Foldable wheelchairs

Abstract

The foldable wheelchair includes rear wheel frame 1, seat frame 2, front wheel frame 3, armrest frame (4, Fig 1), and a locking mechanism (6, Fig 1). The locking mechanism comprises two movable plates

Description

Technical Field The invention relates to foldable wheelchairs. Background Art The design of traditional wheelchairs only considers the basic mobility function and structural stability. Most of them are fixed structures and cannot be folded for storage. Therefore, they take up a large indoor space when not in use and are not convenient for storage. In order to solve this problem, foldable wheelchairs have gradually appeared on the market. However, existing foldable wheelchairs often have complex folding structures and cumbersome operations. In addition, the volume after folding is still large, occupying more space, and the effect is not ideal. In addition, due to the lack of a reliable locking mechanism, these folding wheelchairs may lack sufficient stability and safety during the folding and unfolding process. Not only are the load-bearing capacity and service life poor, but they may also be suddenly unlocked during use, causing the wheelchair to fold, posing a safety hazard to the user. Summary of the Invention An object of the invention is to provide foldable wheelchair designs that solve one or more technical problems existing in the above-mentioned background technology, or at least to provide an alternative to existing products on the market. The invention provides a foldable wheelchair comprises a rear wheel frame, a seat frame, a front wheel frame, an armrest frame, an oblique connecting rod and a locking mechanism, wherein the front wheel frame is hinged to the bottom of the seat frame, the rear side of the seat frame is hinged to the middle part of the rear wheel frame, the armrest frame is respectively hinged to the rear wheel frame and the seat frame, one end of the oblique connecting rod is hinged to the front wheel frame, the other end of the oblique connecting rod is hinged to the rear wheel frame, the vertical height of the hinge point of the oblique connecting rod and the front wheel frame is higher than the vertical height of the hinge point of the oblique connecting rod and the rear wheel frame; the locking mechanism comprises two movable plates, a connecting beam and a tension spring, the movable plates are hinged to the seat frame, the movable plates are respectively connected to the two ends of the connecting beam, one end of the tension spring is fixed to the movable plate, the other end of the tension spring is fixed to the seat frame, the side of the movable plate close to the tension spring is against the seat frame and the front wheel frame, and the top of the front wheel frame is against the bottom of the seat frame. Preferably, the locking mechanism further includes a first locking pin and a second locking pin, the first locking pin is arranged on the inner side of the seat frame, the second locking pin is arranged on the inner side of the front wheel frame, and the movable plate abuts against the first locking pin and the second locking pin. Preferably, a raised limiting portion and a hook-shaped limiting portion are provided on the upper and lower sides of a side of the movable plate close to the tension spring, and the raised limiting portion and the hook-shaped limiting portion are respectively abutted against the first locking pin and the second locking pin. Preferably, it also includes a first connecting member, the top of which is provided with a first positioning groove matching the bottom of the seat frame, the top of the first connecting member is connected to the seat frame, the bottom of the first connecting member is provided with a hinge shaft, the top of the front wheel frame is provided with a second positioning groove matching the bottom of the seat frame, the first positioning groove and the second positioning groove are both in contact with the bottom of the front wheel frame, a connecting portion is provided on one side of the front wheel frame, and the connecting portion is hinged to the first connecting member through the hinge shaft. Preferably, the locking mechanism also includes a first fixing bolt and a second fixing bolt, one end of the tension spring is fixed to the movable plate through the first fixing bolt, the other end of the tension spring is fixed to the first connecting memberthrough the second fixing bolt, and the second fixing bolt is coaxially arranged with the hinge axis. Preferably, it also includes two second connecting members and a reinforcing beam, the two second connecting members are arranged on the left and right sides of the middle part of the rear wheel frame, the two ends of the reinforcing beam are respectively connected to the two second connecting members, one end of the second connecting member is connected to the rear wheel frame, and the other end of the second connecting member extends forward and is hinged to the seat