Wheel-track combined type stair climbing wheelchair

Abstract

The utility model discloses a wheel-track combined type stair-climbing wheelchair, which belongs to the technical field of stair-climbing wheelchairs and comprises a wheelchair body, a controller, a walking stair-climbing device and a seat adjusting device, the walking stair-climbing device comprises a wheel type mechanism, a track mechanism and a switching mechanism, and the wheel type mechanism comprises small front wheels and large rear wheels; the crawler belt mechanism comprises a crawler belt located at the bottom of the wheelchair body, driving wheels, thrust wheels and guide wheels; the switching mechanism comprises an electric push rod I and a parallelogram mechanism. On the premise of meeting the basic requirements of the stair climbing wheelchair, the experience of plane driving is improved, and the use comfort of a wheelchair user is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of stair-climbing wheelchairs, and particularly relates to a wheel-track composite stair-climbing wheelchair. Background Art

[0002] At present, there are many people who have lost their normal walking ability due to congenital disabilities, sports injuries, aging or other reasons. For these people with limited mobility, stairs have become an insurmountable obstacle, and they often need to rely on the help of others to complete the task of going up and down stairs. However, this dependence not only limits their personal independence but also restricts their development in areas such as family, education, and occupation.

[0003] Therefore, the technology of stair-climbing wheelchairs has emerged. A stair-climbing wheelchair is an innovative assistive tool that enables people with limited mobility to move freely up and down stairs by combining a traditional wheelchair and a vertical movement mechanism. This technology provides a new option for people with limited mobility, enabling them to better integrate into social life.

[0004] Based on the comprehensive analysis of various existing stair-climbing wheelchairs, each has its unique advantages and disadvantages.

[0005] The caterpillar-track type stair-climbing wheelchair has strong step adaptability and stability, and provides good comfort. However, it has a large walking resistance, a relatively heavy overall weight, requires a high-power motor, and may cause damage to the steps during use.

[0006] The walking type stair-climbing wheelchair also has excellent step adaptability, but its stability is poor, the center of gravity changes greatly, and its structure and control principle are relatively complex.

[0007] In contrast, the wheel-group type stair-climbing wheelchair is relatively simple in control and structure. However, the radius of its wheel group needs to be customized according to the step size, so it is usually only applicable to steps of specific sizes, and its step adaptability is weak and the stability is average.

[0008] The backrest wheel-track composite stair-climbing wheelchair is applicable to steps of various sizes. Four wheels are used for planar travel, and when climbing stairs, it relies on the caterpillar track on the back of the wheelchair to crawl. Although it meets the stair-climbing requirements, it sacrifices a part of the planar travel ability. Because its rear wheels are small, it is easy to jolt up and down when passing obstacles during planar travel. Also because of the small size of the rear wheels, when turning is required at the stair conversion, the helper will feel that it is relatively heavy to turn the wheelchair, and the small size design of the rear wheels is difficult to ensure the comfort of the wheelchair user. Content of the Utility Model

[0009] In view of the above deficiencies of the prior art, the present utility model provides a wheel-track composite stair-climbing wheelchair; on the premise of meeting the basic requirements of a stair-climbing wheelchair, the wheel-track composite stair-climbing wheelchair improves the experience of planar travel and ensures the comfort of wheelchair users.

[0010] To solve the above technical problems, a wheel-track composite stair-climbing wheelchair provided by the present utility model includes a wheelchair body, a controller, a walking and stair-climbing device, and a seat adjusting device. The walking and stair-climbing device includes a wheel mechanism, a crawler mechanism, and a switching mechanism. The wheel mechanism includes a small front wheel and a large rear wheel; the crawler mechanism includes a crawler located at the bottom of the wheelchair body, a driving wheel, a supporting wheel, and a guiding wheel; the switching mechanism includes an electric push rod I and a parallelogram mechanism.

