GB1601824A

GB1601824A - Clip fastening arrangements

Info

Publication number: GB1601824A
Application number: GB188078A
Authority: GB
Original assignee: Nimlok Ltd
Current assignee: Nimlok Ltd
Priority date: 1978-05-26
Filing date: 1978-05-26
Publication date: 1981-11-04
Also published as: NL8006683A

Description

(54) CLIP FASTENING ARRANGEMENTS (71) We, NIMLOK LIMITED, a British Company, of 1 9a Floral Street, London WC2E 9DS, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to fastening arrangements comprising clips and cylindrical members onto which the clips may be fastened.

The invention has particular, but not exclusive, reference to fastening arrangements for use in erecting temporary structures such as displays.

British Patent Specification No. 1 270242 describes a fastening arrangement in which a clip which is securable to a tube comprises a resilient arcuate portion and a foot, the resilient arcuate portion being co-operable with the cylindrical member, and subtending an angle at the centre of the arcuate portion of 215 . The clip can be snap-fitted onto a suitably sized tube the distal ends of the arcuate portion of the clip being forced apart during the snap-fitting of the tube. By selecting suitable dimensions and suitable materials for the clip and tube the snap-fit can provide a strong fastening. However it has been found that if, once the clip has been fitted on the tube, the clip is subjected to a moment pulling the arcuate portion away from the tube at one end of the clip and pushing the arcuate portion towards the tube at the other end of the clip then it is relatively easy to detach the clip from the tube. It will be appreciated that this can be a disadvantage.

It is an object of the invention to provide a fastening arrangement which overcomes at least in part this disadvantage.

According to the invention a fastening arrangement comprises a clip having a resilient arcuate portion and a foot portion wherein the arcuate portion subtends at its centre an angle in the range of 215 + 304 and defines a cavity of substantially smoothly curved round cross-section, and wherein one and only one of the ends of the arcuate portion has an in-turned hook portion, and a cylindrical member of a size and shape suitable for receiving the arcuate portion of the clip around a major part of the periphery of the member, the member having a generally smoothly curved outer surface interrupted by one or more discontinuities each of which includes a longitudinal wall which lies in a plane transverse to the generally smoothly curved outer surface.

The hook portion may be formed as an integral part of the clip.

The or each longitudinal wall may be formed as a sudden step in the radial dimension of the cylindrical member, the outer surface of the cylindrical member being smoothly contoured on both sides of the sudden step.

The cylindrical member may be of generally circular cross-section. The or each step may be formed by a gradual change in the radial dimension of the member from the general radius to a second radius and then a sudden change in the radius of the member from the second radius to the general radius.

Each discontinuity may be formed in a recess lying within the general outline of the member, one wall of the recess being defined by the longitudinal wall.

The number of discontinuities is not critical. As will become apparent from the description of an embodiment of the invention, each discontinuity provides a position in which the clip may be more securely fastened to the cylindrical member.

If too many discontinuities are provided, for example about thirty, the surface of the cylindrical member ceases to be generally smoothly curved and the clip cannot readily be attached to the cylindrical member. For a member of generally circular cross-section and diameter about one and quarter inches six discontinuities are satisfactory.

The discontinuities may be equiangularly spaced around the cylindrical member.

The cylindrical member may be of hollow tubular form. The member may form one of the tubes of an interlocking arrangement of the form described with reference to Figures 9 and 10 of British Patent Specification No.

1,270,242 or one of the the tubes of an interlocking arrangement of the form de scribed and claimed in copending British Patent Application No. 80.05491 (Serial No.

2,071,194) entitled "Tubular Fastening Arrangements" According to another aspect of the invention a clip comprises a resilient arcuate portion and a foot portion wherein the arcuate portion subtends at its centre an angle in the range of 215" +30" and has an in-turned hook portion, the arcuate portion defines a cavity of substantially smoothly curved round cross-section, and wherein one and only one of the ends of the arcuate portion has an in-turned hook portion, the arcuate portion being suitable for fastening around a major part of the periphery of a cylindrical member.

By way of example, certain illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an end view of a clip.

