EP0549336A1

EP0549336A1 - Lintels

Info

Publication number: EP0549336A1
Application number: EP92311741A
Authority: EP
Inventors: Michael Gwyn Williams
Original assignee: Catnic Ltd
Current assignee: Caradon Catnic Ltd
Priority date: 1991-12-23
Filing date: 1992-12-23
Publication date: 1993-06-30
Also published as: GB2262756A; GB9226852D0; GB2262756B

Abstract

A lintel 1 for use over an aperture in a cavity wall, comprising plates 2, 3 having respective parts 4, 5 which lie substantially parallel to one another with a heat insulating member 6 therebetween, an extension of one part of one plate 4 being folded around a free edge 8 of the other part 5 to lie substantially parallel to both parts 4, 5 and the heat insulating member 6 whereby to secure the two plates 2, 3 together with no mechanical fixing such as welding being required.

Description

The invention relates to lintels.
Lintels fabricated from sheet metal angle members, whether of box or so-called inverted 'T'-section, are known. Usually the members are formed together by mechanical means such as rivets or welding. However, such constructional methods tend to produce corrosion points in the lintel and where a "thermal break" or heat insulator is utilised between adjacent members, such constructional methods rupture the insulator, and so destroy its effect. Even where no mechanical means is utilised the members are not securely tied together with consequent danger that a wall in which the lintel is installed will collapse with the lintel when loads are applied to the lintel.
It is an object of the invention to seek to mitigate these disadvantages.
According to one aspect of the invention there is provided a lintel for use over an aperture in a cavity wall, comprising plates having respective parts which lie substantially parallel to one another with a heat insulating member therebetween, an extension of one part of one plate being folded around a free edge of the other part to lie substantially parallel to both parts, whereby to secure the plates together.
One plate may comprise at least part of a limb of an angle section member having a flange for supporting part of an outer skin of the cavity wall and the limb may extend upwardly in use from or from near one edge of the flange. This provides a relatively simple one piece construction of the angle section member.
The other plate may comprise at least part of a limb of another angle section member having a flange for supporting part of an inner skin of the cavity wall, and the limb may extend upwardly in use from or from near an edge of the flange. This provides a relatively simple construction of this particular angle section member.
The respective flanges may lie substantially in the same plane and may be spaced apart whereby to provide a spacing between the respective limbs as they extend from that plane. This essentially provides a lintel of 'T'-shape the limb of the 'T' lying in the cavity in use.
The limbs may be inclined towards one another and respectively terminating in the plates. This provides a continuous construction.
The one plate may have an additional fold intermediate its length whereby the one plate may underlie the other plate over part of the length thereof. This provides additional strength in the formed lintel.
The member may be a member bridging the spacing between the flanges and the members may be heat insulated from the angle section member. This provides rigidity under compressive forces.
The bridging member may be secured by securing means to the flange of another angle section member. This is a relatively inexpensive fixing method.
The bridging member and the angle section member may be insulated by a plastic insulating member which is interposed therebetween. This provides a "thermal break" at the base of the lintel in use.
The member may be a snap or push fit over an upstaning (in use) lip of the bridging member. This provides for ease of assembly.
The bridging member may comprise a channel section member which may be a push fit between the angle section members. This is an alternative, relatively simple assembly method.
The channel shaped bridging member and the angle section member may be insulated by a plastic insulating member which may be a snap or push fit over a limb of the channel shaped bridging member. This provides for a relatively simple assembly of the insulating member and bridging member.
The channel section bridging member may comprise a metal member which is coated with a plastic heat insulation material. This provides for production by extrusion or spray coating.
The channel section bridging member may comprise a plastic member with stiffening means extending between the limbs thereof. This again assists in dealing with applied compression forces.
The limbs may have facing seatings in which the stiffening means is received. This is a relatively simple construction.
The stiffening means may comprise an elongate metal stiffener received in the seatings and extending substantially over the length of the lintel; alternatively the stiffening means may comprise a plurality of discrete metal stiffeners and each received in the seatings. In either case, additional support is provided if required.
Free edges of the limbs of the channel section member may be turned inwardly towards the interior of the spacings, suitably towards the thereof the channel section bridging member and terminating short thereof. This provides both a strengthening of the member per se and a key for any insulation in the spacing of the lintel.
The bridging member may comprise means to key plaster to the lintel. This assists in after work after the lintel is installed in a wall.
Suitably the keying means may comprise through holes, or configurations of substantially nove-tail configuration on an eternal (in use) surface of the bridging member . Either device provides a simple way with which plaster cement or the like can be secured to a surface of the lintel.
There may be an insulating material within-the spacings suitably of polystyrene from, or polystyrene beads which may be secured in the lintel by being steamed and expanded. Again, the arterial may comprise a board of polystyrene formed to the profile of the spacings, and preferably the plates may be formed therearound and secured together to form the lintel. Using such materials the lintel per se can be thermally insulated as a whole.
The angle section member may be precoated with a heat insulating material prior to assembly to form the lintel. This provides an integral the break. The front, in use, angle section member may comprise stainless steel. A bi-metal lintel can therefore be provided the front angle requiring no additional anti-corrosion treatment.
According to a second aspect of the invention there is provided a method of making a lintel as hereinbefore described, comprising providing the plates, providing a heat insulating member, assembling the plates and the insulating member so that that member is between substantially parallel parts of the plates and securing the plates together by a folding operation whereby to form the lintel.
According to a third aspect of the invention there is provided a method of erecting a cavity wall having an aperture therein comprising building up buttresses with inner and outer skins of the cavity wall on both sides of the intended aperture, mounting a lintel as hereinbefore defined on the buttresses, and building up the inner and outer skins over the aperture supported by the lintel and so that the parts lie in the cavity.
Lintels embodying the invention are hereinafter described, by way of example, with reference to the accompanying drawings.

