GB2234008A

GB2234008A - Locking tubular elements

Info

Publication number: GB2234008A
Application number: GB9015376A
Authority: GB
Inventors: Fredrick Usher
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-07-12
Filing date: 1990-07-12
Publication date: 1991-01-23
Anticipated expiration: 2010-07-12
Also published as: BE1001644A7; IE61795B1; IE892242A1; GB2234008B; GB9015376D0

Abstract

A display stand 1 comprises a base 3, uprights 4 and a crown or head piece 5 which in this case is provided with sockets 6, each for receiving an upright tubular member 7 having an outwardly extending arm 8. The tubular element is locked in position in the upright 4 by a locking device according to the invention. The tubular element 7 has two opposed circular apertures 10 and two spheres 12, are associated with each aperture 10, project through the apertures 10. A wedging element 15 is spring biassed into a position urging the spheres outwardly against the inner wall of the tubular element 4 to lock the tubular element 7 in a desired position. The wedge 15 is released by an actuating button 25. <IMAGE>

Description

"A Locking Device" The invention relates to a locking device and in particular to a locking device for locking one tubular element within another, particularly for use in display stands such as garment racks.

U.K. Patent Application No. 2 175 974A describes a locking arrangement for tubular members which comprises a rectangular tubular element having at its telescopically received end a housing supporting two cylindrical rollers arranged with their axes parallel and transverse to the axis of the tube and supported within the housing so as to be capable of movement in a direction such as to increase the spacing between the axes of the rollers. A wedge is introduced between the rollers to move them apart and cause them to jam against the inside surface of an outer rectangular tube.

There are some difficulties with this locking device.

Firstly, it is relatively expensive and difficult to manufacture particularly as a separate housing element is required. Further, the housing for the rollers is generally exposed and may be easily damaged making the unit difficult to operate or the rollers can, in some cases, fall out.

This invention is directed towards providing an improved locking device to overcome at least some of these disadvantages.

According to the invention there is provided a locking device for locking one tubular element within another, the locking device comprising: an inner tubular element having an aperture extending through the wall of the tubular element, a locking element located in the aperture and having a largest dimension which is greater than that of the aperture, wedge means for urging the locking element outwardly partially through the aperture to engage and lock the inner tubular element within an outer tubular element, and actuating means for moving the wedge means from a normally locked position in which the locking element is engaged with the outer tubular element and a release position in which the locking element is released from the outer tubular element but is retained in the inner tubular element.

In one embodiment of the invention the inner tubular element has at least two generally transversely opposed apertures and a separate locking element as provided for each aperture.

In a particularly preferred embodiment of the invention the or each locking element comprises a generally spherical ball and the or each aperture in the inner tubular element is of generally circular shape, the diameter of the aperture being less than that of the spherical ball.

In one embodiment of the invention the actuating means comprises an elongate rod to which the wedge means is mounted and which extends axially partially through the inner tubular element and an actuating button connected to the rod by a connecting arm, the button being external of the inner tubular element and the connecting arm extending through an axial slot in the inner tubular element, the button being slidably movable from a locked position to a release position to draw the rod and wedge means upwardly to the release position releasing the or each locking element from the or each respective aperture and allowing the inner tubular element to be freely moved within the outer tubular element.

In a preferred arrangement the wedge means is spring biased into the normally locked position by a spring biasing means.

Preferably the spring biasing means comprises a coil spring around the actuating rod and extending between a flange on the inner tubular element, biasing of the spring being overcome on upward movement of the actuating button.

In one embodiment of the invention the flange on the inner tubular element is provided by a lower leg of a channel member which is mounted in the inner wall of the inner tubular element, the rod extending through aligned holes in both legs of the channel member, in use.

Preferably the wedge means comprises a generally truncated cylindrical member.

The invention also provides a display stand incorporating one or more locking devices according to the invention.

The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a display stand having a locking device according to the invention, Fig. 2 is a cross sectional view of portion of the display stand showing the locking device, in use, Fig. 3 is a transverse cross sectional view of the locking device, Fig. 4 is a cross sectional view of the locking device in a different position, Fig. 5 is a perspective view of the locking device, and Fig. 6 is a plan cross sectional view of the detail of the locking device, and Fig. 7 is a perspective view of another display stand incorporating a number of the locking devices.

Referring to the drawings and initially to Figs. 1 and 2 thereof there is illustrated a display stand 1 according to the invention incorporating a locking device 2 also according to the invention. The display stand 1 comprises a base 3, tubular uprights 4 and a crown or a head piece 5 which in this case is provided with four tubular sockets 6. The sockets 6 and uprights 4 each define an outer tubular element for receiving an inner upright tubular element 7 having an outwardly extending arm 8 which may be of any desired shape and configuration for example, for hanging garments. It will be noted that in this case all of the elements of the display stand are of substantially rectangular shape in transverse cross section. This is the preferred shape, however, it will be appreciated that the various elements may be of any desired tubular shape.

Each inner tubular element 7 is locked in position in the respective outer tubular element 6 by a locking device according to the invention which is illustrated in detail in Figs. 2 to 4.

The inner tubular element 7 has two transversely opposed, generally circular, apertures 10 extending through the wall of the inner tubular element 7 at the lower end thereof. Locking elements for locking the inner tubular element 7 within the outer tubular element 6 are in this case provided by two spheres 12, one associated with each of the apertures 10. The diameter of the spheres 12 is greater than the smallest dimension of the apertures 10 so that the spheres 12 cannot pass outwardly through the apertures 10 when the inner tubular element 7 is removed from the outer tubular element 6.

