GB2136846A

GB2136846A - Lintel

Info

Publication number: GB2136846A
Application number: GB08402022A
Authority: GB
Inventors: I G Walters
Original assignee: IG LINTELS Ltd
Current assignee: IG LINTELS Ltd
Priority date: 1983-03-11
Filing date: 1984-01-26
Publication date: 1984-09-26
Also published as: GB8402022D0; GB2136846B

Abstract

The invention provides a lintel having expanded metal mesh (15) held in position below the rear flange (6) by having one edge portion secured to the rear edge of the flange by means of an integrally-formed channel portion (19). The channel is formed on the mesh by expanding the metal with a continuous central strip which is slit down the centre and thereafter bent over twice at rightangles. <IMAGE>

Description

SPECIFICATION Improvements in or relating to lintels and methods of manufacturing metal mesh for such lintels This invention relates to lintels, and is particularly concerned with lintels for use in buildings which are constructed with cavity walls.

Lintels are placed over openings in the walls of buildings, such as openings for doors or windows, and act to carry courses of bricks or other constructional material extending upwardly above such openings. These lintels are commonly formed by beams of reinforced concrete, but more recently metal lintels have been used. One particular type of metal lintel forms the subject matter of United Kingdom Patent Specification No. 1 388 391.

Most metal lintels are formed with front and rear flange portions and, when the lintel is used in a building constructed with walls, the front flange portion of the lintel spans the opening in the outer wall skin, while the rear flange portion spans the opening in the inner wall skin. Usually it is necessary for the underside of the rear flange portion to be covered with plaster or the like and, accordingly, it is normal practice to provide the rear flange portion with some means effective to form a key for the plaster. These means may, for example, take the form of a strip of expanded metal or the like attached to the underside of the rear flange portion. Normally the strip of expanded metal is secured to the rear flange portion by welding, but it has also been proposed to attach the strip by means of tongues pressed out of the rear flange portion.

The methods of attaching the plaster key to the lintel referred to in the preceding paragraph are relatively expensive and accordingly attempts have been made to provide a more economical method. In particular in Patent Specification No. 1 566 1 60 there is described and claimed a lintel in which there is a web portion between the front and rear flange portions, wherein a distance piece is clamped in the web portion, and wherein the strip of expanded metal is secured along one of its edges to the rear flange portion and along the other of its edges to the distance piece, In the embodiments described in the said Patent Specification No. 1 566 1 60 the rear edge of the expanded metal mesh is held in position by being folded round the rear edge of the rear flange.

It is an object of the present invention to provide a simpler and better method of fastening the rear edge of the expanded metal mesh to the rear flange of the lintel.

From one aspect the invention consists in a lintel comprising front and rear flanges and an intermidiate web wherein a strip of material adapted to form a plaster key is provided on the underside of said rear flange, said strip being secured along one of its edges to said rear flange by means of an integrally formed channel which fits over the rear edge of said rear flange.

From another aspect the invention consists in expanded metal mesh formed with an integral channel along one edge.

From yet another aspect the invention consists in a method of manufacturing expanded metal mesh, wherein a strip of metal is expanded to form two mesh portions with a central continuous portion, wherein said strip is divided into two sub-strips along the centre line of said continuous portion and wherein the remaining continuous portion on each of said sub-strips is folded twice to form a channel.

From yet another aspect the invention consists in any feature of novelty, taken singly or in combination, of the lintel hereinafter described with reference to the accompanying diagrammatic drawings.

From yet another aspect the invention consists in any features of novelty, taken singly or in combination, of the method of manufacturing expanded metal mesh as hereinafter described with reference to the accompanying diagrammatic drawings.

In the drawings: Figure 1 is an end view of a lintel in accordance with the invention, Figure 2 is a perspective view of a piece of expanded metal mesh in accordance with the invention, and Figure 3 illustrates a number of stages in a method of manufacturing expanded metal mesh in accordance with the invention.