Fig. 1 is an end elevational view of a first lintel according to the invention;
Fig. 2 is an end elevational view of a second lintel according to the invention;
Fig. 3 is an end elevational view of a third lintel according to the invention;
Fig. 4 is an end elevational view of a fourth lintel according to the invention;
Fig.5 is an end elevational view of a fifth lintel according to the invention;
Fig. 6 is an end elevational view of a sixth lintel according to the invention;
Fig. 7 is an end elevational view of a seventh lintel according to the invention;
Fig. 9 is an end elevational view of part of a ninth lintel according to the invention;
Fig. 10 is an end elevational view of part of a tenth lintel according to the invention;
Figs. 11 and 11A show end elevational views of first base plates for closing off respectively 50 mm and 70 mm wide cavities in lintels according to the invention;
Figs. 12 and 12A show end elevational views of second base plates according to the invention for closing off respectively 50 mm and 70 mm wide cavities in lintels;
Figs. 13 and 13A show respectively an enlarged Fig 12A and an enlarged slot detail of Figs. 12A and 13;
Fig. 14 shows an end elevation of a third base plate according to the invention;
Fig. 15 shows an end elevation of a fourth base plate according to the invention;
Fig. 16 shows an end elevation of a fifth base plate according to the invention;
Fig. 17 shows an end elevation of a sixth base plate according to the invention;
Figs. 18 and 18A show respectively transverse sectional and plan views of a seventh embodiment of a base plate according to the invention, Fig. 8 being a section taken on the line 'A' - 'A' of Fig. 18A;
Figs. 19, 19A and 19B show respectively transverse sectional, plan and enlarged sectional part views of an eighth embodiment of lintel according to the invention, Fig. 19 being a section on line 'C' - 'C' of Fig. 19A and Fig. 19C being an enlarged longitudinal sectional view on line 'B' - 'B' of Fig. 19;
Fig. 20 shows the base plate of Figs. 12A, 13 and 13A in use; and
Fig. 21 shows an alternative base plate according to the invention in use.

