NZ618996B2 - A Rear Steer Portable Wheelchair - Google Patents

Abstract

618996 A rear steer wheelchair is collapsible inwardly by pivotable links connected between side frames of the wheelchair. The side frames are each top and bottom tubes. A pull handle is provided to unlock the pivotable links so as to collapse the wheelchair.

Description

A REAR STEER PORTABLE WHEELCHAIR FIELD OF THE INVENTION The present invention relates to improvements in the design of a rear steer portable wheelchair. The portable wheelchair is collapsible for ease of deployment, handling and transport, while also providing a strong and manoeuvrable wheelchair.

BACKGROUND OF THE INVENTION Portable and collapsible wheelchairs have been developed in the past and one such hair is described in US5857688. r no rear steer wheelchairs have been described that provide a lightweight and portable wheelchair with an ability to be maneuvered over tely rough n.

It is therefore an object of the invention to provide the public with a useful choice or to at least provide the public with a useful alternative.

SUMMARY OF THE ION The present invention es a rear steer portable and collapsible wheelchair having; (a) a pair of side frame assemblies each having an upper tube member and a lower tube member and forward and aft sections; and (b) a scissor hinge assembly mounted on the side frame assemblies, which hinge extends centrally between the side frame assemblies, which hinge ly is foldable from between an in-use on to a collapsed position; (c) a pair of front wheels with each wheel being attached to the forward section of the side frame assemblies, (d) a pair of rear steer wheels with each wheel being attached to the aft section of the side frame assemblies, (e) a pair of collapsible pushing arms that are attached to the side frame assemblies, (f) a pair of arm rests that are attached to the side frame assemblies, (g) a back support means, which is attached to the aft section of at least one of the side frame assemblies; and (h) a seat t that extends above the scissor hinge and between the side frame assemblies; wherein in use the wheelchair is ed by (i) spreading the side frame assemblies apart to pull the scissor hinge into a locked position and (ii) putting the pair of collapsible pushing arms into a locked in-use position and further wherein in use the wheelchair is collapsed by (i) pulling a handle proximate the central position of the scissor hinge to release the locked position of the scissor hinge to pull the side frames assemblies together, and (ii) collapsing the collapsible arms from their in-use locked position to a folded out of use position into a compact, y lifted and ortable configuration.

In one embodiment, the scissor hinge includes a pair of geared hinge linkages.

In one embodiment the back support means is secured on a pair of back support arms, each back support arm being attached to the aft section of the proximate side frame assembly.

In another embodiment the rear wheel is biased by way of a biasing member to keep the rear steer wheel d in a substantially straight ahead .

In another embodiment the pair of collapsible pusher arms e ergonomically angled handles.

In another embodiment the pair of collapsible pusher arms e a brake lever that activates a front wheel brake in at least one of the front wheels.

In another embodiment the wheelchair is collapsible into a size no greater than about 800mm x about 350mm x about 700mm.

In one embodiment the wheelchair includes a pair of foot rests that are secured to the forward section of the side frame assembly. Preferably the foot rests can pivot through about 90 degrees relative to the side frame assembly.

In another embodiment each foot rest is designed to rotate upwardly against the side frame assembly. More preferably each foot rest is designed to rotate upwardly against the side frame assembly and then to rotate towards the seat support. In an alternative embodiment each foot rest is designed to rotate towards the seat support and then to rotate upwardly against the side frame assembly. In another embodiment the foot rest es a foot restraint.

In another ment the wheelchair further includes a lap safety belt for use by an occupant.

In another embodiment the wheel chair includes at least one hand brake that acts upon at least one of the front wheels.

In another embodiment the handle of the wheelchair that in use is pulled to break the scissor hinge upon se of the wheelchair is also adapted in size and shape to provide a carry handle for the wheelchair in its collapsed configuration.

The ing brief summary broadly describes the features and technical advantages of certain embodiments of the present invention. r technical ages will be described in the ed description of the invention that follows. Novel features which are believed to be characteristic of the invention will be better understood from the detailed description of the invention when considered in connection with any accompanying figures and examples.

However, the s and examples provided herein are intended to help illustrate the invention or assist with developing an understanding of the invention, and are not intended to be definitions of the invention's scope.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a perspective view of one embodiment of a wheelchair.

Figure 2 shows a perspective view of the wheelchair shown in Figure 1 without the seat and back rest in place.

Figure 3 shows a side view of the wheelchair shown in Figure 1.

Figure 4(a) shows a top view of the wheelchair in Figure 1 in a collapsed state.