Wedge means for urging the spheres 12 outwardly through the apertures 10 to engage and lock the inner tubular 7 within the inner tubular element 6 is in this case provided by a generally truncated cylindrical wedging element 15.

Actuating means are provided for moving the wedging element 15 from a normally locked position in which the spheres 12 are engaged with the outer tubular element 6 and a release position in which the spheres 12 are released from the outer tubular element 6 but are retained in the inner tubular element 7. In this case the actuation means comprises an elongate rod 16 which extends axially through the inner tubular 7 and to which the wedge element 15 is mounted. An actuating button 25 has an inwardly extending leg 26 which is attached to the rod 16 by a grub screw 27. The connecting leg 26 is slidably mounted in an elongate slot 28 (see Fig. 5) at the upper end of the outer tubular element 6.The button 25 is slidably movable from a locked position to a release position to draw the rod 16 and the wedging element 15 upwardly to the release position releasing the spheres 12 from each respective aperture 10 and allowing the inner tubular element 6 to be freely moved within the outer tubular element 7.

Spring biasing means for urging the rod 16 into the normally locked position illustrated in Fig. 3 is in this case provided by a coil spring 20 extending between a locating flange 21 mounted on the rod 16 and a flange on the inner tubular element 7. The flange on the inner tubular element 7 is in this case provided by a lower leg 18 of a channel member which is mounted to the inner wall of the inner tubular element 7 the rod 16 extending through aligned holes in both legs of the channel member, in use. The spring 20 urges the flange 21 and hence the rod 16 and the wedge element 15 downwardly in the direction of the arrow A in Fig. 3.

In use, a display stand is typically assembled on site by inserting the tubular uprights 4 onto the base 3 and attaching the crown or head piece 5 to the uprights 4. In the case of the stand illustrated in Fig. 1 there is only one particular type of support arm illustrated, however, it will be appreciated that any one or combination of a range of various possible arms may be used. One alternative arrangement is illustrated in Fig. 7. To fit each inner tubular element 7 into one of the desired outer tubular elements 6 the actuating button 25 is pushed upwardly in the direction of the arrow B in Fig. 3 against the biasing of the spring 20 to lift the wedge element 15 upwardly and allow the spheres 12 to pass inwardly through the apertures 10 into the position illustrated in Fig. 4.In this position the spheres 12 are disengaged from the inside surface of the outer tubular element 6 so that the outer element 7 may be moved within the element 6 for height adjustment or insertion or withdrawal of the tubular element 7 into the tubular element 6. When the inner tubular element 7 is in the desired position the button 25 is released and the wedge element 15 travels downwardly in the direction of the arrow A in Fig. 3 under the biasing of the spring 20 to push the spheres 12 outwardly against the inside surface of the outer tubular element 6 to lock the inner tubular element 7 in position in the outer tubular element 6.

The locking device according to the invention is of relatively simple and cheap construction and is easy to operate and use.

Because the locking elements in the form of spheres are housed in apertures which are part of the tubular element, they cannot be dislodged.

It will be appreciated that while the invention has been described with reference to a locking device for use with display stands, the locking device may be applied to any situation in which it is desired to fit one tubular element within the other. As point contact using locking spheres is used, the locking device may be used with tubular elements of any desired cross section including tubular elements of circular cross section.

These and many other modifications and alterations on the invention will be readily apparent and accordingly the invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims

CLAINS

1. A locking device for locking one tubular element within another, the locking device comprising: an inner tubular element having an aperture extending through the wall of the tubular element, a locking element located in the aperture and having a largest dimension which is greater than that of the aperture, wedge means for urging the locking element outwardly partially through the aperture to engage and lock the inner tubular element within an outer tubular element, and actuating means for moving the wedge means from a normally locked position in which the locking element is engaged with the outer tubular element and a release position in which the locking element is released from the outer tubular element but is retained in the inner tubular element.

2. A locking device as claimed in claim 1 wherein the inner tubular element has at least two generally transversely opposed apertures and a separate locking element is provided for each aperture.

3. A locking device as claimed in claim 1 or 2 wherein the or each locking element comprises a generally spherical ball and the or each aperture in the inner tubular element is of generally circular shape, the diameter of the aperture being less than that of the spherical ball.

4. A locking device as claimed in any preceding claim wherein the actuating means comprises an elongate rod to which the wedge means is mounted and which extends axially partially through the inner tubular element and an actuating button connected to the rod by a connecting arm, the button being external of the inner tubular element and the connecting arm extending through an axial slot in the inner tubular element, the button being slidably movable from a locked position to a release position to draw the rod and wedge means upwardly to the release position releasing the or each locking element from the or each respective aperture and allowing the inner tubular element to be freely moved within the outer tubular element.

5. A locking device as claimed in claim 4 wherein the wedge means is spring biased into the normally locked position by a spring biasing means.

6. A locking device as claimed in claim 5 wherein the spring biasing means comprises a coil spring around the actuating rod and extending between a flange on the inner tubular element, biasing of the spring being overcome on upward movement of the actuating button.

7. A locking device as claimed in claim 6 wherein the flange on the inner tubular element is provided by a lower leg of a channel member which is mounted in the inner wall of the inner tubular element, the rod extending through aligned holes in both legs of the channel member, in use.

8. A locking device as claimed in any preceding claim wherein the wedge means comprises a generally truncated cylindrical member.

9. A locking device substantially as hereinbefore described with reference to the accompanying drawings.

10. A display stand incorporating one or more locking devices as claimed in any preceding claim.