GB1566160A

GB1566160A - Lintels

Info

Publication number: GB1566160A
Application number: GB1696577A
Authority: GB
Original assignee: IG LINTELS Ltd
Current assignee: IG LINTELS Ltd
Priority date: 1978-04-03
Filing date: 1978-04-03
Publication date: 1980-04-30

Description

(54) IMPROVEMENTS IN OR RELATING TO LINTELS (71) We, I G. LINTELS LIMITED, a British Company, of Avondale Road, Cwmbran, Gwent, NP4 lXY, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 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. 1388391.

Most metal lintels are formed with front and rear flange portions and, when the lintel is used in a building constructed with cavity 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.

Known methods of attaching the plaster key to the lintel are relatively expensive and, accordingly, it is an object of the invention to provide a more economical method of attaching the plaster key.

From one aspect the invention consists in a lintel comprising front and rear flange portions and a web portion having spaced front and rear portions respectively upstanding from said front and rear flange portions, wherein at least said web portion consists of resilient material, wherein at least one distance piece extending along at least part of the length of the lintel is retained between the upstanding portions by the clamping action exerted by the resilience of said web material, and wherein a strip of material adapted to form a plaster key is provided on the underside of said rear flange portion, being secured along one of its edges to said rear flange portion, and along the other of its edges to said distance piece or pieces.

If only a single distance piece is provided, it preferably extends along the whole length of the lintel apart from a gap at each end corresponding to the part of the lintel which is supported by the walls adjacent to the sides of the window or door opening, If a plurality of distance pieces are used they are preferably spaced apart along a similar length of the lintel.

In one embodiment of the invention the distance piece or pieces consist of timber and the strip of material forming the plaster key is secured along said one of its edges by folding an edge portion around the rear edge of the rear flange portion of the lintel, and is secured along said other one of its edges to the distance piece or pieces by means of staples driven into the timber.

Preferably the timber block or blocks extend a substantial distance into the web portion of the lintel and, in certain cases, may even extend right to the top of the lintel.

It, or they, may also extend to the bottom of the web portion so that their lower edges are, for example, co-planar with the lower edges of the front and rear flange portions, but, alternatively, they may terminate a substantial distance above the lowest part of the web-portion. In this case, the space at the bottom of the web portion of the lintel may be used, for example, to acconi modate the top member of a window or door frame.

In another embodiment of the invention, the distance pieces consist of short lengths of channel-section metal, and the material forming the plaster key is held in position by means of metal straps spaced along the length of the lintel, each metal strap being secured at one end by being folded round the rear edge of the rear flange portion of the lintel, and being secured at the other end by being folded round one of the sides of a respective one of the channel-section distance pieces.

Preferably the cross-section of the lintel is substantially as shown in the said Patent Specification No. 1 388 391 and the height of the web will depend on the length of the lintel. It is, of course, to be understood that the distance piece or pieces provided in accordance with the present invention will normally replace the tie-pieces of the continuous plate provided in the lintels described in said Patent Specification No. 1 388 391.

A lintel in accordance with the present invention is initially formed in substantially (:le same manner as shown in said Patent Specification No. 1 388 391, except that the angles at the head of the web portion are made more acute so that the width of the web at the base thereof is less than the width of the head thereof. The two flange portions are then pulled apart to open the base of the web, and the timber block or blocks or the metal distance pieces are inserted along the length of the lintel. When the flange portions are released, the spring pressure will hold the distance piece or pieces securely in place.Tests have indicated that when a lintel in accordance with the invention is incorporated in a building, the weight of the brick-work or other material on the two flange portions, tends to increase the pressure on the distance piece or pieces.

If desired, additional means may be provided for retaining the distance piece or pieces in the web of the lintel. For example, in the case of timber distance pieces, some of the distance pieces may be held in position by means of screws passing through one portion of the web into the timber.

Alternatively, lugs may be pressed out of either or both portions of the web to assist in retaining the timber pieces within the web.

In the case of metal distance pieces, some of these may, if desired, be held in position by means of rivets or projections such as dimples which may be provided in one or both portions of the web to engage in apertures or recesses in the sides of the distance pieces.

Methods of performing the invention will now be described with reference to the accompanying diagrammatic drawings, in which: Figure 1 is an end view of a main struc tural member for use in the production of a lintel in accordance with the invention; Figure 2 shows a distance piece being inserted in the member illustrated in Figure 1; Figure 3 shows the final position of the distance piece illustrated in Figure 2; Figure 4 shows a differently-shaped dis tance piece in position together with the plaster key; Figure 5 shows an alternative embodiment of the invention; Figure 6 is a perspective view indicating the use of a single distance piece; and Figure 7 is a perspective view indicating the use of a plurality of distance pieces.