frame. Preferably, the armrest frame includes an armrest rod, a third connecting member and a support rod, one end of the armrest rod is hinged to the rear wheel frame, one end of the support rod is hinged to the seat frame, the third connecting member is hinged to the other end of the support rod and the bottom of the armrest rod, and a third positioning groove matching the bottom of the armrest frame is provided on the top of the third connecting member, and the third positioning groove is in contact with the bottom of the armrest frame. Preferably, it further comprises a footrest bracket, the front wheel frame is provided with a footrest support rod extending downward, and the footrest bracket is hinged to the footrest support rod. Preferably, it also includes a front wheel assembly, a rear wheel assembly, a seat cushion, a back cushion and an armrest pad, the front wheel assembly is arranged at the bottom of the front wheel frame, the rear wheel assembly is arranged at the bottom of the rear wheel frame, the back cushion covers the upper and middle part of the rear wheel frame, the cover is on the seat frame, and the armrest pad covers on the armrest frame. Preferably, the front wheel assembly is rotatably connected to the bottom of the front wheel frame. Compared with the prior art, the beneficial effect of embodiments of the foldable wheelchair are that by providing a front wheel frame hinged to a seat frame, the seat frame hinged to a rear wheel frame, an armrest frame hinged to the rear wheel frame and the seat frame, and an oblique connecting rod hinged to the front wheel frame and the rear wheel frame, the wheelchair as a whole can be unfolded for use and folded for storage, and is convenient to use. When unfolded for use, a movable plate of a locking mechanism remains in contact with the seat frame and the front wheel frame under the elastic biasing force of a tension spring, thereby locking the seat frame and the front wheel frame and so avoiding sudden unlocking during use that might cause the wheelchair to fold and cause a safety hazard. BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be well understood, some embodiments thereof, which are given by way of example only, will now be described with reference to the drawings in which: FIG lisa schematic diagram of an embodiment of a foldable wheelchair according to an embodiment of the invention; FIG 2 is a schematic diagram of the frame and locking mechanism of the foldable wheelchair of FIG 1; FIG 3 is an enlargement of the portion that is circle in FIG 2; and FIG 4 is a perspective view of a part of a locking mechanism of the foldable wheelchair of FIG 1. DETAILED DESCRIPTION Referring to Figures 1 and 2, an embodiment of a foldable wheelchair comprises a rear wheel frame 1, a seat frame 2, a front wheel frame 3, armrest frames 4, an oblique connecting rod 5 and a locking mechanism 6. The front wheel frame 3 is hinged to the underside of the seat frame 2, the rear side of the seat frame 2 is hinged to the middle of the rear wheel frame 1, the armrest frames 4 are hinged to the rear wheel frame 1 and the seat frame 2, a first end of the oblique connecting rod 5 is hinged to the front wheel frame 3 at a first position and a second end of the oblique connecting rod 5 is hinged to the rear wheel frame 1 at a second position The vertical height of the hinge point between the oblique connecting rod 5 and the front wheel frame 3 is higher than the vertical height of the hinge point between the oblique connecting rod 5 and the rear wheel frame 1. Referring to Figures 3 and 4, the locking mechanism 6 includes first and second movable plates 61, a connecting beam 62 and a tension spring 63. The first and second movable plates 61 are hinged to the seat frame 2 and are connected to respective ends of the connecting beam 62. A first end of the tension spring 63 is fixed to the first movable plate 61 and a second end of the tension spring 63 is fixed to the seat frame 2. The side of the movable plate 61 closest to the tension spring 63 faces inwardly of the seat frame 2 and front wheel frame 3 and the opposite side of the movable plate 61 is against the seat frame 2 and the front wheel frame 3. The upper end of the front wheel frame 3 abuts the underside of the seat frame 2 when the foldable wheelchair is in an unfolded use condition, as shown in Figures 1 to 3. By arranging the front wheel frame 3 to be hinged to the seat frame 2, the seat frame 2 to be hinged to the rear wheel frame 1, the armrest frame 4 to be hinged to the rear wheel frame 1 and the seat frame 2, and the oblique connecting rod 5 to be hinged to the front wheel frame 3 and the rear wheel frame 1, the front wheel frame 3, the seat frame 2 and the armrest frame 4 can be folded toward the rear wheel frame 1 as a whole, and a stable wheelchair structure is formed when unfolded. The wheelchair can be folded or unfolded without complicated steps, thereby improving the convenience of use. The movable plate 61, the tension spring 63 