AU641405B2

AU641405B2 - Folding wheelchair frame

Info

Publication number: AU641405B2
Application number: AU58580/90A
Authority: AU
Inventors: Robert Gilbert Bosshard
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-06-23
Filing date: 1990-06-21
Publication date: 1993-09-23
Anticipated expiration: 2010-06-21
Also published as: AU5858090A

Description

FOLDING WHEELCHAIR FRAME

Field of the Invention

The present invention relates to a folding wheelchair frame and more particularly to such a wheelchair which is foldable about axes transverse to its longitudinal axis. Prior Art

Wheelchairs are well known and generally comprise a frame incorporating a seat and four wheels. The wheels generally comprise a pair of casters at the front of the frame and a pair of drive wheels near the back of the frame. The drive wheels are preferably of such a size that they may be grasped by a user of the wheelchair and used to both propel the wheelchair and to steer it. The frames of such wheelchairs are known to be made foldable about axes substantially parallel to the longitudinal axis of the wheelchair. The present invention is directed to an alternative construction of wheelchair frame which may be folded about axes transverse to the longitudinal axis of the wheelchair. Disclosure of Invention

The present invention consists in a folding wheelchair frame comprising a back portion, a bottom portion pivotably connected at a rear end to a lower end of the back portion, a seat portion pivotably connected at a rear end to the back portion intermediate the ends thereof, and a front portion pivotably connected at its upper end to the seat portion at a position distal to its rear end, the front portion being releasably connectable at a lower end to the front end of the bottom portion, the pivotable connections all being pivotable about axes substantially normal to the longitudinal axis of the wheelchair frame, and the frame being provided with means whereby wheels may be connected to the frame.

The various portions making up the wheelchair frame according to this invention are preferably formed from tubular synthetic plastics members joined by tubular synthetic plastics joiners.

The frame preferably also includes a pair of arm rests each of which is pivotably connected to the back portion and releasably engageable with the front portion or the seat portion. The frame also preferably includes a foot rest pivotably connected to the front portion.

In a preferred embodiment of the invention the means whereby wheels may be connected to the frame comprise an axle extending horizontally through the back portion and projecting at either end therefrom onto which a pair of drive wheels may be connected. A pair of sockets are preferably provided on either side of the lower end of the front portion to respectively receive the spindle of one of a pair of casters.

In another preferred embodiment of the invention the wheels include, and are releasably connected to the axle by, a lock plate. The lock plate comprises a plate with a first hole large enough to freely receive the axle and a superimposed slightly offset smaller hole, said smaller hole being adapted to engage with a circumferential groove on the axle.

It is also preferred that the front portion is releasably connected to the front end of the bottom portion and that the arm rests are releasably engageable with the front portion. Each of the releasable connections is preferably by way of a lock plate located on one of the portions or arm rest which releasably locks with a groove on a shaft on the opposite portion. The lock plate comprising a plate with a large hole and a superimposed slightly offset smaller hole.

In a preferred embodiment of the invention each of the lock plates is slidably mounted in a support member forming part of the hub of a wheel or of a frame member and is biassed into a locked position by a spring. The wheelchair frame according to this invention is preferably fitted with a brake mechanism. This brake mechanism is preferably mounted on a front portion and includes a pivotable handle portion which acts to cause an actuator member to be moved along a substantially linear path between a first position in which it engages a wheel mounted on the frame and a second position in which it is clear of the wheel.

In a particularly preferred embodiment of the invention the actuator is constrained to move along a linear path by engagement with constraining means on the frame and is moved between the first and second position by a pin on the handle portion which projects into a slot in the actuator. The slot is inclined to the axis of movement of the actuator so that it acts as a cam following the movement of the pin as the handle portion is rotated.

Brief Description of Drawings

Hereinafter given by way of example only is a preferred embodiment of the present invention described with reference to the accompanying drawings in which: -

Figure 1 is a side elevational view of a wheelchair frame according to the present invention in an unfolded state and with wheels and brake mechanism attached, Figure 2 is a side elevational view of the wheelchair frame of Figure 1 in a folded state and with the drive wheels and brake mechanism removed,

Figure 3 is a front elevational view of the wheelchair frame of Figure 1 in a folded state and with the drive wheels and brake mechanism removed,

Figure 4 is a front elevational view of the wheelchair frame of Figure 1 in an unfolded state and with wheels attached, .

Figure 5 is a face view of the lock plate preferably used to releasably connect the wheels to the axle, the front portion to the front end of the bottom portion and the lower portion of the arm rests to the front portion or the seat portion,

Fig 6 is a vertical sectional view through the axle and hub with a wheel attached to the frame of Figure 1 with the lock plate in a locked position, and

Fig. 7 is an exploded perspective view of the brake mechanism shown in Fig. 1. Best Mode of Carrying Out the Invention The wheelchair frame 10 comprises a back portion 11, a bottom portion 12, a seat portion 13, a front portion 14, caster wheels 15 and drive wheels 16.

