GB2302673A

GB2302673A - Wheelchair kerb climber

Info

Publication number: GB2302673A
Application number: GB9617106A
Authority: GB
Inventors: Derek Alan Charles; Donald W Ruddick
Original assignee: Huntleigh Technology Ltd
Current assignee: Huntleigh Technology Ltd
Priority date: 1993-03-22
Filing date: 1993-03-22
Publication date: 1997-01-29
Anticipated expiration: 2013-03-22
Also published as: GB2276361B; EP0812585A3; DE69410327D1; EP0617943B1; GB9617106D0; GB2276361A; EP0617943A2; EP0617943A3; GB9305921D0; GB2302673B; EP0812585A2

Description

WHEELCHAIR 2302673 This invention relates to wheelchairs and more

particularly to power driven unitary wheelchairs.

It is well known to provide power driven wheelchairs with kerb climbers. The aim of the invention is to provide improvements.

According to the present invention there is provided a wheelchair comprising a main frame having two front wheels, a battery pack, drive means comprising two rear wheel units, and two swinging kerb climbers, each kerb climber being adapted to be pivotable about a respective pivot joint between a first operative position and a second inoperative position wherein each pivot joint comprises a torsion bush. The torsion bush provides a very smooth kerb climbing movement and furthermore has a long life.

Preferably the torsion bush is formed of an annular rubber sleeve held between inner and outer rigid cylindrical sleeves which may be made of metal.

Each kerb climber is preferably connected to one of said inner and outer cylindrical sleeves of a respective pivot joint, the other of said inner and outer sleeves being supported on the main frame.

Each pivot joint preferably additionally comprises locking means and biassing means for biassing its respective kerb climber to engage with said locking means to hold the respective kerb climber in the first or second position.

In a particularly preferred embodiment, each kerb climber is connected to the inner cylindrical sleeve, the outer cylindrical sleeve being mounted on a foot rest which is removably mountable on the main frame.

According to another aspect of the present invention there is provided a foot rest for releasably mounting on a power driven wheelchair, the foot rest comprising a support member, a foot plate and swinging quadrant kerb climber mounted on the support member at a pivot joint comprising a torsion bush, the kerb climber being pivotable and the joint between a first operative position and a second inoperative position.

The present invention will now be described in more detail by way of example with reference to the accompanying ddrawings, in which:

Figure 1 illustrates a front portion of a wheelchair showing a kerb climber in the operative position; Figure 2 illustrates a front portion of a wheelchair showing a kerb climber in the inoperative position; Figure 3 shows an exploded view of the kerb climber of Figures 1 and 2; Figure 4 shows a sectional view of the pivot joint of the kerb climber of Figure 3; and Figure 5 shows an end view of the pivot joint of Figure 4.

Figures 1 and 2, illustrate a foot rest support member 34 also providing support for a swinging quadrant kerb climber 100.

Because the foot rests are removably mountable on the wheelchair main frame 10, the kerb climbers are also removably mountable on the wheelchair.

Each kerb climber comprises an arm 102 and an arcuate foot 104, the foot being provided with a rubber shoe 106 in the conventional way. The arm 102 is connected to the support member 34 at a pivot joint 108 to be described in more detail hereinafter. When the arm is in the operative position shown in Figure 4A and the front wheels 18 of the chair approach a kerb, the foot 104 will meet the kerb before the wheels and act to lift the front wheels smoothly over the kerb, as is already well known.

The present invention allows the kerb climbers to be moved from the operative to the inoperative position as shown in Figure 2 when the kerb climbing facility is not required e.g. indoors.

Referring now to Figures 3 to 5, the pivot joint 108 comprises a cylindrical housing 110 fixed to the support member 34 by welding or any other suitable means. A further cylindrical housing 112 is formed at the proximal end of the arm 102, having substantially the same outer diameter as housing 110 and having an extending portion 114 of smaller diameter which fits inside housing 110. A torsion bush connector 116 fits inside housing 110. The connector 116 has protruding stem 118 with flats 120 which fits through a cooperating aperture in housing 112, such that the stem 118 engages with the housing 112 and rotates with the housing 112. A nut 122 engages with screw threads 124 on the stem 118 to secure the connector 116 inside housings 110 and 112.

