Foldable wheelchair

Abstract

The foldable wheelchair comprises a wheelchair frame and a wheel assembly, the wheelchair frame comprises a backrest rod, a seat rod, a seat supporting rod, a bottom supporting rod and an inclined supporting rod, the backrest rod, the seat rod, the seat supporting rod and the bottom supporting rod form a four-connecting-rod mechanism, and the lower end of the inclined supporting rod is rotationally connected with the middle of the bottom supporting rod, and the upper end of the inclined supporting rod is rotationally connected with the middle of the backrest rod through a second rotating shaft. A sliding groove comprising a main body groove and branch grooves is formed in an inclined supporting rod, so that the extending direction of the main body groove is parallel to the inclined supporting rod, a plurality of branch grooves are vertically communicated with the main body groove, and a second rotating shaft is inserted into the sliding groove in a sliding mode; when the second rotating shaft slides to the branch groove, the wheelchair frame can be stably kept in at least two states through a triangular structure formed by the inclined supporting rod, the backrest rod and the bottom supporting rod, and safety is good; when the second rotating shaft slides to the main body groove, the wheelchair frame can be switched among the states by utilizing a crank sliding block mechanism composed of the inclined supporting rod, the backrest rod and the bottom supporting rod, unfolding or folding is achieved, the structure is exquisite, and the advanced sense is high.

Description

Technical Field

[0001] The utility model belongs to the technical field of medical equipment, and in particular relates to a foldable wheelchair. Background Art

[0002] A wheelchair is a medical device that assists patients in treatment and rehabilitation. In order to facilitate storage, foldable wheelchairs have appeared on the market, but most of these wheelchairs can only be stably maintained in the unfolded state. In the folded state, the relative positions of the rods are not fixed, but can move relatively. When it is placed under a bed, in a locker and other areas and is in a static state, this structure has no problem. However, when it is placed on a car, train, airplane and other means of transportation and moves with it, during the acceleration and deceleration process, due to inertia, the rods are prone to relative movement, making it impossible for the foldable wheelchair to be stably maintained in the folded state, posing certain safety hazards. At the same time, the structure of this type of foldable wheelchair is relatively complex, and the sense of refinement and luxury is relatively poor. Utility Model Content

[0003] The purpose of the utility model is to overcome one or more disadvantages of the prior art and to provide a foldable wheelchair with a sophisticated structure, good safety and a high-end feel.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is that a foldable wheelchair comprises a foldable wheelchair frame and a wheel assembly arranged at the bottom of the wheelchair frame, wherein the wheelchair frame comprises a backrest rod, a seat rod, a seat support rod and a bottom support rod constituting a four-bar linkage mechanism, the rear end of the seat rod is rotatably connected to the middle part of the backrest rod, the upper end of the seat support rod is rotatably connected to the middle part of the seat rod, the lower end of the seat support rod is rotatably connected to the middle part of the bottom support rod, and the rear end of the bottom support rod is rotatably connected to the lower end of the backrest rod;

[0005] The wheelchair frame also includes an oblique support rod extending obliquely from the front lower direction to the rear upper direction, the lower end of the oblique support rod is rotatably connected to the middle part of the bottom support rod through a first rotating shaft, and the upper end of the oblique support rod is rotatably connected to the middle part of the backrest rod through a second rotating shaft; a slide groove is provided on the oblique support rod, and the slide groove includes a main groove and a branch groove, the extension direction of the main groove is parallel to the extension direction of the oblique support rod, the branch groove is vertically connected to the main groove, the branch groove has a plurality of branch grooves and is arranged at intervals, and the second rotating shaft is slidably inserted in the slide groove;

[0006] When the second rotating shaft slides to the branch groove, the diagonal support rod, the backrest rod and the bottom support rod form a triangular structure, so that the wheelchair frame can be stably maintained in at least two states including an unfolded state and a folded state; when the second rotating shaft slides to the main groove, the diagonal support rod, the backrest rod and the bottom support rod form a crank slider mechanism, so that the backrest rod and the bottom support rod can rotate relative to each other, thereby driving the seat rod and the seat support rod to follow the rotation through the four-bar linkage mechanism, so that the wheelchair frame can be transformed between these states, thereby realizing the unfolding or folding of the wheelchair frame.

