WO2013134059A1

WO2013134059A1 - Improved metal web

Info

Publication number: WO2013134059A1
Application number: PCT/US2013/028552
Authority: WO
Inventors: Scott Mcandrew; Scott Mckenzie
Original assignee: Illinois Tool Works Inc.
Priority date: 2012-03-07
Filing date: 2013-03-01
Publication date: 2013-09-12
Also published as: GB2500030A; GB201204027D0; GB2500030B

Abstract

The invention provides a bracing element for spacing timber elements in a truss or joist, the bracing element comprising an elongate spacing portion and attachment means for attaching the bracing element to the timber elements, wherein the bracing element comprises at least one aperture in the elongate spacing portion.

Description

IMPROVED METAL WEB

Field of the Invention

The invention relates to a bracing element for spacing timber chords in a joist or truss. In particular, the invention relates to a bracing element comprising an aperture provided as a burst through, the bracing element being suitable for use in a web of a joist or truss. The invention relates particularly, though not exclusively, to an improved metal web for use in a joist or a truss. The invention also relates to a joist comprising a bracing element of the invention and a blank for forming the bracing element of the invention.

Background to the Invention

Bracing elements for connecting and spacing parallel chords of a joist or truss are known in the building and construction industry. In particular, bracing elements formed of metal are well known, such metal bracing elements being attached to the parallel chords of the joist or truss so as to form the web between the parallel chords.

Open, bracing element-type joists or trusses are commonly used in floor and roof structures and the like. Typically they include an upper timber chord, a lower timber chord and one or more bracing elements, typically metal bracing elements, extending in diagonal or vertical orientation between the upper and lower chords.

Various configurations of bracing element are known, and these include I-shaped, V- shaped, S-shaped and W-shaped elements.

In use, parallel chord joists are arranged with an upper timber chord positioned at a predetermined distance above, and generally parallel to, a lower timber chord. Bracing elements extending between the chords connect the chords and maintain them in the required spaced relation. Open, bracing element-type joists or trusses provide the advantage that utilities such as piping and wiring may be passed through the spaces between chords. Bracing elements may be attached to the chords by a number of methods, but are commonly attached by connector plates (or nail plates) having protruding teeth that embed in the wooden chord. Typically, the connector plates are attached to a side surface of the, or each, chord of the joist. The connector plates or nail plates are typically formed integrally with the elongate body portion of the bracing element.

Joists or trusses are usually manufactured in a factory and transported to a construction site for installation. During manufacture of such joists or trusses, the connector plates (or nail plates) of the bracing elements are pressed into the side faces of the timber chords to form the web of the joist or truss. One problem that may arise during manufacture is that the pressing step may cause displacement of one or both timber chords.

This problem has been described in EP1985774 (Wolf Systems Limited), which discloses a metal bracing element for connecting timber elements in a truss. This document describes a bracing element, which is configured such that the step of pressing the nail plates into side faces of the chords causes projections from the bracing element to embed in opposing inner faces of the chords. This is said to prevent displacement of the chords during the pressing step. Joists can be prone to failure if a bracing element buckles or becomes detached from a timber chord. Therefore the strength of a bracing element - particularly in its elongate spacing portion - is important to prevent buckling. Further, nail plates or other attachment means must firmly secure the bracing element to the timber chords, as detachment of one or more bracing elements may also lead to failure of a joist. It would be desirable to provide an improved bracing element.

Summary of the Invention

In a first aspect the present invention provides a bracing element for spacing timber elements in a truss or joist, the bracing element comprising an elongate spacing portion and attachment means for attaching the bracing element to the timber elements, wherein the bracing element comprises at least one aperture in the elongate spacing portion. In certain embodiments, the aperture is provided as a burst-through formed by a punching operation through the material of the elongate spacing portion of the bracing element.

In certain embodiments, the at least one aperture comprises a flange upstanding from a surface of the elongate spacing portion. More specifically, the flange may be upstanding from a rear surface of the elongate spacing portion. Even more specifically, the flange is formed at the edge of the elongate spacing portion about the aperture. The material of the elongate spacing portion in the region of the circumference of the at least one aperture is folded out of the plane including the elongate spacing element forming a flange upstanding from the elongate spacing portion at the edge of the aperture.

