GB2284444A - Clamp - Google Patents

Abstract

A clamp or cleat comprises a polygonal, in particular a generally triangular, structure formed of side members (1, 2, 3) joined at apices of the structure by bolts (4, 8, 9). When a bolt (4) is released, one side member (1) can pivot about the adjacent apex. A retainer (24) is provided to keep that side member in the plane of the structure, and engages it frictionally to enable the clamp to be held open. The retainer may be a spring metal planar member apertured to receive the side member and having a projection (26) to urge the side member to an open position. <IMAGE>

Description

CLAMP The present invention relates to clamps for clamping one or more bodies, such as cables and pipes, and is applicable particularly, but not exclusively, to clamps, cleats or straps of a generally triangular configuration for clamping or strapping cables, pipes and the like in a trefoil arrangement or singly.

Such clamps of a triangular configuration generally comprise three side members defining the sides of the configuration. One of the side members may constitute a base member, by which the clamp, and thus a cable or cables, may be bolted to a support. At the apices there are displaceable attachments, normally incorporating a bolt at at least one apex, enabling the clamp to be assembled and then tightened about a cable or cables by tightening the apex bolt or bolts. Pads or cushioning layers may be disposed between the side members and the cables, or the side members may be profiled to conform to the shape of cables. Examples of such clamps are shown in GB1587532 and GB722084.

Advantageously the clamp would be designed so as to accommodate a variety of sizes of cable, but in the examples given above the range of sizes is very limited owing to the amount of adjustment catered for at the one or more apices provided with an adjustment bolt.

International Patent Application PCT/GB91/00045 proposed a clamp which can mount cables or the like having a range of diameters because the connections between the side members at the regions of the apices allow for relative movement therebetween, so that the clamp can expand and contract whilst maintaining the same polygonal shape.

According to one aspect of the present invention, there is provided a clamp for clamping one or more bodies, the clamp having a generally n-sided polygonal configuration defined by n-substantially rigid side members, the side members being coupled in pairs by napex couplings, the apex couplings being such that one is releasable, an associated side member being then displaceable generally in the plane of the polygonal configuration to allow insertion or removal of the body or bodies, there being, at that region of the configuration at the other apex associated with said associated side member, retaining means operable to maintain the side member substantially in the same plane whilst the clamp is opened up and also to provide a retaining action to retain that associated side member in its displaced position whilst the clamp is open.

Preferably all the apex couplings are adjustable to accommodate different sizes of cable. Thus the arrangement is desirably such that adjustment can be accomplished whilst maintaining the same geometry without one of the bodies being more tightly clamped than the other(s) and avoiding 'nipping'. Such couplings might thus include apex bolts, studding or other screw-threaded members allowing the side members to move towards and away from one another whilst maintaining the geometry.

Preferred embodiments are in the main generally triangular.

In one embodiment the retaining means is in the form of a channel between the side walls of which the region of the side member at the other apex sits to provide a guide for guiding the side member substantially in said plane, the channel additionally providing a frictional engagement with the side member to enable it to be retained in an open position.

In a further embodiment the retaining means is a spring member engaging the side member and tending to urge it to an open position. Preferably the spring member is provided with guides between which the side member sits to provide guiding motion substantially in said plane. Preferably, the spring member is of substantially planar material with an aperture through which the side member passes, the aperture incorporating inwardly projecting members acting as spring portions to act on the side member in the sense tending to urge it towards an open position. The aperture may provide an external fit around the side member ensuring that, as the side member is pivoted away from the remainder of the clamp, it is maintained in more or less the same plane. This aperture and spring portion arrangement is preferably duplicated in a single retaining member so that the spring member will engage the apex regions of two side members in the region of said other apex.

Preferably pads are provided, being carried by the side members and giving an engagement surface for engaging the outer surface of the body or bodies concerned.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is an end view of a trefoil cable cleat; Figure 2 is a view of the cleat of Figure 1 in its fully open condition; Figure 3 is an end view of a retainer of the cleat of Figure 1; Figure 4 is an end view of an alternative form of trefoil cable cleat for mounting to a framing channel; Figure 5 is a side view of the cleat of Figure 4; Figure 6 is an end view of a further embodiment of cleat; Figure 7 is a side view of the cleat of Figure 6; Figure 8 is a view of a stabiliser of the cleat of Figures 6 and 7; and Figure 9 is a side view of a cable strap.