[0007] Preferably, the diagonal support rod is located on the inner side of the backrest rod and the bottom support rod, and the notch of the slide groove faces outward.

[0008] Further preferably, the axis centerline of the second rotation axis is perpendicular to the plane where the notch is located.

[0009] Preferably, the angle between the diagonal brace and the horizontal plane is 30° to 45°.

[0010] Preferably, the first rotation axis is located behind the seat stay and the second rotation axis is located below the seat stay.

[0011] Preferably, there are two branch grooves, and the two branch grooves are respectively located at two ends of the main groove.

[0012] Preferably, the branch groove is located above and in front of the main groove.

[0013] Further preferably, a tension spring is provided between the diagonal support rod and the bottom support rod, and both ends of the tension spring hook the hook holes on the diagonal support rod and the bottom support rod, and the tension spring has a tendency to drive the diagonal support rod to rotate backward around the first rotation axis.

[0014] Preferably, the rear end of the bottom support rod is connected to a tail rack, the tail rack extends in a direction perpendicular to the bottom support rod, the upper end of the tail rack is rotatably connected to the lower end of the backrest plate, and the lower end of the tail rack is connected to a telescopic rod extending backwards.

[0015] Further preferably, the wheel assembly includes a front wheel assembly, a rear wheel assembly and an auxiliary wheel assembly, the front wheel assembly is rotatably connected to the bottom front portion of the bottom support rod, the rear wheel assembly includes a rotatable rear wheel and a motor for driving the rear wheel to rotate, the motor is detachably fixed to the rear of the tail frame, and the auxiliary wheel assembly is connected to the rear end portion of the telescopic rod.

[0016] Preferably, the wheelchair frame further comprises an armrest and an armrest support rod for supporting the armrest, the armrest support rod comprises a lower support rod and an upper support rod axially slidably arranged on the lower support rod, and the foldable wheelchair further comprises a locking mechanism for locking the relative positions of the upper support rod and the lower support rod.

[0017] Further preferably, the locking mechanism includes a locking groove and a locking block, the locking groove is opened on the lower support rod and passes through the side wall of the lower support rod, there are multiple locking grooves and they are arranged at intervals along the extension direction of the lower support rod, the locking block is connected to the bottom of the upper support rod and is located inside the lower support rod, and the locking block is provided with a retractable lock tongue plate toward the side wall of the locking groove, when a part of the lock tongue plate extends out and is inserted into the locking groove, the locking mechanism is locked, and when the lock tongue plate is completely out of the locking groove, the locking mechanism is unlocked.

[0018] Further preferably, the locking block is provided with a lock tongue plate groove for accommodating the lock tongue plate on the side facing the locking groove, the lock tongue plate groove is a blind groove, the extension direction of the lock tongue plate groove is perpendicular to the lower support rod, and the side wall of the locking block adjacent to the lock tongue plate groove is provided with a first waist-shaped groove, and the first waist-shaped groove is parallel to and connected with the lock tongue plate groove.

[0019] Further preferably, the locking mechanism also includes an unlocking fork and an unlocking pin, the upper end of the unlocking fork can be axially slidably inserted in the upper support rod, the lower end of the unlocking fork is forked on a pair of side walls of the locking block adjacent to the lock tongue plate groove, the lower end of the unlocking fork is provided with an oblique groove that is neither parallel nor perpendicular to the lock tongue plate groove, the middle part of the unlocking pin is inserted in the pin hole on the lock tongue plate, the two ends of the unlocking pin pass through the first waist-shaped hole and are inserted in the oblique groove, when the unlocking fork slides axially relative to the upper support rod, the oblique groove drives the unlocking pin to slide along the first waist-shaped hole, so that the lock tongue plate slides along the lock tongue plate groove, thereby realizing the extension and retraction of the lock tongue plate.

[0020] Further preferably, the locking mechanism also includes an adapter block slidably arranged in the upper support rod and an unlocking handle slidably connected to the outer wall of the upper support rod, the adapter block is connected to the upper end of the unlocking fork, a part of the unlocking handle passes through the second waist-shaped hole on the outer wall of the upper support rod and is connected to the adapter block, and the second waist-shaped hole extends in a direction parallel to the upper support rod.

[0021] Further preferably, the locking mechanism further comprises a return spring, which is arranged at the upper end of the upper support rod and presses against the adapter block, and has a tendency to drive the adapter block to slide downward.

