Thermally broken lintel

Abstract

A lintel comprising first and second elongate metal load bearing members 10, 12 that extend in parallel, where the first may be taller and their upper edges may be bent to lie partially over the therm

Description

[0001] This invention relates to thermally broken lintels and to methods of assembling thermally broken lintels.

[0002] Thermally broken lintels are intended to reduce heat transfer across the lintel, such as from inside a building to outside, or vice versa. Such lintels find particular use in cavity walls, in which an inner and outer wall are separated by a space, the “cavity”, which reduces thermal conductivity between the inner and outer walls. Such lintels comprise separate “inner” and “outer” metal parts with a gap between them to provide a thermal barrier. GB2271130 describes one such lintel.

[0003] Thermally broken lintels are essentially separate lintels for the inner and outer walls and can have a layer of insulating core material disposed between them. The lintel described in GB2271130 also has a metal spacer between the inner and outer parts that holds the two parts in relative position. In other designs, a base plate has been provided between the inner and outer parts, or clips have been used to hold the two parts in position.

[0004] It has recently become practice to eliminate such spacers, plates, or clips to reduce thermal conductivity across the lintel. Because the lintel parts are held securely in place once built into a wall, it is only necessary that they be secured together while the lintel is being handled prior to and during installation. This can be achieved by gluing the metal parts to the insulating core material.

[0005] GB2535601 describes a method of manufacturing a thermally broken lintel in which an insulating core material is disposed between the parts and there is no metal to metal contact across the insulating core. The metal parts are glued to the insulating core so that the parts of the lintel stay together when being handled and installed. GB2535601 describes the use of a hot melt glue which is applied to the surface of the metal part contacting the insulating core material. The use of a hot melt glue can be challenging as the amount of time available to manipulate the pieces before the glue sets can be very short, especially if the glue is applied directly to metal parts. This can lead to the need to heat the metal parts to melt the glue and achieve adhesion with the insulating core. The manufacturing process is complex and if the glue does not adhere properly, the lintel can become disassembled due to shocks in handling or installation.

[0006] Cold set glues do not require heating but take longer to set. The time for which the lintel must be left undisturbed in order for the glue to set may be impractical. Again, if the glue fails, the lintel can be easily damaged.

[0007] This invention aims to address some or all of these problems.

[0008] A first aspect of the invention comprises a lintel, comprising: first and second elongate metal load bearing members extending parallel to each other; a layer of thermally insulating material located between the load bearing members; and connectors extending through bores in the load bearing members and the layer of thermally insulating material; wherein the connectors have head portions larger than the diameter of the bores and a thermally insulating shank extending between the head portions, and the shank is in tension such that head portions act on the load bearing members to hold the thermally insulating layer in compression between them.

[0009] The head portions of the connectors can be made of metal, such as steel, and the thermally insulating shank can be made from a polymeric material, such as nylon.

[0010] At least the second load bearing member is L-shaped. The base of the L can provide a surface for locating building elements such as bricks or blocks.

[0011] The first load bearing member can be taller than the second load bearing member. This means that water flowing onto the upper surface of the lintel will be directed towards the second load bearing member, which can be located at an outside surface.

[0012] The upper edge of the first and / or second load bearing member can be bent so as to partially overlie the upper surface of the thermally insulating material. This helps protect the thermally insulating material from damage.

[0013] The shank and head portions of the connector have inter-engagable threads such that the head portions can be screwed onto the shank to tension the shank and compress the thermally insulating material between the load bearing members.

[0014] A layer of adhesive, such as a cold set adhesive, can be disposed between each load bearing member and a respective contact surface of the thermally insulating material.

[0015] A second aspect of the invention comprises a method of assembling the lintel, comprising: placing the load bearing members on opposite sides of the thermally insulating material; forming bores through the thermally insulating material; inserting the connectors such that the shanks extend through the bores; and engaging the head portions on the load bearing members to compress the thermally insulating material and place the shank in tension.

[0016] Further aspects of the invention will be apparent from the description below.

[0017] Figure 1 shows a partial view of a lintel according to one embodiment of the invention.

[0018] Figure 2 shows the internal structure of the lintel of Figure 1.

[0019] Figure 3 shows the connector used in the lintel of Figure 1.

[0020] The lintel shown in Figure 1 comprises first and second elongate load bearing members 10, 12. The load bearing members 10, 12 are made from galvanised steel profiles. In this embodiment, both the first and second load bearing members are substantially L-shaped, each having a nominally vertical upright 10a, 12a and a nominally horizontal base 10b, 12b, and are arranged spaced apart and back-to-back to that the bases12a, 12b extend away from each other. The first member vertical 10a is taller than the second member vertical 12a.