The embodiments to be described below are examples of a variety of alternative forms of clamp to which the invention may be applied. A non-exhaustive list of such clamps is as follows: Cleats (where the product is bolted to a structure) (a) 2-bolt fixing for mounting to a wall or structure (Fig. 1 and Fig. 6); (b) l-bolt fixing for mounting to a wall or structure; (c) l-bolt fixing for mounting to a framing channel (Fig. 4); Cable straD (where the product is not provided with means for mounting) for mounting at intervals between cleats (Fig. 9).

Regardless of type, the clamp is designed so as to have the strength required to absorb the enormous forces that can be created by short-circuit conditions in power cables.

Figures 1 to 3 show an embodiment of a two-bolt fixing trefoil cleat design for clamping a trefoil cable arrangement to a support. This cleat has a generally triangular configuration defined by three side members 1, 2 and 3. At the upper apex of the configuration, the end regions of the members 1 and 2 are apertured to receive a bolt 4 secured in place by means of a washer 5, a nut 6 and a lock nut 7.

At the base apices of the cleat the end regions of the side members 1 and 3 and the side members 2 and 3 in each case are apertured by slots (elongate in the length direction of the side members) through which bolts 8 and 9 pass. The inter-engagement between the bolts and side members at the lower apices because of the slots is such that both of the side members 1 and 2 may be pivotally displaced, in plane, to the positions shown in Figure 2 when the upper bolt 4 has been removed, these positions being defined by the dimensions of the slots relative to the bolts. Each bolt is secured with the use of washers, nuts and lock nuts as for the upper apex in this example where the two associated side members are to be pivotable. In a variant in which, say, only the side member 1 is required to pivot, the side member 2 to be fixed may instead have a circular hole at its lower apex region to receive its associated bolt. A lock nut is then used on the bolt 9 at that side of member 2 opposite the illustrated washer, nut and lock nut to give this joint rigidity so that the side members 2 and 3 of the cleat can act as a cradle for the cables when the side member 1 is in its 'open' position. Moreover, the bolt might be arranged threadably to engage the side member 2 for further rigidity.

In its assembled condition as shown in Figure 1, the cleat clamps a trefoil arrangement of cables 10 which are located in place by means of plastics pads 11 which are of generally channel form in order to clip around the side members. The pads are each provided with two part circular recesses in order to provide engagement surfaces corresponding to the configuration of the outer surface of three cables when in a trefoil arrangement. It will be apparent that these pads can readily be replaced by pads with a single recess to clamp a single body in the cleat.

The lower or base side member 3 is in this example extended at both of its ends to provide apertured attachment zones 12 by which the cleat may be bolted by bolts 13 to a support.

At the base apices of the cleat there are provided retainers or stabilisers 14 each of which is a plastics moulding of channel-form as shown by the end view in Figure 3. This channel provides side walls 15 having projecting ribs 16 running along all or part of their lengths, these ribs 16 being in frictional engagement with the side members 1 and 3, and 2 and 3 as the case may be. A rib 17 runs across the width of the retainer to abut an adjacent cable and within the channel there is a projection 18 which provides a location element for the associated bolt 8 or 9.

When the upper bolt 4 is removed it will be apparent that one or both of the side members 1 and 2 may be pivoted to a "open" position such as is shown in Figure 2 in order that cables may be mounted in the cleat. In order to facilitate the use of this cleat, the retainers 14 provide, by means of their side walls 15 and ribs 16, guide means for guiding the side members 1 and 2 in their pivoting motion such that that motion remains substantially in the plane of the cleat.

Furthermore, when the side member 1 or 2 reaches its angular limit, as shown in Figure 2, the frictional engagement of the ribs 16 with the side member will retain it in place, freeing the hands of the operator to further assemble the cables in the cleat.

Such a cleat would normally be assembled in the factory, with the size of the bolts selected, and the bolts and nuts adjusted, so that the cleat correctly accommodates a trefoil cable arrangement of a given size.