[0011] In a further improvement of the present utility model, a front rod and a front triangular connecting rod are provided at the front bottom of the parallelogram mechanism. The front rod is connected to the small front wheel, and the front triangular connecting rod is connected to the driving wheel; a rear rod and a rear triangular connecting rod are provided at the rear bottom of the parallelogram mechanism. The rear rod is connected to the large rear wheel, and the rear triangular connecting rod is connected to the guiding wheel; the push rod of the electric push rod I is connected to the rear rod.

[0012] Through the above design, this solution can more conveniently switch between the wheel mechanism and the crawler mechanism.

[0013] In a further improvement of the present utility model, the front rod is an integrally extended rod downward from the front side rod of the parallelogram mechanism, and the front rod is rotationally connected to the axle of the small front wheel.

[0014] Through the above design, this solution can more conveniently switch the small front wheel.

[0015] In a further improvement of the present utility model, the rear rod is an integrally extended rod downward from the rear side rod of the parallelogram mechanism, and the rear rod is rotationally connected to the axle of the large rear wheel.

[0016] Through the above design, this solution can more conveniently switch the large rear wheel.

[0017] In a further improvement of the present utility model, the seat adjusting device adopts a fixed-angle seat adjusting mechanism. The fixed-angle seat adjusting mechanism includes an adjusting rod, a locking mechanism, and an angle scale mechanism.

[0018] Through the above design, this solution can more conveniently adjust the seat angle.

[0019] In a further improvement of the present utility model, the seat adjusting device adopts an inclination sensing type seat adjusting mechanism. The inclination sensing type seat adjusting mechanism includes an inclination sensor, an electric push rod II, and an adjusting rod.

[0020] Through the above design, this solution can more conveniently adjust the seat angle.

[0021] Compared with the prior art, the utility model has the following beneficial effects:

[0022] On the premise of meeting the basic requirements of a stair-climbing wheelchair, the utility model improves the experience of traveling on a flat surface and ensures the comfort of wheelchair users. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the background art or the technical solution of the present utility model, the attached drawings used in the prior art or the specific embodiments are briefly introduced below; obviously, the structures, ratios, sizes, etc. shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present utility model. Therefore, they do not have technical substance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present utility model can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model.

[0024] Figure 1 It is a schematic structural diagram of the specific embodiment of the present utility model.

[0025] Figure 2 It is a schematic structural diagram of the wheel mechanism of the specific embodiment of the present utility model.

[0026] Figure 3 It is a schematic structural diagram of the crawler mechanism of the specific embodiment of the present utility model.

[0027] Figure 4 It is a schematic diagram of the seat adjustment of the specific embodiment of the present utility model.

[0028] Figure 5 It is a schematic structural diagram of the inclination angle sensing type seat adjustment mechanism of the specific embodiment of the present utility model.

[0029] As shown in the figure: 1, small front wheel; 2, large rear wheel; 3, crawler; 4, drive wheel; 5, idler wheel; 6, guide wheel; 7, electric push rod I; 8, parallelogram mechanism; 9, front rod; 10, front triangular link; 11, rear rod; 12, rear triangular link; 13, electric push rod II; 14, inclination angle sensor. SPECIFIC EMBODIMENTS

[0030] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative work should fall within the scope of protection of the present invention.

[0031] At the same time, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like cited in this specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0032] At the same time, in the description of this specification, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood by specific circumstances.

[0033] According to a comprehensive analysis of various existing stair climbing wheelchairs, each of them has its own unique advantages and disadvantages.

[0034] Therefore, the design concept of this application is to redesign the wheel-track composite stair-climbing wheelchair, and to design it based on the defects of the wheel-track composite stair-climbing wheelchair. On the premise of meeting the basic needs of the stair-climbing wheelchair, it improves the experience of flat driving and ensures the comfort of the wheelchair user.

