GB2208246A - Clamp - Google Patents

Abstract

A clamp, for example for a use in providing diagonal bracing for a roof truss of a building, comprises a pair of clamping plates (10, 12) for clamping the members of a roof truss therebetween and collapsible spacer means (16) positioned between the plates. Clamp securing means such as a bolt (14) and a nut (34) pass through apertures formed in the clamping plates and into fastening means such as an attachment plate (30) for fastening the clamp to a diagonal bracing member. Spring washers (18, 20) maintain the clamping force. <IMAGE>

Description

CLAMP The present invention relates to a clamp which may be employed, for example, in a diagonal bracing member for the roof of a building.

It is well known that the majority of modern houses have roofs which incorporate timber prefabricated trussed rafters. It has been found that many of these houses have insufficient resistance to lateral movement and require diagonal bracing or additional diagonal bracing to render them stable. Such diagonal 1 bracing is required to be secured to the trusses as close as possible to the level of the eaves of a house where space is severely limited and it is currently necessary either to remove the tiles, tiling battens and roofing felt or to remove an area of the ceiling of the house in order to provide adequate access.

Both of these methods are costly and cause considerable inconvenience to the occupants of the house.

It is an object of the present invention to provide a clamp which permits the installation. of a diagonal bracing member in the roof of a house economically and with minimal inconvenience.

According to the present invention there is provided a clamp comprising: first and second clamping plates for clamping a first element therebetween; collapsible spacer means positioned between said first and second clamping plates; clamp securing means passing through apertures formed in each of said clamping plates; and means for fastening the clamp to a second element.

The clamp securing means may include spring means, such as at least two opposed Belleville springs, for urging the first and second clamping plates towards each other.

Preferably, the first and second clamping plates are each provided with a reinforcing rib. The clamping plates may each be provided with protrusions for engaging the first element.

The clamp securing means may pass through a part of each clamping plate which is inclined relative to the part thereof intended to clamp against the first element.

The collapsible spacer means may be made of a plastics material.

The clamp securing means may comprise a bolt and a nut and means for preventing rotation; of one of said bolt and said nut.

The clamp may include means for preventing rotation of the clamping plates relative to the fastening means.

The fastening means may comprise a plate, a bolt passing through the plate, a toothed connector for engaging with said second element, and a nut. The fastening means may include spring means, such as a Belleville spring, for urging the second element against the connector.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made; by way of example, to the accompanying drawings in which: Figure 1 is an exploded view of one embodiment of a clamp according to the present invention; Figure 2 is a side view of a clamping plate forming part of the clamp of Figure 1; and Figure 3 is an end view of the clamping plate shown in Figure 2.

The clamp shown in Figure 1 comprises first and second clamping plates 10 and 12 respectively which, in use, clamp between the outer portions thereof two different parts of a prefabricated truss (not shown). The clamping plates will be described in more detail hereinafter. A coach bolt 14 passes through the two clamping plates and a collapsible spacer sleeve 16 of plastics material is passed over the bolt 14 between the plates 10,12. The spacer sleeve may alternatively comprise a spring. Because timber is subject to expansion and contraction over a period of time, Belleville springs 18,20 are employed to maintain the clamping force on the truss. In the embodiment shown in Figure 1, two springs are shown acting in each direction, but this number may be varied depending on the type of spring employed and the clamping force required.The springs 18,20 are maintained in place by a bush 22, for example made of brass.

An anti-rotational strap 24 is passed over the bolt 14 and has an arm 26 which extends adjacent to the clamping plates 10,12 and a pair of flanges 28 which engage with an attachment plate 30. The strap 24 inhibits rotation of the clamping plates 10,12 relative to the attachment plate 30.