Figure 4(b) shows a side view of the wheelchair in Figure 1 in a collapsed state.

Figure 4(c) shows a bottom view of the wheelchair in Figure 1 in a collapsed state.

Figure 4(d) shows a front view of the hair in Figure 1 in a sed state.

Figure 5 shows a perspective view of the wheelchair in Figure 1 in a collapsed state.

Figure 6(a) shows a side view of the right side frame assembly of the wheelchair.

Figure 6(b) shows a top perspective view of the side frame assembly shown in Figure 6(a).

Figure 6(c) shows a bottom perspective view of the side frame assembly shown in Figure 1 in a collapsed state.

Figure 7(a) shows a scissor hinge of the present invention as it would appear in a wheelchair ready for use.

Figure 7(b) shows a scissor hinge of the present invention as it would appear in a wheelchair that has been collapsed for transport.

Figure 8(a) shows the ng of a front wheel to the forward section of the side frame assembly.

Figure 8(b) shows the mounting of a front wheel hand brake proximate the forward section of the side frame assembly.

Figure 8(c) shows the mounting of a front hub disc brake between the front wheel and the side frame assembly and also the components that allow for the mounting of the front wheel hand brake shown in Figure 8(b).

Figure 9(a) shows a side view of the relationship between the handle, arm rest and the upper tube of the side frame assembly in the position when the wheelchair is in deployment mode.

Figure 9(b) shows a side view of the detail from section c of Figure 9(a).

Figure 9(c) shows a side view of the onship between the handle, arm rest and the upper tube of the side frame assembly when the hair is in a partially collapsed mode.

Figure 9(d) shows a side view of the relationship n the handle, arm rest and the upper tube of the side frame assembly when the wheelchair is in sed mode.

Figure 10(a) shows a side view of the rear wheel connection to the aft section of the side frame assembly where the rear wheel is being propelled in a straight ahead direction.

Figure 10(b) shows a side view of the rear wheel connection to the aft section of the side frame assembly where the wheel is being turned.

Figure 10(c) shows a perspective ed view of the components of the rear wheel mounting connection to the side frame assembly.

Figure 10(d) shows a side view of the rear wheel showing the trail of the hub of the wheel relative to the centre of the pivot mount of the wheel to the side frame.

Figure 11 shows the top and bottom perspective views of a rigid d plastics seat for use in the wheelchair of the invention.

Figures 12(a) to 12(c) show the dual rotation feature of a footrest of the invention.

DETAILED DESCRIPTION OF THE INVENTION Prior to setting forth the invention in detail, it may be helpful to provide definitions of certain terms to be used herein.

The term “about” as used herein in connection with a referenced numeric indication means the referenced numeric indication plus or minus up to 10% of that referenced numeric indication. For example, the ge “about 50” units covers the range of 45 units to 55 units.

With reference to Figures 1 to 3 a wheelchair 1 of one embodiment of the invention is shown. The wheelchair includes a pair of side frame assemblies, 2 and 3 respectively. The side frame lies 2 and 3 are equivalent in configuration, shape and dimensions except for the fact that each ly is a mirror image of the other. The wheelchair 1 has a right side frame assembly 2 and a left side frame assembly 3 when looking at the wheelchair from the back of the chair to the front of the chair. The shape and configuration of the right hand side frame assembly 3 is shown in particular detail in Figures 6(a) to 6(c). The side frame assemblies are constructed from metal tubing, having a round, elliptical or square cross section. The tubing is ably made from aluminum or some other metal preferably light weight metal of about 25 mm -32 mm (1 inch – 11/4 inch) in er or cross sectional width and depth. The side frame assembly includes an upper tube member 4 and a lower tube member 5. The upper and lower tube members are shaped by bending around formers into the desired shape. The upper tube member 4 is ted to the lower tube n in both the forward section 6 and aft section 7. The lower and upper tube s are joined together at their respective forward and aft sections by welds. The upper tube member 4 of the side frame assembly also provides an arm rest link 8 that is connected by a bolt and bracket system to the upper tube 4. With reference to Figures 6(a) to 6(c) the side frame assemblies include an aft upper tube bracket 9 that is used to t to a back support arm 10 as shown in Figures 2 and 9(a).