[0035] As shown in Figures 1-5, the present application provides a wheel-and-track composite stair-climbing wheelchair, comprising a wheelchair body, a controller, a walking and climbing device, and a seat adjustment device. The walking and climbing device comprises a wheel mechanism, a track mechanism, and a switching mechanism. The wheel mechanism comprises a small front wheel 1 and a large rear wheel 2; the track mechanism comprises a track 3, a driving wheel 4, a supporting wheel 5, and a guide wheel 6 located at the bottom of the wheelchair body; the switching mechanism comprises an electric push rod Ⅰ7 and a parallelogram mechanism 8 arranged on the wheelchair body, and the parallelogram mechanism 8 is respectively connected to the wheel mechanism and the track mechanism.

[0036] Among them, a front rod 9 and a front triangular connecting rod 10 are arranged at the front bottom of the parallelogram mechanism 8. The front rod 9 is rotationally connected to the small front wheel 1, and the front triangular connecting rod 10 is connected to the driving wheel 4. A rear rod 11 and a rear triangular connecting rod 12 are arranged at the rear bottom of the parallelogram mechanism 8. The rear rod 11 is rotationally connected to the large rear wheel 2, and the rear triangular connecting rod 12 is connected to the guiding wheel 6. The push rod of the electric push rod I 7 is rotationally connected to the rear rod 11.

[0037] Among them, the front rod 9 is an integrally extended rod downward from the front side rod of the parallelogram mechanism 8, and the front rod 9 is rotationally connected to the axle of the small front wheel 1. The rear rod 11 is an integrally extended rod downward from the rear side rod of the parallelogram mechanism 8, and the rear rod 11 is rotationally connected to the axle of the large rear wheel 2.

[0038] During use, the electric push rod I 7 extends, pushing the rear rod 11 to rotate clockwise. The rear triangular connecting rod 12 descends as the rear rod 11 rotates. The front rod 9 rotates clockwise as the rear rod 11 rotates clockwise. The front triangular connecting rod 10 descends as the front rod 9 rotates. The whole crawler mechanism descends to contact the ground, and the wheeled mechanism is lifted. The electric push rod I 7 retracts, pushing the rear rod 11 to rotate counterclockwise. The rear triangular connecting rod 12 rises as the rear rod 11 rotates. The front rod 9 rotates counterclockwise as the rear rod 11 rotates counterclockwise. The front triangular connecting rod 10 rises as the front rod 9 rotates. The whole crawler mechanism rises, and the wheeled mechanism descends to contact the ground.

[0039] Among them, the seat adjusting device adopts a fixed-angle seat adjusting mechanism, and the fixed-angle seat adjusting mechanism includes an adjusting rod, a locking mechanism and an angle scale mechanism.

[0040] Among them, the seat adjusting device adopts an inclination sensing type seat adjusting mechanism, and the inclination sensing type seat adjusting mechanism includes an inclination sensor 14, an electric push rod II 13 and an adjusting rod.

[0041] The specific design points of this application are as follows:

[0042] (1) The wheelchair has two functions: climbing stairs and traveling on a flat surface. The power system of the wheelchair should be simple in structure and high in efficiency, and the safety and stability should be ensured during the stair climbing process.

[0043] (2) When the stair climbing wheelchair is used as a conventional wheelchair to walk on the ground, it should meet the national standard parameters of the wheelchair, that is, the wheelchair size, traveling speed, etc. need to meet the national requirements.

[0044] (3) The seat of the wheelchair should have an adjusting function so that the occupant can still maintain a horizontal position when using the wheelchair to climb stairs, and the occupant can maintain a horizontal position whether on a flat surface or during stair climbing.

[0045] (4) The size of the wheelchair's rear wheels should be as large as possible to improve the user's comfort.

[0046] like Figure 2 The wheel mechanism shown in the figure, during the movement of the wheelchair, the larger diameter rear wheel can provide a larger contact area and increase the stability of the wheelchair, which is particularly useful for traveling on bumpy roads. The larger rear wheel can more easily overcome small obstacles, such as door sills, uneven roads or slopes. The large-diameter wheelchair rear wheels have stronger rotation capabilities and can more easily pass these obstacles. The pushing force of the large-diameter rear wheels is more effective than that of the small-diameter wheels, because each time the larger wheels rotate, each pushing action will bring a greater moving distance, which can reduce the force required to push the wheelchair. Since the larger rear wheels can provide a greater moving distance per rotation, this also allows them to help the wheelchair reach a higher speed. The larger rear wheels can also help the assistant turn more easily at the turning mouth of the stairs during the climbing process.

