Wheelchair chassis wheel retracting and releasing mechanism for welfare seat

Abstract

The utility model discloses a wheel retracting and releasing mechanism of a wheelchair chassis for a welfare seat, and belongs to the technical field of vehicle welfare seats. According to the wheel folding and unfolding mechanism, a traditional complex wheelchair chassis structure is optimized, when the wheels are folded and unfolded, only the lead screws on the two sides need to be driven by the motor to rotate, then the front wheel connecting rod and the rear wheel connecting rod are driven to move, and the front wheels and the rear wheels can be driven to be unfolded or folded; meanwhile, through the scientific design of the shape of the connecting rod, after the front wheel and the rear wheel move in place, the connecting rod can play a role in supporting or limiting and fixing the wheels, and the stability of the wheels during unfolding and folding is guaranteed; meanwhile, due to the design of a pull wire, after the rear wheel is unfolded, self-locking of the rear wheel supporting rod can be achieved, the stability of the unfolded wheel is guaranteed, meanwhile, when the wheel is folded, the function of assisting the rear wheel to be folded can be achieved, and in addition, due to the auxiliary function of an air spring, the action of folding and unfolding the wheel is more stable and smoother; and the stability of overall movement is guaranteed, design is scientific and reasonable, and practicability is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to a vehicle welfare seat technical field, concretely is a welfare seat wheel chair chassis folding wheel mechanism. BACKGROUND

[0002] The welfare seat is mainly applied to the business car, and the base has the functions of rotating and lifting, so that the welfare seat can cooperate with the wheel chair, facilitates the getting on and off of some special groups such as the old and the disabled, and avoids the problem of manual wheel chair carrying.

[0003] When the detachable welfare seat is used, the passenger is lifted into the car by the wheel chair lift, and the wheel chair is fixed to the car by the wheel chair fixing device. When the detachable welfare seat is used, the folding wheel function of the wheel chair needs to be considered, that is, the wheels need to be folded after entering the car, and the wheels need to be unfolded after leaving the car. However, the current wheel chair folding wheel structure is complex and cumbersome, the processing cost is high, and the failure rate is high.

[0004] Therefore, we design a wheel chair chassis folding wheel mechanism for the welfare seat. The mechanism greatly optimizes the folding wheel structure of the wheel chair chassis. By controlling the lead screw to drive the connecting rod to move, the folding and unfolding of the wheels can be easily realized. With the cooperation of the pull wire, the wheels can be locked after folding, and the function of assisting the folding of the wheels is realized. Through the scientific design of the connecting rod, the connecting rod can support the wheels after folding, ensuring that the support rod is evenly stressed, without the need for additional complex locking and supporting devices. The chassis structure is simplified, and the failure rate is effectively reduced. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a wheel chair chassis folding wheel mechanism for a welfare seat to solve the problems in the above background technology.

[0006] To achieve the above purpose, the utility model provides the following technical scheme:

[0007] A wheel chair chassis folding wheel mechanism for a welfare seat, comprising a chassis frame, a front wheel and a rear wheel, a front wheel support rod and a rear wheel support rod are arranged on the front wheel and the rear wheel respectively, the front wheel support rod and the rear wheel support rod are rotatably connected to the chassis frame through a front wheel support shaft and a rear wheel support shaft, and the wheel chair chassis folding wheel mechanism further comprises

[0008] A front wheel connecting rod, one end of which is rotatably connected to the front wheel support rod and used for driving the front wheel support rod to rotate;

[0009] A rear wheel connecting rod, one end of which is rotatably connected to the rear wheel support rod and used for driving the rear wheel support rod to rotate;

[0010] The linkage drive mechanism is used to drive the front wheel linkage and the rear wheel linkage to move synchronously, so as to retract or extend the front wheel and the rear wheel at the same time.