In use, the lower side member would be bolted to a support and the bolt 4 would be detached. In this condition, and especially by virtue of the retainers, a relatively longitudinally stable structure is provided which at the same time provides for 'opening' at least one side member to give a clear access for cables to the interior of the cleat via the opening created by pivoting the side member(s). When the cable arrangement has been inserted, the bolt 4 is reinserted and the whole finally secured together by reattaching its nuts 6 and 7. The cleat structure may then be tightened as required by turning the nuts, this enabling the cleat to adapt its size to the particular trefoil arrangement being clamped, without a significant change of geometry.

It will thus be seen that this form of cleat can be readily mounted, providing a relatively stable structure during such mounting and during the insertion of the cables, and is designed in such a way that insertion is not unreasonably impeded. Moreover it inherently has a significant adjustment to cater for a variety of cable sizes.

Figures 4 and 5 show an alternative l-bolt fixing cleat which thus differs in that the base side member 3 is provided with a central aperture 19 enabling the cleat to be secured readily to a British Standards framing channel 20. A bolt 21 threadably engages a spring-loaded nut 22 which engages the overturned edges 23 of the framing channel, as shown in Figure 5.

Figures 6 and 7 shows an embodiment having an alternative design of retainer. Whilst this example is a 2-bolt fixing cleat, it may alternatively be constructed as any other of the alternative types, e.g.

in a similar manner to that shown for either of the earlier embodiments, with any one of a variety of provisions for securing the cleat as may be necessary to a support or a framing channel. The major feature of this embodiment is that the retainers are provided by means of stabilisers which are substantially planar plastics springs 24, a plan view of one of which is shown in Figure 8. The stabiliser incorporates two apertures 25 into which project three interdigitate spring portions 26, 27 and 28, the centre one of which 26 engages the inwardly facing surface of the associated side member whereas the two outer spring portions 27 and 28 engage the outwardly facing surface.

As manufactured, the centre portion 26 is bent slightly upwardly out of the plane of the paper. All the spring portions act in the sense tending to urge the associated side member outwardly, thus retaining it in its open position, as shown for the right-hand side member 2 in Figure 6. Moreover, the sides of the apertures 25 engage the side members to ensure that, as a side member is swung away from the 'closed' position, it is held in the same plane as the side member 3 at the base.

This embodiment is also useful in describing a modified construction. In this modification, the lower holes of the side members 1 and 2 are tapped to be threadably engaged by the bolts 8 and 9. These bolts are then secured by locking nuts 7, the nuts 6 being omitted. The third side member 3 remains the same with its elongate holes so that, on releasing apex bolt 4, the side member 1 and/or 2 will pivot with the associated bolt 8 and/or 9 about just the third side member. This variation is of course applicable to each of the other embodiments described herein.

When cleating high power electrical cable, it would be usual to use a cleat in any of the above forms every 1.2 to 1.5 meters and, at midpoints therebetween, to put a band around the cables to prevent their flying apart in the event of a short circuit.

Figure 9 shows an embodiment of the invention which may be used for such cable banding at the intermediate points and which is termed herein a strap.

In Figure 9, parts corresponding to those shown in Figures 6 to 8 are given the same numerals. Indeed, it will be seen that only side member 3 is different from the preceding embodiment in that it does not have the apertured end extensions of the side member 3 of Figure 6.

The above examples constitute only some possible forms of the invention and it will be readily apparent that various modification can be made. For example, the apex connections need not be by way of bolts or set screws. For example, they may incorporate some other form of elongate, substantially rigid, member, preferably having a circular cross-section and preferably threaded at at least one end region. As one example, studding may be employed, with threading at both ends for use in engaging to the side members.

Claims (20)

CLAIMS:

1. A clamp for clamping one or more bodies, the clamp having a generally n-sided polygonal configuration defined by n-substantially rigid side members, the side members being coupled in pairs by napex couplings, the apex couplings being such that one is releasable, an associated side member being then displaceable to allow insertion or removal of the body or bodies, characterised in that the said associated side member is displaceable generally in the plane of the polygonal configuration, there being, at that region of the configuration at the other apex associated with the said associated side member, retaining means operable to maintain the side member substantially in the same plane whilst the clamp is opened up and also to provide a retaining action to retain that associated side member in its displaced position whilst the clamp is open.

