Wheelchairs

#The present invention relates to wheelchairs, particularly but not exclusively to manual and attendant push wheelchairs.

#Conventional wheelchairs are typically built around a chassis. Often the core of the chassis is a rectangular box-frame, which serves as the principal load-bearing structure of the wheelchair. Components, such as the wheels and seat, and accessories, such as footrests and armrests, can be mounted directly on the chassis.

#The inventors have realised that although conventional wheelchairs can be adequate for their essential purpose of providing mobility for persons who are unable to walk (hereinafter referred to as invalids), they have drawbacks. For example, the chassis cannot be readily modified to accommodate invalids of extreme sizes. In addition, the chassis and the components and accessories mounted thereon often cannot be adjusted easily to suit the needs of an invalid, e.g. with particular postural requirements. This means that known wheelchairs may have to be separately modified to suit individual needs. Furthermore, conventional wheelchairs can on the whole be uncomfortable for the invalid and, where they are of the attendant push type, be inconvenient for the attendant to use. A significant drawback is a tendency towards chassis weakness that can make the conventional wheelchair unsuited to withstanding the forces exerted during a crash. This may be particularly important when an invalid is sat in the wheelchair when travelling in a motor vehicle.

#Specific embodiments of the different aspects of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings in which:

#FIG. 1 is a front perspective view from one side and above of a wheelchair embodying one aspect of the present invention;

#FIG. 2 is a rear perspective view from one side and above of the wheelchair of FIG. 1;

#FIGS. 1 and 2 show a wheelchair (10) comprising a chassis (12) and a seat member (14) mounted on the chassis (12). The chassis (12), which is shown in more detail in FIG. 3, comprises a horizontal support beam (16) which extends between a pair of spaced apart side elements (18). Each side element (18) depends from the support beam (16) and has a first part (20) supporting a front wheel (22) and a second part (24) supporting a rear wheel (26). The first and second parts (20,24) are disposed on opposite lateral sides of the support beam (16). Each front wheel (22) is part of a castor assembly (30) which is mounted on the first part (20). A bracing member (32)—parallel to and spaced from support beam (16)—extends between the second parts (24).

#Each second part (24) includes a forked arrangement (40) with tines (42) defining therebetween a channel (44) in which at least part of the respective rear wheel (26) is received. The tines (42) may include two or more spaced-apart axle couplings (46), each capable of receiving the rear axle (48) of one of the rear wheels (26). The axle couplings (46) allow the wheel base “L”—that is, the spacing from the front axle (50) to the rear axle (48)—to be varied. Each rear wheel (26) may be mounted in any one of the axle couplings (46) using so-called “quick release” couplings.

#FIG. 4 illustrates an alternative chassis arrangement (12′), in which features in common with those of FIG. 3 are labelled with the same reference number, marked with a “′”. As can be seen, the second parts (24′) of the side elements (18′) are a mirror image of the first parts (20′), with all four wheels (22′ and 26′) each being part of a respective castor assembly (30′).