[0022] Further preferably, the angle between the oblique groove and the bolt plate groove is 40° to 60°.

[0023] Further preferably, a compression spring is provided in the lock tongue plate groove, and two ends of the compression spring respectively press against the bottom wall of the lock tongue plate groove and the lock tongue plate, and the compression spring has a tendency to drive the lock tongue plate to extend outward.

[0024] Further preferably, a bushing for reducing friction is provided between the lower support rod and the upper support rod, and the bushing is embedded in the upper opening of the lower support rod, and a part of the bushing extends into the lower support rod, separating an annular cavity between the lower support rod and the upper support rod, and when the lock tongue plate is completely disengaged from the locking groove, a part of the lock tongue plate is located in the annular cavity and presses against the inner wall of the lower support rod.

[0025] Further preferably, the lower end of the lower support rod is connected to the middle portion of the backrest rod, and the upper end of the upper support rod is connected to the bottom rear portion of the armrest.

[0026] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0027] When the second rotating shaft slides to the branch groove, the triangular structure composed of the diagonal support rod, the backrest rod and the bottom support rod can be used to stably maintain the wheelchair frame in at least two states including the unfolded state and the folded state, and the safety is good; when the second rotating shaft slides to the main groove, the crank slider mechanism composed of the diagonal support rod, the backrest rod and the bottom support rod can be used to make the backrest rod and the bottom support rod rotate relative to each other, thereby driving the seat rod and the seat support rod to follow the rotation through the four-bar linkage mechanism, so that the wheelchair frame can be changed between these states, and the wheelchair frame can be unfolded or folded; the structure is exquisite and has a high-end feel. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a three-dimensional schematic diagram of a preferred embodiment of the utility model, at this time, the wheelchair frame is in an unfolded state.

[0029] Figure 2 yes Figure 1 Schematic diagram of the left side.

[0030] Figure 3 yes Figure 1 A schematic diagram of the left side of the wheelchair frame in the folded state.

[0031] Figure 4 yes Figure 1 A cross-sectional diagram showing the diagonal brace and the slideway.

[0032] Figure 5 yes Figure 1 Schematic diagram of the assembly and disassembly of the middle handrail and handrail support rod.

[0033] Figure 6 yes Figure 1 A schematic cross-sectional view of the middle armrest and the armrest support rod, at which time the bolt plate is inserted into the lowest locking groove.

[0034] Figure 7 yes Figure 1 A schematic cross-sectional view of the middle armrest and the armrest support rod, at which time the bolt plate is inserted into the second highest locking groove.

[0035] Among them: 10. wheelchair frame; 11. backrest rod; 12. seat rod; 13. seat support rod; 14. bottom support rod; 141. second hook hole; 142. tail frame; 143. telescopic rod; 15. diagonal support rod; 151. first rotating shaft; 152. second rotating shaft; 153. main body groove; 154. branch groove; 155. notch; 156. first hook hole; 16. tension spring; 17. handrail; 181. lower support rod; 182. upper support rod; 183. through groove; 184. second connecting hole; 185. connecting pin; 186. second waist-shaped groove; 187. bushing; 188. annular cavity; 20 .Wheel assembly; 21. Front wheel assembly; 221. Rear wheel; 222. Motor; 23. Auxiliary wheel assembly; 31. Locking groove; 32. Locking block; 321. Lock tongue plate; 322. Lock tongue plate groove; 323. First waist-shaped groove; 324. Pin hole; 325. Compression spring; 326. Groove; 327. Boss; 328. First connecting hole; 33. Unlocking fork; 331. Oblique groove; 332. Through hole; 34. Unlocking pin; 35. Adapter block; 351. Slot; 352. Column; 353. Connecting groove; 354. Accommodating groove; 36. Unlocking handle; 361. Part; 37. Reset spring. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art.

[0037] The front and rear, up and down, left and right directions described in the utility model are for users to ride Figure 1 The front-to-back, up-down, left-to-right directions observed when using a foldable wheelchair.