The back portion 11 comprises a length of tubular plastics material bent to form a pair of spaced apart parallel side members 20, a pair of inwardly inclined members 17, at the upper ends of the side members, which are joined by a horizontal member 18. The side members 20 are joined a little above their lower ends by a horizontal synthetic plastics tube 30 which surrounds a horizontal axle 19 which projects on either side from the back portion 11 and to which the drive wheels 16 are releasably connectable. At the lower end of each of the side members a hinge 21 is connected the hinge pivoting about on axis parallel to axle 19 and thus normal to the longitudinal axis of the frame 10.

The bottom portion 12 comprises a pair of side members 22 of tubular synthetic plastics material each connected at one end to one of the hinges 21. The side members 22 are interconnected intermediate their length by a transverse member 23 also formed of a tubular synthetic plastics material.

The seat portion 13 comprises a tubular synthetic plastics member bent to form a pair of side members 24 and a front member 25. The free ends of the side members 24 are pivotably connected to the side members 20 of the back portion 11 by plates 26 which are each pivotable about a pin 27 extending through the associated one of the side members 20.

The front portion 14 comprises a pair of tubular synthetic plastics members 28 connected to the underside of the side members 24 of the seat portion 13. Each of these members 28 carries at its front end a hinge 29 pivotable about an axis normal to the longitudinal axis of the wheelchair. Each of the hinges 29 is connected to the upper end of a tubular synthetic plastics leg 31 which carries at its lower end a fitting 32 which both carries a spindle for one of the casters 15 and includes a tubular socket to releasably receive the tubular side member 22 of the bottom portion 12. A foot rest 33 is provided on the front portion 14 and comprises a first U-shaped member 34 formed of tubular synthetic plastics material and having side arms 35 and a base member 36 interconnecting the upper ends of the side arms 35. The side arm 35 are each connected to the inside frame of the legs 31 and each carries at its lower end a hinge 40. A U-shaped tubular member 33 is connected at each end to one of the hinges 40.

The seat portion 13; the back portion 11, between the pins 27 and inwardly sloping members 17; and the footreεt 33 are each covered with a fabric preferably formed of a synthetic plastics material.

In a preferred version, the seat portion, instead of being covered with fabric, includes a toilet seat. In an especially preferred version the over fabric on the seat portion 13 can be readily removed and a toilet seat can be attached to the seat portion 13.

A pair of arm rests 38 are formed of tubular synthetic plastics material each bent into an L-shape having a horizontal run pivotably connected to one of the side arms 20 of the back portion 11 and a vertical run releasably connected to a lug 39 projecting outwardly from one of the legs 31 of the front portion 14.

In a preferred version when it is desired to convert the wheelchair frame 10 from the unfolded to the folded state the wheels 16 are removed and the arm rests 38 are disengaged from lugs 39 and folded down inwardly, the front portion 14 is released from the bottom portion 12 by release fittings 32. The bottom portion 12 can then fold up against the back portion 11. The foot rest 33 is then folded against the front portion 13. The seat portion 13 is folded up against the back portion 11 carrying with it the front portion 14.

The method of releasable connection of the wheel 16 to the axle 19, the side member 22 to fitting 32 and the armrests 38 to lug 39 is preferably by way of a lock plate 40 as shown in Figure 5.

The lock plate 40 includes a large hole 42 with an offset super imposed smaller hole 43. The lock plate is slidably mounted in a support member 50 and is biassed into the locked position by a spring 45 as shown in Fig 6. The spring 45 can be depressed when wanting to disengage the relevant section, thus moving the lock plate into a position to allow disengagement.

For example, with reference to Fig 6, the wheel 16 is held on the axle 19 by a lock plate 40. The lock plate, when in the locked position is positioned such that the small hole 43 engages with a groove 48 on the axle 19 and firmly holds the wheel 16 to the axle. To release the wheel 16 from the axle 19 the lock plate 40 is moved, preferably by pushing the lock plate on end 41 against a spring 45, such that the large hole 42 aligns with the circumference of the axle 19 thus allowing removal of the wheel.

It is envisaged that a similar lock plate system is used to releasably connect the arm rest 38 to lug 39 and also the side member 22 to fitting 32.

Further, in operation, it is envisaged that the lock plates installed to releasably connect side members 22 to fittings 32 can be simultaneously moved into a release position by deflecting a cable that connects both lock plates and is stretched between the two lock plates parallel to transverse member 23.

