GB2145983A - Device to assist a wheelchair surmount steps kerbs and the like - Google Patents

Abstract

The device comprises a transverse member attachable to the wheelchair and pivotally mounting a sector-like member (15) which presents an abutment surface (26) spaced from the pivotal axis of the sector-like member by a distance greater than the radius of the front wheels (17) of the wheelchair. Biasing means e.g. helical springs are provided to bias the sector-like member (15) into a position so that its abutment surface (26) is forward of the leading part of the front wheel (17) of the wheelchair when in a normal running position. <IMAGE>

Description

SPECIFICATION Kerb climbing devices for wheelchairs The present invention relates to devices provided on, or for attachment to, wheelchairs to enable the wheelchair to negotiate small step-like objects such as small steps, roadside kerbs and the like.

The present invention is primarily but not exclusively applicable to wheelchairs for use by invalids, which wheelchairs may have large rear wheels but are generally provided with relatively small front wheels which are often castor wheels.

It is an object of the present invention to provide in or for a wheelchair a device to assist in the surmounting of small steps, kerbs and the like by the wheelchair.

According to one aspect of the present invention we provide in or for a wheelchair a transverse member, means for attaching the transverse member at or adjacent each end thereof to a respective side of the wheelchair, said transverse member having secured thereto a sector-like member or assembly mounted for pivotal movement about a pivotal axis and presenting an abutment surface spaced from said pivotal axis by a distance greater than the radius of the front wheels of the wheelchair, and wherein means are provided to bias said sector-like member to a position such that it presents its abutment surface forwardly of the leading part of the front wheels of the wheelchair when in a normal running position.

Preferably said sector-like member is mounted for pivotal movement about the longitudinal axis of said transverse member and spring means are provided to bias the sector-like member relative to the transverse member into its position in which it presents its abutment surface forwardly of the circumference of the leading part of the front wheel of the wheelchair.

Preferably the wheelchair is a folding wheelchair having a pair of side frames, each side frame carrying a rear wheel and a front wheel and wherein the sector-like member and transverse member are readily detachable from an in use position or are foldable relative to the wheelchair in order to enable the wheelchair to be folded in a manner to bring the side frames thereof towards each other.

Preferably the means for mounting said transverse member of the wheelchair may comprise a pair of cup-like or socket members, one provided on a respective side frame of the wheelchair and wherein said transverse member has end regions locatable within said cup-like or socket members.

Preferably said stector-like member is of framelike construction so as to reduce the weight thereof and said transverse member comprises a tubular member.

It is envisaged that a plurality of sector-like members may be provided but preferably a single member is provided and is positioned on said transverse member so that in use it is substantially midway between the side frames of the wheelchair.

It will be appreciated that, particularly where the wheelchair is a folding wheelchair, it is desirable to minimise the weight thereof and the kerb climbing device of the present invention provides additional rigidity to the wheelchair through the provision of the transverse member and may itself form a structural part of the wheelchair, the sector-like members preferably being of frame-like construction contributing very little to the overall weight of the wheelchair. Bearing means may be provided which preferably, in order to minimise weight, may be made from a plastics material.

Whereas the abutment surfaces of the sector-like member is preferably arcuate having a radius of curvature considerably greater than the radius of curvature of the front wheels of the wheelchair, it is envisaged that the abutment surface may be substantially straight or any other desired configuration. Furthermore, the sector-like member may comprise a single strut-like part secured at one end to a curved part affording said abutment surface.

A considerable benefit is obtained by providing a single sector-like member mounted for limited pivotal movement approximately midway between the side frames of the wheelchair since its positioning prevents interference with the feet of the occupant or the footrests often provided secured to the side frames of the wheelchair and, not only is weight significantly reduced compared with the provision of a large wheel, but the sector-like member ensures that space above the pivotal axis thereof which, if a large wheel was provided would be used, is left free thus providing either storage space or, more importantly, room to store batteries and other control means associated with electrically powered wheelchairs.

According to another aspect of the invention we provide a folding wheelchair comprising a pair of side frames each carrying a front wheel of the wheelchair, said frames being interconnected by link members, the link members enabling a folded condition of the wheelchair in which said side frames are substantially adjacent to each other and an in use position in which the links maintain the wheelchair frames in spaced apart relationship, and wherein the wheelchair is provided with a transverse member having end regions each connectable with a respective side frame of the wheelchair, and wherein said transverse member assists in maintaining the wheelchair in its in use condition, said transverse member being provided with a sector-like member mounted thereon for pivotal movement relative to the side frames of the wheelchair about the longitudinal axis of said transverse member, said sector-like member having an abutment surface spaced from said longitudinal axis by a distance greater than the radius of the front wheels of the wheelchair, said sector-like member being positioned such that said abutment surface projects forwardly of the forward surface of said front wheels when in their normal running position.

The invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a partly broken away partly perspec tive view of the kerb climbing device secured to a wheelchair; and Figure 2 is a view along the line B-B shown in Figure 1.

Referring to the drawings, a kerb climbing device is shown and comprises a transverse member generally indicated at 10 mounted at one end 11 to a side frame of the wheelchair generally indicated at 12 and at another end 13 to the other side frame genrally indicated at 14, the transverse member 10 carrying a sector-like member generally indicated at 15.

The side frame 12 is provided with a socket 16 in which a spigot (not shown) of castor wheel 17 extends, the castor wheel having a relatively small radius R1.

The socket 16 carries a further inverted cup-like member 18 in which the end 11 of transverse member 10 is located and retained therein by resilient clip 19 which retains the transverse member 10 in the inverted cup-like member 18.

The other end 13 of the transverse member is located in a similar cup-shaped member 20 and retained therein by spring clip 21.

The spring clips 19 and 21 may easily be withdrawn to enable the transverse member 10, which comprises a tubular part, to be drawn from the cup-like members 18 and 20.

Approximately midway between the wheelchair side frames 12 and 14 is a sector-like member 15.

The sector-like member 15 is of "frame-like" construction and may be made from an injection moulding of plastics material, or alternatively may comprise an extrusion which is subsequently "sliced", such extrusion may be aluminium or a plastics material. Secured to the sector-like member 15 is an abutment member 25 presenting an abutment surface 26. The abutment member 25 may be secured to the sector-like member 15 by means of threaded fasteners shown at 27 and may additionally or alternatively be secured by adhesive.

The abutment member 25 may be made from a natural synthetic rubber-like material to provide some shock absorbing means when the sector-like member 15 comes into contact with a kerb, step or the like.

The sector-like member is mounted for limited pivotal movement about the transverse member 10.

A two-part bearing member 31 and 32 are arranged on the transverse member 10, which bearing members 31 and 32 locate sector-like member 15 by projecting into a throughbore 33 provided therein.

Either side of the two-part bearing member 31 and 32 are spring carrying members 34 and 35 respectively on which are located helical springs 36 and 37 respectively, each of the helical springs 36 and 37 having elongate ends, the spring 36 having elongate ends 38 and 39, the spring 37 having elongate ends 40 and 41.

The spring carrier 34 and bearing part 31 are each provided with respective throughbores 42 and 43 through which pin 44 extends, the pin 44 passing between the elongate ends 38 and 39 spring 36. The bearing part 32 and spring carrier 35 have similar throughbores 46 and 47 respectively through which a pin 48 passes, this pin 48 passing between the elongate ends 40 and 41 of spring 37.

The spring carriers 34 and 35 are secured to the transverse member 10 by threaded fasteners 50 and 51 respectively, thus preventing any relative pivotal movement between the spring carriers 34 and the transverse member 10.

The throughbores locating pins 44 and 48 and holes in the transverse member 10 to accept threaded fasteners 50 and 51 are selected so that the elongate ends of the springs 36 and 37 are positioned as shown in Figure 2 such that a rod 53 located in the throughbore 54 provided in sectorlike member 15 and passed between the elongate ends 40 and 41 and 39 and 38 of springs 37 and 36 respectively thus biasing the sector-like member 15 into the position as shown in the drawings.

The bias position will ensure that as the wheelchair approaches a kerb, step or other irregularity, contact between the kerb or step will first be made between the impact surface 26 of sector-like member 15 which, because of the large radius of curvature of the surface, will contact the kerb or step and tend to cause immediate pivotal movement of the sector-like member 15 relative to the wheelchair, the momentum of the wheelchair driving the wheelchair forwards thus lifting the front end of the wheelchair to allow the relatively small diameter wheels of the wheelchair 17 to be at least partially raised from the ground before making contact with the corner of the kerb or other steplike abutment. The ability, therefore, of the wheelchair to overcome such obstacles is considerably enhanced.

As soon as the front wheels of the wheelchair are situated on the upper surface of the abutment, the springs 36 and 37 will return the sector-like member 15 to its kerb climbing position as shown in the drawings.