[0038] like Figures 1 to 7As shown, the foldable wheelchair provided by the utility model comprises a foldable wheelchair frame 10 and a wheel assembly 20 arranged at the bottom of the wheelchair frame 10, wherein the wheelchair frame 10 comprises a backrest rod 11, a seat rod 12, a seat support rod 13 and a bottom support rod 14 constituting a four-bar linkage mechanism, specifically, the rear end of the seat rod 12 is rotatably connected to the middle part of the backrest rod 11, the upper end of the seat support rod 13 is rotatably connected to the middle part of the seat rod 12, the lower end of the seat support rod 13 is rotatably connected to the middle part of the bottom support rod 14, and the rear end of the bottom support rod 14 is rotatably connected to the lower end of the backrest rod 11; the wheelchair frame 10 also comprises an oblique support rod 15 extending obliquely from the front lower direction to the rear upper direction, and the lower end of the oblique support rod 15 is connected to the The middle part of the bottom support rod 14 is rotatably connected by a first rotating shaft 151, and the upper end of the diagonal support rod 15 is rotatably connected to the middle part of the backrest rod 11 by a second rotating shaft 152. The first rotating shaft 151 is located behind the seat support rod 13, and the second rotating shaft 152 is located below the seat rod 12; a slide groove is also provided on the diagonal support rod 15, and the slide groove includes a main groove 153 and a branch groove 154. The extension direction of the main groove 153 is parallel to the extension direction of the diagonal support rod 15, and the branch groove 154 is vertically connected with the main groove 153. There are two branch grooves 154, and the two branch grooves 154 are arranged at intervals and located at the two ends of the main groove 153. The second rotating shaft 152 can be slidably inserted in the slide groove.

[0039] The advantages of this setting are:

[0040] When the second rotating shaft 152 slides to the branch groove 154 (one of the branch grooves 154 corresponds to the unfolded state of the wheelchair frame 10, and the other corresponds to the folded state of the wheelchair frame 10), the triangular structure composed of the diagonal support rod 15, the backrest rod 11 and the bottom support rod 14 can be used to stably maintain the wheelchair frame 10 in the unfolded state and the folded state, thereby improving the safety of the wheelchair frame 10, especially the safety of the wheelchair frame 10 when it is in the folded state, so that the safety of the foldable wheelchair is better; when the second rotating shaft 152 slides to the main groove 153, the crank slider mechanism composed of the diagonal support rod 15, the backrest rod 11 and the bottom support rod 14 can be used to make the backrest rod 11 and the bottom support rod 14 rotate relative to each other, thereby driving the seat rod 12 and the seat support rod 13 to rotate with the above-mentioned four-bar linkage mechanism, so that the wheelchair frame 10 can be changed between the unfolded state and the folded state, thereby realizing the unfolding or folding of the wheelchair frame 10; so that the foldable wheelchair has a delicate structure, a refined and high-end feel.

[0041] To prevent the second rotating shaft 152 from sliding and rotating in the slide groove and clamping foreign objects such as trouser legs, in this embodiment, the diagonal support rod 15 is located on the inner side of the backrest rod 11 and the bottom support rod 14, the slot 155 of the slide groove faces outward, and the axis of the second rotating shaft 152 is perpendicular to the plane where the slot 155 is located. More preferably, the outer rods on the same side of the backrest rod 11 and the bottom support rod 14 are located in the same plane.

[0042] To prevent the diagonal support rod 15 from rotating due to its own weight and causing the second rotating shaft 152 to disengage from the branch groove 154, in this embodiment, the branch groove 154 is located in the front and upper part of the main groove 153; to ensure the stability of the triangular structure formed by the diagonal support rod 15, the backrest rod 11 and the bottom support rod 14 and to reduce the resistance of the second rotating shaft 152 sliding in the slide groove as much as possible, preferably, the angle between the diagonal support rod 15 and the horizontal plane is 30° to 45°. In this embodiment, when the wheelchair frame 10 is in the unfolded state, the angle is 34°, and when the wheelchair frame 10 is in the folded state, the angle is 40°.

[0043] In order to enable the diagonal support rod 15, the backrest rod 11 and the bottom support rod 14 to automatically form a triangular structure, in the present embodiment, a tension spring 16 is provided between the diagonal support rod 15 and the bottom support rod, and the two ends of the tension spring 16 are bent and respectively hooked on the first hook hole 156 on the diagonal support rod 15 and the second hook hole 141 on the bottom support rod 14, and the tension spring 16 has a tendency to drive the diagonal support rod 15 to rotate backward around the first rotating shaft 151. When the second rotating shaft 152 slides to the end of the main groove 153, the tension spring 16 can be used to drive the diagonal support rod 15 to rotate, so that the second rotating shaft 152 slides into the branch groove 154, so that the diagonal support rod 15, the backrest rod 11 and the bottom support rod 14 can automatically form a stable triangular structure.