[0011] The cable locking mechanism is used to limit and fix the rear wheel support rod on the chassis frame after the rear wheel is deployed;

[0012] The front wheel link and the rear wheel link are equipped with support limiting parts to prevent the front wheel support rod and the rear wheel support rod from automatically retracting after being deployed, and to provide support force for the front wheel and the rear wheel after being deployed.

[0013] As a further preferred embodiment of this utility model: the linkage drive mechanism includes a lead screw rotatably disposed on both sides of the chassis frame, a slider slidably disposed on the chassis frame and threadedly connected to the lead screw, an L-shaped plate rotatably connected to the outside of the slider, the front side of the L-shaped plate rotatably connected to the front wheel connecting rod, the lower end of the L-shaped plate being fixedly connected to the rear wheel connecting rod, and a motor for driving the lead screw to rotate is disposed on the chassis frame.

[0014] As a further preferred embodiment of this utility model: the rear wheel support axle includes an inner fixed shaft that is fixedly connected to the chassis frame, an outer rotating tube that is rotatably fitted outside the inner fixed shaft, and the rear wheel support rod that is fixedly connected to the outer rotating tube.

[0015] As a further preferred embodiment of this utility model: the cable locking mechanism includes a fixed sleeve fixed on the rear wheel support rod, one end of the fixed sleeve is connected to the outer rotating tube, a sliding head is slidably arranged inside the fixed sleeve, one end of the sliding head passes through the fixed sleeve and the outer rotating tube and is inserted into the inner fixed shaft, a spring is arranged between the other end of the sliding head and the fixed sleeve, a cable is connected to the side of the sliding head away from the inner fixed shaft, the cable passes through the fixed sleeve and is connected to the cable adjusting rod, the cable adjusting rod is movably arranged on the chassis frame and is used to pull the cable.

[0016] As a further preferred embodiment of this utility model: the support limiting part includes a front wheel support shaft contact part and a rear wheel support shaft contact part. The front wheel support shaft contact part is located on the front side of the middle part of the front wheel connecting rod and is used to abut against the front wheel support shaft. The rear wheel support shaft contact part is located on the rear side of the rear wheel connecting rod and is used to abut against the rear wheel support shaft.

[0017] As a further preferred embodiment of this utility model: the lower end of the rear wheel connecting rod is provided with a rear wheel support shaft slot corresponding to the rear wheel support shaft. When the rear wheel support rod is retracted, the rear wheel support shaft slot can be locked onto the rear wheel support shaft.

[0018] As a further preferred embodiment of this utility model: the pull wire adjustment rod is rotatably disposed in the middle of the chassis frame, one end of the pull wire adjustment rod is provided with a pull wire connecting plate, and a pull wire guide tube for guiding the pull wire is provided on the chassis frame, with one end of the pull wire passing through the pull wire guide tube and connecting to the pull wire connecting plate.

[0019] As a further preferred embodiment of this utility model: a limiting slot is provided on the front side of the rear wheel connecting rod, and a rear wheel connecting rod limiting plate corresponding to the limiting slot is provided on the side wall of the chassis frame. When the rear wheel support rod is unfolded, the limiting slot is locked onto the rear wheel connecting rod limiting plate.

[0020] As a further preferred embodiment of this utility model: a gas spring is hinged to the front side of the side wall of the chassis frame, and the output end of the gas spring is hinged to the rear wheel connecting rod.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] This wheelchair chassis retraction and extension mechanism for welfare seats optimizes the traditional complex wheelchair chassis structure. When retracting or extending the wheels, a motor drives the lead screws on both sides to rotate, which in turn moves the connecting rods of the front and rear wheels, thus enabling the front and rear wheels to unfold or retract. Simultaneously, through the scientific design of the connecting rod shape, after the front and rear wheels are in position, the connecting rods can support or limit and fix the wheels, ensuring stability during wheel unfolding and retraction. Furthermore, the cable design allows the rear wheel support rod to self-lock after the rear wheel is unfolded, ensuring stability after the wheel is unfolded. It also assists in retracting the rear wheel, and with the assistance of the gas spring, the wheel unfolding and retraction movements are more smooth and fluid, ensuring overall stability. The design is scientifically sound and highly practical. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of the wheelchair chassis retractable wheel mechanism of this utility model when the wheels are deployed. Figure 1 ;

