GB2327872A

GB2327872A - Adjustable leg

Info

Publication number: GB2327872A
Application number: GB9823722A
Authority: GB
Inventors: Clifford Royston Fox
Original assignee: Fox Design International Ltd
Current assignee: Fox Design International Ltd
Priority date: 1996-10-23
Filing date: 1996-10-23
Publication date: 1999-02-10
Anticipated expiration: 2016-10-23
Also published as: GB9823722D0; GB9622054D0; GB2327872B; GB2318505A; GB2318505B

Abstract

An adjustable leg comprising inner and outer parts (12, 10) the inner part (12) of which is slidable within the outer part (10) to enable the leg to be telescopically adjustable in length. A locking member (40) is provided with an aperture (46) through which the inner leg passes. The locking member (40) is held directly or indirectly on the outer leg part (10) and is resiliently urged by a resilient member (48) to adopt an angle with regard to the inner leg part (12) so that edge portions defining the aperture (46) engage the inner leg part (12) and hold it in position relative to the outer leg part (10). The locking member (40) is provided with a thumb-engageable portion (44) which extends outwardly from the outer leg part (10), and in which an abutment (34) is provided to resist transverse movement of the locking member (40) in a direction away from the side of the outer leg part (10) from which the thumb-engageable portion (44) projects.

Description

Adjustable leg The present invention relates to an adjustable leg comprising inner and outer parts the inner part of which is slidable within the outer part to enable the leg to be telescopically adjustable in length, there being a locking member provided with an aperture through which the inner leg passes, which locking member is held directly or indirectly on the outer leg part and is resiliently urged by a resilient member to adopt an angle with regard to the inner leg part so that edge portions defining the aperture engage the inner leg part and hold it in position relative to the outer leg part.

Such a leg is useful as part of a chair, a bedchair, or a tackle box, for example, where the length of the leg needs to be adjustable to account for uneven ground.

In one such telescopically adjustable leg which has already been proposed, the resilient member comprises a helical spring which surrounds the inner leg portion. As a result, any slight lateral movement thereof will tend to reduce the ease with which the inner leg will slide relative to the outer leg.

The present invention seeks to provide a remedy.

A further problem encountered with previously proposed constructions of adjustable leg is that the locking member does not have adequate abutment to resist lateral movement of the locking member relative to the inner leg.

This again can result in friction contact between the locking member and the inner leg even when the locking member is substantially perpendicular thereto, to the extent that gravitational forces acting on the inner leg part are insufficient to move it.

Accordingly, the present invention is directed to an adjustable leg having a construction set out in the opening paragraph of the present specification, in which the locking member is provided with a thumb-engageable portion which extends outwardly from the outer leg part, and in which an abutment is provided to resist transverse movement of the locking member in a direction away from the side of the outer leg part from which the thumb-engageable portion projects.

An advantage of such a construction is that the length of the leg can be readily adjusted with the use of one hand only, in that the locking member can be shifted so that it is substantially perpendicular to the inner leg, whereupon the inner leg will readily drop down to the desired position under gravitational action. The locking member can then be released to secure the inner leg once again relative to the outer leg.

Preferably the portion of the locking member which surrounds the inner leg part is surrounded by a housing which is secured to a lower end of the outer leg part. A slot may then be provided therein through which extends the thumb-engageable portion of the locking member.

The abutment may be provided on the inside of the housing, on the opposite side of the inner leg part to the thumb-engageable portion of the locking member. The abutment and a lower limit of the slot may be positioned relative to one another so that when the locking member is pushed to abut the lower limit of the slot the locking member is substantially perpendicular to the inner leg part.

An example of an adjustable leg made in accordance with the present invention is illustrated in the accompanying drawings, in which Figure 1 is a cross-sectional axial view of the adjustable leg; and Figure 2 is a cross-sectional view of the leg taken in the plane indicated by the line II-II in Figure 1.

The adjustable leg shown in Figures 1 and 2 comprises an outer leg part 10 and an inner leg part 12 which, apart from a locking mechanism which is to be described hereinafter, is slidable in the outer leg part 10 so that the leg is telescopically adjustable in length.