[0044] It should be noted that, during the unfolding or folding of the wheelchair frame 10, the backrest rod 11 needs to rotate relative to the slide groove on the diagonal support rod 15. Regardless of whether the second rotating shaft 152 can rotate relative to the backrest rod 11, the second rotating shaft 152 will rotate relative to the slide groove, that is, the second rotating shaft 152 is actually slidably and rotatably inserted in the slide groove.

[0045] When the wheelchair frame 10 is folded, in order to make the bottom support rod 14, the backrest rod 11 and the seat rod 12 as parallel as possible, thereby saving the occupied space, in this embodiment, the rear end of the bottom support rod 14 is connected to a tail frame 142, and the tail frame 142 extends in a direction perpendicular to the bottom support rod 14. The upper end of the tail frame 142 is rotatably connected to the lower end of the backrest board 11, and the lower end of the tail frame 142 is connected to a telescopic rod 143 extending backward.

[0046] Furthermore, the wheel assembly 20 includes a front wheel assembly 21, a rear wheel assembly and an auxiliary wheel assembly 23. The front wheel assembly 21 is rotatably connected to the bottom front part of the bottom support rod 14. The rear wheel assembly includes a rotatable rear wheel 221 and a motor 222 for driving the rear wheel 221 to rotate. The motor 222 is connected to the hub of the rear wheel 221 and is detachably fixed to the rear of the tail frame 142. The auxiliary wheel assembly 23 is connected to the rear end of the telescopic rod 143 and is suspended in the air to facilitate crossing obstacles.

[0047] In order to improve the comfort during use and further enhance the sense of luxury, in the present embodiment, the wheelchair frame 10 also includes an armrest 17 and an armrest support rod for supporting the armrest 17, the armrest support rod including a lower support rod 181 and an upper support rod 182 axially slidably arranged on the lower support rod 181, the lower end portion of the lower support rod 181 is connected to the middle portion of the backrest rod 11, and the upper end portion of the upper support rod 182 is connected to the bottom rear portion of the armrest 17. In the present embodiment, in order to further reduce the space occupied by the wheelchair frame 10 after being folded, the lower end portion of the lower support rod 181 is rotatably connected to the middle portion of the backrest rod 11. Of course, the lower end portion of the lower support rod 181 and the middle rotating portion of the backrest rod 11 are also provided with a locking assembly for locking the relative position of the lower support rod 181 and the backrest rod 11, so as to facilitate fixing the position of the armrest 17 when the wheelchair frame 10 is unfolded. The locking assembly can be implemented using existing technology and will not be repeated here.

[0048] The foldable wheelchair also includes a locking mechanism for locking the relative positions of the upper support rod 181 and the lower support rod 182, the locking mechanism includes a locking groove 31 and a locking block 32, the locking groove 31 is opened on the lower support rod 181 and passes through the side wall of the lower support rod 181, there are four locking grooves 31 and are arranged at intervals along the extension direction of the lower support rod 181 to form a plurality of locking gears, the locking block 32 is connected to the bottom of the upper support rod 182 and is located in the lower support rod 181, and the locking block 32 is provided with a retractable locking tongue plate 321 on the side wall of the locking groove 31, when a part of the locking tongue plate 321 extends out and inserts into the locking groove 31, the locking mechanism is locked, and when the locking tongue plate 321 is completely separated from the locking groove 31, the locking mechanism is unlocked.

[0049] Specifically, a lock tongue plate groove 322 for accommodating the lock tongue plate 321 is provided on the side of the locking block 32 facing the locking groove 31, the lock tongue plate groove 322 is a blind groove, and the extension direction of the lock tongue plate groove 322 is perpendicular to the extension direction of the lower support rod 181, and the side wall of the locking block 32 adjacent to the lock tongue plate groove 322 is provided with a first waist-shaped groove 323, and the first waist-shaped groove 323 is parallel to and connected with the lock tongue plate groove 322.

