GB2321927A

GB2321927A - A releasable coupling

Info

Publication number: GB2321927A
Application number: GB9702219A
Authority: GB
Inventors: Bryan George Insley
Original assignee: Uni-Lite International Ltd
Current assignee: Uni-Lite International Ltd
Priority date: 1997-02-04
Filing date: 1997-02-04
Publication date: 1998-08-12
Anticipated expiration: 2017-02-04
Also published as: GB9702219D0; GB2321927B

Abstract

A releasable coupling for joining together a first and second tubular member for a display board frame is described. The dimensions of the tubular members being such that the first tubular member can slide within the second, the first tubular member including a lug which protrudes through an appropriately sized hole in the wall of the first tubular member, the lug being mateable with an appropriately sized hole on the second tubular member. The lug is mounted on a resiliently deformable support located inside the first tubular member and extending transverse to the longitudinal axis of the first tubular member to prevent slippage. A display board frame comprising a plurality of said tubular members is also described. A method of constructing such a display board frame is also defined. The support is shaped so that its outer surface mimics the shape of the internal surface of the first tubular member.

Description

A RELEASABLE COUPLING The present invention relates to a releasable coupling and, in particular, but not exclusively to a releasable coupling for joining together a first and second tubular member for a display board frame.

Display stands for exhibitions and the like generally include a plurality of tubular rods and a number of connecting units so that the rods can be assembled into a frame work. Generally the connecting units comprise a number of short tubes with each tube at right angles to the adjacent short tube to allow the construction of a three-dimensional frame work. The short tubes are dimensioned so that the tubular rods can be slid therein so that the two parts are held together by a friction fit due to the friction between the outer surface of the tubular rods and the inner surface of the short tubes on the connecting unit. Such an arrangement allows for a quick assembly of the relevant frame work. Unfortunately, the frame work offers little flexibility as once the parts are fixed together the arrangement becomes very rigid so that rotation of the connection unit to allow three dimensional alteration of the display board frame work becomes difficult. Furthermore, disassembly of the frame work is hampered by the frictional connection between the connecting parts. In some cases, if the connecting parts have been urged together too strongly it becomes extremely difficult to separate the parts of the frame work without causing damage to the parts.

It is an object of the present invention to address the above and other problems which will become apparent from a reading of the specification.

According to a first aspect of the present invention there is provided a releasable coupling for joining together a first and second tubular member for a display board frame the dimensions of the tubular members being such that the first tubular member can slide within the second, the first tubular member including a lug which protrudes through an appropriately sized hole in the wall of the first tubular member so that, in use, at least a portion of the lug protrudes above the exterior surface of the first tubular member, the lug being mateable with an appropriately sized hole on the second tubular member, wherein the lug is mounted on a resiliently deformable support located inside the first tubular member and extending transverse to the longitudinal axis of the first tubular member.

Preferably, in use, the support is in its compressed state so that it is urged against the internal surface of the first tubular member.

Preferably, the tubular members are circular in cross-section.

Preferably, in the case where the tubular members are circular in cross-section, the support is shaped to form an arc whose circumference is less than the internal circumference of the first tubular member but whose uncompressed radius is equal to or greater than the radius of the internal surface of the first tubular member. In this manner, the support may be compressed and placed in the tube so that it is urged against the interior walls of the tube and so that the mounted lug located in and protruding through the hole in the first tubular member is resiliently deformable.

Advantageously, as the support is disposed transverse to the longitudinal axis of the tube it is far more difficult to dislodge than the known twin armed spring which is disposed longitudinally and tends under its own spring load to project itself, in use, so that it travels longitudinally in the tube and becomes dislodged.

Preferably, a ring of holes is provided in each second tubular member to give a plurality of locating positions for the lug of the first tubular member.

For convenience, a ring of holes may also be provided on the end of the first tubular member to give a plurality of locating holes for the lug but such an arrangement is not preferred. A plurality of longitudinal holes may also be provided on each second tubular member if a plurality of longitudinal positions are required for the particular application. However, in the preferred embodiments only a single ring of holes is provided on each second tubular member.

Preferably, a plurality of second tubular members is provided in an integral connecting unit.

The connecting unit, typically, comprises an octahedral arrangement of six short second tubular members each disposed at right angles to the four neighbouring members and aligned with the opposing member. Thus, up to six first tubular members may be fitted thereto.

It is envisaged that, by using the connecting units with the plurality of second tubular members and the first tubular members, a framework can be constructed of the desired size and shape.