A lintel in accordance with the invention includes a main structural member formed from a single sheet of hot-dipped galvanised steel. This structural member includes a front flange portion 2 adapted to span an opening for a door or window in the outer wall skin of a cavity wall. The portion 2 is provided with a downwardly inclined drip extension 4 at the outer edge thereof. Up standing 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.

The structural member illustrated in Figure 1 may be formed, for example, in the manner described in Patent Specification No. 1 388 391 with reference to Figure 5 of the drawings of that Specification, except that the angles at the head of the web por tion are made more acute so that the width at the base thereof is less than the width at the head thereof. The two flange portions 2 and 6 are then pulled apart to open the base of the web and a distance piece is inserted as shown, for example, in the case of the timber block 12 illustrated in Figure 2. In this particular case, the timber block shown has a height which is not greatly less than that of the web. However, as can be seen from Figure 3, when the timber block 12 has been comPletely inserted in the web, a space 13 remains below the block, and this space may be used, for example, to accommodate the top member of a window or door frame. Since the steel used for the structural member is resilient, the sides of the web will press against the sides of the timber block 12 as soon as the trac tive force on the flanges is released. This pressure will be sufficient to hold the timber block in position.

Figure 4 of the drawings shows an embodiment in which the height of a timber block 14 is considerably less than that of the timber block 12 shown in Figures 2 and 3. Figure 4 also shows expanded metal mesh 15 held in position by having one edge 16 folded round the rear edge of the rear flange 6, and having the other edge fastened to the block 14 by means of galvanised staples as shown at 17.

Figure 5 shows an alternative embodiment in which a metal channel section 18 is used in place of the timber blocks 12 or 14. In this case, the expanded metal mesh 15 is held in position by means of a plurality of metal straps 19, each secured at one end by being folded round the rear edge of the rear flange 6 of the lintel as shown at 20, and being secured at the other end by being folded round one of the sides 21 of the channel member 18.

Figure 6 shows that the lintel may include a single continuous timber block either of the kind shown at 12 in Figures 2 and 3, or of the kind shown at 14 in Figure 4, extending throughout the length of the lintel apart from a gap of about six inches at each end of the lintel.

Figure 7 shows that the single timber block of Figure 6 may be replaced by a plurality of separate timber blocks, whether the height of each block is as shown at 12 or as shown at 14.

Similarly the channel section member 18 may be a single member extending along the length of the lintel as in the case of the timber blocks shown in Figure 6, or may be replaced by a plurality of individual members as in the case of the timber blocks shown in Figure 7. In the latter case, normally one strap 19 will be provided for each channel section member 18.

WHAT WE CLAIM IS: 1. A lintel comprising front and rear flange portions and a web portion having spaced front and rear portions respectively upstanding from said front and rear flange portions, wherein at least said web portion consists of resilient material, wherein at least one distance piece extending along at least part of the length of the lintel is retained between the upstanding portions by the clamping action exerted by the resilience of said web material, and wherein a strip of material adapted to form a plaster key is provided on the underside of said rear flange portion, being secured along one of its edges to said rear flange portion, and along the other of its edges to said distance piece or pieces.

2. A lintel as claimed in Claim 1, wherein a single distance piece extends along the whole length of the lintel apart from a gap at each end.

3. A lintel as claimed in Claim 1, wherein a plurality of distance pieces are spaced apart along the length of the lintel.

4. A lintel as claimed in any of the preceding Claims, wherein the, or each, distance piece consists of timber.

5. A lintel as claimed in Claim 4, wherein the strip of material forming the plaster key is secured along said one of its edges by being folded around the rear edge of the rear flange portion, and is secured along said other one of its edges by means of staples driven into the timber.

6. A lintel as claimed in Claim 4, or Claim 5, wherein the timber extends into the web portion of the lintel substantially to the top of said web portion.

7. A lintel as claimed in Claim 6, wherein the timber is spaced from the bottom of the web portion.

8. A lintel as claimed in Claim 1, wherein a plurality of lengths of channel section metal are spaced along the length of the lintel.

9. A lintel as claimed in Claim 8, wherein the strip of material forming the plaster key is held in position by means of metal straps spaced along the length of the lintel, each metal strap being secured at one end by being folded around the rear edge of the rear flange portion of the lintel, and being secured at the other end by being folded around one of the sides of a respective one of the lengths of channel-section metal.