[0024] Figure 2 for Figure 1 Enlarged structural diagram of the L-shaped plate in the middle;

[0025] Figure 3 This is a three-dimensional structural diagram of the wheelchair chassis retractable wheel mechanism of this utility model when the wheels are deployed. Figure 2 ;

[0026] Figure 4 for Figure 3 Enlarged schematic diagram of the structure at the center tie rod;

[0027] Figure 5 for Figure 3 Enlarged schematic diagram of the structure at the middle and rear wheel connecting rod limiting plate;

[0028] Figure 6 This is a three-dimensional structural diagram of the wheelchair chassis retractable wheel mechanism of this utility model when the wheels are deployed. Figure 3 ;

[0029] Figure 7 This is a side view of the wheelchair chassis retractable wheel mechanism of the present invention when the wheels are deployed;

[0030] Figure 8 This is a cross-sectional structural schematic diagram of the fixing sleeve of the wheelchair chassis retractable wheel mechanism of the present utility model for a welfare seat;

[0031] Figure 9 for Figure 8 Enlarged schematic diagram of the structure at the fixed sleeve;

[0032] Figure 10 This is a three-dimensional structural diagram of the wheelchair chassis retracting and extending wheel mechanism of this utility model when the wheels are retracted. Figure 1 ;

[0033] Figure 11 This is a three-dimensional structural diagram of the wheelchair chassis retractable wheel mechanism of this utility model when the wheels are deployed. Figure 2 ;

[0034] Figure 12 for Figure 11 Enlarged schematic diagram of the structure at the bayonet joint of the middle and rear wheel support axles.

[0035] In the diagram: 1. Chassis frame; 2. Cable adjustment rod; 3. Front wheel; 4. Rear wheel; 5. Front wheel support rod; 6. Front wheel support axle; 7. Cable lock head; 8. Cable; 9. Rear wheel support rod; 10. Rear wheel support axle; 11. Rear wheel connecting rod; 12. Rear wheel support axle latch; 13. Front wheel connecting rod; 14. Front wheel support axle contact part; 15. Lead screw; 16. Slider; 17. Motor; 18. Drive shaft; 19. Gear steering box; 20. Gas spring; 21. Cable connecting plate; 22. Cable guide tube; 23. Rear wheel support axle contact part; 24. Sliding head; 25. Fixing groove; 26. Spring; 27. Fixing sleeve; 28. Rear wheel connecting rod limiting plate; 29. ​​Limiting latch; 30. Inner fixed shaft; 31. Outer rotating tube; 32. L-shaped plate. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0037] Please see Figures 1-12This embodiment provides a wheelchair chassis retraction and deployment mechanism for welfare seats, including a chassis frame 1, front wheels 3, and rear wheels 4. Front wheel support rods 5 and rear wheel support rods 9 are respectively provided on the front wheels 3 and rear wheels 4. The front wheels 3 and rear wheels 4 are rotatably connected to the front wheel support rods 5 and 9, which is a conventional design and will not be described in detail. The front wheel support rods 5 and 9 are rotatably connected to the chassis frame 1 via front wheel support shafts 6 and rear wheel support shafts 10, respectively. In practical applications, the retraction and deployment of the front wheels 3 and rear wheels 4 are achieved by the rotation of the front wheel support rods 5 and 9 on the chassis frame 1. The above structure is a conventional design familiar to those skilled in the art and will not be described in detail.

[0038] In this application, to achieve the movement of the front wheel support rod 5 and the rear wheel support rod 9 on the chassis frame 1, a reciprocating front wheel link 13 and a reciprocating rear wheel link 11 are designed. Specifically, the front wheel link 13 and the rear wheel link 11 are arranged on both sides of the chassis frame 1, corresponding to the front and rear wheels. One end of the front wheel link 13 is rotatably connected to the front wheel support rod 5 to drive the front wheel support rod 5 to rotate, and one end of the rear wheel link 11 is rotatably connected to the rear wheel support rod 9 to drive the rear wheel support rod 9 to rotate.