Advantageously, the flange is formed integrally with the elongate spacing portion. By forming the flange integrally with the elongate spacing portion strength is provided to the bracing element.

In certain embodiments, the flange is substantially continuous about the aperture. Such a continuous flange may advantageously be provided by a so-called "burst through" in which the material forming the elongate spacing portion of the bracing element is punched through forming an aperture in the material of the bracing element and a flange about the edge of the aperture. The flange formed in this way is continuous about the edge of the aperture. This aperture formation differs from a folding operation, for example, wherein the flange about the aperture is formed by folding the material of the bracing element so as to form the flange about the aperture therein. This alternative arrangement also forms part of the present invention.

In certain embodiments, the flange about the at least one aperture is profiled at its outer edge such that the flange changes in width dimension about the perimeter of the at least one aperture. More specifically, the width dimension of the flange is the dimension measured from the plane including the surface of the elongate spacing portion of the bracing element to the outer edge of the flange in a direction perpendicular to the plane including the surface of the elongate spacing portion of the bracing element.

In certain embodiments, the flange about the at least one aperture is discontinuous about the aperture. More specifically, the flange may be profiled about its outer edge such that the flange reduces to have no width dimension about certain portions of the perimeter of the at least one aperture.

The flange may extend substantially perpendicularly from the surface of the elongate spacing portion of the bracing element. In various embodiments, the flange comprises at least one bearing element. More specifically, the at least one bearing element is adjacent the attachment means. Even more specifically, the at least one bearing element is located at or adjacent the portion(s) of the bracing element where the elongate spacing portion is connected to the attachment means. In a preferred embodiment, the at least one bearing element is located and configured to bear onto a timber element in a joist when the bracing element forms the web of such a joist. This bearing element provides additional stability and strength during manufacture of the joist and in use of the bracing element of the invention. It is much preferred that the at least one bearing element is located and configured to bear onto an upper or a lower face of a timber chord of a joist.

In certain embodiments, the at least one bearing element is formed integrally with the flange about the edge of the at least one aperture of the bracing element. More specifically, the flange in the region of the at least one bearing element has an increased width dimension. Preferably, the at least one bearing element comprises a curved profile. This prevents the at least one bearing element from penetrating a timber chord in use. More specifically, the flange about the at least one aperture has an outer edge with a curved profile.

In certain embodiments, the at least one aperture in the elongate spacing portion may be a single elongate aperture extending longitudinally of the elongate spacing portion.

In alternative embodiments, the bracing element may comprise a plurality of apertures in the elongate spacing portion. In such embodiments, each of the plurality of apertures is preferably provided as a burst through formed by a punching operation through the material of the elongate spacing portion of the bracing element. In alternative embodiments each aperture may be cut from the material of the elongate spacing portion.

In embodiments comprising a plurality of apertures in the elongate spacing portion, each aperture preferably comprises a flange upstanding from the surface of the elongate spacing portion of the bracing element thereabout. More specifically, the flange about each aperture may be upstanding from a rear surface of the elongate spacing portion of the bracing element. Even more specifically, each flange is formed at the edge of the elongate spacing portion about its respective aperture. The material of the elongate spacing portion in the region of the circumference of each aperture is folded out of the plane including the elongate spacing element forming each flange upstanding from the elongate spacing element at respective edges of each aperture.

Advantageously, each flange is formed integrally with the elongate spacing portion of the bracing element. By forming each flange integrally with the elongate spacing portion of the bracing element strength is provided to the bracing element. In certain embodiments, each flange is substantially continuous about its respective aperture.

Such continuous flanges about each aperture are provided by a so-called "burst through" in which the material forming the elongate spacing portion of the bracing element is punched through forming each aperture in the material of the bracing element and a flange about the edge of each aperture. Each flange formed in this way is continuous about the edge of its respective aperture.

