GB2318510A - Walking aid with shock absorber - Google Patents

Abstract

A walking aid such as a crutch 20 has a shaft 22 on which is slidaby fitted a shock absorber member 24 at its foot. The member includes an upper sleeve 28 on the shaft and a lower part 38 which can slide over the sleeve. A spring 26 provides resilience and can be replaced by another of different resilience by removal of disc 46 which threadedly engages skirt 40. Airhole 36 prevents pressure or suction effects in the space 42. A non-slip foot 48 is provided.

Description

Walking Aids The present invention relates to walking aids and in particular, but not exclusively, to crutches, but the invention may also be applied in relation to walking sticks, walking frames and other similar walking aids.

A conventional crutch consist of a rigid pole on which the user leans, either by gripping and leaning on a handle, or by placing part of the crutch under the armpit. By leaning on the crutch in this way, the user may support at least part of his or her weight on the crutch, thereby relieving their leg or legs by reducing or removing the weight to be borne by them.

Long term users of crutches experience considerable discomfort from the use of the crutch or crutches. In the case of an armpit crutch, soreness, bruising and muscular pain results from the unnatural application of large forces to the shoulder region. Crutches with handles gripped by the user are now more common then armpit crutches, but result in muscular pain in the user's hands, arms and shoulders. The repeated jarring occasioned by use of the crutch can make crutch usage so painful that a user becomes immobile through inability to use crutches and a refusal to use a wheelchair and suffer the stigma which can attach to this.

The present invention seeks to address these problems.

According to the invention, there is provided a walking aid on which a user may lean to support at least part of the user's weight and relieve the leg or legs of the user, the aid comprising first and second members through which supported weight is transmitted to the ground and which tend to move in a first direction relative to one another when under load, and resilient means acting between the said members to resist movement in the first relative direction, whereby the weight being borne is resiliently supported.

Preferably one of the first and second members comprises or is attached to a handle through which the user may lean on the aid. The arrangement may allow the handle to move generally downwardly under load, against bias provided by resilient means.

The first and second members are preferably movable telescopically relative to each other. The first and second members are preferably upper and lower members respectively, during use. The upper member may be adapted to be attached to the lowermost end of an otherwise rigid walking aid such as a crutch.

The resilient means are preferably so arranged as to allow the degree of resilience to be changed. The resilient means may comprise a spring member removable for replacement by a stronger or weaker spring member.

The second member may comprise a body, the first member being movable down into the body during use. The resilient means may be located within the body and may comprise a resilient member located under the first member, to resist downward movement thereof. The body may have a removable part through which the resilient member is accessible for removal and replacement. One or more of the members may comprise a air hole to relieve air pressure within the body during use.

The invention also provides a walking aid attachment comprising a first member which may be attached to a walking aid on which a user may lean to support at least part of the user's weight and relieve the leg or legs of the user, and a second member through which supported weight is transferred from the first member to the ground, the first and second members tending to move in a first direction relative to one another when under load, and the attachment further comprising resilient means which acts between the said members to resist movement in the first relative direction, whereby the weight being borne is resiliently supported.

The attachment may comprise any or all of the preferred features set out above.

One example of apparatus according to the invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which: Fig. 1 is a schematic perspective view of a conventional crutch; Figs. 2a and 2b are a schematic vertical section and elevation showing an attachment according to the invention; and Figs. 3, 4, 5 and 6 show the body, sleeve, foot and gaiter of the apparatus of Fig. 2, on an enlarged scale.

Fig. 1 shows a conventional crutch 10 of modern design, consisting of a generally upright, rigid pole 12 with a rubber, non-slip foot 14 at the lowermost end and a generally horizontal handle 16 which may be gripped by the user's hand in order to lean on the crutch. A collar 18 loosely locates around the forearm of the user, during use.

The pole 12 may be of fixed length or may have releasable locking means which allow the length of the pole to be changed to suit different users.