[0050] In order to facilitate the extension and retraction of the bolt plate 321, thereby facilitating the locking and unlocking of the locking mechanism, the locking mechanism further includes an unlocking fork 33 and an unlocking pin 34. The upper end of the unlocking fork 33 can be axially slidably penetrated in the upper support rod 182, and the lower end of the unlocking fork 33 is forked on a pair of side walls of the locking block 32 adjacent to the bolt plate groove 322. The lower end of the unlocking fork 33 is provided with an oblique groove 331 which is neither parallel nor perpendicular to the bolt plate groove 322. The middle part of the unlocking pin 34 is vertically penetrated into the pin hole 324 on the lock tongue plate 321, so that the unlocking pin 34 and the lock tongue plate 321 are connected as a whole, and the two ends of the unlocking pin 34 pass through the first waist-shaped groove 323 and are inserted into the oblique groove 331. When the unlocking fork 33 slides axially relative to the upper support rod 182, the oblique groove 331 drives the unlocking pin 34 to slide along the first waist-shaped groove 323, so that the lock tongue plate 321 slides along the lock tongue plate groove 322, thereby realizing the extension and retraction of the lock tongue plate 321.

[0051] To facilitate the resetting of the lock tongue plate 33, in the present embodiment, a compression spring 325 is provided in the lock tongue plate groove 322, and the two ends of the compression spring 325 respectively press against the bottom wall of the lock tongue plate groove 332 and the lock tongue plate 321, and the compression spring 325 has a tendency to drive the lock tongue plate 321 to extend outward. To facilitate the alignment of the compression spring 325, further, the lock tongue plate 321 is provided with a groove 326 for accommodating one end of the compression spring 325 towards the end of the compression spring 325, and the bottom wall of the lock tongue plate groove 322 is provided with a convex column 327, and the end of the compression spring 325 away from the lock tongue plate 33 is sleeved on the convex column 326.

[0052] In order to reduce the resistance of the oblique groove 331 to the movement of the unlocking pin 34, preferably, the angle between the oblique groove 331 and the bolt plate groove 322 is 40° to 60°. In the present embodiment, the angle is 49°.

[0053] To facilitate the connection and alignment between the locking block 32 and the lower support rod 182, the upper end of the locking block 32 is further inserted upward from the bottom opening of the lower support rod 182. At the same time, in order to allow the lock tongue plate 321 to extend, the side wall of the lower support rod 182 is provided with a through groove 183. When the locking block 32 is inserted upward to the set position, the through groove 183 is aligned with the lock tongue plate groove 322. Under the action of the compression spring 325, a part of the lock tongue plate 321 enters the through groove 183.

[0054] To prevent the locking block 32 from detaching from the lower support rod 182, a first connecting hole 328 is further provided at the lower end of the locking block 32. The first connecting hole 328 is located below the first waist-shaped hole 323, and a second connecting hole 184 is provided at the bottom of the upper support rod 182. When the locking block 32 is inserted upward to the set position, the first connecting hole 328 is aligned with the second connecting hole 184, and is locked by a connecting pin 185 inserted into both the first connecting hole 328 and the second connecting hole 184.

[0055] In order to facilitate the unlocking fork 33 to slide relative to the upper support rod 182 from the outside, in the present embodiment, the locking mechanism further includes a transfer block 35 slidably arranged in the upper support rod 182 and an unlocking handle 36 slidably connected to the outer wall of the upper support rod. The transfer block 35 is connected to the upper end of the unlocking fork 33. Specifically, a card slot 351 is provided at the lower end of the transfer block 35. The card slot 351 penetrates the bottom wall and one side wall of the transfer block 35. The bottom wall of the card slot 351 is provided with a card column 352 extending upward. The upper end of the unlocking fork 33 is provided with a through hole 332. The through hole 332 is sleeved on the card column 352, so that the upper end of the unlocking fork 33 is connected to the lower end of the transfer block 35. At the same time, a part of the unlocking handle 36 passes through the second waist-shaped groove 186 on the outer wall of the upper support rod 182 and is connected to the adapter block 35. Specifically, the unlocking handle 36 passes through the part 361 of the second waist-shaped hole 186 and is inserted into the connecting groove 353 on the adapter block 35. The connecting groove 353 is located above the card slot 351. The connecting groove 353 is a blind groove, so that the unlocking handle 36 and the adapter block 35 are connected as a whole. The second waist-shaped groove 186 extends in a direction parallel to the upper support rod 182. In this way, when the unlocking handle 36 is pushed from the outside to slide relative to the upper support rod 182, the unlocking fork 33 can be driven to slide relative to the upper support rod 182 through the adapter block 35.