The connecting units may comprise any number of second tubular members to provide corner units or side units in the framework, for instance, a corner unit may comprise four arms disposed at right angles to each other with either two adjacent or two aligned arms omitted depending on the application. However, for display boards the use of a unit with the adjacent arms omitted is particularly preferred as this provides a corner of a forward facing display with a dividing panel. The adjacent arms of the connecting units may not necessarily be disposed at right angles. Preferably, the integral units are provided with strengthening supports between adjacent arms to give additional strength to the structure. Preferably, the supports are provided with slots so that, in use, a display board may be located therein.

Preferably, the supports are double webs which are laterally spaced to provide a slot therebetween.

Typically, the webs are shaped in the form of right angled triangles with two sides each flush with the surface of its respective adjacent arm. Advantageously the triangular shape of the webs provides strong support between adjacent arms and also provides a locating corner for the display board.

Preferably, a lug is located at either end of each first tubular member so that each end may be rigidly connected to a connecting unit.

Preferably, the mating end of the second tubular member is chamfered on its internal edge to facilitate the depression of the lug as the front edge of the lug is urged against the edge of the second tubular member during push-fit assembly. Typically, the lug is also chamfered to facilitate the process.

All parts may be made of any suitable material but plastic is preferred. Manufacture of plastic parts may be carried out by injection moulding, tubular parts may also be manufactured by extrusion moulding. The holes may be punched or cut using any suitable technique known to the skilled man.

According to a second aspect of the present invention there is provided a display board frame comprising a plurality of tubular members and a plurality of connecting units, each connecting unit including at least two tubular elements, each tubular element being coupled with one tubular member, each coupled tubular element and tubular member being dimensioned so that one is at least partially located within the other to form inner and outer tubular parts wherein a resiliently deformable lug is provided which is located in and protrudes through a hole in the inner tubular part and wherein a hole is formed in the outer tubular part so that the lug may be located therein to join the parts together.

Advantageously, the frame may be constructed using a push-fit technique so that when the tubular elements and members are pushed together the lug is depressed and becomes flush with the inner surface of the outer tubular part until it is located under the hole in the outer tubular part which causes it to spring outwards to locate itself therein.

Preferably, the lug is mounted on a resiliently deformable support located inside the inner tubular part.

Preferably, the support extends transverse to the longitudinal axis of the inner tubular part.

Preferably, the lug and support are located in each tubular member.

Other preferred features and advantages of the arrangement include those mentioned in respect of the first aspect of the invention discussed above with the words tubular member(s) replacing first tubular member(s), the words tubular element(s) replacing second tubular member(s) and the words tubular element(s) and member(s) replacing tubular member(s).

According to a third aspect of the present invention there is provided a method of constructing a display board frame comprising the steps of: a) rigidly connecting a tubular member to a connecting unit by a push-fit action, and b) locating a resiliently deformable lug on one of the connecting parts in a close fitting hole in the other connecting part.

The method may include the step of rotating one of the connecting parts to locate the lug in a different hole disposed in the other connecting part.

The method may incorporate the step of removing the tubular member by depressing the lug and pulling the connecting parts apart.

Preferred features of the display board frame may be ascertained by reference to the first and second aspect of the present invention.

According to a fourth aspect of the present invention there is provided a releasable coupling for joining together a first and second tubular member for a display board frame the dimensions of the tubular members being such that the first tubular member can slide within the second, the first tubular member including a lug which protrudes through an appropriately sized hole in the wall of the first tubular member so that, in use, at least a portion of the lug protrudes above the exterior surface of the first tubular member, the lug being mateable with an appropriately sized hole on the second tubular member, wherein the lug is mounted on a resiliently deformable support located inside the first tubular member and wherein the support is shaped so that its outer surface mimics the shape of the internal surface of the first tubular member. Preferably, the outer surface of the support is in contact with the internal surface of the first tubular member for substantially the whole of the said outer surface.

Preferably, the outer surface of the support lies in continuous contact with the inner surface of the tube except during lug depression. This arrangement gives maximum stability to the support by being urged against the inner surface of the tube across the whole of its surface as oppose to two points of contact as found in the known twin armed spring. Furthermore, the frictional forces between the outer surface of the support and the inner surface of the tube will also act to stabilise the support and prevent its dislodgement.

Other preferred features of the releasable coupling may be ascertained by reference to the first aspect of the invention and all features of the first aspect and, preferred features not explicitly mentioned with respect to the fourth aspect are incorporated here by reference.