[0047] The climbing mechanism is composed of a left-right symmetrical crawler mechanism, such as Figure 3 Shown is a simplified view of the crawler mechanism, which consists of crawler tracks, drive wheels, guide wheels, supporting wheels and other parts.

[0048] The track mechanism has strong climbing ability and can better climb stairs and overcome uneven ground by dispersing weight and providing a larger contact area; the track mechanism has high stability and can provide better stability, reduce shaking and swaying during climbing, and improve the safety and comfort of users when using wheelchairs; the track mechanism has good traction and can provide better propulsion ability on uneven surfaces, which is very useful for overcoming slopes, climbing stairs or traversing uneven terrain; the track mechanism is highly adaptable and suitable for different environments and scenarios.

[0049] The drive wheels can provide traction. The drive wheels are driven by a motor and drive the movement of the wheelchair by rotating the drive tracks. They provide the necessary traction to move the wheelchair up or down to overcome vertical or inclined surfaces such as stairs or ramps. The drive wheels provide stability and maneuverability for the wheelchair through their motion control and power transmission. When climbing stairs, the rotation and traction distribution of the drive wheels help maintain the balance and stability of the wheelchair. The drive wheels provide power, traction and stability, enabling the wheelchair to climb stairs or travel on inclined surfaces. Placing the drive wheels at the rear of the climbing direction of the stair-climbing wheelchair helps to keep the center of gravity of the stair-climbing wheelchair stable. When the wheelchair climbs stairs or inclined surfaces, the center of gravity will tilt backwards, which can avoid being too heavy at the front and reduce the risk of tipping over. The rear drive wheels provide better traction and stability when climbing stairs. By placing the drive wheels at the rear, when the center of gravity is tilted, the drive wheels can better contact the ground, provide greater traction, and thus climb stairs more efficiently.

[0050] The guide wheels help determine the traveling direction of the wheelchair. They are located at the front of the crawler system. By rotating or steering the guide wheels, the user can control the steering and traveling direction of the stair-climbing wheelchair. The position and angle of the guide wheels are crucial for the stability and balance of the stair-climbing wheelchair. They help maintain the balance of the wheelchair and prevent tipping or imbalance during travel. The correct adjustment and position of the guide wheels can provide better stability and make it easier for the user to control the wheelchair.

[0051] The idler wheels are used to share the weight load of the wheelchair and the user. They support and disperse the weight of the wheelchair by contacting the ground or stairs, reducing the load on the crawler and the drive wheels, thereby protecting the durability and lifespan of the entire crawler system. The idler wheels play an important role in the stability and balance of the stair-climbing wheelchair. Their correct position and adjustment can help maintain the balance of the wheelchair and prevent tipping or imbalance during travel. By supporting and stabilizing the weight of the wheelchair, the idler wheels provide additional stability and make it easier for the user to control the wheelchair. The idler wheels also help reduce the vibration and shock of the crawler system and the wheelchair during travel. They absorb and disperse the vibration on the ground or stairs, reducing the discomfort and shock to the wheelchair and the user, which provides a smoother and more comfortable traveling experience.

[0052] To ensure that the crawler maintains a stable climbing speed and effective anti-slip ability during stair climbing, the crawler should be in contact with at least two or more steps at any time when climbing the stairs. After comprehensive consideration, it is decided to select a step height of 170 mm and a step width of 295 mm as the step numerical standard for the design of this stair-climbing wheelchair. According to the calculation, the length of the crawler should be no less than 680 mm. To increase stability and traction, and also to achieve the purpose of anti-slip and reducing step damage, a crawler made of rubber material is selected. The drive wheel of the crawler is installed coaxially with the output shaft of the motor and has a diameter of 150 mm. The guide wheels are connected to the chassis of the wheelchair through triangular connecting plates.