and the oblique connecting rod 5 not only provide a reliable locking function, but also effectively prevent the wheelchair from accidentally folding during use, thereby greatly reducing the safety hazard to the user. Referring to Figures 3 and 4, the locking mechanism 6 also includes a first locking pin 21 and a second locking pin 33, the first locking pin 21 is arranged on the inner side of the seat frame 2, the second locking pin 33 is arranged on the inner side of the front wheel frame 3, and the first movable plate 61 abuts the first locking pin 21 and the second locking pin 33 when the locking mechanism is in a locking condition. By arranging the first locking pin 21 on the seat frame 2 and the second locking pin 33 on the front wheel frame 3, locking points with the seat frame 2 and the front wheel frame 3 are provided for the first movable plate 61. When the wheelchair is unfolded for use, the first movable plate 61 maintains contact with the first locking pin 21 and the second locking pin 33, so that the locking mechanism 6 can keep the seat frame 2 and the front wheel frame 3 locked, effectively preventing the wheelchair from accidentally moving or folding when in a folded or unfolded state. Furthermore, a protruding limiting portion 611 and a hook-shaped limiting portion 612 are respectively disposed adjacent the upper and lower ends of the first movable plate 61 near the tension spring 63. The protruding limiting portion 611 and the hook-shaped limiting portion 612 respectively abut the first locking pin 21 and the second locking pin 33 when the locking mechanism is in the aforementioned locking condition. By arranging a protruding limiting portion 611 and a hook-shaped limiting portion 612 on the first movable plate 61, it is ensured that the first movable plate 61 can engage the first locking pin 21 and the second locking pin 33 at the same time. By the abutment between the protruding limiting portion 611 and the first locking pin 21 and the abutment between the hookshaped limiting portion 612 and the second locking pin 33, the movable plate 61 maintains abutment with the seat frame 2 and the front wheel frame 3 when the wheelchair is unfolded for use, ensuring that the wheelchair will not accidentally fold or slide during use. Referring to Figure 2, the foldable wheelchair preferably also includes a first connecting member 7. A first positioning groove 71 matching the bottom of the seat frame 2 is formed at the top of the first connecting member 7. The top of the first connecting member 7 is connected to the seat frame 2. A hinge shaft is formed at the bottom of the first connecting member 7, a second positioning groove 31 matching the bottom of the seat frame 2 is formed at the top of the front wheel frame 3. Both the first positioning groove 71 and the second positioning groove 31 are fitted with the bottom of the front wheel frame 3. A connecting portion 32 is provided on one side of the front wheel frame 3 and is hinged to the first connecting member 7 by a hinge shaft. The first connecting member 7, the seat frame 2 and the front wheel frame 3 are hinged by the first connecting member 7, so that when the wheelchair is unfolded for use, the second positioning groove 31 on the top of the front wheel frame 3 fits with the bottom of the seat frame 2, increasing the contact area and stability between the seat frame 2 and the front wheel frame. This makes the wheelchair more stable during use. By providing the first positioning groove 71 on the first connecting member 7, the contact area between the first connecting member 7 and the seat frame 2 is increased. When the first connecting member 7 is connected to the seat frame 2, rivets or bolts can be used to pass through the first positioning groove 71 and the seat frame 2 to achieve connection, thereby improving the stability of the connection. Referring to Figure 3, the locking mechanism 6 preferably further includes a first fixing bolt 64 and a second fixing bolt 65. One end of the tension spring 63 is fixed to the movable plate 61 through the first fixing bolt 64 and the other end of the tension spring 63 is fixed to the first connecting member 7 through the second fixing bolt 65. The second fixing bolt 65 is coaxially arranged with the hinge axis. By arranging the first fixing bolt 64 and the second fixing bolt 65, the two ends of the tension spring 63 are fixed. Referring to Figure 2, the seat frame 3 preferably includes two second connecting members 8 and a reinforcing beam 81. The two second connecting members 8 are arranged on the left and right sides of the middle part of the rear wheel frame 1. The two ends of the reinforcing beam 81 are respectively connected to the two second connecting members 8. One end of each second connecting member 8. is connected to the rear wheel frame 1 and the other end of each second connecting member 8 extends forward and is hinged to the seat frame 2. By arranging the second connecting members 8 on the left and right sides of the rear wheel