Referring to the drawings, in which like parts are referred to by like reference numerals, there is shown, in Fig. 1 for example, a lintel 1 for use over an aperture in a cavity wall (not shown), comprising plates 2, 3 having respective parts 4, 5 which lie substantially parallel to one another with a heat insulating member 6 therebetween, an extension 7 of one part of one plate 4 being folded around a free edge 8 of the other part 5 to lie substantially parallel to both parts 4, 5 and the heat insulating member 6 whereby to secure the two plates 2, 3, together. Thus no mechanical fixing such as welding is required.
One plate 2 comprises at least part of a limb of a metal angle section member 9 having a flange 10 for supporting part of an outer skin of the cavity wall, the one plate 2 extending upwardly, in use and as viewed, from one edge 11 in use at the inner surface of the outer skin of the wall, of the flange 10. The other plate 3 comprises at least part of a limb of another or second metal angle section member 12 having a flange 13 for supporting part of an inner skin of the wall, the limb 3 extending upwardly in use and as viewed in Fig. 1 upwardly from one edge 14, in use, at the other surface of the inner skin of the wall of the flange 13.
The extension 7 is folded as by a hydraulic press round the free edge 8 of the part 5, so trapping the heating insulating member 6 between the part 4 and the extension 7 and part 5. The member 6 is of generally U-shape, and may be a plastic extrusion. It extends over the whole surface area of the parts 4, 5 and extension 7, and indeed protrudes beyond the free end of the extension 7, and beyond a bend 15 in the limb 3 leading to the part 5. Thus there is complete insulation so that the metal parts/limbs cannot touch, which if they did would otherwise form a thermal bridge between the limb 2 and the limb 3. Moreover, where the angle section 9 is made of stainless steel and the angle section 12 is made of mild steel, whether galvanised or not, contact between the two metals would set up electrical potential differences which cause corrosion. The member 6 obviates this, as well as providing a thermal break.
The angle section member 9 comprises the flange 10, a substantially upright member 16 rising therefrom leading to an inclined member 17 which in turn leads to the part 4 and the extrusion 7. The inclined member 17 forms an integral damp-proof course in use. The angle section member 12 comprises the flange 13, a substantially upright member 18 rising therefrom to an inclined 19 which extends toward the member 17 and which leads into the part 5 via the bend 15. The upright members 16, 18 are spaced apart by substantially the width of the cavity of the wall, and define a spacing 20.
The lateral extent of the folded over part 4,5,6,7,8 (to the left as viewed) is to the right (as viewed) of or extends no further to the left (as viewed) of the plane of the upright member 18. Thus when the lintel 1 is installed over an aperture in a cavity wall and the inner and outer skin of the wall are built up on and supporter by the flanges 10 and 13 respectively, the part of the lintel defined by the members 4,5,6,7,8 lies entirely within the cavity. Stated in another way, the inner skin of the wall can be built up vertically on the flange 13 to higner than the height of the lintel 1 without hindrance of impedence from the folded-over extension 4,5,6,7,8. (It will be understood that buttresses of the cavity wall are built up on either side of the extended aperture, to the desired height, whereafter the lintel 1 is laid in place on the buttresses across the aperture, the flanges 10, 13 essentially lying in substantially the same plane).
The spacing 20 is bridged by a bridging member 21 of 'L'- shape, a limb 22 of which projects into the spacing 20 adjacent the member 16 from which it is separated by a heat insulating member 23 in the form of a plastic extrusion which is snap-engaged over, or a push fit on the limb 22, to provide a thermal break. The limb 21 is secured to the flange 13 as by welding in a rebated part 24 of the flange 13. The briding member 21 by have means for the keying of external plaster, and also means for the briding of a thermal insulating medium which might be c ontained in the spacing 20.
Turning now to Fig.2, the embodiment of lintel 200 shown is similar to the lintel 1 of Fig.1, except that the flange 13 is planar, without the rebate 24. It will be understood too that although not shown, there is heat insulation like that6, 23 of Fig.1.