The attachment plate 30 may be made of 2mm galvanised mild steel. The bolt 14 passes through an aperture in the attachment plate 30 and a washer 32 and nut 34 are mounted on the end of the bolt. The attachment plate 30, which may be made by pressing, includes an end plate 36 through which the bolt 14 passes, a base plate 38 for attachment to a bracing timber (not shown), and two reinforcing portions 40 which strengthen the plate 30. A coach bolt 42 passes through a square aperture in the plate 30 and through a toothed connector plate 44 which, in use, bears against one face of the bracing timber. The bolt 42 also passes through a washer plate 46, which in use bears against the other face of the bracing timber, and through two Belleville springs 47 which compensate for expansion and contraction of the timber as described hereinbefore.A washer 48 and a nut 50 are mounted on the end of the bolt 42.

The clamping plates 10,12 are shown in more detail in Figures 2 and 3 and it can bt seen that a strenthening or reinforcing rib 52 extends along the length of the plate and a plurality of protrusions in the form of teeth 54 are pressed out of the plate to engage with the timber of the truss. In order to establish the desired orientation of the bracing timber within the roof a raised portion 56 is pressed out of the plate so as to form an inclined surface through which the bolt 14 passes. The bolt passes through an aperture 58 which in the plate 10 is circular but in the plate 12 is square so as to engage non-rotatably with the bolt 14. The clamping plates may be pressed from 2mm galvanised mild steel.

In use, the clamp is secured to the end of a bracing timber by means of the bolt 42 and nut 50 together with the other components described hereinbefore. The sleeve 16 maintains the spacing of the plates 10,12 and the strap 24 prevents rotation of the plates relative to the bracing timber.

Despite the limited space available in the roof space of a house, the bracing timber can be manoevred such that the plates 10,12 are on opposite sides of the timbers of a truss with the clamp close to the level of the eaves and the wall plate. One end of the plates 10,12 engages with a horizontal timber while the other end of the plates 10,12 engages with an inclined timber. In this situation, the clamping plates can be tightened against the truss by rotating the nut 34 in the appropriate direction. This can be accomplished from a considerable distance by employing a suitable socket and extension arm. As the plates 10,12 move together the sleeve 16 collapses and does not detract from the clamp load. Once the clamp has been secured, the bracing timber can then be secured to other trusses which form the roof of the house.

It will be appreciated that the clamp according to the present invention allows bracing timbers to be installed in the roof of a house without the need to remove the roof tiles or any part of the ceiling despite the severely restricted space available.

A number of modifications may be made to the clamp. These include reversing the bolt 14 so that the head replaces the nut 34 in Figure 1. The nut 34 can then be supported at the free end of the bolt by a retaining plate which prevents rotation of the nut relative to the plates 10,12.

This permits the plates 110,12 to be identical and facilitates installation of the clamp. Further, the bush 22 can be omitted.

Claims (13)

1. A clamp comprising: first and second clamping plates for clamping a first element therebetween; collapsible spacer means positioned between said first and second clamping plates; clamp securing means passing through apertures formed in each of said clamping plates; and means for fastening the clamp to a second element.

2. A clamp as claimed in claim 1, wherein the clamp securing means includes spring means for urging the first and second clamping plates towards each other.

3. A clamp as claimed in claim 2, wherein the spring means comprises at least two opposed Belleville springs.

4. A clamp as claimed in any preceding claim, wherein the first and second clamping plates are each provided with a reinforcing rib.

5. A clamp as claimed in any preceding claim, wherein the first and second clamping plates are each provided with protrusions for engaging the first element.

l

6. A clamp as claimed in any preceding claim, wherein the clamp securing means passes through a part of each clamping plate which is inclined relative to the part thereof intended to clamp against the first element.

7. A clamp as claimed in any preceding claim, wherein the collapsible spacer means is made of a plastics material.

8. A clamp as claimed in any preceding claim, wherein the clamp securing means comprises a bolt and a nut and means for preventing rotation of one of said bolt and said nut.

9. A clamp as claimed in any preceeding claim and including means for preventing rotation of said clamping plates relative to said fastening means.

10. A clamp as claimed ini any preceding claim, wherein the fastening means comprises a plate, a bolt passing through said plate, a toothed connector for engaging with said second element, and a nut.

11. A clamp as claimed in claim 10 and including spring means for urging said second element against said connector.

12. A clamp as claimed in claim 11, wherein the spring means comprises at least one Belleville spring.

13. A clamp substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.