frame 1 and arranging a reinforcing crossbeam 81 between the two second connecting members 8, the overall structural strength of the rear wheel frame 1 is improved, making the wheelchair more stable and durable during use. Since the second connecting members 8 extend forward, the arrangement of the second connecting members 8 also enables the seat frame 2 to fit more closely to the rear wheel frame 1 when folded, reducing the volume after folding and further optimizing the space utilization. Preferably, each armrest frame 4 includes an armrest rod 41, a third connecting member 42 and a support rod 43. One end of the armrest rod 41 is hinged to the rear wheel frame 1, one end of the support rod 43 is hinged to the seat frame 2 and the third connecting member 42 is hinged to the other end of the support rod 43 and the bottom of the armrest rod 41 A third positioning groove 421 matching the bottom of the armrest frame 4 is provided at the top of the third connecting member 42 and is in contact with the bottom of the armrest frame 4. By having one end of the armrest rod 41 hinged to the rear wheel frame 1, one end of the support rod 43 hinged to the seat frame 2, and the third connecting member 42 hinged to the armrest rod 41 and the support rod 43 respectively, the armrest frame 4 as a whole can be folded in the direction of the rear wheel frame 1 when the wheelchair is folded. When the wheelchair is in the unfolded state, the armrest rod 41, the third connecting member 42 and the support rod 43 form a stable structure under the action of the seat frame 2, thereby improving the stability of the armrest frame 4. By providing a third positioning groove 421 matching the bottom of the armrest rod 41 at the top of the third connecting member 42 that fits with the bottom of the armrest rod 41, when the wheelchair is unfolded and used, the contact area between the handrail rod 41 and the third connecting member 42 is increased, thereby further improving the structural stability. Preferably, a footrest 12 is further included, and the front wheel frame 3 is provided with a footrest support rod 13 extending downward. The footrest 12 is hinged to the footrest support rod 13. By providing the footrest 12, a comfortable foot support can be provided for the user. Having the footrest 12 and the footrest support rod 13 hinged to the front wheel frame 3, the footrest 12 can be folded with the front wheel frame 3, further reducing the space occupied by the foldable wheel chair. Preferably, the foldable wheelchair also includes a front wheel assembly 91, a rear wheel assembly 92, a seat cushion 93, a back cushion 94 and an armrest pad 95. The front wheel assembly 91 is arranged at the bottom of the front wheel frame 3 and the rear wheel assembly 92 is arranged at the bottom of the rear wheel frame 1. The back cushion 94 covers the middle and upper part of the rear wheel frame 1 and covers the seat frame 2, and the armrest pad 95 covers the armrest frame 4. Preferably, the front wheel assembly 91 is rotatably connected to the bottom of the front wheel frame 3. By setting the rotatable connection between the front wheel assembly 91 and the front wheel frame 3, the angle of the front wheel assembly 91 can be adjusted when folding, so that the front wheel fits more closely to the seat frame 2, further reducing the overall space occupied after folding. The working principle of this embodiment is as follows. The foldable wheelchair of this embodiment has two states: unfolded and folded. When unfolded, the frames are unfolded to form the wheelchair use structure shown in Figures 1 and 2. Once fully unfolded, the movable plates 61 are kept in contact with the seat frame 2 and the front wheel frame 3 under the elastic force of the tension spring 63, so as to lock the seat frame 2 and the front wheel frame 3. At the same time, the oblique connecting rod 5 forms a stable structure with the seat frame 2 and the rear wheel frame 1, avoiding the safety hazard caused by the wheelchair folding due to sudden unlocking during use. When folding, the tension spring 63 is stretched by pulling the connecting beam 62, so that the protruding limiting portion 611 is separated from the first locking pin 21 and the hookshaped limiting portion 612 is separated from the second locking pin 33, so that the locking mechanism 6 as a whole is away from the seat frame 2 and the front wheel frame 3, and the seat frame 2 and the front wheel frame 3 are unlocked, so that the front wheel frame 3 can be folded toward the seat frame 2, the seat frame 2 can be folded toward the rear wheel frame 1, and the armrest frame 4 can be folded toward the rear wheel frame 1, thereby realizing the overall folding of the wheelchair, which is easy to operate. The technical principle of the present invention is described above in combination with specific embodiments. That description is only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the scope of the present invention, which is limited only by the appended claims.