10. A lintel as claimed in any of the preceding Claims, wherein said spaced front and rear portions of the web are joined by front and rear head portions which slope in opposite directions to meet at an apex substantially in the middle of the web.

11. A method of manufacturing a lintel as claimed in any of the preceding Claims, wherein said front and rear flange portions and said web portion are formed by bending a single sheet of resilient metal so that the width of the web at the base thereof is less than the width at the head thereof, wherein the two flange portions are then pulled apart to open the base of the web, and wherein the distance piece, or pieces, is, or are, inserted in the web, the arrangement being such that, when the flange portions are released, the resilience of the metal

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Claims

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pressure will be sufficient to hold the timber block in position.

Figure 4 of the drawings shows an embodiment in which the height of a timber block 14 is considerably less than that of the timber block 12 shown in Figures 2 and 3. Figure 4 also shows expanded metal mesh 15 held in position by having one edge

16 folded round the rear edge of the rear flange 6, and having the other edge fastened to the block 14 by means of galvanised staples as shown at 17.

Figure 5 shows an alternative embodiment in which a metal channel section 18 is used in place of the timber blocks 12 or 14. In this case, the expanded metal mesh 15 is held in position by means of a plurality of metal straps 19, each secured at one end by being folded round the rear edge of the rear flange 6 of the lintel as shown at 20, and being secured at the other end by being folded round one of the sides 21 of the channel member 18.

Figure 6 shows that the lintel may include a single continuous timber block either of the kind shown at 12 in Figures 2 and 3, or of the kind shown at 14 in Figure 4, extending throughout the length of the lintel apart from a gap of about six inches at each end of the lintel.

Figure 7 shows that the single timber block of Figure 6 may be replaced by a plurality of separate timber blocks, whether the height of each block is as shown at 12 or as shown at 14.

Similarly the channel section member 18 may be a single member extending along the length of the lintel as in the case of the timber blocks shown in Figure 6, or may be replaced by a plurality of individual members as in the case of the timber blocks shown in Figure 7. In the latter case, normally one strap 19 will be provided for each channel section member 18.

WHAT WE CLAIM IS: 1. A lintel comprising front and rear flange portions and a web portion having spaced front and rear portions respectively upstanding from said front and rear flange portions, wherein at least said web portion consists of resilient material, wherein at least one distance piece extending along at least part of the length of the lintel is retained between the upstanding portions by the clamping action exerted by the resilience of said web material, and wherein a strip of material adapted to form a plaster key is provided on the underside of said rear flange portion, being secured along one of its edges to said rear flange portion, and along the other of its edges to said distance piece or pieces.
2. A lintel as claimed in Claim 1, wherein a single distance piece extends along the whole length of the lintel apart from a gap at each end.
3. A lintel as claimed in Claim 1, wherein a plurality of distance pieces are spaced apart along the length of the lintel.
4. A lintel as claimed in any of the preceding Claims, wherein the, or each, distance piece consists of timber.
5. A lintel as claimed in Claim 4, wherein the strip of material forming the plaster key is secured along said one of its edges by being folded around the rear edge of the rear flange portion, and is secured along said other one of its edges by means of staples driven into the timber.
6. A lintel as claimed in Claim 4, or Claim 5, wherein the timber extends into the web portion of the lintel substantially to the top of said web portion.
7. A lintel as claimed in Claim 6, wherein the timber is spaced from the bottom of the web portion.
8. A lintel as claimed in Claim 1, wherein a plurality of lengths of channel section metal are spaced along the length of the lintel.
9. A lintel as claimed in Claim 8, wherein the strip of material forming the plaster key is held in position by means of metal straps spaced along the length of the lintel, each metal strap being secured at one end by being folded around the rear edge of the rear flange portion of the lintel, and being secured at the other end by being folded around one of the sides of a respective one of the lengths of channel-section metal.
10. A lintel as claimed in any of the preceding Claims, wherein said spaced front and rear portions of the web are joined by front and rear head portions which slope in opposite directions to meet at an apex substantially in the middle of the web.
11. A method of manufacturing a lintel as claimed in any of the preceding Claims, wherein said front and rear flange portions and said web portion are formed by bending a single sheet of resilient metal so that the width of the web at the base thereof is less than the width at the head thereof, wherein the two flange portions are then pulled apart to open the base of the web, and wherein the distance piece, or pieces, is, or are, inserted in the web, the arrangement being such that, when the flange portions are released, the resilience of the metal

will hold the distance piece, or pieces, in place.
12. A lintel substantially as hereinbefore described, with reference to, and as illustrated in, any of Figures 4 to 7 of the accompanying diagrammatic drawings.