[0056] To facilitate the resetting of the unlocking handle 36, in the present embodiment, the locking mechanism also includes a reset spring 37, which is disposed in the upper support rod 182 and located at the upper end of the upper support rod 182. The two ends of the reset spring 37 are respectively pressed against the adapter block 35 and the armrest 17. The reset spring 37 has a tendency to drive the adapter block 35 to slide downward. To prevent the reset spring from tilting, the upper end surface of the adapter block 35 is further provided with a receiving groove 354 for accommodating the lower end of the reset spring 37.

[0057] In this embodiment, a bushing 187 for reducing friction is provided between the lower support rod 181 and the upper support rod 182. The bushing 187 is embedded in the upper opening of the lower support rod 181. A portion of the bushing 187 extends into the lower support rod 181 and is engaged with the lower support rod 181. An annular cavity 188 is separated between the lower support rod 181 and the upper support rod 182. When the lock tongue plate 321 is completely disengaged from the locking groove 31, a portion of the lock tongue plate 321 is located in the annular cavity 188 and presses against the inner wall of the lower support rod 181.

[0058] The advantage of such a configuration is that the abutment between the locking tongue plate 321 and the lower edge of the bushing 187 can be utilized to prevent the upper support rod 182 from being separated from the lower support rod 181 due to excessive upward pulling of the armrest 17 .

[0059] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly. They cannot be used to limit the protection scope of the utility model. All equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A foldable wheelchair, comprising a foldable wheelchair frame and a wheel assembly arranged at the bottom of the wheelchair frame, wherein the wheelchair frame comprises a backrest rod, a seat rod, a seat support rod and a bottom support rod constituting a four-bar linkage; Features: The wheelchair frame also includes a diagonal support rod extending obliquely from the front lower direction to the rear upper direction, the lower end of the diagonal support rod is rotatably connected to the middle part of the bottom support rod by a first rotating shaft, and the upper end of the diagonal support rod is rotatably connected to the middle part of the backrest rod by a second rotating shaft; a slide groove is provided on the diagonal support rod, and the slide groove includes a main groove and a branch groove, the extension direction of the main groove is parallel to the extension direction of the diagonal support rod, the branch groove is vertically connected to the main groove, there are multiple branch grooves and they are arranged at intervals, and the second rotating shaft can be slidably inserted in the slide groove.

2. The foldable wheelchair according to claim 1, characterized in that: The diagonal support rod is located at the inner side of the backrest rod and the bottom support rod, and the notch of the slide groove faces outward.

3. The foldable wheelchair according to claim 2, characterized in that: The axis center line of the second rotation axis is perpendicular to the plane where the notch is located.

4. The foldable wheelchair according to claim 1, characterized in that: The angle between the diagonal brace and the horizontal plane is 30° to 45°.

5. The foldable wheelchair according to claim 1, characterized in that: The first rotation axis is located behind the seat stay, and the second rotation axis is located below the seat stay.

6. The foldable wheelchair according to claim 1, characterized in that: There are two branch grooves, and the two branch grooves are respectively located at two ends of the main groove.

7. The foldable wheelchair according to claim 1, characterized in that: The branch groove is located above and in front of the main groove.

8. The foldable wheelchair according to claim 7, characterized in that: A tension spring is provided between the diagonal support rod and the bottom support rod, and the two ends of the tension spring hook the hook holes on the diagonal support rod and the bottom support rod. The tension spring has a tendency to drive the diagonal support rod to rotate backward around the first rotation axis.

9. The foldable wheelchair according to claim 1, characterized in that: The rear end of the bottom support rod is connected with a tail frame, which extends in a direction perpendicular to the bottom support rod. The upper end of the tail frame is rotatably connected to the lower end of the backrest rod, and the lower end of the tail frame is connected with a telescopic rod extending backwards.

