[0001] This invention relates to a lintel, suitable for use over an aperture in a cavity
wall comprising two spaced leaves.
[0002] The terms "lateral", "upwardly", "upper", and "lower" and similar terms are used
in the following description and claims. It is to be appreciated that these terms
are used to define the relative location and orientation of different parts of a lintel,
when in use.
[0003] According to the present invention there is provided a lintel, suitable for use over
an aperture in a cavity wall comprising two spaced leaves, which lintel comprises
first and second angle sections and a locking member, each of the angle sections comprising
a lateral flange for supporting, in use, a portion of a respective leaf of the cavity
wall above said aperture, and an upwardly-extending panel, with upper free edges of
the upwardly-extending panels secured together by the locking member.
[0004] The two angle sections can be symmetrical about a vertical plane.
[0005] It is expected that the provision of two separate angle sections, which are held
together by.a separate locking member should have a number of advantages. The construction
need not include any welds, thus eliminating problems due to weld failure. The lintel
can be assembled simply by sliding or clipping the locking member onto the two angle
sections. Thus, the lintel can be assembled on a building site, and the final selection
of the two types of angle section for a lintel only has to be made immediately prior
to assembly. There is the possibility of using different angle sections in one lintel.
In current building practice, most of the imposed loads on a cavity wall are applied
to the inner leaf. If heavy loads are applied, it is possible that the inner angle
section supporting the inner leaf would have to carry 75% of the load, whilst the
outer angle section supporting the outer leaf would only have to carry 25% of that
load. To allow for this, the angle section for the inner leaf can be made from heavier
gauge steel; for example, the inner anple section could be 10 gauge and the outerangle
section 12 gauge.
[0006] There is also the possibility that different finishing treatments could be applied
to the two angle sections. For example, the inner angle section could be made from
pre-galvanised steel, i.e. from steel sheet which is galvanised before it is formed
into the angle section, whilst the outer angle section could be post-galvanised, i.e.
the galvanising treatment is applied after the steel sheet has been formed into the
angle section. Pre- galvanising tends to be less expensive than post- galvanising,
but it has the disadvantage that raw steel edges are left in the finished angle section;
nevertheless, this may be acceptable for the inner angle section. Use of pre-galvanised
steel for the external angle section can lead to unsightly rust marks resulting from
rusting of the exposed raw edges. This is prevented by the use of post-galvanised
steel for the outer angle section.
[0007] Also, as the lintel can be assembled on site, the angle sections can be stacked for
transportation.
[0008] For a better understanding of the present invention, and to show more clearly how
the same may be carried into effect, reference will now be made, by way of example,
to the accompanying drawing in which Figure 1 is a vertical cross-section through
a lintel (a modification being shown in Figure lA) and corresponding sections through
a cavity wall.
[0009] The lintel comprises a first angle section 1 supporting a part 3 of an outer leaf
of the cavity wall, and a second angle section 2 supporting a part 4 of an inner leaf
of the cavity wall. The ends of the angle sections 1 and 2 are supported on portions
of the cavity wall which are not shown and which are located on either side of the
aperture below the lintel. A window frame 5 is located immediately below the lintel.
[0010] The first angle section 1 comprises a lateral, generally horizontal flange 10 and
an upwardly-extending panel 11. The part 3 of the outer leaf is supported on the flange
10. The angle sections 1 and 2 are substantially symmetrical about a vertical plane
between the two angle sections 1 and 2. The angle section 2 similarly comprises a
' lateral, generally horizontal flange 20 and an upwardly extending panel 21.
[0011] The upwardly-extending panel 11 comprises a lower portion 12 which extends substantially
vertically from the respective flange 10. An intermediate portion 13 is inclined to
the lower portion 12 and extends from the lower portion 12 towards the other panel
21. From the end of the intermediate portion 13, an upper portion 14 extends substantially
vertically and it has a free edge region 15 which is inclined downwardly away from
the other upwardly-extending panel 21. The upwardly extending panel-21 of the second
angle section 2 correspondingly comprises a lower portion 22, an intermediate portion
23 and an upper portion 24 which has a free edge region 25.
[0012] A locking member 30 engages the free edge regions 15 and 25. The locking member 30
is generally cap shaped, and its edges 31 and 32 curve under the free edge regions
15 and 25 to enclose them. The locking member 30 can be fitted by sliding it longitudinally
relative to the two angle sections 1 and 2. The locking member is preferably of such
a shape and size that, when fitted, it holds the angle sections 1 and 2 rigidly together.
[0013] The lower portions 12 and 22 can be maintained spaced apart by various means, such
as blocks or lengths of wood or other material. a continuous U-shaped channel or intermittent
flat or U-shpaed straps. The drawinq shows a U-shaped channel 40. In the case of such
a U-shaped channel 40 or intermittent strips formed of metal, they can be secured
by welding, although it is preferable if welding is avoided. One possibility is to
design the angle sections 1 and 2 and the locking member 30 so that when the lintel
is assembled and unstressed, the portions 12 and 22 converge slightly from top to
bottom. The channel 40, or other spacing means, can then be retained in place by the
resulting clamping action.