Figure 2 is an enlarged sectional view of a clip secured on a tube, Figure 3 is a side view of the clip secured on the tube, Figure 4 is an enlarged end view of an alternative form of tube, Figure 5 is an enlarged end view of a fastening arrangement including a clip and another alternative form of tube, and Figures 6A, 6B and 6C are end views of alternative forms of clip.

Referring to Figure 1 the clip I comprises an arcuate portion 2 having a hook portion 4 on one of the non-arcuate ends of the arcuate portion portion 2 and a foot portion 3. In its unstressed position the arcuate portion forms an arc of a circle subtending an angle of 215 at the centre of the circle and defining a cavity of smoothly curved round cross-section. The arcuate portion 2 and the foot portion 3 may be formed separately in which case the portion 2 can be cut from a tube and the foot can be secured to the portion 1 with a suitable adhesive, for example an epoxy resin. In the illustrated embodiment, however, the clip is made by extruding a single section and cutting off a length of the section to form a clip.

The foot portion 3 is formed with laterally extending tongues 9 at the base of the portion 3 and a longitudinal channel 5 in its upper surface and another longitudinal channel 6 in its lower surface. In the centre of the foot portion 3, a threaded hole is formed and a grub screw 7 is located in the hole. Thus the foot portion can be fixed to a member 8 (shown in dotted outline in Figure 1) with the screw 7 bearing against the end of the member 8 and pressing the tongues 9 against walls of grooves formed in the member 8.

Alternatively the foot portion 3 may be connected to a member by engagement of a tenon on the member with the channel 6 in the foot portion; in this case the screw 7 is omitted or a shorter screw used. A further alternative is to attach the foot portion 3 to a member by passing the shank of a headed screw through a hole in the foot portion and securing the shank of the screw in the member 8.

The arcuate portion 2 of the clip can be clipped over a tube 10 as shown in Figure 2.

The tube 10 is characterised in that its outer wall is of generally circular cross-section but is formed with six equiangularly spaced discontinuities in the form of shallow longitudinal recesses 11. It will be seen that each recess has a short radial wall 12 and a long straight wall 13 which starts at the base of the wall 12 and meets the portion of the outer wall of circular cross-section. Dotted lines 14 in Figure 2 show circular imaginary lines over the recesses 11. As viewed in Figure 2 all the radial walls 12 face in the anticlockwise direction. The recesses 11 are sized such that the hook portion 4 of clip 1 can be received in the recess.

It will be appreciated that the crosssections of the tube 10 and the clip 1 must be such that the clip can be snapped over the tube in which position the distal ends of the arcuate portion of the clip are inwardly urged against the tube. Preferably, as shown in Figure 2 the arcuate portion of the clip 1 contacts the outer wall of the tube 10 around the circular parts of the outer wall of the tube.

In the position shown in Figure 2 (only part of the clip being fully shown) the radial wall formed on the hook portion 4 abuts the radial wall 12 of the tube 10. If an attempt is made to separate the tube and clip at one end but not at the other, by applying a moment M to the clip as indicated in Figure 3 it will be clear that the hook portion 4 of the clip at the lower end (as seen in Figure 3) of the clip will engage the wall 12 thus preventing tilting of the clip. Such a force is likely to be applied to the clip if, for example, its foot portion 3 is holding a load in a cantilever mode. However if a user wishes to separate the clip from the tube he merely rotates the clip in an anticlockwise direction until the hook portion 4 is no longer engaged by the wall 12 and then separates the clip from the tube with a cantilever action.

The use of the clip 1 and the tube lO*will now be clear. By snapping the clip 1 onto the tube 10 and then rotating the clip relative to the tube to a position corresponding to that shown in Figure 3 the clip is secured to the tube in such a manner that the clip and tube cannot be separated merely by a moment whose effect is to pull the clip and the tube apart at one end and push them together at the other end.