Turning now to Fig.3, the embodiment of lintel 300 shown is similar to that of Fig.2, saving that the dimensions differ, so that the angle of inclination of the incline member 17, 19 is respectively 6O° and 30°. Again, insulating members 6, 23 are utilised.
Turning now to Fig.4, the lintel 400 shown differs from the lintels 1, 200 and 300 in that the inclined plate 17 has a fold 401 in it leading to a further inclined part 402 which leads to the part 4. The fold increases the strength or 'I' factor of the lintel 400.
Fig.5 is a development of Fig.4 in showing a lintel 500 in which the fold 501 in the inclined part 17 produces a 90° angle and at 15 too so that the part 4 is L-shaped, a limb 502 of the 'L' being below and substantially parallel to the part 19. The lintel 500 is made by assembling two angle sections 9, 12 as in Fig.1 and then with suitable means such as a hydraulic press forming the two folds 15, 501 in one pass. The lintel 500 could be modified by making the fold 501 deeper and the fold 15 in the inner section 12 deeper too. In either case the two folds 15, 501 increase the rigidity or 'I' factor of the lintel. The two folds then provide a return fold as the parts 4,5,6,7,8 return to lie over the folds 15, 501 and this secures the sections 9,12 together, the folding/pressing step resulting in a slight drawing up of the angle section 9 so that the sections 9, 12 are drawn tightly together so making a stable lintel construction without the need for welds. Stated in another way, the forces applied during the pressing steps provide vertical reaction forces which tie the angle sections 9, 12 together and lock the heat insulating member 6 in place to provide the thermal break.
The lintel 600 shown in Fig. 6 is similar to that of Fig.1, saving that in this case the extension 601 is on the part 5 and is folded round the free end 602 of the part 4 and lies substantially parallel thereto and to the insulating member 6. Again, there would be an insulating member at the limb 22.
Fig. 7 shows a lintel 700 embodying the invention which has a bridging member in the form of a metal channel or steel member 701 inserted between the limbs 16, 18, one of the legs 702 of the channel 701 being secured as by welding to the limb 18. There is a heat insulating member 23 between the leg 703 and the limb 16 to provide a thermal break. The web 704 may have means such as perforations 705 in order to provide a key for plaster applied to the external surface of the lintel 700.
Fig. 8 shows an embodiment of lintel 800 similar to Fig. 7 the bridging member 801 being a rigid P.V.C. extrusion with an extension 802 of the web which is secured to the flange 13 as by rivets 803. The web of the extrusion includes perforations or grooves for providing a keying means for plaster, cement or the like. Again, though not shown, there are heating insulating members at 6, 23.
Figs. 9 and 10 show other embodiments of bridging member. In Fig.9, the bridging member 900 is a channel shaped continuous plastic extrusion the legs of which are inserted in the spacing 20 and the web of which is effectively a continuation of the flanges 10 and 13. The legs are a push fit in the spacing 20 and have facing integral seatings 901 wich receive a transverse metal stiffener 902 which extends continuously over the length of the lintel. Alternatively the stiffener 902 could comprise a plurality of discrete stiffeners spaced apart over the length of the lintel. The web of the extrusion may be perforated or grooved for providing a plaster key. The bridging member 900 being plastic, it is instrinsically a thermal break.
The bridging member 1000 of Fig. 10 is a continuous channel of steel coated with plastic to provide a thermal break. The legs of the channel are a push fit in the spacing 20, and have inwardly directed lips, nibs or tangs 1001 at the free edges. The tangs 1001 serve to tie in insulation on the spacing 20 by becoming embedded therein.
Referring now to Figs. 11 to 21 of the drawings, there are shown bridging members or base plates 2001 for mounting on a lintel 2000, Fig. 20, comprising a body 2003 which is adapted to close an internal cavity 2004 of the lintel 2000, means 200 of the body for mounting the body on the lintel, and means 2006 of the body for providing a keying means for plaster or the like applied in use to the lintel.