A pair of diametrically opposed slots 126 are provided in the free end of the housing 110, and two angularly spaced apart pairs of diametrically opposed slots 128 and 130 are provided in the corresponding free end of connector 116. A locating or locking strip 132 locates in the pair of slots 126 in the housing and in one of the two pairs of slots in the connector. An end cover 134 fits behind the locking strip 132 and is held in place by a pin 136 which extends through the locking strip, through the connector and into the interior of housing 112. Alternatively, the locking strip could be held to the end cover by welding or in any other suitable way. A helical spring 138 is located between the nut 122 and a further nut 140 fitted on to the threaded end 142 of the pin 136. A press fit plug 144 is fitted into the end of the housing 122 to cover the internal parts of the pivot joint.

As can be seen most clearly in Figure 4, the connector 116 comprises an inner sleeve 146 extending to form the stem 118, and an outer sleeve 148, incorporating the slots 128 and 130, the inner and outer sleeves being connected together by means of an annular rubber bush 150.

When the pivot joint is in the position shown in Figure 4, any rotary movement of the kerb climber arm 102 about the axis 152 of the pivot joint rotates housing 112 and thus rotates inner sleeve 146 via flats 120. The locking strip 132 is located in the slots on both the outer sleeve 148 and on the housing 110 thus locking the outer sleeve to the housing to prevent rotation o the outer sleeve. The rubber bush 150 between the inner and outer sleeves 146 and 148 acts as a resilient torsion member resisting excessive rotation of the inner sleeve but permitting about 45 degrees of rotation between the inner and outer sleeves when the arm 102 rotates during kerb climbing, the rubber torsion bush then restoring the arm 102 to its operative rest position after kerb climbing is completed.

The use of such a rubber torsion bush produces a very smooth kerb climbing movement and the bush has proved to have a very long life.

When the kerb climber arm 102 is in the operative position shown in Figure 4A, the locking strip 132 is located in slots 126 on the housing 110 and in slots 128 in the connector 116, as shown in Figure 5, where the end cover 134 has been removed. In order to move the arm 102 to the inoperative position shown in Figure 2, the arm and housing 112 are pulled longitudinally along axis 152 in the direction of arrow 154 against the bias of spring 138. This also pulls connector 116 in the direction of arrow 154 since the connection is joined to the housing 112 by the nut 122. Once the slots 128 in the outer housing 148 of the connector have disengaged from the locking strip 132, the whole connection is free to rotate with the arm 102 about axis 152 until the slots 130 in the outer housing are aligned with the locking strip 132. Spring 138 then biasses the connector 116 in the direction opposite to that of arrow 154 to locate slots 130 over the locking strip to hold the connector, and therefore the housing 112 and the arm 102 in the inoperative position shown in Figure 2.

Although the kerb climbers of the present invention have been described with reference to a unitary collapsible wheelchair, clearly they could be fitted with only minor modifications to any other power-driven wheelchair. However, the embodiment of the invention described above is particularly preferred since it provides a wheelchair which can be fully dismantled into easily portable component parts for storage and transportation.

Claims

1. A wheelchair comprising a main frame having two front wheels, a battery pack, drive means comprising two rear wheel units, and two swinging kerb climbers, each kerb climber being adapted to be pivotable about a respective pivot joint between a first operative position and a second inoperative position wherein each pivot joint comprises a torsion bush.

2. A wheelchair according to Claim 1 wherein the torsion bush comprises an annual rubber sleeve held between inner and outer rigid cylindrical sleeves, which may be of metal.

3. A wheelchair according to Claim 2 wherein one of the inner and outer sleeves is secured to the kerb climber and the other of the inner and outer sleeves is secured to the portion of the wheelchair on which the kerb climber is mounted.

4 A wheelchair according to Claim 3 wherein the other of the inner and outer sleeves is securable to the portion of the wheelchair on which the kerb climber is mounted in two alternative positions to provide, respectively, the first and second positions of the kerb climber.

5. A wheelchair according to any one of Claimsl to 4 wherein each pivot joint additionally comprises locking means and biassing means for biassing its respective kerb climber to engage with said locking means to hold the respective kerb climber in the first or second position.

-7 0 c 0 0. ' o.4-, h 4 4 4

6. A wheelchair according to any one of Claims 1 to 5 wherein each kerb climber is connected to a foot rest assembly of the wheelchair which, in turn, is removably mounted on the main frame whereby each kerb climber and its associated foot rest assembly may be removed, as a unit, from the remainder of the wheelchair.

7. A wheelchair comprising a frame and at least one foot rest assembly releasably mounted on the wheelchair frame, the foot rest assembly comprising a support member, a foot plate, and a swinging kerb climber mounted on the support member by a pivot joint comprising a torsion bush, the or each kerb climber being pivotable about the pivot joint between a first operative position and a second inoperative position.

8. A wheelchair, substantially as hereinbefore described with reference to the accompanying drawings.