The brake mechanism 51 includes a boss 52 mounted on the front portion 14 of the wheelchair frame 10, an actuator 53 adapted to move along a linear path between a first position in which it engages the tyre of wheel 16 and a second position in which it is clear of that tyre, and a handle 54 pivotably mounted on the boss 52.

The boss 52 includes at its free end a parallel sided projection 55. This projection 55 extends into and forms a sliding fit with a parallel sided slot (not shown) on the side of the actuator 53 abutting the boss 52. The cooperation between the projection 55 and the slot in the actuator defines the direction of the linear movement of the actuator.

A pin 56 projects through a hole 57 in the handle 54, through a slot 58 in the actuator 53 and into an axially extending bore 59 in the boss 52. The handle 54 pivots about the pin 56 and the slot 58 allows the actuator 53 to slide relative to the pin 56 between its first and second positions.

The handle 54 carries at one end a pin 60 which extends from the handle 54 in a direction parallel to the pin 56 and into a slot 61 formed in the actuator 53. The slot 61 is inclined to the direction of movement of the actuator 53 such that arcuate movement of the pin 60 as the handle 54 is pivoted provides a cam-like action against the walls of the slot 61 which in turn moves the actuator 53 between its first and second positions. The slot 61 includes a portion 62 at its lower end inclined at right angles to the direction of movement of the actuator 53. When the actuator is fully into its first position the pin 60 enters the portion 62 of slot 61. In this position there is no tendency for the brake to inadvertently release due to the pressure between the actuator 53 and the wheel 16.

It will be appreciated by persons skilled in the art that numerous modifications and alterations could be made to the wheelchair frame according to this invention without departing from the essential features hereinbefore defined. The front portion could rise vertically to connect with the seat portion 13 at its end distal to the back portion 11. It is preferred however that the front portion be angled reasonably to connect with the seat portion 13 intermediate its ends.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: -

1. A folding wheelchair frame comprising a back portion, a bottom portion pivotably connected at a rear end to a lower end of the back portion, a seat portion pivotably connected at a rear end to the back portion intermediate the ends thereof, and a front portion pivotably connected at its upper end to the seat portion at a position distal to its rear end, the front portion being releasably connectable at a lower end to the front end of the bottom portion, the pivotable connections all being pivotable about axes substantially normal to the longitudinal axis of the wheelchair frame, and the frame being provided with means whereby wheels may be connected to the frame.

2. A wheelchair frame as claimed in claim 1 in which the wheelchair frame includes a pair of arm rests each of which is pivotably connected to the back portion and releasably engageable with the front portion or the seat portion.

3. A wheelchair frame as claimed in claim 1 or claim 2 in which the wheelchair frame includes a foot rest pivotably connected to the front portion.

4. A wheelchair frame as claimed in any one of claims 1 to 3 wherein the means for connecting the wheels to the frame comprise an axle extending horizontally through the back portion and projecting at either end therefrom onto which a pair of drive wheels may be connected.

5. A wheelchair frame as described in any one of claims 1 to 4 further comprising sockets on either side of the lower end of the front portion adapted for connection to a pair of castors.

6. A wheelchair frame as claimed in any one of claims 1 to 5 wherein each wheel is connected to the frame by an axle, each wheel including a lock plate slidably mounted on a hub of the wheel, the lock plate having therethrough a large hole and a slightly superimposed offset smaller hole and the edge of said small hole releasably engaging with a circumferential groove on the axle.

7. A wheelchair frame as claimed in any one of claims 1 to 5 wherein the front portion is releasably connected at a lower end to the front end of the bottom portion by a lock plate, the lock plate being slidably mounted on one of the portions, the lock plate having therethrough a large hole and a superimposed slightly offset smaller hole, the edge of the smaller hole releasably engaging with a circumferential groove formed on a pin mounted on the other of the portions.

8. A wheelchair frame as claimed in any one of claims 2 to 5 wherein the arm rests are releasably engageable with the front portion or the seat portion by a lock plate, the lock plate being slidably mounted on either the arm rests or the front portion and/or the seat portion, the lock plate having therethrough a large hole and a superimposed slightly offset smaller hole, the edge of the smaller hole releasably engaging with a circumferential groove formed on a pin mounted on the other of the portions.

9. A wheelchair frame as claimed in any one of claims 6, 7 or 8 wherein the lock plate is biassed into a locking position by a spring.

10. A wheelchair frame as claimed in any one claims 1 to 9 in which a brake mechanism is mounted on the front portion of the wheelchair frame, the brake mechanism including a pivotable handle portion adapted to cause an actuator member to be moved along a substantially linear path between a first position in which it engages a wheel mounted on the frame and a second position in which it is clear of the wheel.