Figs. 2a and 2b show the lower end of a walking aid 20 in accordance with the present invention, such as a crutch. The crutch 20 has a first member 22 which is a rigid pole corresponding with the pole of Fig. 1, and likewise carries a handle and collar at its upper end, neither of which are shown. The pole 22 may be a hollow aluminium tube. A second member in the form of a body 24 is located at the lower end of the pole 22. The body 24 forms a foot on the pole 22 so that the weight supported by the crutch is transmitted to the ground beneath, through the pole 22 and body 24. The body 24 is a sliding fit on the pole 22, as will be described, and the pole 22 tends to move in a first, downward direction relative to the body 24 when under the load of the weight W of a user. A spring 26 or other resilient means acts between the pole 22 and body 24 to urge those members to move in the reverse relative direction, i.e. to raise the pole 22 relative to the body 24, whereby the weight W being borne by the crutch is resilient supported.

In more detail, Fig. 2 shows the lowermost end of a rigid crutch pole 22 over which a sleeve 28 is fitted. The sleeve 28 consists of a generally vertical and substantially circular cylinder divided by a partition 30 into an upper space which receives the pole 22, and a lower space at 32. A circumferential flange 34 extends around the lowermost edge of the sleeve 28. The partition 30 is pierced at the central axis to leave an opening 36, for reasons to be described.

The body 24 consists of two parts. An upper body part 38 is generally frusto conical with a downwardly extending circular cylindrical skirt at 40, and is hollow to leave a space 42. A passage 44 extends upwardly from the space 42 and receives the sleeve 28. The sleeve 28 is a sliding fit in the passage 44.

The space 42 is dosed below by a disc 46 which is threaded around its periphery to engage with a complementary thread formed on the inner wall of the skirt 40. The disc 46 can thus be removed to gain access to the space 42, and thereafter replaced to close the space 42.

A rubber non-slip foot 48 is a push fit over the skirt 40 after the disc 46 has been screwed into position.

The spring 26, which is a compression spring in the example shown, is located in the space 42 and extends up from the disc 46 into the lower space 32 to bear on the bottom face of the partition 30.

The spring 26 urges the sleeve 28 (and hence the pole 22) to move upwardly relative to the disc 46. The restoring force provided by the spring 26 can be modified by exchanging the spring for a stronger or lighter spring. This is made possible by the removable nature of the disc 46.

An elastic gaiter 50 covers the upper end of the sleeve 28 and an adjacent part of the pole, for aesthetic reasons and to assist securing together the pole 22 and sleeve 28.

During use, the user will lean on the crutch 20, compressing it between the user and the floor. Thus, the user exerts a force in the direction of the arrow W. This force passes through the sleeve 28 to the spring 26 which thus compresses until the force W is balanced. The spring 26 is compressed by means of the sleeve 28 sliding down the passage 44 into the body 24. The length of movement will depend on the force applied to the crutch, which in turn will depend on the weight of the user but it is envisaged that in use, the spring strength can be set to allow the downward force to be absorbed by a movement of about 10mum, but with the body and sleeve dimensions being set to allow a total movement of about 15mm. The necessary spring strength can therefore be calculated for any particular patient, bearing in mind that it is most unlikely that the whole of the patient's weight would be applied to the crutch. There would usually be one or more legs of the patient bearing some of the weight, or another crutch.

When the weight W is removed from the crutch, the spring 26 will restore the initial position by pushing the sleeve 28 out of the body 24, i.e. by forcing the sleeve 28 to move upwardly relative to the body 24. Upward movement is eventually limited by abutment of the flange 34 with a corresponding step 52 formed within the body 24.

It will be apparent that as the sleeve 28 slides in the passage 44, this will vary the volume defined within the body 24 below the partition 30. In the event of a tight fit between the sleeve and passage, this could give rise to suction and compression effects within the space 42, thus preventing or adversely affecting smooth movement. This difficulty is overcome by the opening 36 which allows air pressure within the space 42 to equalise with atmosphere by communication through the hollow pole 22.