The aft section 7 of the side frame assembly also includes a rear wheel mounting bracket 11. The forward section 6 of the lower tube member 5 provides a mount 12 for a front wheel 13 (as shown in Figure 8) The forward section of the upper tube member 4 is adapted to e means to mount a foot rest 14 (as shown in Figure 1) and also means for mounting a mount 15 for a front wheel hand brake 16. The f oot rest 13 in this embodiment is a standard off the shelf hinged foot rest constructed from a light plastics material. Preferably the foot rest is pivotable through about 90 degrees relative to the side frame to ease occupant ingress. The height of the footrests may be positioned at a plurality of heights along the upper side frame 4 to suit the occupant as ed. As shown in the foot rest embodiment in Figures 12(a) to 12(c) a dual rotation foot rest mechanism is illustrated. The foot rest 14 is first rotatable about 90 s towards the side frame as shown in Figure 12(c) about a first axle or pivot 121. The folded footrest 14 is then further rotatable towards the seat of the wheelchair about a second pivot point 122. The footrest when folded about the second pivot point 122 (as shown in Figure 12(c) shows the foot rest folded against the side frame and out of the space through which a user must step to get into or out of the seat.

In one embodiment the foot rest may include a foot restraint, such as but not limited to a foot strap that would go over the foot of the wheelchair occupant and where the strap can be tightened to secure the occupant’s foot to the foot rest.

The front and rear wheels 13 and 17 respectively may optionally include mudguards to protect the chair occupant from splashes or dirt and dust ng of the wheels. The front wheel 13 is preferably between 8-20 inches in diameter (more preferably around 16 inch) and includes preferably plastic or metal spoked rims, or the front wheel is a composite wheel, which by way of example is, constructed from c spokes and an um rim. The front wheel preferably has either an inflatable pneumatic tyre or polyurethane foam filled rubber tyre. The size of the rear wheel is a 12.5 inch wheel but it is envisaged that a range of wheel size from 6 inch to 14 inch would be suitable.

The rear wheel preferably includes c or metal spoked rims, or the rear wheel is a composite wheel, which by way of example is, constructed from plastic spokes and an aluminum rim. The rear wheel preferably has either an inflatable pneumatic tyre or polyurethane foam filled rubber tyre. It is also preferred that the front and ally the rear wheels are removable from their axle mounts by a quick release axle, that is a hub push button release system or spring clip. It is also preferred that the front wheel includes an internal expanding shoe drum brake 18 as shown in Figure 8(c) that is cable operated. With reference to Figure 1, the cable (not shown) for the brake 18 runs through to the pushing handle 19 proximate which a brake handle 20 is provided to activate the brake. In one embodiment it is also ged that it may be desirable to have the two front brakes activated by a single brake lever that may activate both front wheel drum brakes 18 simultaneously.

The collapsibility of the wheelchair is achieved by a scissor hinge assembly 21 as shown in Figures 7(a) and 7(b). The scissor hinge assembly is mounted to the pair of side frames by way of a pair of hinge mounts 22 and 23 respectively that are positioned between the upper and lower tube members of the side frame assemblies 2 and 3. The hinge mounts 22 and 23 are located ntially lly along the length of the upper and lower tube members of the side frame assemblies as shown in Figures 6(a) to 6(c). The hinge mounts span between the upper and lower tube members. With reference to Figure 7(a) the scissor hinge includes a pair of geared hinge units 24 and 25 respectively. Each geared hinge unit includes an upper hinge linkage (upper hinge linkages (26 and 28) respectively and lower hinge linkages (27 and 29)) respectively. However, it is to be appreciated that these hinge units 24 and 25 could be rotated 90 degrees to provide a front and rear/aft facing linkage. The hinge linkage s about a pivot point through a pair of involute sector spur gears 30 and 31 that positively engage with each other and lead to a locked hinge arrangement when the wheel chair is ed for use. The gears 30 and 31 maintain the correct relative positions of the linkages. In use, the arrangement of the hinge linkages is such that you can achieve a locking action brought about by an over centre arrangement/geometry of the linkages. Preferably the scissor hinge assembly would include a positive stop on the upper and lower linkages that prevents the linkages from clashing around the central pivot section 32. In use, when the wheelchair 1 is being sed, the hinge linkages are broken by pulling on a handle 33 attached to the upper pair of es 26 and 28 at the central pivot section 32. With reference to Figures 1 and 5 the handle 33 is pulled to extend h the seat base 34 and collapsed back rest 35 to bring the side frame lies 2 and 3 of the wheelchair 1 together. It is to be appreciated that the hinge linkages may be made out of a lightweight metal (such as aluminum, titanium or pressed steel) or a rigid plastics al or a composite or plastic and metal.