[0039] To achieve the movement of the front wheel link 13 and the rear wheel link 11, a link drive mechanism is provided on the chassis frame 1. This mechanism drives the front wheel link 13 and the rear wheel link 11 to move synchronously, thereby enabling the front wheel 3 and the rear wheel 4 to retract or extend simultaneously. Figure 1 , Figure 2 as well as Figure 6 As shown, it includes lead screws 15 rotatably mounted on both sides of the chassis frame 1, and sliders 16 threadedly connected to the lead screws 15 and slidably mounted on the chassis frame 1. An L-shaped plate 32 is rotatably connected to the outer side of the slider 16. The front side of the L-shaped plate 32 is rotatably connected to the front wheel connecting rod 13, and the lower end of the L-shaped plate 32 is fixedly connected to the rear wheel connecting rod 11. A motor 17 for driving the lead screws 15 to rotate is mounted on the chassis frame 1. It should be noted that the drive of the lead screws 15 should be a conventional design familiar to those skilled in the art. Preferably, in this application, the motor 17 is located on the front side of the chassis frame 1. To simultaneously drive the retraction and unfolding of both wheels, a dual-axis motor is preferably used, with drive shafts 18 connected to both output ends. The transmission between the drive shafts 18 and the lead screws 15 is achieved on the chassis frame 1 via a gearbox 19. The gearbox 19 is a conventional and common structure in the art, readily available through customization, and will not be described in detail here. Those skilled in the art can also achieve the rotation of the lead screws 15 through other conventional designs, which will not be described or limited in this application.

[0040] To ensure stability after the front and rear wheels are deployed, the mechanism is also equipped with a cable locking mechanism. Additionally, support and limiting parts are provided on the front wheel link 13 and the rear wheel link 11.

[0041] The cable locking mechanism is used to limit and fix the rear wheel support rod 9 on the chassis frame 1 after the rear wheel 4 is deployed; specifically, in conjunction with Figure 1 , Figure 3 , Figure 4 , Figure 8 as well as Figure 9 As shown, the rear wheel support axle 10 includes an inner fixed shaft 30 fixedly connected to the chassis frame 1. An outer rotating tube 31 is rotatably fitted outside the inner fixed shaft 30. The rear wheel support rod 9 is fixedly connected to the outer rotating tube 31. The cable locking mechanism includes a fixed sleeve 27 fixed to the rear wheel support rod 9. One end of the fixed sleeve 27 is connected to the outer rotating tube 31. A sliding head 24 is slidably disposed inside the fixed sleeve 27. One end of the sliding head 24 passes through the fixed sleeve 27 and the outer rotating tube 31 and is inserted into the inner fixed shaft 30. That is, a slot corresponding to the sliding head 24 is provided on the inner fixed shaft 30. A spring 26 is provided between the other end of the sliding head 24 and the fixed sleeve 27. A cable 8 is connected to the side of the sliding head 24 away from the inner fixed shaft 30. The cable 8 passes through the fixed sleeve 27 and is connected to the cable adjusting rod 2. The cable adjusting rod 2 is movably disposed on the chassis frame 1 and is used to pull the cable 8. Specifically, refer to Figure 3 as well as Figure 4 The pull cable adjusting rod 2 is rotatably mounted in the middle of the chassis frame 1. One end of the pull cable adjusting rod 2 is equipped with a pull cable connecting plate 21. The chassis frame 1 is equipped with a pull cable guide tube 22 for guiding the pull cable 8. One end of the pull cable 8 passes through the pull cable guide tube 8 and connects to the pull cable connecting plate 21. When the pull cable adjusting rod 2 moves downwards, the pull cable 8 should be in a relaxed state. Figure 8 As shown, the spring 26 should exert force to push the sliding head 24 into the inner fixed shaft 30, so that the outer rotating tube 31 is locked, thus fixing the rear wheel 4 after it is unfolded; conversely, when the drive cable adjusting rod 2 moves upward, the cable 8 tightens, causing the sliding head 24 to leave the inner fixed shaft 30, and the spring 26 is compressed. At this time, the limiting fixation of the outer rotating tube 31 is released, and the lead screw 15 can be driven to rotate, thereby causing the front wheel connecting rod 13 and the rear wheel connecting rod 11 to drive the two support rods to rotate, thus retracting the wheel.