[0053] Due to the increase in the diameter of the rear wheels, the traditional backrest-crawler design cannot meet the space required for the rear wheels when climbing the stairs, as Figure 1 shown. Changing the crawler from the backrest type to the under-seat type and adding a wheel-crawler switching mechanism can solve the problem of the space occupied by the rear wheels.

[0054] By connecting the electric push rod I and the parallelogram mechanism, the connection with the wheel-track switching mechanism of the stair-climbing wheelchair is realized. This mechanism controls the lifting and lowering of the front and rear wheels by switching the telescoping of the electric push rod. When the front and rear wheels on both sides rise, the track mechanism gradually contacts the ground, achieving the purpose of switching to the stair-climbing mode; conversely, when the front and rear wheels descend and contact the ground, the track mechanism rises and leaves the ground, thus switching to the planar driving mode. This design enables the stair-climbing wheelchair to freely switch between the two motion modes according to different usage environments.

[0055] This stair-climbing wheelchair uses an under-seat track, and its motion mode is backward stair-climbing. From the perspective of the occupant, during the stair-climbing process, the stair-climbing direction is opposite to the direction the occupant is facing. If the seat position cannot be adjusted, it may cause the occupant to lose balance and be prone to tipping during the stair-climbing process. In order to keep the occupant stable in the horizontal position, a seat adjustment mechanism needs to be added.

[0056] The following are two common seat adjustment schemes

[0057] Fixed-angle seat adjustment mechanism. This adjustment mechanism relies on a fixed-angle seat adjuster, which usually includes an adjustment rod, a locking device, angle scales, etc. The adjustment rod is a rod-shaped device that can be rotated or moved to change the angle of the seat. By turning or pushing and pulling the adjustment rod, the user can adjust the seat to the fixed angle they need. The locking device is used to lock the seat in the selected angle position to ensure that the seat remains stable. Once the user finds the appropriate angle, they can use the locking device to fix the seat in this position to prevent it from moving accidentally. The angle scales are used to indicate the current angle position of the seat, which enables the user to accurately adjust the seat to a specific angle or restore it to a specific angle position when needed. It should be noted that fixed-angle seat adjusters usually only provide a limited adjustment range and cannot achieve continuous angle adjustment. The seat adjustment schematic diagram is as Figure 4 shown.

[0058] Inclination-sensing seat adjustment mechanism. This seat angle adjuster realizes precise and convenient seat angle adjustment by using an inclination sensor and an electric push rod (as Figure 5 shown). The inclination sensor is a device that can measure the current tilt angle of the seat. It is usually installed at key positions of the seat and provides accurate feedback data by detecting the tilt angle of the seat. The electric adjustment push rod is an electric device that adjusts the seat angle by pushing or pulling the adjustment rod of the seat. With the help of the electric mechanism, the user can precisely control the forward tilt, backward tilt, or other angle adjustments of the seat by pressing a button or the control panel.

[0059] A seat angle adjuster with an inclination sensor and an electric adjustment push rod is usually equipped with a control system for receiving feedback data from the inclination sensor and controlling the movement of the electric push rod. The control system can be a button, a touch screen, or integrated with other control systems of the device. Some advanced seat angle adjusters also have an automatic adjustment function. Through the inclination sensor and the control system, the seat can automatically adjust to the optimal angle position according to the user's weight, height, and posture to provide maximum comfort and support. The inclination sensor-based seat adjustment mechanism provides precise, convenient, and highly personalized seat adjustment functions. They can help users find the best seat angle and provide good comfort. It is worth noting that this adjustment mechanism is more expensive than traditional adjustment mechanisms.

[0060] The prices and comfort levels of the two seat adjustment mechanisms are different, and users can choose the required technical solutions according to their own situations.