With reference to Figures 1 and 2, the pair of side frame assemblies 2 and 3 also support a pair of arm rests 36 and 37 by way of an arm rest link 8 (see Figure 6(a)-6(c) by a bolt and bracket system. A pair of conventional arm rests 36 and 37 are provided and are shown in the embodiment ified.

It is to be appreciated that unconventional or modified arm rests may be provided where an occupant’s specific needs require a modified arm rest.

With reference to Figure 9 (a) and section c as shown expanded in Figure 9(b) the rear of the arm rest 36 is mounted partway along the length of the pushing handle and the back rest upright 10. It can be seen from Figure 9(a) that there is a four bar linkage hinge between the collapsible pushing arms 37 and the arm rest 36. As shown in Figure 9(b) the bracket for the aft section of the arm rest 36 also mounts the bracket or link 38 for the collapsible pushing arm 37. The pushing arm 37 at its lower end is lly attached to the side frame assembly 2 by an arm rest link 8. The arm rest link 8 is a folded plate, die cast or extrusion linkage which also connects to an arm rest linkage 44.

The connection between the pushing arm 37 and the pushing arm link 40 is controlled by a releasable or retractable locking pin 41 that is mounted on the lower part of the pushing arm 37. The locking pin 41 ts the rotation of the g handle 37 relative to the pushing arm link 40. The locking pin 41 slides in a sleeve 42 mounted on the pushing arm 37. The locking pin 41 can be retracted clear of the pushing handle link 40 by retracting the pin into the sleeve 41 by an actuating means 43. The pushing arm 37 at its upper end is shaped and dimensioned to provide an ergonomically positioned handle 19.

The pushing handle 19 also supports a brake lever 20 that controls in this example front wheel brakes and ally other controls such as, rear brakes and rear wheel pivot limiters or the like.

The brake levers 20 also preferably include a locking pin (not shown) so that the brakes can be engaged on a permanent basis until selectively disengaged.

With reference to Figure 1, the back rest uprights 10 may optionally include a support link between the back rest ts. The back rest 35 and seat support 34 may be made from a wear resistant fabric, such as an acrylic canvas or a nylon canvas. Alternatively the back rest and or seat support may be a solidly contoured detachable insert that is put in place as required. A suitable shaped seat t is shown in figure 11. The molded plastic fibreglass or plastics seat base 45 would clip onto the side frame and would optionally e a foam pad on the seat pad to provide cushioning for the nt. The back rest may also include a molded plastic or fibreglass support that slides over the back rest uprights. The back rest may be adapted to include pockets or fixtures to secure water bottles and/or to provide a head support for the occupant. Similarly the back rest or the seat base may be d to provide fixtures to secure or n a catheter bag or other medical devices required by the wheelchair occupant.

With reference to Figures 10(a) to 10(d) each rear wheel 17 is mounted to the side frame assembly by a leg 45 sliding into a rear wheel mounting bracket 11. It is also envisaged that a quick release mechanism provided by a depressible pin that fits into a complimentary hole on the leg 46 would allow for the rear wheel 17 and leg 46 to be quickly d for compact transport reasons. To enhance the stability of the rear steer wheelchair, the connection of the rear wheel 17 to the side frame assembly 2 has been achieved by using a biasing swivel connection assembly such that when the chair is being propelled forward the wheel trails behind the leg by a trail distance of around 50-60 mm. This is achieved by using a biased swivel connection 47 to (i) keep the wheel in a trailing position and discourage the wheel from g and becoming unstable and (ii) to hold the wheel in a forward facing position when the wheel chair is collapsed and folded up into a packed on. The biasing may be by spring 48 and face cam 49, 50 as shown in Figures 10(a) – 10(c), but it is to be appreciated that other biasing means may be employed. One such biasing means would be the use of a detent system or a pin system that biases the wheel into the desirable In the embodiment illustrated the angle of the side frame extending to the leg relative to the normal of the ground is about 4 to 8 degrees. In the embodiment shown in Figure 10(d) the trail 51 of the wheel is about 57 mm.

It is to be appreciated that the overall centre of gravity of the chair, and therefore stability of the chair, can be modified by moving the side frames forward or back relative to the wheels of the chair. Similarly adjustments in the height of the seat relative to the wheels will also affect the l centre of gravity of the chair.