In certain embodiments, each flange about its respective and adjacent aperture is profiled at its outer edge such that the flange changes in width dimension about the perimeter of the aperture. More specifically, the width dimension of the flange is the dimension measured from the plane including the surface of the elongate spacing portion of the bracing element to the outer edge of the flange in a direction perpendicular to the plane including the surface of the elongate spacing portion of the bracing element.

In certain embodiments, each flange is discontinuous about the aperture. More specifically, each flange may be profiled about its outer edge such that the flange reduces to have no width dimension about certain portions of the perimeter of the aperture.

Each of the plurality of flanges may extend substantially perpendicularly from the surface of the elongate spacing portion of the bracing element. In various embodiments, each flange comprises at least one bearing element. More specifically, the at least one bearing element of each flange is adjacent the attachment means.

In a preferred embodiment, the at least one bearing element of each flange is configured to bear onto a timber element in a joist. Each bearing element provides additional stability and strength during manufacture of the joist and in use of the bracing element of the invention. It is much preferred that the at least one bearing element of each flange is configured to bear onto an upper or a lower face of an adjacent timber chord of a joist.

In certain embodiments, the at least one bearing element of each flange is formed integrally with that flange. More specifically, each flange in the region of its at least one bearing element has an increased width dimension.

Preferably, the at least one bearing element comprises a curved profile. This prevents the at least one bearing element from penetrating a timber chord in use. More specifically, the flange about each of the apertures has an outer edge with a curved profile.

Each of the plurality of apertures may be formed as a kidney-shaped aperture in the elongate spacing portion. More specifically, the elongate spacing portion may comprise two apertures. In certain embodiments, each aperture is kidney-shaped.

In certain embodiments, the elongate spacing portion comprises two apertures with each aperture located at an end of the elongate spacing portion. More specifically, the two apertures are located at opposing ends of the elongate spacing portion. In this way, each aperture is located proximate an attachments means of the bracing element.

In is much preferred that each aperture comprises a flange and a bearing portion. In certain embodiments, the bearing portion of each aperture is located at the part of the aperture proximate the adjacent attachment means. In this way, in use, compression forces applied to the elongate spacing portion of the bracing element are directed onto and through the timber chord through the bearing element of the flange about each aperture.

In certain embodiments, the bracing element may comprise a single aperture provided as a burst through.

A single burst through aperture may extend substantially along the length of the elongate spacing portion. A single burst through aperture may comprise one or more flanges and one or more bearing portions. In certain embodiments, the attachment means comprises at least one connector plate.

In certain embodiments, the bracing element comprises at least two connector plates. In preferred embodiments, the bracing element comprises two connector plates, one at each end of the elongate spacing portion.

In various embodiments, the, or each, connector plate is a nail plate. More specifically, the, or each, nail plate may comprise a plurality of integral nail fasteners pressed from the material of the, or each, nail plate.

Alternative or additional fastener apertures may be provided in the, or each, connector plate. Known fasteners such as nails, screws or staples or the like may be located in the fastener apertures in order to facilitate attachment of the bracing element to the timber element.

In embodiments, the bracing element further comprises at least one edge flange depending from an outer edge thereof. More specifically, the at least one edge flange may depend from an outer edge of one or more of the elongate spacing portion and/or one or more of the attachment means.

In certain embodiments, a first edge flange depends from a first outer edge of the elongate spacing portion. The first edge flange, in various embodiments, extends from an end of the first outer edge of the elongate portion along a first, uppermost outer edge of the lowermost connector plate. The first edge flange may be continuous along the entire length of the outer edge of the first outer edge of the elongate portion to the end of the first outer edge of the lowermost connector plate. The first edge flange may be continuous along the entire length of the first outer edge of the elongate spacing portion and the first outer edge of the lowermost connector plate. Alternatively, the first edge flange may be discontinuous along the length of the first outer edge of the elongate spacing portion and the first outer edge of the lowermost connector plate. In exemplary embodiments, the discontinuity in the first edge flange may be located at the join between the first outer edge of the elongate spacing portion and the first outer edge of the connector plate. Alternatively or, in addition, the bracing element further comprises a second edge flange depending from a further outer edge thereof. More specifically, the second edge flange may depend from another outer edge of one or more of the elongate spacing portion and/or one or more of the attachment means.