Claims

1. A foldable wheelchair comprising a rear wheel frame, a seat frame, a front wheel frame, two armrest frames, an oblique connecting rod and a locking mechanism,wherein the front wheel frame is hinged to an underside of the seat frame, a rear side of the seat frame is hinged to the rear wheel frame, the armrest frames are each hinged to the rear wheel frame and the seat frame, a first end of the oblique connecting rod is hinged to the front wheel frame at a first position and a second end of the oblique connecting rod is hinged to the rear wheel frame at a second position,wherein said first position at which the first end of the oblique connecting rod is hinged to the front wheel frame is higher than said second position at which the second end of the oblique connecting rod is hinged to the rear wheel frame,wherein the locking mechanism includes a connecting beam having a first end and a second end, a first movable plate connected to said first end of the connecting beam and a second movable plate connected to said second end of the connecting beam and a tension spring, wherein the first and second movable plates are hinged to respective sides of the seat frame, a first end of the tension spring is fixed to said first movable plate, a second end of the tension spring is fixed to the seat frame, the side of the first movable plate closest to the tension spring faces away from the respective side to which it is hinged, and an upper end of the front wheel frame abuts said underside the seat frame when the foldable wheelchair is in an unfolded use condition.

2. The foldable wheelchair according to claim 1, wherein the locking mechanism further comprises a first locking pin and a second locking pin, the first locking pin is arranged on an inner side of the seat frame, the second locking pin is arranged on an inner side of the front wheel frame and said first movable plate abuts the first locking pin and the second locking pin when said locking mechanism is in a locking condition.

3. The foldable wheelchair according to claim 2, wherein said first movable plate is provided with a protruding limiting portion and a hook-shaped limiting portion that are respectively disposed adjacent an upper end and a lower end of the first movable plate, andwherein the protruding limiting portion and the hook-shaped limiting portion respectively abut the first locking pin and the second locking pin when said locking mechanismis in said locking condition.

4. The foldable wheelchair according to claim 1, 2 or 3, further comprising a first connecting member,wherein an upper end of the first connecting member is provided with a first positioning groove configured to match said underside of the seat frame, the upper end of the first connecting member is connected to the seat frame, a lower end of the first connecting member is provided with a hinge shaft, said upper end of the front wheel frame is provided with a second positioning groove configured to match said underside of the seat frame, the first positioning groove and the second positioning groove are both in contact with said underside of the seat frame when said foldable wheelchair is in said unfolded use condition, a connecting portion is provided on one side of the front wheel frame, and the connecting portion is hinged to the first connecting member by the hinge shaft.

5. The foldable wheelchair according to claim 4, wherein the locking mechanism further includes a first fixing bolt and a second fixing bolt, said first end of the tension spring is fixed to the first movable plate via the first fixing bolt, said second end of the tension spring is fixed to seat frame via the first connecting member and the second fixing bolt, and the second fixing bolt is coaxially arranged with the hinge shaft.

6. The foldable wheelchair according to any one of the preceding claims, wherein the rear wheel frame comprises a left side second connecting member connected at a first end to a left side of said rear wheel frame, a right side second connecting member connected at a first end to a right side of said rear wheel frame and a reinforcing cross beam having respective ends connected to the left side second connecting member and the right side second connecting member, andwherein respective second sends of said left side second connecting member and said right side second connecting member are disposed forwardly of the rear wheel frame and the seat frame is hinged to the rear frame via said second ends of the left side second connecting member and the right side second connecting member.

7. The foldable wheelchair according to any one of the preceding claims, wherein each armrest frame includes an armrest rod, a third connecting member and a support rod, a first end of thearmrest rod is hinged to the rear wheel frame, a first end of the support rod is hinged to the seat frame, the third connecting member is hinged to a second end of the support rod and an underside portion of the armrest rod, a topside of the third connecting member is provided with a third positioning groove configured to match said underside portion of the armrest frame, and the third positioning groove is in contact with said underside portion of the armrest frame when the foldable wheelchair is in said unfolded use condition.

8. The foldable wheelchair according to any one of the preceding claims, further comprising a footrest,wherein the front wheel frame is provided with a footrest support rod extending downwards and the footrest is hinged to the footrest support rod.

9. The foldable wheelchair according to claim any one of the preceding claims, further comprising a front wheel assembly, a rear wheel assembly, a seat cushion, a back cushion and two armrest pads,wherein the front wheel assembly is arranged at a lower end of the front wheel frame, the rear wheel assembly is arranged at a lower end of the rear wheel frame, the back cushion is fitted against an upper and middle part of the rear wheel frame, the seat cushion is disposed on the seat frame, and the armrest pads are fitted to respective said armrest frames.

10. The foldable wheelchair according to claim 9, wherein the front wheel assembly is rotatably connected to the lower end of the front wheel frame.A

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