded state, in this embodiment, when the seat assembly 20 is unfolded, the lower front support rod 32 is perpendicular to the rear support rod 33, so that the lower front support rod 32, the chassis 10, and the rear support rod 33 form a stable right-angled triangle structure. The part where the lower front support rod 32 is rotatably connected to the extension 221 is located above and behind the part where the lower front support rod 32 and the rear support rod 33 abut. Due to the limitation of the angle between the backrest rod 22 and the vertical direction, the distance between the rotatable connection part and the abutment part is relatively short, so that the torque radius of the force of the backrest rod 22 flipping backward on the abutment part is relatively short, thereby improving the stability during support.

[0024] To further enhance the comfort of riding and improve the advanced features of the foldable wheelchair, in this embodiment, when the seat assembly 20 is unfolded, the seat pole 21 is at a 5° angle to the horizontal plane with the front higher than the back. The seat pole 21 is also parallel to the chassis 10. In other words, the chassis 10 is in an inclined state with the front higher than the back. This state can be achieved by adjusting the rotation radius of the wheel assembly 11 and the connection position between the wheel assembly 11 axle and the chassis 10.

[0025] To further enhance riding comfort, a rotatable armrest 23 is connected to the middle of the backrest bar 22. The armrest 23 can be configured with a locking function using existing technology.

[0026] To facilitate connection, the chassis 10 is also provided with a connecting seat 12 for rotatably connecting the lower front support rod 32 and the rear support rod 33. The connecting seat 12 protrudes upward and is located on the outer side of the first plane to avoid interference with the movement of the two four-bar linkages.

[0027] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. Foldable wheelchair, including: A chassis with wheel assemblies attached to the bottom; A seat assembly including a seat post and a backrest post, the seat post being located above the chassis, the backrest post being rotatably connected to the seat post, and the backrest post extending downward from the rotatable connection between the backrest post and the seat post to form an extension; The support assembly includes an upper front strut, a lower front strut, and a rear strut. The upper end of the upper front strut is rotatably connected to the middle of the seat rod, the lower end of the upper front strut is rotatably connected to the middle of the lower front strut, the upper end of the lower front strut is rotatably connected to the middle of the extension, the lower end of the lower front strut is rotatably connected to the front of the chassis, the upper end of the rear strut is rotatably connected to the lower end of the extension, and the lower end of the rear strut is rotatably connected to the rear end of the chassis. This allows the first four-bar linkage mechanism consisting of the extension, seat rod, upper front strut, and lower front strut to be linked with the second four-bar linkage mechanism consisting of the rear strut, extension, lower front strut, and chassis. Its features are: The lower front strut and the rear strut are located on the first plane, and the upper front strut and the extension are located on the second plane. The first plane and the second plane are arranged sequentially in the left-right direction. The extension direction of the extension coincides with the axial direction of the backrest rod. The upper end of the rear support rod extends beyond the rotatable connection between the rear support rod and the extension. When the seat assembly is unfolded, the backrest rod extends backward and upward at an angle of 10-20° with the vertical direction. The lower front support rod is perpendicular to the upper front support rod, and the upper end of the rear support rod abuts perpendicularly to the lower front support rod. This abutment is located in front of and below the rotatable connection between the rear support rod and the extension, forming a stable right-angled triangular structure with the lower front support rod, chassis, and rear support rod. The rotatable connection between the rear support rod and the extension, and the vertical abutment between the upper end of the rear support rod and the lower front support rod are all on the same straight line. This results in a short radius of torque when the force of the backrest rod flipping backward acts on the vertical abutment between the lower front support rod and the rear support rod, thereby improving stability during support.

2. The foldable wheelchair according to claim 1, characterized in that: When the seat assembly is deployed, the seat post is higher in the front and lower in the back, and is parallel to the chassis.

3. The foldable wheelchair according to claim 1, characterized in that: The chassis is provided with a connecting seat for rotatably connecting the lower front support rod and the rear support rod.

4. The foldable wheelchair according to claim 3, characterized in that: The connector is located outside the first plane.

5. The foldable wheelchair according to claim 1, characterized in that: A rotatable armrest is connected to the middle of the backrest bar.

6. The foldable wheelchair according to any one of claims 1 to 5, characterized in that: The chassis has a frame structure, and the vertical projection of the chassis is square. The wheel assembly is connected to the four corners of the bottom of the chassis.

7. The foldable wheelchair according to claim 6, characterized in that: The wheel assembly includes an electric wheel assembly.

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