In certain embodiments, the second edge flange depends from a second outer edge of the elongate spacing portion. The second edge flange, in various embodiments, extends from an end of the second outer edge of the elongate portion along a first, lowermost outer edge of the uppermost connector plate. The second edge flange may be continuous along the entire length of the second outer edge of the elongate portion to the end of the first, lowermost outer edge of the uppermost connector plate. The second edge flange may be continuous along the entire length of the second outer edge of the elongate spacing portion and the first, lowermost outer edge of the uppermost connector plate. Alternatively, the second edge flange may be discontinuous along the length of the second outer edge of the elongate spacing portion and the first, lowermost outer edge of the uppermost connector plate. In exemplary embodiments, the discontinuity in the second edge flange may be located at the join between the second outer edge of the elongate spacing portion and the first, lowermost outer edge of the uppermost connector plate.

The first and, if present, the second edge flanges provide additional strength to the bracing element. In various embodiments, at the end of the or each edge flange, the flange may comprise a locating lug. More specifically, the locating lug(s) is/are configured to bear onto a surface of a timber chord in use of the bracing element. More specifically, the locating lug(s) is/are located at the end of the or each flange depending from an outer edge of the attachment means.

The or each edge flange is configured such that a portion of the or each edge flange is operable to bear onto an upper or a lower surface of a timber chord when the bracing element is positioned between two parallel timber chords in a joist. More specifically, the portion of the or each edge flange depending from an outer edge of a connector plate is configured such that that portion of the or each edge flange is operable to bear onto an upper or a lower surface of a timber chord when the bracing element is positioned between two parallel timber chords in a joist. In certain embodiments the bracing element comprises an attachment means plateedge flange at an outer edge thereof. In certain embodiments, the attachment means edge flange is located at a lower outer edge and/or an upper outer edge of the, or each, connector plate. The attachment means edge flange may extend about the join between the edge of the connector plate and the elongate spacing portion. Alternatively or additionally the attachment means edge flange is located at the end edge of the, or each, connector plate.

It is preferred that the outer edge of the attachment means edge flange is serrated. In this way, the attachment means edge flange may be embedded into a surface of a chord of a joist so as to provide an attachment having increased stability and strength than would otherwise be the case.

The bracing element may be substantially V shaped, I-shaped or W-shaped. Alternatively, the bracing element may be substantially L-shaped.

In certain embodiments, the bracing element is initially formed as a pair of bracing elements. In these embodiments, each bracing element comprises a pair of connector plates, spaced apart by an elongate spacing element. One of the pair of connector plates of a first bracing element of the pair is initially attached to one of the pair of connector plates of the other bracing element of the pair. The pair of bracing elements is separable along an attachment line between the attached connector plates.

The bracing element may be formed of any suitable material. In certain embodiments, the bracing element is a metal bracing element. The bracing element may be formed of galvanised steel or aluminium or the like, for example. The bracing element is preferably a metal bracing element for forming a metal web of a metal web joist.

In a second aspect the invention provides a joist comprising at least one bracing element according to the first aspect of the invention. Preferably the joist is a parallel chord type joist comprising an upper chord and a lower, parallel chord spaced apart from one another by at least one bracing element according to the first aspect of the invention.

In preferred embodiments, the joist comprises a plurality of bracing elements each according to the first aspect of the present invention, each bracing element being attached to the upper and lower chords of the joist so as to form a web.

In certain embodiments the plurality of bracing elements are each and all attached to an outer side surface of the upper and the lower chords of the joist. In alternative embodiments, each of the plurality of bracing elements is attached to an inner side surface of the upper and the lower chords of the joist. In yet further alternative embodiments, a first pair of bracing elements is attached to an inner side surface of the upper and the lower chords of the joist and a second pair of bracing elements is attached to an outer side surface of the upper and the lower chords of the joist. In such embodiments, the first and the second pair of bracing elements may be staggered along the length of the joist such that there bracing elements do not overlap. Alternatively, the first and the second pair of bracing elements may be located at opposing side surfaces of the chords of the joist at the same longitudinal position along the joist.

