WO2011048028A1

WO2011048028A1 - A walking aid

Info

Publication number: WO2011048028A1
Application number: PCT/EP2010/065555
Authority: WO
Inventors: Conall Stokes
Original assignee: Conall Stokes
Priority date: 2009-10-21
Filing date: 2010-10-15
Publication date: 2011-04-28

Abstract

A walking aid comprises a shaft having upper and lower axially disposed sections (12, 14), the upper section having a handle (16) and the lower section having a ground-engaging foot (20). The end (26) of the upper section slidably and rotatably engages in the open end of the lower section such that the upper section is rotatable relative to the lower section about the axis of the shaft. A spring inside the shaft holds the upper and lower sections together such that the upper and lower sections may be disengaged and folded over against the bias of the spring.

Description

A Walking Aid

This invention relates to a crutch, cane or similar walking aid.

A problem with conventional crutches and like walking aids is that in use a twisting motion of the user on the upper end of the crutch after it is placed on a ground can cause undue wear on the rubber foot typically

provided at the lower, ground-engaging the end of the crutch. This can cause the crutch to fail, for example by exposing bare metal and causing the crutch to slip on the ground. US 4,947,882 discloses a walking stick comprising a shaft, a foot defining a supporting polygon, and a ball- and-socket joint connecting the shaft to the foot. A resilient means keeps the shaft in a predetermined position relative to the foot, such that when the foot stands on substantially horizontal ground and the

resilient means are in a holding position, the shaft remains in a substantially vertical position.

According to the present invention there is provided a walking aid comprising a shaft having upper and lower axially disposed sections, the upper section having a handle and the lower section having a ground-engaging foot at its free end, wherein the end of one of the upper and lower sections slidably and rotatably engages in an open end of the other section such that the upper section is rotatable relative to the lower section about the axis of the shaft, the walking aid further comprising at least one spring inside the shaft holding the upper and lower sections together such that the upper and lower sections may be disengaged and folded over against the bias of the spring .

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows an adjustable crutch according to a first embodiment of the invention in its "in use"

configuration.

Figure 2 shows the crutch partially folded over for storage or carriage. Figure 3 shows the crutch fully folded over.

Figure 4 is a cross-section through the centre portion of a second embodiment of the invention. Referring to the drawings, a forearm crutch comprises a hollow tubular lightweight metal shaft 10 having upper and lower axially disposed sections 12, 14 respectively. The upper section 12 has a conventional handle 16 and forearm support 18. The lower section 14 has a ground- engaging foot at its lower, free end, the foot 20 comprising a rubber stopper 22,24.

The lower end of the upper section 12 has a portion 26 of reduced diameter which slidably and rotatably engages in the open upper end 28 of the lower section 14; thus the upper section 12 can rotate relative to the lower section 14 about the axis of the shaft. A compression spring 30 surrounding the portion 26 bears at each end upon respective collars 32, 34 to bias the upper and lower sections 12, 14 away from one another in the axial direction of the shaft.

The upper and lower sections 12, 14 are held together in sliding engagement by at least one tension spring (not shown) inside the shaft, which acts in opposition to the compression spring 30. This allows the upper and lower sections 12, 14 to be pulled apart and folded over against the bias of the tension spring, which remains attached to both the upper and lower sections by at least one chain 36 (Figures 2 and 3) . The lower section 14 comprises coaxial inner and outer parts 14a, 14b telescoped together, the overall length of the lower section 14, and hence the overall length of the crutch, being adjustable by drawing the inner part 14a to a greater or lesser out of the outer part 14b. Any desired length setting is maintained by a conventional tab stop 38.

The foot 20 is connected to the free end of the lower section 14 by a strong tightly-wound steel spring 40 which allows a degree of lateral deflection of the foot relative to the free end of the section 14.

In use the crutch is employed as normal. However, as the upper section 12 of the shaft is free to rotate relative to the lower section 14, the rubber pad 22 engaging the ground is not subject to the same scrubbing action as in the prior art. Also, the spring 40 joining the foot 20 to the lower section 14 allows the entire shaft 10 to pivot relative to the foot in use, again reducing wear on the rubber pad. The compression spring 30 forms a shock absorber against the shock of the crutch impacting the ground . In further variations, a second compression spring (not shown) can be fitted over the inner part 14a between the stopper 24 and the outer part 14b again to absorb shock. Where the spring 40 is employed, the second spring needs to be flexible enough to bend with the flexion of the spring 40 while providing its additional shock

absorption .

In a second embodiment, Figure 4, the upper shaft section 12 comprises a main section 12B with a relatively short tubular extension 12A at its lower end, and the lower shaft section 14 comprises a main section 14B with a relatively short tubular extension 14A at its upper end. The short tubular extensions 12A, 14A are rotatable and slidable relative to one another. These extensions are first coupled together as a separate sub-assembly in the following manner, after which the sub-assembly is fitted to the main sections 12B, 14B of the shaft 10. In the following description the components are assumed to have a generally vertical orientation as shown in Figure 4.

