GB2177132A - Lintel - Google Patents

Abstract

A lintel made from two Z-shaped members 1,2 having respective leaf flanges 8,12 for supporting outer and inner leaves of a cavity wall. The members 1,2 each have central web portions 7,11 from which head flanges 10,13 respectively extend so as to overlie and be secured together by rivets 3. The channel 14 formed between the web portions locates a timber support block 4, and a strip of mesh 6 for keying plaster extends across the face of the block 4 and the inner leaf flange 12. To provide a thermal barrier in the lintel, a strip 5 of plastics is located between the overlying head flanges 10,13 and the rivets 3 may extend through flanged sleeves of plastics to prevent direct metal contact. The members 1 and 2 may be of different metals and one member may be coated with a plastics material, and the mesh may be omitted. <IMAGE>

Description

SPECIFICATION Fabricated lintel Description This invention relates to an improved fabricated lintel, and is particularly concerned with a lintel ofthe kind adapted to supportthe inner and outer leaves of a cavity wall.

Many forms of fabricated metal, usually steel, lintels are known, but many of these are very expensive to manufacture because of the complex configurations of the sections used requiring special tools and presses. Often the sections are assembled and se cured together bywelding, and this also requires special expensive equipment.

It is an object ofthis invention to provide a fabricated metal lintel which can be manufactured simply and cheaply.

It is a further object ofthis invention to provide a special form of fabricated lintel which is of unique construction permitting, if required, the use of diffe rent metals for different parts of the lintel.

It is a further object ofthis invention to provide a lintel in which, if desired, a thermal barrier may be incorporated.

Other objects ofthis invention will be described or revealed later herein with reference to certain advantages and otherfeatures ofthe invention.

According to this invention, we provide a lintel having opposed leafflanges each for supporting a leaf of cavity wall and a head portion for closing the cavity between the inner and outer leaves ofthe cavity wall, the lintel comprising first and second elongate members of substantially constant section and each member having a centre web portion with a leafflange extending therefrom to one side and with a head flange extending therefrom to the other side, the first and second members being assembled with the leaf flanges extending oppositely to each other in substantiallythe same plane with the centre web portions being spaced apart and with one head flange overlying the other, the first and second members being secured together by rivets extending through the head flanges and an elongate support block being located within the inverted channel defined by the web portions and the head flanges.

By this invention, the lintel is fabricated from two main memberswhich are rivettedtogetheralong the length of overlying head flanges, and this is a simple manufacturing operation. The inverted channel formed in the assembly when the first and second members are so secured together is used to locate the support block that ensures rigidity and prevents twisting movement of the lintel assembly.

Thefirstandsecond membersare preferably of metal, such as steel. The same metal may be used for each member, but most conveniently, due to the rivetted construction, different metals can be used for each member. Bythis use of different metals, many problems with existing lintels can be overcome, particularlythose arising from the different environ mental conditions on the outer leafofthe wall and those on the inner leaf of the wall.

Preferably, where different metals are used forthe firstandsecond member,thefirstmemberfor supporting the outer leaf of the wall is of stainless steel. Thus, the faces ofthe lintel that may extend to the outer weathering environment are ensured to be resistant to corrosion and other weathering or deleterious effects.

The support block is preferably located in the channel between the web portions and is an interfer ence fit therein with the outer face ofthe block extending substantially the same plane as the leaf flanges.

By this arrangement, the underside of the lintel has co-planarfaces which assist in the finishing of the building structure and the fitting of window or door frames and applying any finish treatment.

Preferably the support block is oftimber or a material of wood-like composition, such as resin bonded wood particles or chips, or of a suitabie plastics material or composition.

By using a timber or wood-like material, then the lintel provides a longitudinal face to the underside which can be used with conventional building or joinery techniques and materials for fitting frames or the like.

The lintel may include meansfor providing a key for plasterorotherwall finish, and this key may be a strip of mesh which extends over the underface of one leaf flange and aroundthe peripheral edge thereof and furtherextends and is securedto the outerface ofthe support block.

By this means a simple key finish can be provided on the lintel, and conveniently the mesh may be nailed or pinnedto the support block and wrapped around the peripheral edge of the leaf flange which is to support the inner leaf of the wall in use.

