GB2078508A

GB2078508A - Adjustable locking mechanism

Info

Publication number: GB2078508A
Application number: GB8115145A
Authority: GB
Original assignee: Carters J and A Ltd
Current assignee: Carters J and A Ltd
Priority date: 1980-05-19
Filing date: 1981-05-18
Publication date: 1982-01-13

Abstract

There is provided an adjustable locking mechanism, which comprises a first member 3 having a tubular portion which has an end 5 flared with respect to a second member 1 adapted to fit within the end and the tubular portion and a wedge means 9 adapted to be gripped between the second member and the end so as to prevent movement of the second member further into the tubular portion of the first member 3 when the wedge means is so gripped. The mechanism may be used in an invalid walking aid, such as a crutch or walking stick, provided with such an adjustable locking mechanism. The means 9 may take the form of a rubber ring. <IMAGE>

Description

SPECIFICATION Adjustable locking mechanism This invention relates to an adjustable locking mechanism such as may be used in, for example, an invalid walking aid, such as a crutch or a walking stick.

Conventional invalid walking aids, such as crutches and walking sticks, often comprise two tubular members, the inner member of which telescopes within the outer member and is lockable at a series of discrete positions in relation to the outer member. A locking mechanism currently in use is of the "spring button" type, in which the inner member is provided with a hole which can be aligned with any of a series of holes provided in the outer member so that a spring-biased button can protrude through two aligned holes from the inside of the inner tubular member. To adjust the length of, for example, a walking stick having such a mechanism, it is necessary to depress the spring-biased button so that it is within the outer member; the two members are then slid relative to one another until the button engages with the desired hole in the outer member.Of course, with this arrangement, it is only possible to have a limited range of lengths to which the walking stick may be adjusted. An adjustable locking mechanism which did not rely on a series of discrete locking positions would give a far greater range of possible lengths to the invalid walking aid.

According to a first aspect of the present invention, there is provided an adjustable locking mechanism comprising a first member having a tubular portion which has an end flared with respect to a second member adapted to fit within the end and the tubular portion and a wedge means adapted to be gripped between the second member and the end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

The first, external member may be cylindrical with the second, internal member being tapered, for example conically. Instead of this, the arrangement may be such that the second, internal member is cylindrical with the first, external member being flared.

Preferably, the wedge means is a resilient annular ring composed of, for example, rubber.

According to a second aspect of the present invention, there is provided an adjustable locking mechanism comprising a first member having a tubular portion which has a flared end, a second member adapted to fit within the flared end and the tubular portion and a wedge means adapted to be gripped between the second member and the flared end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

A mechanism in accordance with the invention may find ready application as part of an invalid walking aid, such as a crutch or walking stick. Thus, according to a third aspect of the present invention, there is provided an invalid walking aid being provided with an adjustable locking mechanism which comprises a first member having a tubular portion which has a flared end, a second member adapted to fit within the flared end and the tubular portion and a wedge means adapted to be gripped between the second member and the flared end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which: FIGURE 1 shows a sectional view of an adjustable locking mechanism in accordance with the present invention, and FIGURE 2 shows an elevational view of a walking stick embodying an adjustable locking mechanism in accordance with the invention, parts of the walking stick being omitted for clarity.

Figure 1 shows a first tubular member 1 located within, and projecting from an end of, a second tubular member 3. An end of the second member has a radially outwardly flared portion 5 so that an annular wedge shaped space 7 is defined between the first member 1 and the flared portion 5 of the second member 3. Within this space is located a rubber annular "O"-ring 9 which serves as a wedge means.

When the first member 1 is pushed further into the second member 3, the "O"-ring 9 is forced towards the apex of the annular wedge shaped space 7, whereby the first member 1 is locked with respect to the second member 3. To adjust the position of the first member 1 with respect to the second member 3, the first member 1 is pulled (not necessarily completely) out of the second member 3. The ring 9 will then be released from the apex of the wedge shaped space 7 and can be re-positioned as desired along the length of the first member 1. The first member 1 is then moved so that the rubber ring 9 re-engages in the annular wedge shaped space 7.

Figure 2 shows a walking stick 11, which is adjustable in length by means of an adjustable locking mechanism in accordance with the present invention. The walking stick 11 comprises a main stem portion 13 having a rubber cap 15 at the intended lower end and a handle 17 having a hand grip 19 at right angles to the main stem portion at the intended upper ends. The main stem portion comprises two tubular members 13a and 13b, inner member 13a being located within, and projecting from an end of, outer member 13b. The inner member 1 3a forms the intended lower part of the main stem portion and thus has the rubber cap 15 attached to the end remote from the end located within the outer member 13b.The outer member 13b forms the intended upper part of the main stem portion and is attached to the handle 17 at the end remote from the end from which the inner member 13a projects.

The end of the outer member 1 3b from which the inner member 13a projects is flared at 21; an annular wedge shaped space 23 is consequently defined between the inner member 13a and the flared end 21 of the outer member 13b. Within the annular wedge shaped space 23 is located a rubber ring 25. When the walking stick is, in use, leant on, the flared end 21 of the outer member 13b will be forced down onto the ring 25 and thus, effectively, the ring 25 is forced towards the apex of the annular wedge shaped space 23. Substantial relative movement of the outer member 13b with respect to the inner member 13a is thus prevented, because the resilient ring 25 forms a grip locking the inner member 13a and the outer member 13b.

It is, of course, desirable that the material from which the ring 25 is made has such a resilience, and the shape thereof should be such, that the inner member 13a does not fall out of the flared end 21 of the outer member 13b when the walking stick 11 is lifted from the ground. However, the resilience, and shape, should be such that, when a person grips the inner member 13a with one hand and the outer member 13b with the other hand and pulls the two members in opposite directions, the ring 25 allows the two members 13a and 13b to disengage. The ring 25 may ordinarily be retained on the inner member 13a and can then readily be moved to a new position; the flared end 23 of the outer member 13b is then moved to re-engage the ring 25. This is all that is required to change the length of the walking stick.

Claims

1. An adjustable locking mechanism, which comprises a first member having a tubular portion which has an end flared with respect to a second member adapted to fit within the end and the tubular portion and a wedge means adapted to be gripped between the second member and the end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

2. Amechanism according to Claim 1, wherein the first external member is cylindrical and the second internal member is tapered.

3. A mechanism according to Claim 1, wherein the first, external member is flared and the second, internal member is cylindrical.

4. A mechanism according to Claim 1,2 or3 wherein the wedge means comprises a resilient annular ring.

5. An adjustable locking mechanism, which comprises a first member having a tubular portion which has a flared end, a second member adapted to fit within the flared end and the tubular portion and a wedge means adapted to be gripped between the second member and the flared end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

6. An invalid walking aid provided with an adjustable locking mechanism which comprises a first member having a tubular portion which has a flared end, a second member adapted to fit within the flared end and the tubular portion and a wedge means adapted to be gripped between the second member and the flared end so as to prevent movement of the second member further into the tubular portion of the first member when the wedge means is so gripped.

7. An aid according to Claim 6, wherein the wedge means is a resilient annular ring.

8. An aid according to Claim 6 or 7, which is a crutch or walking stick.

9. Any novel feature or combination of features described herein.