Preferably, the support is in the form of a leaf spring.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing which shows a connecting unit, tube and lug in accordance with the present invention.

Referring to Figure 1, a rod like tube 2 has a lug 4 which protrudes through a hole 6 formed in the wall of the tube 2. The lug 4 is mounted on a resiliently deformable support 8 which is shaped to form an arc having a circumference less than the internal circumference of the tube 2 and an uncompressed radius greater than the radius of the internal surface of the tube 2. In this manner, the support may be compressed so that the distance between the upper surface of the lug 4 and the outer surface of the opposed side of the support is less than the diameter of the inner surface of the tube 2 so that the support may be pushed into the tube and the lug may be located in the hole 6 so that it is urged upwardly under the spring action of the support which itself is urged against the interior surface of the tube 2.

As the support is transverse to the longitudinal axis of the tube it is far more difficult to dislodge then the known twin arm spring which tends to ride down the tube along its longitudinal axis. Furthermore, advantageously, the surface of the support lies in continuous contact with the inner surface of the tube. This arrangement gives maximum stability to the support by being urged against the inner surface of the tube across the hole of its surface as oppose to two points of contact found in the typical twin armed spring. Furthermore, the frictional forces between the outer surface of the support and the inner surface of the tube will also act to stabilise the support and prevent its dislodgement.

The connecting unit 12 comprises four short tubular arms 14, 16, 18 and 20 which are arranged so that each adjacent arm is at right angles and so that only one pair of arms 14, 18 is aligned. Each tubular arm 14, 16, 18, 20 has a ring of four equally circumferentially spaced holes. The holes are disposed at 45 with respect to imaginary vertical planes of symmetry in which the panels (not shown) of the display board will lie. Between each adjacent short tubular member 14, 16, 18, 20 is disposed in the vertical plane a pair of triangular webs 22, 24, 26, 28, 30. The webs are in the form of right angled triangles with the right angle disposed in the right angle between adjacent short tubular members. Each pair of webs is parallel and spaced apart to provide a triangular slot which can be utilised to locate display boards or panels (not shown). The short tubular members 14, 16, 18, 20 are hollow to allow further passage of electrical wires or other connection leads through the assembled frame work.

The outer edges of each short tubular member 14, 16, 18, 20 are chamfered on their interior edge to facilitate the depression of the lug as the front edge of the lug is urged against the edge of the short tubular member during push-fit assembly. The lug is also chamfered to facilitate the same process.

The frame may be constructed using a push-fit technique so that when the tubular elements and member are pushed together the lug is depressed owing to the chamfered edge of the lug and the front inner edge of the short tubular arm 16, so that the upper surface of the lug becomes flush with the inner surface of the short tubular member 16 and then advanced and turned if necessary until it is located under the hole 30 in the outer tubular part which causes it to spring outwards to locate itself in the hole 30.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A releasable coupling for joining together a first and second tubular member for a display board frame the dimensions of the tubular members being such that the first tubular member can slide within the second, the first tubular member including a lug which protrudes through an appropriately sized hole in the wall of the first tubular member so that, in use, at least a portion of the lug protrudes above the exterior surface of the first tubular member, the lug being mateable with an appropriately sized hole on the second tubular member, wherein the lug is mounted on a resiliently deformable support located inside the first tubular member and extending transverse to the longitudinal axis of the first tubular member.

2. A releasable coupling according to claim 1, wherein in use, the support is in its compressed state so that it is urged against the internal surface of the first tubular member.

3. A releasable coupling according to claims 1 and 2, wherein the tubular members are circular in cross-section.

4. A releasable coupling according to claim 3, wherein the support is shaped to form an arc whose circumference is less than the internal circumference of the first tubular member but whose uncompressed radius is equal to or greater than the radius of the internal surface of the first tubular member.

5. A releasable coupling according to any preceding claim, wherein a ring of holes is provided in each second tubular member to give a plurality of locating positions for the lug of the first tubular member.

6. A releasable coupling according to any preceding claim, wherein a ring of holes is provided on the end of the first tubular member to give a plurality of locating holes for the lug.

7. A releasable coupling according to any preceding claim, wherein a plurality of second tubular members is provided in an integral connecting unit.

8. A releasable coupling according to claim 7, wherein the connecting unit comprises an octahedral arrangement of six short second tubular members each disposed at right angles to the four neighbouring members and aligned with the opposing member.