When the sector-like member 15 is in its kerb climbing position as shown in the drawings it will not normally be in contact with the ground, therefore preventing any detrimental intrusion on the normal running condition of the wheelchair.

Whereas the kerb climbing device has been shown the have only a single sector-like member, it is envisaged that more than one such sector-like member may be provided, however there are significant advantages both in reducing cost, weight and ease of positioning on a wheelchair without interference only attained in the provision of a single sector-like member Whereas the sector-like member has been shown of frame-like construction, it is envisaged that it may be of any suitable construction so long as the distance between the pivotal axis 60 and the impact surface 26 is greater than the radius R1 of the front wheels of the wheelchair.

In order to prevent ingress of dirt, grit and like foreign bodies that may be detrimental to the efficient pivotal movement of the sector-like member 15, a cover member 61 is provided which also en hances the appearance of the device as a whole.

Claims (13)

CLAIMS:

1. In or for a wheelchair a device to asist in the surmounting of small steps, kerbs and the like said device comprising a transverse member, means for attaching the transverse member at or adjacent each end thereof to a respective side of the wheelchair, said transverse member having secured thereto a sector-like member or assembly mounted for pivotal movement about a pivotal axis and presenting an abutment surface spaced from said pivotal axis by a distance greater than the radius of the front wheels of the wheelchair, and wherein means are provided to bias said sector-like member to a position such that it presents its abutment surface forwardly of the leading part of the front wheels of the wheelchair when in a normal running position.

2. The device as claimed in Claim 1 wherein said sector-like member is mounted for pivotal movement about the longitudinal axis of said transverse member and spring means are provided to bias the sector-like member relative to the transverse member into its position in which it presents its abutment surface forwardly of the circumference of the leading part of the front wheel of the wheelchair.

3. The device as claimed in Claim 1 or Claim 2 wherein said wheelchair is a folding wheelchair having a pair of side frames, each side frame carrying a rear wheel and a front wheel and wherein the sector-like member and transverse member are readily detachable from an in use position or are foldable relative to the wheelchair in a manner to permit of the wheelchair to be folded in a manner to bring the side frames thereof towards each other.

4. The device as claimed in any one of the preceding claims wherein the means for mounting said transverse member on the wheelchair comprises a pair of cup-like or socket members, one provided on a respective side frame of the wheelchair and wherein said transverse member has end regions locatable within said cup-like or socket members.

5. The device as claimed in any one of the preceding claims wherein said sector-like member is of frame-like construction and said transverse member comprises a tubular member.

6. The device as claimed in any one of the preceding claims wherein a single sector-like member is provided and is positioned on said transverse member substantially midway between the ends thereof.

7. The device as claimed in Claim 4 wherein each of said cup-like or socket members is provided with a through bore and wherein said transverse member is provided with a through bore and a pair of elongate members is provided to pass through respective aligned through bores in said transverse member and said cup-like or socket member to securely locate said transverse member in said cup-like or socket members.

8. The device as claimed in any one of the preceding claims wherein said biasing means comprises at least one helical spring located on said transverse member, said helical spring having an elongate end part and wherein said sector-like member carried an abutment extending between said elongate end part of said helical spring, the arrangement being such that movement of said sector-like member from its normal at rest position causes contact between said abutment member and a respective elongate end part of said helical spring to resiliently deform the spring.

9. The device as claimed in Claim 8 wherein a pair of said helical springs are provided, each of said springs being located on said transverse member and positioned on a respective said of said sector-like member.

10. A folding wheelchair comprising a pair of side frames each carrying a front wheel of the wheelchair, said frames being interconnected by link members, the link members enabling a folded condition of the wheelchair in which said side frames are substantially adjacent to each other and an in use position in which the links maintain the wheelchair frames in spaced apart relationship, and wherein the wheelchair is provided with a transverse member having end regions each connectable with a respective side frame of the wheelchair, and wherein said transverse member assists in maintaining the wheelchair in its in use condition, said transverse member being provided with a sector-like member mounted thereon for pivotal movement thereon for pivotal movement relative to the side frames of the wheelchair about the longitudinal axis of said transverse member, said sector-like member having an abutment surface spaced from said longitudinal axis by a distance greater than the radius of the front wheels of the wheelchair, said sector-like member being positioned such that said abutment surface projects forwardly of the forward surface of said front wheels when in their normal running position.

11. A device for assisting a wheelchair in surmounting small steps, kerbs and the like substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

12. A wheelchair comprising a device to assist in the surmounting of small steps, kerbs and the like substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A device having any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.