The joist may comprise opposing bracing elements positioned on either side surface of the chords of the joist.

In a third aspect the invention provides a structure comprising a plurality of joists according to the second aspect of the invention.

The structure may be a floor, roof or other structure in which joists are commonly used.

In a fourth aspect the invention provides a sheet metal blank for forming a bracing element of the first aspect of the invention. Where the terms "upper", "lower", "uppermost", "lowermost" are used within the specification, they should be considered as no more than relative, as the bracing element of the invention may be used in any appropriate orientation.

Brief Description of the Drawings Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure la is a perspective front view of an embodiment of a bracing element according to the first aspect of the invention;

Figure lb is a perspective rear view of the bracing element of Figure la; Figure 2 is a partial perspective view of an embodiment of a joist according to the second aspect of the invention;

Figure 3 is a partial perspective view of an alternative embodiment of a bracing element according to the first aspect of the invention;

Figure 4 is a partial perspective view of an alternative embodiment of a joist according to the second aspect of the invention illustrating an embodiment of the flange about the aperture in the elongate spacing element of a bracing element of Figure 3;

Figure 5 is a perspective view illustrating an embodiment of the curved profile of the flanges about two apertures in the elongate spacing element of a bracing element of the invention; Figure 6 is a schematic representation of two different attachment means edge flanges each on a connector plate of a bracing element according to the invention;

Figure 7 shows an alternative embodiment of a bracing element according to the first aspect of the invention;

Figure 8 shows a bracing element having alternative fastener apertures according to embodiments of the present invention; Figure 9 shows a bracing element having an alternative elongate spacing element profile according to embodiments of the present invention; and

Figure 10 shows an alternative attachment means edge flange according to an embodiment of the present invention. Detailed Description of the Preferred Embodiments

As shown in Figures la and lb, a bracing element 1 comprises an elongate spacing portion 2, extending between two nail plates 3. Nail plates for attaching bracing elements to the timber chords of joists are known in the art and are commonly used to attach metal bracing elements to timber chords. It will, however, be apparent that alternative known attachment means suitable for attaching a bracing element to a timber joist, such as nails, screws, staples and the like, may be employed in the invention.

As illustrated in the Figures, nail plates 3 comprise a sheet-like portion or plate, in which a number of teeth 5 are formed by pressing or stamping small portions of material from the plate 3, to form teeth 5 upstanding from the rear surface 3b of each nail plate 3.

Figure lb shows the rear surface lb of the bracing element 1 and first and second edge flanges 6 depending from opposing outer edges of the bracing element 1. The edge flanges 6 are upstanding from the plane of the rear surface lb of the bracing element 1 at an angle of approximately 90 degrees thereto. Edge flanges 6 provide additional strength to the bracing element 1, which prevents buckling of the bracing element under compressive loads and/or torsional forces.

Each edge flange 6 extends along the elongate spacing portion 2 from an outer edge 7 of one nail plate 3, to an inner edge 8 of another nail plate 3. At the outer edge 7 of each of the nail plates 3, each edge flange 6 terminates in a locating lug 9. Locating lugs 9 assist in locating and maintaining correct positioning the bracing elements 1 on the chords 11, 12, as shown in Figure 2. In alternative embodiments (not shown), the edge flange 6 may extend discontinuously along only a portion of the edge of the bracing element. Adjacent the inner edge 8 of each nail plate 3, each edge flange 6 terminates in a curved edge 16, which in use, bears onto an lower face 11c, or upper face 12c of a timber chord in a truss (see Figure 2).

A joist 10 comprising twobracing elements 1 at each side of a pair of parallel timber chords 11, 12 is illustrated in Figure 2. Each bracing element 1 extends between an upper chord 11 and a lower chord 12. Opposing lower and upper faces 11c, 12c of the timber chords 11, 12 are held substantially parallel to, and facing one another. In use, the opposing lower and upper faces 11c, 12c are substantially horizontal and the side faces 17 of the timber chords 11, 12 are substantially vertical.