[0061] The stair-climbing wheelchair designed in this application is equipped with a pair of large rear wheels for rolling smoothly on flat ground and providing basic mobility. The track mechanisms are located on both sides of the wheelchair and are made of strong materials with strong grip, wear resistance, and anti-slip properties, enabling the wheelchair to travel smoothly on stairs. To provide power, the wheelchair is equipped with an electric drive system that is powered by a battery and drives the track system through a motor. Users can manipulate the up-and-down movement of the stair-climbing wheelchair through control buttons. To ensure the safety of users, the stair-climbing wheelchair is usually equipped with a variety of safety protection devices, including seat belts, anti-tipping systems, and emergency braking devices, to ensure that users are fully protected during use. The wheel-track combined stair-climbing wheelchair provides greater flexibility and reliability by combining wheels and tracks, enabling users to overcome obstacles such as stairs and uneven ground. This design makes the stair-climbing wheelchair suitable for various environments and terrains, providing users with more freedom and independence.

[0062] By analyzing the development status, comparing the advantages and disadvantages of various types of stair-climbing wheelchairs, and improving the common track-type stair-climbing wheelchair, this paper designs a wheel-track composite multi-functional stair-climbing wheelchair. The designed stair-climbing wheelchair improves the problem of the relatively weak flat-ground driving ability of traditional stair-climbing wheelchairs and ensures the safety and reliability during the stair-climbing process. The stair-climbing wheelchair designed this time has the following characteristics:

[0063] (1) In this stair-climbing wheelchair, the diameter of the main driving wheels (rear wheels) in the flat-ground driving mechanism is relatively large, which increases the experience during flat-ground driving and improves the comfort of users when encountering road bumps.

[0064] (2)The main body of this stair-climbing wheelchair is a wheel-track combined structure. However, different from the common backrest-track type in the market, the track of the stair-climbing wheelchair designed in this project is located under the seat of the wheelchair. During the stair-climbing process, it no longer relies on tilting the backrest part for climbing, but instead uses the wheel-track switching structure under the wheelchair seat to switch between the flat-ground mode and the stair-climbing mode.

[0065] Although the present utility model has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present utility model is not limited thereto. Without departing from the spirit and essence of the present utility model, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present utility model, and all such modifications or substitutions should be within the scope of the present utility model. / Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims

1. A wheel-track composite stair climbing wheelchair, comprising a wheelchair body, a controller, a walking stair climbing device and a seat adjustment device, characterized in that: The walking and stair climbing device includes a wheel mechanism, a track mechanism and a switching mechanism. The wheel mechanism includes a small front wheel and a large rear wheel; the track mechanism includes a track located at the bottom of the wheelchair body, a driving wheel, a supporting wheel and a guide wheel; the switching mechanism includes an electric push rod I and a parallelogram mechanism.

2. The wheel-track composite stair climbing wheelchair according to claim 1, characterized in that: The front bottom of the parallelogram mechanism is provided with a front rod and a front triangular connecting rod, the front rod is rotatably connected to the small front wheel, and the front triangular connecting rod is connected to the driving wheel; the rear bottom of the parallelogram mechanism is provided with a rear rod and a rear triangular connecting rod, the rear rod is rotatably connected to the large rear wheel, and the rear triangular connecting rod is connected to the guide wheel; the push rod of the electric push rod I is rotatably connected to the rear rod.

3. The wheel-track composite stair climbing wheelchair according to claim 2, characterized in that: The front rod is an integrally extended rod extending downward from the front side rod of the parallelogram mechanism, and the front rod is rotatably connected to the wheel axle of the small front wheel.

4. The wheel-track composite stair climbing wheelchair according to claim 2, characterized in that: The rear rod is an integrally extended rod extending downward from the rear side rod of the parallelogram mechanism, and the rear rod is rotatably connected to the wheel axle of the large rear wheel.

5. The wheel-track composite stair climbing wheelchair according to claim 1, characterized in that: The seat adjustment device adopts a fixed-angle seat adjustment mechanism, which includes an adjustment rod, a locking mechanism and an angle scale mechanism.

6. The wheel-track composite stair climbing wheelchair according to claim 1, characterized in that: The seat adjustment device adopts a tilt-sensing seat adjustment mechanism, which includes a tilt sensor, an electric push rod II and an adjustment rod.

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