2. A clamp according to claim 1, wherein all the apex couplings are adjustable to accommodate different sizes of cable.

3. A clamp according to claim 2, wherein the arrangement is such, for clamping a plurality of bodies, that adjustment can be accomplished whilst maintaining the same geometry without one of the bodies being more tightly clamped than the other(s).

4. A clamp according to claim 3, wherein the or each apex coupling includes an apex bolt, studding or other screw-threaded member allowing the side members to move towards and away from one another whilst maintaining the geometry of the clamp.

5. A clamp according to any one of the preceding claims wherein n = 3 and the clamp is generally triangular.

6. A clamp according to any one of the preceding claims, wherein the retaining means is in the form of a channel between side walls of which a side member region at the other apex region sits to provide a guide for guiding the side member substantially in said plane, the channel additionally providing a frictional engagement with the side member to enable it to be retained in an open position.

7. A clamp according to any one of claims 1 to 5, wherein the retaining means is a spring member engaging the side member and tending to urge it to an open position.

8. A clamp according to claim 7, wherein the spring member is provided with guides between which the side member sits to provide guiding motion substantially in said plane.

9. A clamp according to claim 8, wherein the spring member is of substantially planar material with an aperture through which the side member passes, the aperture incorporating inwardly projecting members acting as spring portions to act on the side member in the sense tending to urge it towards an open position.

10. A clamp according to claim 9, wherein the aperture is in the form of an elongate figure having two opposite elongate sides, there being two, spacedapart, projecting members projecting from one of those sides and a third member projecting from the opposite side and between the said two projecting members.

11. A clamp according to claim 9 or 10 wherein the aperture provides an external fit around the side member ensuring that, as the side member is pivoted away from the remainder of the clamp, it is maintained in substantially the same plane.

12. A clamp according to claim 9, 10 or 11, wherein the aperture and spring portion arrangement is duplicated in a single retaining member so that the spring member will engage the apex regions of two side members in the region of said other apex.

13. A clamp according to any one of the preceding claims, wherein pads are provided, being carried by the side members and giving an engagement surface for engaging the outer surface of the body or bodies concerned.

14. A clamp according to any one of the preceding claims, wherein one side member has a central portion apertured to receive a securing member to attach the clamp to a support.

15. A clamp according to any one of claims 1 to 13, wherein one side member has projecting end portions apertured to receive securing members to attach the clamp to a support.

16. A clamp according to any one of the preceding claims wherein, at the said other apex, the said associated side member and the side member to which it is joined are joined by an elongate member extending through an aperture in one of those joined side members with a clearance such as to permit pivoting of the said associated side member.

17. A clamp according to claim 16, wherein the elongate member is secured to the other of those joined members so that a single pivoting joint is provided at the said other apex.

18. A clamp for clamping one or more bodies, the clamp having a generally n-sided polygonal configuration defined by n-substantially rigid side members, the side members being coupled in pairs by napex couplings, the apex couplings being such that one is releasable, an associated side member being then displaceable to allow insertion or removal of the body or bodies, characterised in that the said associated side member is displaceable generally in the plane of the polygonal configuration, there being, at that region of the configuration at the other apex associated with the said associated side member, retaining means operable to maintain the side member substantially in the same plane whilst the clamp is opened up.

19. A clamp for clamping one or more bodies, the clamp having a generally n-sided polygonal configuration defined by n-substantially rigid side members, the side members being coupled in pairs by napex couplings, the apex couplings being such that one is releasable, an associated side member being then displaceable to allow insertion or removal of the body or bodies, characterised in that, at that region of the configuration at the other apex associated with the said associated side member, there are retaining means operable to provide a retaining action to retain that associated side member in its displaced position whilst the clamp is open.

20. A clamp substantially as hereinbefore described with reference to Figures 1 to 3, or Figures 4 and 5, or Figures 6 to 8, or Figure 9 of the accompanying drawings.