[0042] The support and limiting part is used to prevent the front wheel support rod 5 and the rear wheel support rod 9 from automatically retracting after being deployed, and to provide support for the front wheel 3 and the rear wheel 4 after they are deployed. Specifically, in combination with Figure 1 , Figure 3 as well as Figure 6As shown, the support and limiting part includes a front wheel support shaft contact part 14 and a rear wheel support shaft contact part 23. The front wheel support shaft contact part 14 is located on the front side of the middle part of the front wheel link 13. When the front wheel 3 is unfolded, it abuts against the front wheel support shaft 6. The rear wheel support shaft contact part 23 is located on the rear side of the rear wheel link 11. When the rear wheel 4 is unfolded, it abuts against the rear wheel support shaft 10.

[0043] Considering the stability after the wheels are folded up, such as Figure 1 , Figure 11 as well as Figure 12 As shown, a rear wheel support shaft slot 12 corresponding to the rear wheel support shaft 10 is provided at the lower end of the rear wheel connecting rod 11. When the rear wheel support rod 9 is retracted, the rear wheel support shaft slot 12 can be locked onto the rear wheel support shaft 10.

[0044] Meanwhile, in order to further ensure the stability of the wheels after they are deployed, such as Figures 5-7 As shown, a limiting slot 29 is provided on the front side of the rear wheel link 11, and a rear wheel link limiting plate 28 corresponding to the limiting slot 29 is provided on the side wall of the chassis frame 1. When the rear wheel support rod 9 is unfolded, the limiting slot 29 is engaged with the rear wheel link limiting plate 28. At this time, the rear wheel support shaft contact part 23 on the rear side of the rear wheel link 11 abuts against the rear wheel support shaft 10, and the rear wheel link 11 achieves front and rear positioning. The front wheel support shaft contact part 14 on the front side of the front wheel link 13 abuts against the front wheel support shaft 6. The front wheel link 13 and the rear wheel link 11 are connected by an L-shaped plate 32. Therefore, the stability of the front wheel link 13 and the rear wheel link 11 after the wheel is unfolded is fully guaranteed.

[0045] Meanwhile, to make the linkage move more smoothly and stably during operation, and to reduce effort when retracting the wheel, such as Figure 1 As shown, a gas spring 20 is hinged to the front side of the side wall of the chassis frame 1. The output end of the gas spring 20 is hinged to the rear wheel connecting rod 11. The gas spring 20 is a conventional structure that can be obtained by purchase, and will not be described in detail in this application.

[0046] To enable those skilled in the art to better understand this application, the working principle of the retractable wheel mechanism will be described below:

[0047] Wheel release state: such as Figure 1 , Figure 5 , Figure 6 , Figure 7 as well as Figure 9As shown, the motor 17 drives the lead screw 15 to rotate. After the slider 16 moves to its position, the gas spring 20 also returns to its initial contracted state. At this time, the front wheel connecting rod 13 pushes the front wheel support rod 5 to open, and the front wheel support shaft contact part 14 on the front wheel connecting rod 13 abuts against the front wheel support shaft 6. At the same time, the rear wheel connecting rod 11 drives the rear wheel support rod 9 to open backward by moving forward, so that the rear wheel 4 opens. At this time, the rear wheel support shaft contact part 23 at the tail of the rear wheel connecting rod 11 abuts against the rear wheel support shaft 10, and the front limit latch 29 is locked onto the rear wheel connecting rod limit plate 28. At the same time, the cable adjustment rod 2 and the cable connecting plate 21 are in the lower position, and the cable 8 is in a relatively relaxed state. At this time, under the action of the spring 26, the sliding head 24 is inserted into the inner fixed shaft 30, so that the rear wheel support rod 9 no longer rotates, which is the open state of the front and rear wheels.

