GB2052600A - Structural support beam - Google Patents

Abstract

A structural member such as a beam or joist comprises a pair of chords (1, 2) held spaced-apart from one another by struts (3, 4) formed integrally with at least one of the chords (1, 2). The struts (3, 4) are formed from parts of the chord (1 or 2) which have been partially cut, bent out of that chord and attached to the other chord. Timber nailing strips may be secured to the chords. <IMAGE>

Description

SPECIFICATION Structural support beam This invention relates to lightweight structural members such as beams, trusses or columns for example. In particular, the invention relates to lattice-like structural members of the type in which a pair of chords are held spaced apart from one another by a series of struts.

Many such structures have previously been proposed, but most of these have either been formed from a solid section, for example in the shape of an I-beam from the web of which apertures have been cut out to provide the struts and lighten the beam, or from a pair of chords to which a central spacing lattice is separately attached. One common type of beam has a pair of metal chords spaced apart from one another by a zig-zag metal wire which runs along the length of the chords and is welded to each of them alternately.

As will be appreciated the methods of constructing these previous designs can be complicated, the first type requiring multiple cutting or punching steps, and the second requiring the accurate positioning of several individual elements. Furthermore, many of the prior configurations are not as lightweight as the basic design will allow, unless apertures are cut in the various individual elements and this of course wastes material and further complicates the method of forming members.

To overcome these problems and in accordance with the present invention a structural member comprises a pair of chords held spaced-apart from one another by struts formed integrally with at least one of the chords, the struts being formed from parts of that chord which have been partially cut, bent out of that chord, and attached to the other chord.

The invention also includes a method of forming a structural member, the method comprising cutting and bending out of a strip of material a plurality of struts and fixing the free ends of the struts to a further strip, whereby the strips form chords spaced apart by the struts.

Structural members formed in accordance with the invention may be used for example as beams, joists or columns.

In one form each of the chords has struts bent out from it, the end of each strut remote from its integral chord being welded or fixed in some other way to the opposite chord. Alternatively, only one of the chords may have the struts formed from it, each of the portions of the chord bent out of the chord being further bent so as to form a 'V', the base of the 'V' being joined to the other chord and the free end of the double-strut being welded or otherwise attached back to the first chord.

In its simplest form, the member has a pair of chords each comprising an elongate flat strip of metal from which are cut and bent out elongate rectangular portions. The free end of each rectangular portion is then welded to the opposite chord. In order to further increase the strength of the members the chords can be formed with ribs or flanges and the struts can be partially bent along a longitudinal axis so as to provide a greater beam effect for each of the struts and chords.

It will be appreciated that the removal of portions of the chords for use as the struts significantly reduces the weight of the members. It is envisaged that the structural members could additionally be used as nailing joists by the provision of timber strips or the like along the chords. These strips could be bolted to the chords, fixed by means of inturned flanges on the chords or glued to the chords.

Examples of structural members according to the present invention will now be described with reference to the accompanying drawings in which Figure 1 is a perspective view of the simplest form of the invention; Figures 2a and 2b show a cross-sections through a second structural member and a cross- section through the strut of this second member, respectively; and, Figures 3a to 3k show various other forms that the chords might take.

In Figure 1 the simple structural metal member comprises upper and lower metal chords 1 and 2 respectively, spaced apart by struts 3 and 4. The struts 3 are integral with the chord 1 and the struts 4 are integral with the chord 2, both struts sets having been cut and bent out from their respective chords. As can be seen from the drawing the chord assemblies 1, 3 and 2, 4 are identical and one is simply turned up-side-down and superimposed on the other. The free ends of the struts 3 and 4 are welded to the opposed chord 2, 1 respectively.

In order to provide additional strength the struts can be given a longitudinal bend so that in cross section the struts are as shown in Figure 2b.

Figure 2a illustrates a cross-section through a structural member to be used as a nailing joist.

The upper and lower chords 11 and 12 respectively include pairs of webs 11' and 12' which lie substantially parallel with the plane in which the struts 1 3 lie, and each of the webs has an inturned flange 11", 1 2" respectively at its free end. The inturned flanges 11" and 12" penetrate elongate timber strips 1 5 and 1 6 into which nails can be driven to fasten, for example, a floor.

In Figures 3a to 3k there are shown various configurations for the chords, all of which are intended for use in structural members to be used as nailing joists or nailing columns for use, for example, in stud walls. The methods of fixing the timber strips are numerous and, for example, there can be used screws 1 7 through side flanges on the chords as shown in Figure 3b or the strips can be bonded with adhesive to a flat part of the chord. The various webs and inturned flanges shown in Figures 3a to 3k all serve to increase the stength of the chords as will be obvious to the reader.

In general, the chords will be able to produced by rolling and bending methods commonly employed for other uses at present and where the struts also require a bend this may be incorporated before the strut is bent out of the chord or, if the process is more suitable, at a later stage. Whilst the struts have been described as being welded to the opposite chord it may of course be possible to provide slots in the opposite chord so that the struts may be fixed by a simple bending and crimping process for example. Various of the sections shown may be incorporated in the same structural member so that the chords may be of different configurations if this is required to suit a particular function. However, in the case where the chords are of the same configuration it is readily apparent that a single element is all that needs to be produced, the element or strip forming the one chord simply being severed as required, turned up-side-down and affixed to a similar length of the same element or strip forming the second chord.

Claims (12)

1. A structural member comprising a pair of chords held spaced-apart from one another by struts formed integrally with at least one of the chords, the struts being formed from parts of that chord which have been partially cut, bent out of the chord and attached to the other chord.

2. A structural member according to claim 1, wherein the chords and struts are metal.

3. A member according to claim 1 or claim 2, wherein each of the chords has struts bent out from it, the end of each strut remote from its integral chord being attached to the opposite chord.

4. A member according to claim 1 or claim 2, wherein the struts are all formed from parts of a single one of the chords, each of the portions of the chord bent out of the chord being bent to a 'V' shape, the base of the 'V' being attached to the other chord, and the free end of the 'V' being attached back to the first chord.

5. A member according to any of the preceding claims, wherein each of the chords comprises an elongate flat strip, and each of the struts comprises a further elongate flat portion bent out from a respective one of the chords.

6. A member according to any of claims 1 to 4, wherein each strut has a V-shaped cross-section.

7. A member according to any of the preceding claims, wherein the struts are attached to the opposite chord by welding.

8. A method of forming a structural member comprising cutting and bending out of a strip of material a plurality of strut portions and fixing the free ends of the strut portions to a further strip, whereby the strips form chords spaced apart by the strut portions.

9. A method according to claim 8, wherein each of the strips has strut portions cut and bent out from it and fixed, at their free ends, to the other strip.

10. A method according to claim 8 or claim 9, wherein the strips and struts are metal and the struts are welded to the opposite strip.

11. A member according to claim 1, substantially as described with reference to any of the examples shown in the accompanying drawings.

12. A method according to claim 8, substantially as described with reference to any of the accompanying drawings.