A rubber piston head 80 is press fitted to the lower open end of the extension 12A and a chain 36 passes through the open centre of the piston head. Outside the extension 12A, the uncompressed piston head has a slightly wider diameter than the outside diameter of the extension 12A, to take up any slack between the extension 12A and the internal surface of the extension 14A. The piston head 80 can of course be fixed in place within the extension by any means including adhesive. A compression spring 42 is dropped into the upper extension 12A from the top end to sit against the rear face of the piston head 80. In the embodiment, the spring is of the scragged type. A washer 50 is placed onto the top of the spring 42 and the chain 36 is dropped through the center of the washer 50 so as to hang through the center of the spring 42 and emerge from the centre of the piston head 80. The top end of the chain 36 is maintained bearing downwardly on the spring 42 by a cross bar 52 passing through the top link of the chain and traversing the mouth of the washer 50.

The compression spring 30 is fitted over the upper extension 12A from below and the lower extension 14A is fitted telescopically over the bottom end of the upper extension 12A. The lower extension 14A is now pushed upwardly relative to the upper extension 12A to compress the spring 30 between the upper end 62 of the extension 14A and a collar 48 welded around the outside

circumference of the upper extension 12A. The spring 30 is compressed sufficiently to allow the bottom end of the chain 36 to extend below a shoulder 64 machined around the inside of the extension 14A. This shoulder is shown a piece projecting in from the wall of the lower extension, but it could also be formed by widening the internal diameter of the lower end of the extension 14A.

While maintaining the spring 30 under compression a washer 56 is inserted into the open bottom of the lower extension 14A and pushed up over the bottom end of the chain 36 and up against the underside of the shoulder 64, and a cross bar 58 traversing the mouth of the washer 56 is passed through the bottom link of the chain 36. Now the upward force on the lower extension 14A is relaxed to allow the spring 30 to expand and the chain 36 to retract upwardly into the extension 12A; however, the cross bar 58 maintains the bottom end of the chain bearing upwardly against the washer 56. In this relaxed state both the springs 30 and 42 are under compression and act with equal and opposite forces against one another.

The sub-assembly thus assembled is fitted to the main sections 12B, 14B of the shaft by pushing the upper part of the tubular extension 12A telescopically into the lower open end of the section 12B until the collar 48 comes to bear on the lower end 66 of the section 12B, and by pushing the lower part of the tubular extension 14A telescopically over the upper open end of the section 14B until the lower end 68 of the section 14B comes to bear on a shoulder 70 around the section 14B. In the drawings, the parts 12A, 12B and 14A, 14B are simply friction fitted to one another, however, it will be appreciated that any suitable positive fixing mechanism, for example, a snap fitting tab and hole of the type typically employed in crutches could be employed.

In the final assembly the compression spring 30 forms a shock absorber against the ground, while the compression spring 42 allows the upper and lower sections 12, 14 to be disengaged and folded over against the compressive bias of the spring 42.

In a variant of this embodiment, rather than extension 14A sitting over the upper end of section 14B, it is sized to act as a male member fitting into the upper end of section 14B. This allows the chain 36 to extend from a hole at the end of the extension rather than within the extension as in Figure 4, so facilitating assembly. In further alternative embodiments, the spring 30 need not necessarily be used a suspension and/or a shock absorber, if any, could be provided elsewhere on the crutch .

In a further variant, a pair of oppositely oriented

Neodymium magnets could be located within respective moving sections to act as shock absorbers. In such an embodiment, consideration would need to be given to the material used in the body of the crutch as this might need to shield the magnets to prevent the crutching picking up magnetic debris.

The invention may also be implemented in an armpit crutch, cane or similar walking aid.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims

1. A walking aid comprising a shaft having upper and lower axially disposed sections, the upper section having a handle and the lower section having a ground-engaging foot at its free end, wherein the end of one of the upper and lower sections slidably and rotatably engages in an open end of the other section such that the upper section is rotatable relative to the lower section about the axis of the shaft, the walking aid further comprising at least one spring inside the shaft holding the upper and lower sections together such that the upper and lower sections may be disengaged and folded over against the bias of the spring.

2. A walking aid according to claim 1, wherein a compression spring surrounding the shaft biases the upper and lower sections in a direction axially away from one another to form a shock absorber, the compression spring acting in opposition to the spring inside the shaft.

3. A walking aid according to claim 1 or 2, wherein the length of the lower section is telescopically adjustable.

4. A walking aid according to any preceding claim, wherein the foot is connected to the free end of the lower section by a spring which allows a degree of lateral deflection of the foot relative to the free end.

5. A walking aid according to any preceding claim, wherein the spring inside the shaft is a compression spring of which one end engages a stop inside one of the upper and lower sections and whose other end engages a stop inside the other section through a substantially inextensible coupling extending axially through the spring .

6. A walking aid according to claim 5, wherein the substantially inextensible coupling is a chain.

7. A component for a walking aid comprising upper and lower axially disposed sections, the upper section being arranged to fit to a handle and the lower section being arranged to fit to a ground-engaging foot at its free end, wherein the end of one of the upper and lower sections slidably and rotatably engages in an open end of the other section such that the upper section is

rotatable relative to the lower section about the axis of the shaft, the component further comprising at least one spring inside the shaft holding the upper and lower sections together such that the upper and lower sections may be disengaged and folded over against the bias of the spring.