[0048] Wheel closing state: such as Figures 10-12 As shown, when retracting the wheel from the extended position, the motor 17 drives the lead screw 15 to move, causing the slider 16 to slide backward. At this time, the cable adjusting rod 2 moves upward under the action of external force, causing the cable connecting plate 21 to tighten the cable 8. The cable 8 then pulls the sliding head 24 to compress the spring 26, causing the sliding head 24 to move away from the inner fixed shaft 30 and contact the limit on the rear wheel support rod 9. Simultaneously, the rear wheel support rod 9 rotates counterclockwise (this direction is towards...). Figure 1 (With the center position as a reference) The force of rotation, combined with the rear wheel linkage 13 moving backward, causes the rear wheel support rod 9 to rotate in the opposite direction, i.e., retract. At the same time, the front wheel linkage 13 pulls the front wheel support rod 5 inward, realizing the retraction of the front and rear wheels. After retraction, the rear wheel support shaft latch 12 on the rear wheel linkage 9 is just locked onto the rear wheel support shaft 10, realizing the limiting and fixing of the linkage after retraction.

[0049] It should be noted that in practical applications, in order to achieve folding and collapsing, gaps should be provided between various components such as the connecting rod and the gas spring 20, and the position design of the rotation point between the connecting rod and the support rod are all conventional designs familiar to those skilled in the art, and this application will not elaborate on or limit them further. Meanwhile, the up-and-down adjustment of the cable adjustment rod 2 should be achieved by a cylinder or other conventional external telescopic structure, which is also a conventional design familiar to those skilled in the art. Its drive structure can be selected according to requirements, and this application will not elaborate on or limit it further.

[0050] It should be noted that, in Figure 1 , Figure 3 , Figure 6 as well as Figure 7 To help those skilled in the art better understand the structure of the pull wire 8, the state of the pull wire 8 after being pulled out of the pull wire guide tube 22 is also shown. In practical applications, the state of the pull wire 8 is as follows: Figure 4As shown, one end of the cable is connected to the cable connecting plate 21, and the other end is guided by the cable guide tube 22 and then connected to the sliding head 24. The cable 8 is connected through the fixing groove 25 in the sliding head 24. The connection method is a conventional design familiar to those skilled in the art and will not be described in detail. The routing of the cable 8 is achieved by the cable guide tube 22, and its arrangement is also a conventional design familiar to those skilled in the art and will not be described in detail.

[0051] It should be noted that the above embodiments are only specific and clear descriptions of the technical solutions and features of this application. Solutions or features that are prior art or common knowledge to those skilled in the art will not be described in detail in the above embodiments.

[0052] Furthermore, the technical solutions of this application are not limited to the above embodiments. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A wheelchair chassis retractable wheel mechanism for welfare seats, comprising a chassis frame (1), front wheels (3) and rear wheels. (4) A front wheel support rod (5) and a rear wheel support rod (9) are respectively provided on the front wheel (3) and the rear wheel (4). The front wheel support rod (5) and the rear wheel support rod (9) are rotatably connected to the chassis frame (1) through the front wheel support shaft (6) and the rear wheel support shaft (10), respectively. Also includes The front wheel link (13) is rotatably connected to the front wheel support rod (5) at one end, and is used to drive the front wheel support rod (5) to rotate. The rear wheel connecting rod (11) is rotatably connected to the rear wheel support rod (9) at one end, and is used to drive the rear wheel support rod (9) to rotate; The linkage drive mechanism is used to drive the front wheel linkage (13) and the rear wheel linkage (11) to move synchronously, so as to realize the simultaneous folding or unfolding of the front wheel (3) and the rear wheel (4); A cable locking mechanism is used to limit and fix the rear wheel support rod (9) on the chassis frame (1) after the rear wheel (4) is unfolded; The front wheel link (13) and the rear wheel link (11) are provided with support limiting parts to prevent the front wheel support rod (5) and the rear wheel support rod (9) from automatically retracting after being unfolded, and to provide support force for the unfolded front wheel (3) and rear wheel (4).

2. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 1, characterized in that, The linkage drive mechanism includes lead screws (15) rotatably mounted on both sides of the chassis frame (1). A slider (16) threadedly connected to the lead screws (15) is slidably mounted on the chassis frame (1). An L-shaped plate (32) is rotatably connected to the outside of the slider (16). The front side of the L-shaped plate (32) is rotatably connected to the front wheel connecting rod (13). The lower end of the L-shaped plate (32) is fixedly connected to the rear wheel connecting rod (11). A motor (17) for driving the lead screws (15) to rotate is mounted on the chassis frame (1).

3. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 1, characterized in that, The rear wheel support shaft (10) includes an inner fixed shaft (30) fixedly connected to the chassis frame (1), and an outer rotating tube (31) is rotatably fitted on the outside of the inner fixed shaft (30). The rear wheel support rod (9) is fixedly connected to the outer rotating tube (31).

4. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 3, characterized in that, The cable locking mechanism includes a fixed sleeve (27) fixed on the rear wheel support rod (9), one end of the fixed sleeve (27) is connected to the outer rotating tube (31), and a sliding head (24) is slidably disposed inside the fixed sleeve (27), with one end of the sliding head (24) penetrating through the fixed sleeve (27). And an outer rotating tube (31) is inserted into the inner fixed shaft (30). A spring (26) is provided between the other end of the sliding head (24) and the fixed sleeve (27). A pull wire (8) is connected to the side of the sliding head (24) away from the inner fixed shaft (30). The pull wire (8) passes through the fixed sleeve (27) and is connected to the pull wire adjusting rod (2). The pull wire adjusting rod (2) is movably set on the chassis frame (1) and is used to pull the pull wire (8).

5. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 1, characterized in that, The support limiting part includes a front wheel support shaft contact part (14) and a rear wheel support shaft contact part (23). The front wheel support shaft contact part (14) is located on the front side of the middle part of the front wheel link (13) and is used to abut against the front wheel support shaft (6). The rear wheel support shaft contact part (23) is located on the rear side of the rear wheel link (11) and is used to abut against the rear wheel support shaft (10).

6. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 2, characterized in that, The lower end of the rear wheel connecting rod (11) is provided with a rear wheel support shaft slot (12) corresponding to the rear wheel support shaft (10). When the rear wheel support rod (9) is retracted, the rear wheel support shaft slot (12) can be locked onto the rear wheel support shaft (10).

7. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 4, characterized in that, The pull wire adjusting rod (2) is rotatably mounted in the middle of the chassis frame (1). One end of the pull wire adjusting rod (2) is provided with a pull wire connecting plate (21). The chassis frame (1) is provided with a pull wire guide tube (22) for guiding the pull wire (8). One end of the pull wire (8) passes through the pull wire guide tube (22) and connects to the pull wire connecting plate (21).

8. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 5, characterized in that, The rear wheel link (11) has a limit slot (29) on its front side. The chassis frame (1) has a rear wheel link limit plate (28) corresponding to the limit slot (29) on its side wall. When the rear wheel support rod (9) is unfolded, the limit slot (29) is locked onto the rear wheel link limit plate (28).

9. The wheelchair chassis retractable wheel mechanism for welfare seats according to claim 2, characterized in that, A gas spring (20) is hinged to the front side of the side wall of the chassis frame (1), and the output end of the gas spring (20) is hinged to the rear wheel connecting rod (11).

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