In Figs. 11 to 20, the base plates shown each comprise a continuous extruded element of PVC, the body 2003 comprising a flat bar or strut, and the mounting means 200 comprising upstanding wings which are a push fit into the interior cavity of the lintel adjacent upstanding plate members 2007, 2008 thereof, and further wings 2009 which are directed oppositely to one another in the same plane and which in use abut the underside (as viewed) of front and rear (in use) support plates 2010, 2011 of the lintel 2000, and which on so abutting these plates limit the insertion of the base plate 2003 in the cavity so that the plates and the body lie substantially on the same plane, so providing a substantially continuous base of the lintel 2000. It will be understood that the support plates 2010 and 2011 respectively support in use front and rear skins 2012 and 2013 of a cavity wall over an aperture 2014 therein and in which the lintel 2000 is installed.
The keying means 2006 varies from base plate to base plate but essentially all embodiments provide means whereof a thickness of plaster, cement, mortar or the like 2015 can be applied to the underside of the lintel 2000 from the inboard side of a frame 2016, such as a door or window frame in the aperture 2014 in the wall, to the rear or inner side of the lintel 2000 for which purpose the rear support plate 2011 is provided with apertures 2017 through which the plaster etc. passes on application.
In Figs. 11 and 11A, the keying means comprises a plurality of spaced apart bars or fingers of inverted 'T' section defining grooves therebetween, the bars of the 'T's helping to provide a key for plaster.
In Fig. 12, the keying means comprises dovetail shaped grooves separated by similarly shaped, inverted fingers or rails. The embodiment of Figs. 12A, 13 and 13A is similar, except that the external and internal corners of the dovetails have a 1 mm radius, in contrast to the 'sharp' profile of Fig. 12.
The embodiments of Figs 14 and 15 illustrate keying means having angularly concave shaped pairs of fingers, while the embodiments of Figs. 16 and 17 have keying means in the form of a V-configuration, the Fig. 77 embodiment having a wider apex angle.
The keying means of the embodiments of Figs. 18, 18A and 19, 19A comprises apertures and depending spaced apart fingers, the apertures being in rows adjacent ones of which are staggered. In Figs. 18 and 18A the apertures are through apertures, while in Figs. 19 and 19A, the material of the base plate is raised up to provide a roof or dome-like configuration of a blind aperture in each case.
Fig. 21 shows an alternative continuous perforated steel base plate 2018 comprising a wing or limb 2019 for insertion in the aperture of the lintel 2000, a body 2020 for extending across and closing the aperture 2004, an extension 2021 of the body 2020 for securing to the rear support plate 2011 and through perforations 2022 comprising the keying means. A thermal barrier 2023 is provided by a J-shaped continuous PVC extrusion mounted on the wing 2019. The base plate 2020 of Fig. 21 thus acts in a similar manner to that of the other embodiments.
It will be understood that the invention described with reference to the drawings could be modified. For example, instead of PVC, any suitable plastic or other material, such as metal coated with plastic, could be used. Also, flanges or wings 2009 could be omitted, the base plate then having a substantially channel shape which locates between the lintel faces 2007, 2008 without abutting the horizontal flanges.
It will also be understood that in every embodiment the heat insulating members 6, 23 may comprise an extrusion, plastic sheet tape or the like, and are formed to the required configuration during the manufacture of the lintel.
The bridging members 21 etc. which may also be glued in position, counter compression under load at 11, 14. Also, the spacing 20 may be filled with an insulating material such as polyurethane foam, polystyrene beads which are filled with the spacing and expanded by the application of steam so that the spacing is filled and the beads are held in place. Alternatively the insulation may comprise a polystyrene board cut to the desired profile and incorporated in the lintel by forming the metal angles 9, 12 round it.
It will be understood that all the lintels are made as described with respect to the lintel of Fig. 1, and are installed in a cavity wall as described with respect to the installation of that lintel.
Using the invention as hereinbefore described with reference to the drawings, it is possible to provide lintels which:-