USE OF THE WHEELCHAIR The wheelchair is expected to be used as any other standard wheelchair would be used. However, with the rear steer aspect and ease of deployment and collapsibility it is anticipated that this wheelchair will appeal to those wheelchair users who like getting out and going places. Furthermore with the use of larger front wheels with wider pneumatic tyres the wheelchair has the ability to go over rougher terrain with ease. ional wheelchairs will stop if their small front wheels hit a pebble or some other imperfection in the ground surface. It is hoped that people associated with wheelchair users will be more inclined to take the wheelchair to places that might not have been suitable for more traditional style wheelchairs.

In use, the hair can be easily deployed by pulling the side frames of the wheelchair apart to lock the scissor hinge in a locked position. The pushing arms of the wheelchair can be readily pulled back into a locked position.

When the occupant is oned in the chair and secured by an optional lap belt, the chair is ready for use. Once the chair has been used and needs to be transported say in a vehicle the pushing arms of the wheelchair can be folded down towards the seat of the chair, the handle that brakes the locked scissor hinge configuration is pulled and passed through the seat of the chair to collapse the scissor hinge and y bring the side frames of the chair closer together. The scissor hinge handle can then be used as a carry handle to carry the wheelchair in its sed configuration. Various views of the collapsed wheelchair are shown in Figures 4(a) to 4(c) and Figure 5.

The present invention and its embodiments have been described in detail.

However, the scope of the present ion is not intended to be limited to the particular embodiments of the invention described in the specification.

Various modifications, substitutions, and variations can be made to the disclosed material without departing from the spirit and/or ial characteristics of the present invention. Accordingly, one of ordinary skill in the art will readily appreciate from the disclosure that later modifications, substitutions, and/or variations performing ntially the same function or achieving substantially the same result as embodiments bed herein may be utilized according to such d embodiments of the present invention.

Thus, the following claims are intended to encompass within their scope modifications, substitutions, and variations to the embodiments of the invention disclosed herein.

Claims (10)

Claims

1. A rear steer portable wheelchair having; (a) a pair of side frame lies each having an upper tube member and a lower tube member and forward and aft sections; and (b) a scissor hinge assembly mounted on the side frame assemblies, which hinge assembly extends centrally between the side frame assemblies, which hinge assembly is foldable from between an in-use position to a collapsed position, and includes a hinge comprising a pair of geared hinge es; (c) a pair of front wheels with each wheel being attached to the forward section of the side frame assemblies, (d) a pair of rear steer wheels with each wheel being attached to the aft section of the side frame assemblies, (e) a pair of collapsible pushing arms that are attached to the side frame assemblies, (f) a pair of arm rests that are attached to the side frame assemblies, (g) a back support means, which is attached to the aft section of at least one of the side frame assemblies; and (h) a seat support that extends above the scissor hinge and between the side frame lies; n in use the hair is deployed by (i) spreading the side frame assemblies apart to pull the r hinge into a locked position and (ii) putting the pair of collapsible pushing arms into a locked in-use position and further wherein in use the wheelchair is collapsed by (i) pulling a handle proximate the central position of the scissor hinge to release the locked position of the scissor hinge to pull the side frames assemblies together, and (ii) collapsing the sible arms from their in-use locked position to a folded out of use on into a compact, readily lifted and transportable configuration.

2. The wheelchair as claimed in claim 1 wherein the back support means is secured on a pair of back support arms, each back support arm being attached to the aft section of the proximate side frame assembly.

3. The wheelchair as claimed in claim 1 or 2 wherein the rear wheel is biased by way of a biasing member to keep the rear steer wheel aligned in a ntially straight ahead manner.

4. The wheelchair as d in any one of claims 1 to 3 wherein the pair of collapsible pushing arms include ergonomically angled handles.

5. The wheelchair as claimed in any one of claims 1 to 4 wherein the pair of collapsible pushing arms include a lever brake that activates a front wheel brake in at least one of the front wheels.

6. The hair as claimed in any one of claims 1 to 5 wherein the wheelchair is collapsible into a size no greater than about 800mm x about 350mm x about 700mm.

7. The wheelchair as claimed in any one of claims 1 to 6 wherein the wheelchair includes a pair of foot rests that are d to the forward section of the side frame assembly.

8. The hair as claimed in any one of claims 1 to 7 wherein the wheelchair further includes a lap safety belt for use by an occupant.

9. The wheelchair as d in any one of claims 1 to 8 wherein the wheel chair includes at least one hand brake that acts upon at least one of the front wheels.

10. The wheelchair as claimed in any one of claims 1 to 9 wherein the handle that in use is pulled to break the scissor hinge upon collapse of the wheelchair is also adapted in size and shape to provide a carry handle for the wheelchair in its collapsed configuration.