Another preferred feature ofthe invented lintel is that one leaf flange is formed with an edge portion that is displaced out of the plane of the flange so as to be inclined away from the head portion ofthe lintel.

By providing this inclined edge portion of a leaf flange, this can be located in use to the outerface of the wall of which the outer leaf is supported on the leaf flange, and the inclined edge portion provides a drip edgeto deflectwaterorthe likeawayfromthe eventual wall structure orwindowordoorextending beneath the lintel.

According to another important aspect of this invention, the lintel can be provided with athermal barrierto prevent the high thermal conductivity between the inner and outer leaf flanges ofthe lintel when in situ.

Inthesimplestformofthermal barrier, one ofthe members may be provided with a low thermal conductivity coating, such as plastics.

The low conductivity coating thus provides a barrier at the interface where the head flanges overlie, and the support block being oftimber orthe like is also of lowthermal conductivity so that there is no path between thefirst and second membersth rough which high rates ofheattransfer can occur.

The coating applied to the one member may be a powder coating which is sintered on the member, or the coating may be provided by dipping process.

The provision ofthe coating, when of plastics, provides another advantage relating to corrosion or providing a decorative finish.

As an alternative or in addition to the coating, a thermal barrier strip may be provided between the head flange priorto assembly and rivetting. Such strip would be of elongateform and of substantiallythe same width ofthe underlying or overlying head flange and be interposed therebetween priorto rivetting.

in eitherconstruction including athermal barrier, further discrete thermal barriers may be provided around or incorporated in each rivet.

Each rivet may itself be coated, at least around it's shank with a plastics or like low thermal conductive material. Alternatively, or additionally, each rivet may be associated with a sleeve of low thermal conductive material which extends around the shank ofthe rivet and prevents direct contact between any exposed metal faces of the two members and the rivet.

Other features ofthis invention with it's various aspects will now be described with referenceto an exemplary embodiment of a lintel according to this invention including athermal barrier as shown in the accompanying drawings wherein FIGURE 1 is an isometric view ofthe exemplary lintel; FIGURE2 is a cross-section of the lintel shown in Figure1; FIGURE3 is a diagrammatic view showing a step in the manufacture ofthe lintel shown in Figures 1 and 2; and FIGURE4 is an enlarged detail showing the section of a rivetted connection in the lintel depicted.

With reference to the drawings, the lintel comprises a first elongate member 1 and a second elongate member 2 which are joined together by rivets 3. The lintel further comprises a timbersupport block4, a strip of plastics 5, and a strip of mesh 6.

The first member 1 is of steel, and could be of stainless steel. The member 1 is generally of Z-shape and comprises a central web portion 7 and along one side of this extends a leaf flange 8 of which the outer edge portion 9 is bent out ofthe plane ofthe major part oftheflange8. In use ofthe lintel, the leafflange 8 is for supporting the outer leaf of a wall (not shown) and the edge portion 9 extends outwardly and inclined downwardlyto provide a drip edge. From the other side ofthe web portion 7 there extends a head flange 10.

The second member2 is also of steel, and could be a steel alloy galvanised or plastics coated. The member 2 is also generally of Z-shaped and has a centrai web portion 11. A leaf flange 12 extends from one side of the web portion 11 and in use ofthe lintel is for supporting the inner leaf of a wall. In the assembled lintel as show, the leaf flanges 8 and 12 extend oppositely and in substantially the same plane. From the other side of the web portion 11 there extends a head flange 13.

The head flange 13 is arranged to overlie the head flange 10 ofthe first member 1 and the enclosed angles between each head flange and the respective web portion are complementary so that the head flanges 10 and 13 with the web portions provide a head portion in the lintel which in use is arranged to extend into a cavity between the outer and inner leaves of a wall, with the head face being inclined downwardly to the outer leaf to ensure that any water or condensation within the cavity is deflected towards theouterwall leaf.

Thetimbersupports block4 is located and held in the channel 14formed between the opposed faces of the web portions7 and 11. Thetimber block4is atight interference fit in the channel 14 and the lower face extends in the same plane as the leafflanges8and 12.

The strip of mesh 6, preferably a galvanised mesh such as of expanded metal, is stretched across the lowerface ofthe support block4 and may be secured thereto by nails or tacks 15 (Figure 2). The outer edge ofthe leafflange 12 has the marginal edge l6ofthe mesh wrapped around to secure same to the assembly.