In one particular example of the invention the arcuate portion of the clip is of 1.25 inches external diameter with walls (away from the foot portion 3 and the hook portion 4) 0.064 inches thick and the tube has an external diameter of 1.25 inches. The length of the clip is a matter of choice; the longer the clip the greater the strength of connection with a tube; clips of 1.25 inches in length are provided in the particular example. In the particular example the tube 10 is made of Duralumin and the clip 1 is made in an aluminium alloy of composition by weight, copper 0.1%, magnesium 0.45 to 0.85%, manganese 0.1%, silicon 0.3 to 0.6%, iron 0.3 to 0.4%, zinc 0.03%, titanium 0.1%, chrome 0.1%, and the remainder aluminium. These clips have a high resistance to fatigue if they are solution treated (heated to 500"C and rapidly cooled by water quenching) and then precipitation treated (reheated for a period of time at 120"C to 200"C). An alloy of, by weight, silicon 1%, magnesium 5/8% and aluminium 983/4% has a poor fatigue strength in the untreated condition.

It will be clear that the fastening arrangements described may be used in a great many applications; for example the clips may be use to attach articles secured by their foot portions to a tubular structure, for instance to attach a partition to a supporting pole.

British Patent Specification No. 1,270,242 describes and claims an aluminium clip similar to that shown in Figure 1 but without the hook portion 4. The specification describes and illustrates various applications of that clip, for which a clip embodying the present invention would be suitable.

British Patent Specification No. 1,270,242 also describes and illustrates (Figures 9 and 10) an arrangement whereby two portions of a tube can be joined together. The two portions of tube have an interior crosssection which is oval and are joined by a short length of tube whose exterior crosssection is oval by inserting opposite ends of the short length of tube into the two portions of tube to be joined and rotating one portion of the tube relative to the other. Figure 4 of the present specification is an end sectional view of a tube 20 embodying the present invention and which may be connected to another tube in the manner described in British Patent Specification No. 1,270,242.

The tube 20 is generally similar to the tube 10 but differs in two unrelated respects. The tube has three recesses formed on its outer surface rather than six. The provision of a smaller number of recesses reduces the number of positions in which a clip can be securely held on the tube against contilever forces but facilitates the location of the clip on the tube. The tube has an interior crosssection which is oval (the external crosssection is circular). The oval interior crosssection of the tube enables two portions of tube to be joined as described above.

A fastening arrangement embodying the invention may also be of the form shown in Figure 5. Figure 5 shows an outer tube 30 on which a clip 1 which is constructed as shown in Figure 1 is snap fitted, and an inner tube 31 which is jammed inside the tube 30. The exterior cross-section of the tube 30 is generally circular and the interior cross-section of the tube 31 is circular. The interior crosssection of the tube 30 and the exterior cross- section of the tube 31 are best understood with reference to Figure 5. It will be seen that the external radial dimension of the inner tube 31 varies around the tube reaching a maximum at three regions equiangularly spaced around the tube, these regions being referenced by the numeral 32. The internal radial dimension of the outer tube 30 similarly reaches a maximum at three regions equiangularly spaced around the tube, these points being referenced by the numeral 33.

The tubes can be joined by inserting one of the tubes into the other and rotating one tube relative to the other. The method ofjoining is described more fully in copending Patent Application No. 80.05491 Serial no 2071194 entitled "Tubular Fastening Arrangements".

As with the tube 20, the tube 30 is formed with three recesses on its outer surface. These recesses are located at the regions 33 where the wall thickness of the tube 30 is greatest.

The recesses are of the same shape as those described with reference to Figures 1 to 3 and the same reference numerals are used to denote corresponding parts.

In Figure 1, the clip 1 is shown with a particular form of foot portion. However, it should be understood that the shape of this foot portion is not important to the snapfitting of the clip onto a tube and that other shapes of foot portion can be employed according to the manner in which the foot portion is to be attached to another member.

Figures 6A, 6B and 6C show alternative forms of foot portions which may be used.

The foot portion shown in Figure 6A has a pair of arms 41 terminating in arcuate portions 42 which define passages 43 through which screws may be passed to secure the clip to a surface.

The foot portion shown in Figure 6B is in the form of a tenon and may be received in a corresponding groove in a member in a similar manner to that in which the foot portion 3 of the clip 1 is received.