In manufacture of a parallel chord joist, such as the joist 10 shown in Figure 2, a bracing element 1 is attached to the timber chords 11, 12 by pressing nail plates 3 onto respective side faces 17 of the chords such that teeth 5 penetrate the timber and secure the bracing element 1 in position. Locating lugs 9 are positioned such that in use, each lug 9 rests against a lower or an upper face 11c, 12c of one of the chords.

The bracing element 1 comprises one or more openings 14 in the elongate spacing portion 2. Each opening 14 is defined by a substantially continuous edge and forms an enclosed hole in the elongate spacing portion 2.

An inner peripheral edge of the bracing element defines the opening 14, which is substantially bounded on all sides by the material of the elongate spacing portion 2 and/or nail plate 3.

In the depicted embodiments, the opening(s) 14 is/are provided as a burst through in the elongate spacing portion 2. Each burst through opening 14 is formed by punching the opening through the sheet metal of the spacing portion 2.

A burst through is formed when the material is pressed and stretched to form a continuous face 90 degrees to the main surface. By providing the opening(s) in the elongate spacing portion as a burst through, a part of the material is bent through 90 degrees from the plane of the remaining material thereby strengthening and stiffening the material.

It has been found that the burst through opening 14 and bearing portion provide reinforcement and strengthening properties to the bracing element and consequently to a joist comprising the bracing element. The burst through opening can be easily manufactured by punching the sheet metal of the bracing element and provides a flange 15 upstanding from the rear surface of the bracing element, which increases strength in the bracing element where material has been removed in the burst through.

The opening(s) in the elongate spacing portion preferably have curved corners. In this way, the burst through opening(s) may be formed without tearing the material of the bracing elements. The bracing element 1 may comprise a single burst through opening as illustrated in the embodiment shown in Figure 3, or more than one burst through opening 14 as illustrated in Figures la, lb, 2 and 4. The punching operation itself may form a flange 15 about the burst through opening 14,

As illustrated in Figures 3 and 5, the flange 15 is a substantially continuous flange defining the periphery of the opening 14, and upstanding from the rear surface lb of the bracing element 1. The flange 15 comprises a bearing portion 15c adjacent the nail plate 3, as illustrated in Figures lb, 3 and 4. In alternative arrangements (not shown) the flange 15 may reduce in width dimension at one of more portions of the flange 15 so as to form a discontinuous flange about the opening(s) 14. In yet further alternatives (not shown), the flange 15 may be replaced may one or more folded lugs of material.

The flange 15 is integral with the elongate spacing portion 2 of the bracing element 1. Alternatively or in addition, the flange 15 may be formed, shaped or modified by pressing or folding operations and its edge may be contoured, such as is shown in the embodiment of Figure 5.

Referring to Figure 5, the flange 15 is contoured to define flange sections 15a, 15b and a curved bearing portion 15c. Section 15a extends adjacent to and substantially parallel to an edge flange 6 of the bracing element 1. Section 15b extends adjacent to and curves in a configuration corresponding to a curved portion 16 of an edge flange 6.

Section 15c of each burst through opening 14 is located adjacent a nail plate 3. The height of the upstanding flange 15 at section 15c is greater than at sections 15b and 15c, which are each of approximately the same height. Sections 15d of the flange 15, are of lower height than, and located between sections 15a and 15b, sections 15b and 15c, and sections 15c and 15a.

The bearing portion 15c has a sloping upper edge and a curved profile. At its highest point, the bearing portion is upstanding at a height approximately equal to the height of the edge flanges 6. As shown in Figure 4, in use, each bearing portion 15c of the bracing element 1 bears onto a respective opposing upper face of the chords in a joist. This provides additional strength and resistance to movement of the bracing element in the joist, both during manufacture and in use. The curved profile of the bearing portion 15c prevents the bearing portion from penetrating a timber chord, which could weaken or fix the bracing element at an incorrect position. It should be understood that the bearing portion 15c may be located any where on the bracing element so long as it bears onto the lower or upper surface of a timber chord. By providing the bearing portion 15c in the diagonal bracing area of the bracing element, the bearing element 15c is in its preferred location for transmitting forces onto the timber chord from the bracing element.