It is envisaged that the sleeve can be made of a nylon material, such as a low friction 40% glass/nylon mixture and can be formed by injection moulding or otherwise. The foot 48 may be silicone or neoprene rubber. The body 24 and disc 46 may be of aluminium for lightness of weight and ease of working.

However, it will be appreciated that many different materials could be used.

It will be apparent that the sleeve and body arrangement shown in the drawings could be fitted retrospectively as an attachment to an existing crutch 10, in place of the foot 14, by pushing the pole 12 down into upper space of the sleeve 28. If this operation is made sufficiently easy to allow convenient retrospective fitting of the accessory, it is possible that the accessory could subsequently work loose and even slip off the pole. The gaiter 50 assists in avoiding this problem, by gripping the pole and sleeve to hold them together.

It will be apparent that many variations and modifications can be made to the apparatus described above without departing from the scope of the present invention. In particular, many different materials and geometries could be chosen. The spring could be a compression spring, as described, or could be replaced by an extension spring with suitable modification to cause the spring to be stretched as the sleeve 28 moves relative to the body 24. It is envisaged that apparatus embodying the invention could be sold either as an accessory for retrospectively fitting to an existing crutch, or as a complete item. In the latter case, the resilience could be provided at a different position in the crutch, such as at the point of attachment between the handle 16 and pole 12.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (19)

1. A walking aid on which a user may lean to support at least part of the user's weight and relieve the leg or legs of the user, the aid comprising first and second members through which supported weight is transmitted to the ground and which tend to move in a first direction relative to one another when under load, and resilient means acting between the said members to resist movement in the first relative direction, whereby the weight being borne is resiliently supported.

2. A walking aid according to claim 1, in which one of the first and second members comprises or is attached to a handle through which the user may lean on the aid.

3. A walking aid according to claim 2, in which the arrangement allows the handle to move generally downwardly under load, against bias provided by resilient means.

4. A walking aid according to any preceding claim, in which the first and second members are movable telescopically relative to each other.

5. A walking aid according to any preceding claim, in which the first and second members are upper and lower members respectively, during use.

6. A walking aid according to claim 5, in which the upper member is adapted to be attached to the lowermost end of an otherwise rigid walking aid.

7. A walking aid according to claim 6, in which the rigid walking aid is a crutch.

8. A walking aid according to any preceding claim, in which the resilient means are so arranged as to allow the degree of resilience to be changed.

9. A walking aid according to any preceding claim, in which the resilient means comprises a spring member removable for replacement by a stronger or weaker spring member.

10. A walking aid according to any preceding claim, in which the resilient means comprises a resilient member located under the first member, to resist downward movement thereof.

11. A walking aid according to any preceding claim, in which the second member comprises a body, the first member being movable down into the body during use.

12. A walking aid according to claim 11, in which the resilient means is located within the body.

13. A walking aid according to claim 12, in which the body has a removable part through which the resilient member is accessible for removal and replacement.

14. A walking aid according to any of claims 11 to 13, in which one or more of the members comprises an air hole to relieve air pressure within the body during use.

15. A walking aid attachment comprising a first member which may be attached to a walking aid on which a user may lean to support at least part of the user's weight and relieve the leg or legs of the user, and a second member through which supported weight is transferred from the first member to the ground, the first and second members tending to move in a first direction relative to one another when under load, and the attachment further comprising resilient means which acts between the said members to resist movement in the first relative direction, whereby the weight being borne is resiliently supported.

16. An attachment according to claim 15, in which the attachment comprises any or all of the features of claims 2 to 14.

17. A walking aid substantially as described above with reference to Figs. 2 to 6 of the accompanying drawings.

18. A walking aid attachment substantially as described above with reference to Figs. 2 to 6 of the accompanying drawings.

19. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.