Have no welds;
Have no additional damp-proof course;
Have no mesh;
Have no curtain batten;
Have a thermal break;
Are insulated;
Have a stainless option for outer sein;
Fit a full range of wall constructions;
Have a length up to 4.8m;

Claims

A lintel for use over an aperture in a cavity wall characterised by plates (2, 3) having respective parts (4, 5) which lie substantially parallel to one another with a heat insulating member (6) therebetween and by an extension (7) of one part (4) of one plate (2) being folded around a free edge (8) of the other part (5) to lie substantially parallel to both parts (4, 5), whereby to secure the plates together.
A lintel according to Claim 1, characterised by one plate (3) comprising at least part of a limp (18) of an angle section member (12) having a flange (13) for supporting part of an outer skin of the cavity wall, and by the limb (18) extending upwardly in use from or from near one edge of the flange.
A lintel according to Claim 2, characterised by the other plate (2) comprising at least part of a limb (17) of another angle section member (9) having a flange (10) for supporting part of an inner skin of the cavity wall, and by the limb (17) extending upwardly in use from or from near an edge of the flange.
A lintel according to Claim 3, characterised by the respective flanges (10, 13) lying substantially in the same plane and being spaced apart whereby to provide a spacing (20) between the respective limbs as they extend from that plane.
A lintel according to Claim 4, characterised by the limbs (17, 18) being inclined towards one another and respectively terminating in the parts (4, 5).
A lintel according to Claim 6, characterised by the one plate (2) having an additional fold (501) intermediate its length, whereby the one plate underlies the other plate (3) over part of the length thereof.
A lintel according to any of Claims 4 to 6, characterised by there being a member (21) bridging the spacing between the flanges and being heat insulated from the angle section member.
A lintel according to Claim 7, characterised by the bridging member (21) being secured by securing means to the flange of another angle section member.
A lintel according to Claim 7 or Claim 8, characterised by the bridging member (21), and the angle section member being insulated by a plastic insulating member (23) which is interposed between.
A lintel according to Claim 9, characterised by the member (23) being a snap or push fit over an upstanding (in use) lip (22) of the bridging member (21).
A lintel according to Claim 7, characterised by the bridging member (21) comprising a channel section member (701) which is a push fit between the angle section members.
A lintel according to Claim 11, characterised by the channel shaped bridging member (701) and the angle section member (2) being insulated by a plastic insulating member (703) which is a snap or push fit over a limb of the channel shaped bridging member.
A lintel according to Claim 11, characterised by the channel section bridging (701) comprising a metal member which is coated with a plastic heat insulating material.
A lintel according to Claim 11, characterised by the channel section bridging member comprising a plastic member (900) with stiffening means (902) extending between the limbs thereof.
A lintel according to Claim 14, characterised by the limbs having facing seatings (901) in which the stiffening means (902) is received.
A lintel according to Claim 15, characterised by the stiffening means (902) comprising an elongate metal stiffener received in the seatings (901) and extending substantially over the length of the lintel.
A lintel according to Claim 15, characterised by the stiffening means (902) comprising a plurality of discrete metal stiffeners each received in the seatings.
A lintel according to any of Claims 11 to 17, characterised by free edges (1001) of the limbs of the channel section member (1000) being turned inwardly towards the interior of the spacings.
A lintel according to Claim 18, characterised by the free edges (1001) being turned inwardly and towards the web of the channel section bridging member (1000) and terminating short thereof.
A lintel according to any of Claims 7 to 19, characterised by the bridging member (1000) comprising means to key plaster to the lintel.
A lintel according to Claim 20, characterised by the keying means comprising through holes.
A lintel according to Claim 20, characterised by the keying means comprising configurations (2006) of substantially dove-tail configuration on an external (in use) surface of the bridging member.
A lintel according to any of Claims 4 to 22, characterised by there being an insulating material within the spacing.
A lintel according to Claim 23, characterised by the material comprising polystyrene foam.
A lintel according to Claim 23, characterised by the material comprising polystyrene beads which are secured in the lintel by being steamed and expanded.
A lintel according to Claim 23, characterised by the material comprising a board of polystyrene formed to the profile of the spacing.
A lintel according to Claim 26, characterised by the material comprising a board of polystyrene formed to the profile of the spacing, the plates being formed therearound and secured together to form the lintel.
A lintel according to any of Claims 2 to 27, characterised by the angle section members (9, 12) being precoated with a heat insulating material prior to assembly to form the lintel.
A lintel according to any of Claims 2 to 27, characterised by the front, in use, angle section member (9) comprising stainless steel.
A method of making a lintel according to any preceding claim, characterised by providing two plates (2, 3), providing a heat insulating member (6), by assembling the plates (2, 3) and the insulating member (6) so that that member is between substantially parallel parts of the plates and securing the plates together by a folding operation whereby to form the lintel.
A method of erecting a cavity wall having an aperture therein, characterised by building up buttresses with inner and outer skins of the cavity wall on both sides of the intended aperture, mounting a lintel according to any preceding claim on the buttresses, and building up the inner and outer skins over the aperture supported by the lintel and so that parts lie in the cavity.