In another embodiment as shown in Figure 7, the bracing element 101 is of the V- shaped type and comprises four nail plates 103. In this embodiment, two nail plates 103a and 103d are attachable to a lower chord 12 (not shown) and spaced apart from one another. The other nail plates 103b and 103c are attachable to an upper chord 11 (not shown) adjacent one another. The nail plates 103 may be joined to, or formed integrally with, one another. In one embodiment, the V-shaped bracing element may be separable at the nail platesl03b, 103c to form two bracing elements of the I-shaped type.

In further embodiments, the bracing element may be formed as a substantially L-shaped or W-shaped bracing element, or any other bracing element shapes known in the field. Similarly, such bracing elements may also be separable into component bracing element s such as V-shaped and/or I-shaped bracing elements.

The bracing element 1 may be formed by folding, bending, stamping, punching and/or pressing operations. In manufacture, the bracing element 1 may be initially formed as a sheet metal blank, which is subsequently punched and folded into the desired configuration of the bracing element 1.

The bracing element 1 is preferably formed of a galvanised steel material.

Figure 6 depicts an alternative bracing element 60 according to the first aspect of the invention. Bracing element 60 comprises two nail plates 30 spaced apart and connected together by elongate spacing portion 67. Elongate spacing portion 67 comprises two burst through apertures 65a and 65b each having a continuous flange 66a, 66b about the aperture 65a, 65b. The upper nail plate 30 comprises an outer edge 64 from which depends an attachment means edge flange 61 having a serrated outer edge. The edge flange 61 depends from outer edge 64 at an angle of approximately 90 degrees. The edge flange 61 extends rearwardly of the bracing element 60. The lower nail plate 30 comprises a lower edge 68 from which depends a further attachment means edge flange 62 having a serrated outer edge. The edge flange 62 depends from lower edge 68 at an angle of approximately 90 degrees. The edge flange 62 extends rearwardly of the bracing element 60. In use, the serrated outer edge of edge flanges 61, 62 are embedded into the upper and lower chords respectively of a joist to strengthen to attachment of nail plates 30 to the chords of the joist.

The actual configuration of the serrations provided on the edge flanges 61, 62 is inessential to the invention. The serrations must be capable of penetrating the timber chord of a joist in order to embed therein.

Although not shown in Figure 6, it should be understood that any or all of the edges of the nail plates 30 may having a serrated edge flange depending from one or more edges thereof.

Figure 7 shows a yet further bracing element 101 according to the invention. The bracing element 101 differs from bracing elements 1 and 60 in that the nail plates 103 have fastener apertures 105 in place of nails. In will be readily understood that in a yet further arrangement, the bracing element may be provided with both fastener apertures and teeth on the nail plate(s) thereof.

The fastener apertures 105 are configured to receive any appropriate fastener such as, for example, screws, nails, staples or the like.

The bracing element 101 of Figure 7 is, initially, a V-shaped bracing element, comprising two separable bracing elements 101a and 101b, each comprising an elongate spacing portion 102a, 102b and two connector plates 103a, 103b, 103c, 103d.

Each elongate spacing portion 102a, 102b is provided with a pair of openings 114a, 114b, 114c, 114d. About the edge of each opening 114a, 114b, 114c, 114d is an edge from which depends a flange 115a, 115b, 115c, 115d. Each flange faces rearwardly of the bracing element 101. Each flange 115a, 115b, 115c, 115d comprises a bearing portion 115ac, 115bc, 115cc, 115dc configured and located to bear onto an upper or a lower face of a timber chord in a joist according to the second aspect of the invention.

The lower edge 168a, 168b, 168c, 168d of each connector plate 103a, 103b, 103c, 103d comprises an edge flange 162a, 162b, 162c, 162d with a serrated outer edge. The serrated outer edge of each flange may be embedded into a timber chord during the manufacture of a joist using the bracing element of the present invention. The embedded flanges 162a, 162b, 162c, 162d increase the stability of the joist and, in particular, resist slipping of the bracing element once same is in position on the timber chord.