9. A releasable coupling according to claim 7 or 8, wherein the connecting units may comprise any number of second tubular members to provide corner units or side units in the framework.

10. A releasable coupling according to any of claims 7-9, wherein the integral units are provided with strengthening supports between adjacent arms to give additional strength to the structure.

11. A releasable coupling according to any of claims 7-10, wherein the strengthening supports are provided with slots so that, in use, a display board may be located therein.

12. A releasable coupling according to any of claims 7-11, wherein the supports are double webs which are laterally spaced to provide a slot therebetween.

13. A releasable coupling according to any of claims 7-12, wherein the webs are shaped in the form of right angled triangles with two sides each flush with the surface of its respective adjacent arm.

14. A releasable coupling according to any preceding claim, wherein a lug is located at either end of each first tubular member so that each end may be rigidly connected to a connecting unit.

15. A releasable coupling according to any preceding claim, wherein the mating end of the second tubular member is chamfered on its internal edge to facilitate the depression of the lug as the front edge of the lug is urged against the edge of the second tubular member during push-fit assembly.

16. A releasable coupling according to any preceding claim, wherein the lug is chamfered.

17. A display board frame comprising a plurality of tubular members and a plurality of connecting units, each connecting unit including at least two tubular elements, each tubular element being coupled with one tubular member, each coupled tubular element and tubular member being dimensioned so that one is at least partially located within the other to form inner and outer tubular parts wherein a resiliently deformable lug is provided which is located in and protrudes through a hole in the inner tubular part and wherein a hole is formed in the outer tubular part so that the lug may be located therein to join the parts together.

18. A display board frame according to claim 17, wherein the lug is mounted on a resiliently deformable support located inside the inner tubular part.

19. A display board frame according to claim 17 or 18, wherein the support extends transverse to the longitudinal axis of the inner tubular part.

20. A display board frame according to any of claims 17-19, wherein the lug and support are located in each tubular member.

21. A method of constructing a display board frame comprising the steps of:a) rigidly connecting a tubular member to a connecting unit by a push-fit action, and b) locating a resiliently deformable lug on one of the connecting parts in a close fitting hole in the other connecting part.

22. A method of constructing a board frame according to claim 21, wherein the method may include the step of rotating one of the connecting parts to locate the lug in a different hole disposed in the other connecting part.

23. A method of constructing a display board frame according to any of claims 21-22, wherein the method incorporates the step of removing the tubular member by depressing the lug and pulling the connecting parts apart.

24. A releasable coupling for joining together a first and second tubular member for a display board frame the dimensions of the tubular members being such that the first tubular member can slide within the second, the first tubular member including a lug which protrudes through an appropriately sized hole in the wall of the first tubular member so that, in use, at least a portion of the lug protrudes above the exterior surface of the first tubular member, the lug being mateable with an appropriately sized hole on the second tubular member, wherein the lug is mounted on a resiliently deformable support located inside the first tubular member and wherein the support is shaped so that its outer surface mimics the shape of the internal surface of the first tubular member.

25. A releasable coupling according to claim 24, wherein the outer surface of the support is in contact with the internal surface of the first tubular member for substantially the whole of the said outer surface.

26. A releasable coupling according to any of claims 24 or 25, wherein the outer surface of the support lies in continuous contact with the inner surface of the tube except during lug depression.

27. A releasable coupling according to any of claims 1-16 or 24-26, wherein the support is in the form of a leaf spring.

28. A releasable coupling according to any of claims 1-16, wherein the support is shaped so that its outer surface mimics the shape of the internal surface of the first tubular member.

29. A releasable coupling according to any of claims 1-16 or 28, wherein the outer surface of the support is in contact with the internal surface of the first tubular member for substantially the whole of the said outer surface.

30. A releasable coupling according to any of claims 1-16 or 28 or 29, wherein the outer surface of the support lies in continuous contact with the inner surface of the tube except during lug depression.

31. A releasable coupling as hereinbefore described with reference to the drawings.

32. A display board as hereinbefore described with reference to the drawings.

33. A method of constructing a display board frame as hereinbefore described with reference to the accompanying drawings.

34. A releasable coupling according to any of claims 24-26, having any of the features of claims 1-16.

35. A display board frame according to any of claims 17-20 having any one of the features of claims 1-16, or 24-30.

36. A method of constructing a display board frame according to any of claims 21-23, wherein the frame incorporates any one of the features of claims 1-20 or 24-30.