[0021] The first and second load bearing members 10, 12 are separated by a layer of thermally insulating material 14. In this embodiment, the material is expanded polystyrene (EPS), although other materials may be appropriate. The heights of the sides of the layer 14 are matched to the heights of the respective vertical 10a, 12a, resulting in the layer 14 having a right trapezoid cross-section.

[0022] While both load bearing members 10, 12 are shown as L-shaped, this need not be the case. The second, usually outer, member 12 may often be L-shaped. The first, usually inner, member 10 can have one of a number of shapes, depending on application, e.g. open channel, box, layered channels, or other such structures.

[0023] The upper edges 10c, 12c of the verticals 10a, 10b are folded over towards each other so that they extend partially over the upper surface of the layer 14. This helps protect the edges of the layer 14 from impact damage during handling.

[0024] The first and second members 10, 12 are held against the layer 14 by means of connectors 16, shown in more detail in Figure 3. A layer of a cold melt glue (not shown) is provided between the contacting faces of the first and second members 10, 12 and respective sides of the layer 14, although this can be omitted in certain cases.

[0025] The connectors 16 extend through holes 18a, 18b in the first and second members 10, 12, and through a bore 20 extending through the layer 14 between the holes 18a, 18b.

[0026] Each connector comprises a pair of head portions 24, 26 and a shank 28. The head portions 24, 26, each comprise an outer socket part 24a, 26a with a flange that is larger than the holes 18a, 18b, and an inner tubular part 24b, 26b that is internally threaded. The head portions are made of steel. The shank 28 is formed from a shaft of nylon and is externally threaded to correspond to the thread of the head portions 24, 26.

[0027] The lintel can be assembled by first placing the first member 10 so that the vertical 10a is horizontal with its “front” face uppermost. A layer of cold set glue can be applied to the “front” face. The layer 14 is then positioned on the “front” face and aligned with the ends of the first member 10 and pushed under the edge 10c. A further layer of cold set glue is than applied to the “rear” face of the vertical 12a of the second member 12, which is then place onto the upper side of the layer 14, aligned with the ends, and the edge 12c pushed into contact with the top of the layer 14. The hole 18b, bore 20, and hole 18a are then drilled through the assembled members 10, 12 and layer 14.

[0028] The connector 16 is partially assembled by screwing the shank 28 into one of the head portions 24. The free end of the shank 28 is then inserted through the hole 18b and into the bore 20. The head portion 26 is then inserted through the hole 18a and engaged onto the free end of the shank 28. The head portions 24, 26 are then tightened onto the shank 28 using the sockets until the flanges bear against the outer surfaces of the members 10, 12, and tightened to compress the layer 14, placing the shank 28 in tension. This is sufficient to hold the members 10, 12 in place while the glue sets. In addition, placing the layer 14 in compression provides sufficient strengths and rigidity to the assembly that the various parts are less likely to move relative to each other when being handled, reducing the likelihood of damage to the otherwise fragile layer 14.

[0029] Various changes can be made within the scope of the invention. For example, the materials of the members, layer, and connectors can be selected according to requirements; and the particular form of the connectors can be varied, as can the cross sectional shape of the layer and the profiles of the members.

Claims

1. A lintel, comprising:first and second elongate metal load bearing members extending parallel to each other;a layer of thermally insulating material located between the load bearing members; andconnectors extending through bores in the load bearing members and the layer of thermally insulating material;wherein the connectors have head portions larger than the diameter of the bores and a thermally insulating shank extending between the head portions, and the shank is in tension such that head portions act on the load bearing members to hold the thermally insulating layer in compression between them.

2. A lintel as claimed in claim 1, wherein the head portions are made of metal.

3. A lintel as claimed in claim 1 or 2, wherein the thermally insulating shank ismade from a polymeric material.

4. A lintel as claimed in claim 1, 2, or 3, wherein the at least the second load bearing member is L-shaped.

5. A lintel as claimed in any preceding claim, wherein the first load bearing member is taller than the second load bearing member.

6. A lintel as claimed in any preceding claim, wherein the upper edge of the first and / or second load bearing member is bent so as to partially overlie the upper surface of the thermally insulating material.

7. A lintel as claimed in any preceding claim, wherein the shank and head portions have inter-engaging threads such that the head portions can be screwed onto the shank.

8. A lintel as claimed in any preceding claim, comprising a layer of adhesive disposed between each load bearing member and a respective contact surface of the thermally insulating material.5 9. A lintel as claimed in claim 8, wherein the adhesive is a cold set adhesive.

10. A method of assembling a lintel of any preceding claim, comprising: placing the load bearing members on opposite sides of the thermally insulating material;10 forming bores through the thermally insulating material;inserting the connectors such that the shanks extend through the bores; and engaging the head portions on the load bearing members to compress the thermally insulating material and place the shank in tension.

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