In orderto obtainthetightinterferencefitforthe support block 4, the members 1 and 2 are designed to provide a wedge-like channel tapering towards it's open end into which the support block 4 is entered.

The taper angle of the wedge is calculated to ensure the correct interference fit, and a diagrammatic view of this is shown in Figure 3.

It is envisaged that the interference fit of the support block4could be obtained in an alternative manner buy providing a taper on the opposed side of the support block. The support block 4 may extend continuously forthewhole length ofthe lintel, or there may be a series of sepa rate blocks at spaced apart positions.

The members 1 and 2 are secured together bythe rivets3which extend through the overlying head flanges 10 and 13 and between which the strip of plastics material is interposed. As shown in Figure4, the rivet 3 has a head 17 and a shank 18 and underthe head and extending around the shankthere is a short flanged sleeve 19 of low thermal conductive material such as plastics. The sleeve 18 is engaged in the hole in the head flange 13 and prevents any metal-to-metal contact and provides a thermal barrier. The shank 18 ofthe rivet extends through the strip of material 5 which prevents direct thermal transfer between the overlying head flanges, and the tail ofthe rivet is peened overontheinnerfaceofthe headfiange 10.

The rivets 3 are regularly spaced along the length of the lintel and may be staggered or otherwise arranged to suit the strength and size ofthe lintel. The rivets may be ofthe self-piercing type if desired.

As will be appreciated now from the foregoing description of the embodiment, the invented lintel is of simple form and easyto manufacture. In the exemplary embodiment, the thermal barrierispro- vided, butthe special features providing such thermal barrier can be omitted if desired.

The invented lintel can be madeto a range of widths as desired without departing from the principles of construction and assembly as afore-described. The inclination ofthe head portion can be changed to suit any particular requirement, and in some cases, the head portion can be without any inclination. Where no keying is required in the inside of a building, the mesh can be omitted.

Othervariations or modifications to the invented lintel to accommodate special sizes of leafflanges and changing the type of drip edge or omitting same will be appa rent to those familiarwith this field.

Claims (12)

CLAIMS:

1. A lintel having opposed leafflanges each for supporting a leaf of a cavity wall and a head portion for closing the cavity between the inner and outer leaves ofthe cavity wall, the lintel comprising first and second elongate members of substantially constant section and each member having a centre web portion with a leafflange extending therefrom to one side and with a head flange extending therefrom to the other side, the first and second members being assembled with the leafflanges extending oppositely to each other in substantiallythe same plane with the centre web portions being spaced apart and with one head flange overlying the other, the first and second members being secured together by rivets extending through the head flanges and an elongate support block being located within the inverted channel defined by the web portions and the head flanges.

2. A lintel according to Claim 1 wherein the members are of different metals.

3. A lintel according to Claim 1 wherein one ofthe members is coated with a plastics material.

4. A lintel according to any one of the preceding Claims wherein the support block is of timber and is an interference fit between the web portions of each member.

5. A lintel according to anyone ofthe preceding Claims wherein a mesh extends and is secured to the support block and a leafflangeto providekeyingfor plasteror like finish to be applied to the lintel in use.

6. A lintel according to any one ofthe preceding Claims wherein the peripheral edge of one leaf flange is displaced and inclined away from the plane of the flange so as to be inclined away from the head portion ofthelintel.

7. A lintel according any one ofthe preceding Claims wherein the support block is of a material having low thermal conductivity and the lintel includes a thermal barrierto prevent thermal transfer between the first and second members.

8. A lintel according to Claim 7 wherein the thermal barrier comprises a low thermal conductivity coating on one member.

9. A lintel according to Claim 7 or Claim 8wherein the thermal barrier comprises a strip of low thermal conductive material interposed between the overlying head flanges.

10. A lintel according to anyone of Claims 7, 8or9 and wherein the barrier includes a sleeve of low thermal conductive material extending around the shank of the rivet to prevent direct metal contact.

11. A lintel according to any one of Claims 7, 8or9 and wherein the shank of the rivet is coated with a plastics material of low thermal conductivity.

12. A lintel substantially as herein before described with reference to the accompanying Drawings.