Fig. 1 of the Drawings shows a lintel gener eally similar to that illustrated in Fig. 3 of the Drawings of Patent Specification No. 1 566 1 60. This lintel includes a main structural member formed from a single sheet of hotdipped galvanised steel. This structural member includes a front flange portion 2 adapted to span an opening in a door or window in the outer wall of a cavity wall. The portion 2 is provided with a downwardly inclined drip extension 4 at the outer edge thereof. Upstanding from the rear of the portion 2 is a front web portion 5. The structural member also includes a rear flange portion 6 adapted to span the opening in the inner wall skin, and a rear web portion 8 upstanding from the forward edge of the said rear flange portion 6.

The two web portions 5 and 8 are joined by a front head portion 9 and a rear head portion 10. The two portions 9 and 10 are inclined at the same angle to the horizontal but slope in opposite directions to meet at an apex 11.

Retained between the front and rear web portions 5 and 8 is a timber block 1 2. This block may be retained within the web of the lintel by the resilience of the metal constituting the main structural member as described in the said United Kingdom Patent Specification No. 1 566 160 or by means of tags punched out of the web portions 5 and 8, or by means of bolts or adhesive.

Expanded metal mesh 1 5 is held in position below the rear flange 6 by having one portion 1 7 secured to the timber block 12 by means of galvanised staples 18. As can be seen more particularly from Fig. 2 of the Drawings, the mesh 1 5 is formed at one edge with a channel portion 1 9. This portion is integral with the mesh and is slipped over the rear edge of the flange portion 6 before the mesh is fastened to the timber block 12 by means of the staples 18. It is to be understood that this method of fastening the mesh to the lintel is very much quicker than folding the edge over the flange 6 as described and shown in the said Specification No. 1 566 160. As shown, the two sides of the channel portion 1 9 are perpendicular to the base of the channel.

Fig. 3 shows one method of producing expanded metal mesh in accordance with the invention. As shown in this Drawing, the process starts with a coil of strip metal 31.

This coil is fed into a machine which expands it by the use of tapered punches as illustrated diagrammatically at 32. The expanded metal 33 is formed with a central strip which is not punched, this strip being shown at 20. The expanded metal is cut to length and is then slit down the centre of the unperforated strip 20 to form two separate sub-strips as shown at 34. Each of these sub-strips is then fed to a machine in which the unperforated edge is bent over twice at right-angles to form the channel 19. If desired, the two sides of the channel may be slightly over-bent, so that they have to be sprung apart when they are fitted to the lintel flange. This arrangement helps to hold the mesh in place while the portion 1 7 is being secured by the staples 1 8.

Claims

1. A lintel comprising front and rear flanges and an intermediate web wherein a strip of material adapted to form a plaster key is provided on the underside of said rear flange, said strip being secured along one of its edges to said rear flange by means of an integrally formed channel which fits over the rear edge of said rear flange.

2. A lintel as claimed in any of the Claims of UK Patent Specification No. 1 566 160, wherein the strip is secured to the rear flange by means of an integrally formed channel which fits over the rear edge of said rear flange.

3. A lintel as claimed in Claim 1 or Claim 2, wherein each of the two sides of said channel is perpendicular to the base of the channel.

4. Expanded metal mesh formed with an integral channel along one edge.

5. Expanded metal mesh as claimed in Claim 4, wherein said integral channel comprises one side coplanar with said mesh, a base perpendicular to said one side and a second side parallel to said one side.

6. A method of manufacturing expanded metal mesh, wherein a strip of metal is expanded to form two mesh portions with a central continuous portion, wherein said strip is divided into two sub-strips along the centre line of said continuous portion and wherein the remaining continuous portion on each of said sub-strips is folded twice to form a channel.

7. A method as claimed in Claim 6, wherein each of said folds forms a rightangle.

8. A lintel substantially as hereinbefore described with reference to, and as illustrated in, Figs. 1 and 2 of the accompanying diagrammatic drawings.

9. Expanded metal mesh substantially as hereinbefore described with reference to Fig.

2 of the accompanying diagrammatic drawings.

10. A method of manufacturing expanded metal mesh substantially as hereinbefore described with reference to Fig. 3 of the accompanying diagrammatic drawings.

11. Any features of novelty, taken singly or in combination, of the invention hereinbefore described with reference to the accompanying diagrammatic drawings.