It will be clearly understood that bracing element 101 may be used as a single, V-shaped bracing element or may be separated between connector plates 103b and 103c to form two separate bracing elements 101a and 101b.

Also shown in Figure 7 are ribs 165a and 165b. The ribs 165a and 165b are embossed in the material of elongate spacing portions 102a and 102b and provide additional strength to the bracing element 101.

Figure 8 is a partial view of the bracing element 101 of Figure 7. The alternative fastener apertures 105 are clearly shown together with opening 114 and rib 165. Bearing portion 115c depends from flange 115 in such a location as to bear onto the upper or lower face of a timber chord (not shown) in a joist in which the bracing element 101 forms the web.

Figure 9 shows the bracing element of Figure 8 with rib 165 embossed into the material of elongate spacing portion 102. The elongate spacing portion 102 has an outer edge flange 106 and fastener apertures 105 in connector plate 103. Figure 10 depicts a partial rear view of a bracing element 201. The elongate spacing portion 202 of bracing element 201, comprises an opening 214, from the edge of which depends flange 215. Bearing portion 215c is formed as a portion of flange 215 having a greater width dimension that the rest of the flange 215. The bearing portion 215c is located such that it will bear onto an upper or a lower surface of a timber chord in forming a joist of the invention. Elongate spacing portion 202 is formed integrally with connector plate 203 from a single sheet of galvanised steel. The elongate spacing portion 202 comprises first and second edge flanges 206. The first edge flange 206a extends the length of the edge of the elongate spacing portion 202 along the upper edge of connector plate 203 to an outer edge 207 of connector plate 203. The first edge flange 206a has a locating lug 209 proximate the outer edge 207. The second edge flange 206b, extends the length of the edge of the elongate spacing portion 202 to an inner edge 208 of connector plate 203. Connector plate 203 comprises fastener apertures 205 for receiving any suitable fastener such as nails, screws, staples or the like. Flange 261 depends substantially perpendicularly from the lower edge 268 of connector plate 203. The outermost edge of flange 261 is serrated in order that the flange may be embedded into a timber chord of a joist. Flange 261 extends from the inner edge 208 to the outer edge 207 of the connector plate 203.

Figure 10 also depicts a rib 265 formed in the elongate spacing portion 202. Rib may be formed by embossing, for example, and acts to strengthen the elongate spai portion 202.

Claims

1. A bracing element for spacing timber elements in a truss or joist, the bracing element comprising an elongate spacing portion and attachment means for attaching the bracing element to the timber elements, wherein the bracing element comprises at least one aperture in the elongate spacing portion.

2. A bracing element according to claim 1, the aperture is provided as a burst-through formed by a punching operation through the material of the elongate spacing portion.

3. A bracing element according to claim 1 or 2, wherein the at least one aperture comprises a flange upstanding from a surface of the elongate spacing portion.

4. A bracing element according to claim 3 or 4, wherein the flange is formed integrally with the elongate spacing portion.

5. A bracing element according to any one of claims 3 to 5, wherein the flange is substantially continuous about the aperture.

6. A bracing element according to any one of claims 3 to 5, wherein the flange is discontinuous about the aperture.

7. A bracing element according to any one of claims 3 to 6, wherein the flange comprises at least one bearing element.

8. A bracing element according to any one of the preceding claims, wherein the attachment means comprises at least one connector plate.

9. A bracing element according to any one of the preceding claims, wherein the aperture in the elongate spacing portion is a single elongate aperture extending longitudinally of the elongate spacing portion.

10. A bracing element according to any one of claims 1 to 8, wherein the bracing element comprises a plurality of apertures in the elongate spacing portion.

11. A bracing element according to claim 10, wherein each aperture comprises a flange upstanding from a surface of the bracing element.

12. A bracing element according to claim 11, wherein each flange comprises at least one bearing element.

13. A bracing element according to any one of the preceding claims, wherein the bracing element comprises an edge flange at an outer edge thereof.

14. A bracing element according to any one of the preceding claims comprising an attachment means edge flange.

15. A bracing element according to claim 14, wherein the outer edge of the attachment means edge flange is serrated.