The foot portion shown in Figure 6C has a single arm 43 terminating in a cylindrical bulbous portion 44. By removing material from the arm 43 between the ends of the clip, the bulbous portion 44 adopts the form of a bar or rail and may, for example, act as a bar on which coat-hangers can be hung.

While various particular constructions of foot portions have been described it will be understood that a great many other construc tions are possible.

In the embodiments described the clip 1 and the tube 10 are both made of an aluminium alloy. However they may be made of plastics material or of some other metal, provided that either the clip or the tube have sufficient resilience that the clip can be snapped over the tube. Also it should be noted that the tube 10 may be replaced by a solid bar.

WHAT WE CLAIM IS: 1. A fastening arrangement comprising a clip having a resilient arcuate portion and a foot portion wherein the arcuate portion subtends at its centre an angle in the range of 2l5':t:30' and defines a cavity of substantially smoothly curved round cross-section, and wherein one and only one of the ends of the arcuate portion has an in-turned hook portion, and a cylindrical member of a size and shape suitable for receiving the arcuate portion of the clip around a major part of the periphery of the member, the member having a generally smoothly curved outer surface interrupted by one or more discontinuities each of which includes a longitudinal wall which lies in a plane transverse to the generally smoothly curved outer surface.

2. A fastening arrangement as claimed in claim 1, in which the hook portion is formed as an integral part of the clip.

3. A fastening arrangement as claimed in claim 1 or 2, in which the arcuate portion subtends an angle of 215 .

4. A fastening arrangement as claimed in any preceding claim in which the or each longitudinal wall is formed as a sudden step in the radial dimension of the cylindrical member, the outer surface of the cylindrical member being smoothly contoured on both sides of the sudden step.

5. A fastening arrangement as claimed in any preceding claim in which the cylindrical member is of generally circular cross-section.

6. A fastening arrangement as claimed in any preceding claim in which the or each discontinuity is formed by a gradual change in the radial dimension of the member from the general radius to a second radius and then a sudden change in the radius of the member from the second radius to the general radius.

7. A fastening arrangement as claimed in any preceding claim in which each discontinuity is formed in a recess lying within the general outline of the member, one wall of the recess being defined by the longitudinal wall.

8. A fastening arrangement as claimed in any preceding claim in which there are a plurality of discontinuities equiangularly spaced around the cylindrical member.

9. A fastening arrangement substantially as herein described with reference to and as illustrated by the accompanying drawings.

10. A clip comprising a resilient arcuate portion and a foot portion wherein the arcuate portion subtends at its centre an angle in the range of 215 +30 and has an in-turned hook portion, and arcuate portion defines a cavity of substantially smoothly curved round cross-section, and wherein one and only one of the ends of the arcuate portion has an in-turned hook portion, the arcuate portion being suitable for fastening around a major part of the periphery of a cylindrical member.

11. A clip as claimed in claim 10, in which the hook portion is formed as an integral part of the clip.

12. A clip as claimed in claim 10 or 11, in which the acruate portion subtends an angle of 215".

13. A clip substantially as herein described with reference to and as illustrated by Figures 1, 2, 3 and 5 of the accompanying drawings.

14. A clip as claimed in claim 15 modified substantially as herein described with reference to and as illustrated by Figures 6A, 6B and 6C of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tions are possible. In the embodiments described the clip 1 and the tube 10 are both made of an aluminium alloy. However they may be made of plastics material or of some other metal, provided that either the clip or the tube have sufficient resilience that the clip can be snapped over the tube. Also it should be noted that the tube 10 may be replaced by a solid bar. WHAT WE CLAIM IS:

1. A fastening arrangement comprising a clip having a resilient arcuate portion and a foot portion wherein the arcuate portion subtends at its centre an angle in the range of 2l5':t:30' and defines a cavity of substantially smoothly curved round cross-section, and wherein one and only one of the ends of the arcuate portion has an in-turned hook portion, and a cylindrical member of a size and shape suitable for receiving the arcuate portion of the clip around a major part of the periphery of the member, the member having a generally smoothly curved outer surface interrupted by one or more discontinuities each of which includes a longitudinal wall which lies in a plane transverse to the generally smoothly curved outer surface.