An upper sleeve-shaped portion 14 of a housing 16 fits tightly and is secured to an intended lower end 18 of the outer leg part 10. The housing 16 is hollow, having an internal cross-section which is square-shaped, and which generally conforms to the inner cross-section of the outer leg part 10. The internal cross-section of the housing 16 is wider beyond an internal shoulder 26 thereof, so that the sleeve portion 14 of the housing 16 has a cross-section generally conforming to the outer cross-section of the outer leg portion 10. As a result, the inside surfaces of the lower portion of the housing 16 are flush with the inside surfaces of the upper leg part 10.

A lower part 28 of the inner leg 12 thereof slides within and projects downwardly beyond the internal surfaces of the housing 16.

A tapering slot 30 extends from one side of the housing 16 where it defines a mouth 32 inwardly to an abutment 34 on the inside surface of the opposite side of the housing 16.

The slot tapers in the direction from the mouth 32 to the abutment 34 as viewed from one side so that the lower surface 36 of the slot is generally perpendicular to the inner and outer leg parts 10 and 12, and the upper surface 38 is on a slant relative thereto.

A locking plate 40 has an inner end 42 which rests against the abutment 34, and a thumb-engageable portion 44 which projects outwardly from the housing 16. The plate 40 is provided with a square-shape aperture 46 which is slightly larger than the external cross-section of the inner leg part 12, and surrounds the latter.

A helical compression spring 48 has a lower part situated in a recess of an insert 50, and the upper end of the spring 48 abuts the thumb-engageable portion 44 of the plate 40 to urge the plate 40 upwardly against the slanted surface 38. In this position, inner edges of the aperture 46 dig in to the inner let part 12 and lock the latter in position relative to the outer leg part 10.

To operate the adjustable leg, the outer leg 10 is grasped by one hand and the thumb is used to push the thumbengageable portion 44 of the plate 40 downwardly in to the position shown in Figure 1, against the action of the helical spring 48. In this position, the inner edges of the aperture 46 no longer dig into the inner leg part 12 and the leg is free to slide within the outer leg 10. If the leg is pointed in a generally downwardly direction as shown in Figure 1, the inner leg thereby slides outwardly from the outer leg 10 under the force of gravity until it reaches the desired position whereafter the locking plate 40 is released so that once again the inner and outer leg parts are held firmly relative to one another.

The lower end of the inner leg part 12 is provided with a flanged foot 52 which is swivelable relative to the end of the inner leg part 12 by means of a ball and socket joint 54.

Numerous variations and modifications will readily occur to the reader of the present invention without taking it outside the scope of the present invention. For example, the resilient member can conceivably be placed on the opposite side of the inner leg part 12 relative to the thumb-engageable portion 44, although this would clearly result in a weaker leverage action.

The spring 48 does not necessarily have to be a helical spring but can indeed be a leaf spring or any other kind of resilient member to urge the locking plate 40 into its locking position.

The lower surface 36 may be on a slant relative to the leg parts 10 and 12, albeit at a lesser slant than the upper surface 38.

Means may be provided on the inner leg part and/or the outer leg part to inhibit removal of the inner leg part from the outer leg part beyond a fully extended position of the leg.

Claims

Claims:

1. An adjustable leg comprising inner and outer parts the inner part of which is slidable within the outer part to enable the leg to be telescopically adjustable in length, there being a locking member provided with an aperture through which the inner leg passes, which locking member is held directly or indirectly on the outer leg part and is resiliently urged by a resilient member to adopt an angle with regard to the inner leg part so that edge portions defining the aperture engage the inner leg part and hold it in position relative to the outer leg part, and in which an abutment is provided to resist transverse movement of the locking member in a direction away from the side of the outer leg part from which the thumb-engageable portion projects.

2. An adjustable leg according to claim 1, in which the portion of the locking member which surrounds the inner leg part is surrounded by a housing which is secured to a lower end of the outer leg part.

3. An adjustable leg according to claim 2, in which a slot is provided in the housing through which extends the thumbengageable portion of the locking member.

4. An adjustable leg according to claim 2 or claim 3, in which the abutment is provided on the inside of the housing, on the opposite side of the inner leg part to the thumbengageable portion of the locking member.

5. An adjustable leg according to claim 3, or claim 4 read as appended to claim 3, in which the abutment and a lower limit of the slot are positioned relative to one another so that when the locking member is pushed to abut the lower limit of the slot the locking member is substantially perpendicular to the inner leg part.