10. The foldable wheelchair according to claim 9, characterized in that: The wheel assembly comprises a front wheel assembly, a rear wheel assembly and an auxiliary wheel assembly, wherein the front wheel assembly is rotatably connected to the bottom front portion of the bottom support rod, the rear wheel assembly comprises a rotatable rear wheel and a motor for driving the rear wheel to rotate, the motor is connected to the rear of the tail frame, and the auxiliary wheel assembly is connected to the rear end portion of the telescopic rod.

11. The foldable wheelchair according to claim 1, characterized in that: The wheelchair frame also includes an armrest and an armrest support rod for supporting the armrest, the armrest support rod includes a lower support rod and an upper support rod axially slidably arranged on the lower support rod, and the foldable wheelchair also includes a locking mechanism for locking the relative positions of the upper support rod and the lower support rod.

12. The foldable wheelchair according to claim 11, characterized in that: The locking mechanism includes a locking groove and a locking block. The locking groove is opened on the lower support rod and passes through the side wall of the lower support rod. There are multiple locking grooves and they are arranged at intervals along the extension direction of the lower support rod. The locking block is connected to the bottom of the upper support rod and is located in the lower support rod. The locking block is provided with a retractable lock tongue plate toward the side wall of the locking groove. When a part of the lock tongue plate extends out and inserts into the locking groove, the locking mechanism is locked. When the lock tongue plate is completely separated from the locking groove, the locking mechanism is unlocked.

13. The foldable wheelchair according to claim 12, characterized in that: The locking block is provided with a lock tongue plate groove for accommodating the lock tongue plate on the side facing the locking groove, the lock tongue plate groove is a blind groove, and the extension direction of the lock tongue plate groove is perpendicular to the lower support rod, and the side wall of the locking block adjacent to the lock tongue plate groove is provided with a first waist-shaped groove, and the first waist-shaped groove is parallel to and intersecting with the lock tongue plate groove.

14. The foldable wheelchair according to claim 13, characterized in that: The locking mechanism also includes an unlocking fork and an unlocking pin. The upper end of the unlocking fork can be axially slidably inserted in the upper support rod, and the lower end of the unlocking fork is forked on a pair of side walls of the locking block adjacent to the lock tongue plate groove. The lower end of the unlocking fork is provided with an oblique groove that is neither parallel nor perpendicular to the lock tongue plate groove. The middle part of the unlocking pin is inserted in the pin hole on the lock tongue plate, and the two ends of the unlocking pin pass through the first waist-shaped groove and are inserted in the oblique groove. When the unlocking fork slides axially relative to the upper support rod, the oblique groove drives the unlocking pin to slide along the first waist-shaped groove, so that the lock tongue plate slides along the lock tongue plate groove to realize the extension and retraction of the lock tongue plate.

15. The foldable wheelchair according to claim 14, characterized in that: The locking mechanism also includes an adapter block slidably arranged in the upper support rod and an unlocking handle slidably connected to the outer wall of the upper support rod, the adapter block is connected to the upper end of the unlocking fork, a part of the unlocking handle passes through the second waist-shaped hole on the outer wall of the upper support rod and is connected to the adapter block, and the second waist-shaped hole extends in a direction parallel to the upper support rod.

16. The foldable wheelchair according to claim 15, characterized in that: The locking mechanism further comprises a return spring, which is arranged at the upper end of the upper support rod and abuts against the adapter block. The return spring has a tendency to drive the adapter block to slide downward.

17. The foldable wheelchair according to claim 14, characterized in that: The angle between the oblique groove and the bolt plate groove is 40° to 60°.

18. The foldable wheelchair according to claim 13, characterized in that: A compression spring is arranged in the lock tongue plate groove, and the two ends of the compression spring respectively press against the bottom wall of the lock tongue plate groove and the lock tongue plate, and the compression spring has a tendency to drive the lock tongue plate to extend outward.

19. The foldable wheelchair according to claim 12, characterized in that: A bushing for reducing friction is provided between the lower support rod and the upper support rod. The bushing is embedded in the upper opening of the lower support rod, and a part of the bushing extends into the lower support rod, separating an annular cavity between the lower support rod and the upper support rod. When the lock tongue plate is completely disengaged from the locking groove, a part of the lock tongue plate is located in the annular cavity and presses against the inner wall of the lower support rod.

20. The foldable wheelchair according to claim 11, characterized in that: The lower end of the lower support rod is connected to the middle part of the backrest rod, and the upper end of the upper support rod is connected to the bottom rear part of the armrest.

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