[0014] The lintel can be provided with a mesh 41 or similar means to act as a plaster key
for plaster 42.
[0015] The outer leaf of the wall can comprise, in known manner, bricks 45 and mortar 46,
whilst the inner leaf, supported on the flange 20, could comprise block work 47. Additionally,
a damp proof course 48 is provided. Typical dimensions of a cavity wall are given
in millimetres at the head of the drawing.
[0016] The two angle sections 1 and 2 can be made from different gauges of material, for
supporting different loads, bearing in mind that most imposed loads on the wall are
carried by the inner leaf. Furthermore, the two angle sections 1 and 2 can have different
finishes, for example the outer angle section 1 could be post-galvanised, whilst the
inner angle section 2 is only pre-galvanised.
[0017] If desired, the lintel can include a thermal break. The thermal break can be provided
by a layer of insulating material between the upper portions 14 and.24, and also by
a layer of insulating material between the locking member 30 and the free edge regions
15 and 25 to prevent heat transfer from one angle section to the other via the locking
member 30.
[0018] A further advantage of the lintel described is that, before assembly of the lintel,
the two angle sections 1 and 2 can be nested with each other and with the corresponding
parts of other similar lintels. This reduces the space occupied by the lintels during
transport and storage. It is envisaged that lintels as described could be delivered
to a building site in the knocked-down condition. Workmen on site could then assemble
lintels with the required dimensions and characteristics when they are called for
as work progresses.
[0019] In the modification of Figure lA the free edge regions 15A, 25A of the panels 11A
and 21A are slightly more steeply inclined than the regions 15, 25 of the panels 11
and 21 so far described and a locking member 30A replacing the locking member 30 described
above is of generally diamond configuration in section open along its lower edge.
When in its locking position the locking member 30A bears upon the upper portions
14A and 24A of the panels 11 and 21 approximately mid-way therealong. By gripping
the panels in this fashion the locking member 30A not only holds the panels together
but also acts to resist angular movement apart of the panels pivotting about the upper
edges of the upper portions 14A and 24A.
[0020] The construction of the angle sections 1 and 2 may be such that the portions 12 and
22 tend to diverge from each other from top to bottom when the locking member 30 or
30A is fitted. In such a case, a series of retaining straps may be provided along
the lenqth of the lintel, each strap beinq welded at one end to the flange 10 and
at the other to the flange 20.
[0021] In another modification, the clamping effect at the top of the lintel may be enhanced
by providing spacer plates distributed along the length of the lintel and disposed
between the portions 14 and 24. These plates may be retained in position by tack welding.
1. A lintel, suitable for use over an aperture in a cavity wall comprising two spaced
leaves, which lintel comprises first and second angle sections each of which comprises
a lateral flange for supporting, in use, a portion of a respective leaf of the cavity
wall above the aperture, and an upwardly-extending panel, characterized in that upper
free edges of the upwardly-extendinq panels are secured together by a locking member.
2. A lintel as claimed in claim 1, characterized in that each upwardly-extending panel
comprises:
a lower portion which extends substantially verticallv from the respective flange;
an intermediate portion which is inclined to the lower portion and which extends from
the lower portion towards the other panel; and
an upper portion which extends substantially vertically from the intermediate portion
and is adjacent the upper portion of the other panel.
3. A lintel as claimed in-claim 2, characterized in that, for each angle section,
the upper portion includes a free edge region which extends away from the upper portion
of the other angle section.
4. A lintel as claimed in claim 3, characterized in that each free edge region extends
downwardly and away from the other free edge region.
5. A lintel as claimed in claim 3 or 4, characterized in that the locking member is
substantially cap-shaped.
6. A lintel as claimed in claim 5, characterized in that the locking member is sheet-form
and in that free side edges of the locking member are curved so that they extend back
towards a centre of the locking member, so that the free edge regions of the angle
sections are enclosed by the locking member.
7. A lintel as claimed in claim 3 or 4, characterized in that the locking member is
of generally diamond configuration in section and is open along its lower edge, the
locking member gripping the upper portions of the panels at places spaced from the
upper edges of these upper portions to oppose angular movement apart of the panels.
8. A lintel as claimed in any one of the preceding claims, characterized in that the
angle sections are formed from sheet steel of different gauges.
9. A lintel as claimed in any one of the preceding claims, characterized in that one
angle section is formed from pre-galvanised steel and the other angle section is formed
from post-galvanised steel.
10. A lintel as claimed in any one of the preceding claims, characterized in that
the first and second angle sections are substantially symmetrical about a vertical
plane between them.
11. A kit of parts for assembly into at least one lintel in accordance with any one
of the preceding claims, the kit comprising, for each lintel to be assembled, the
first angle section, the second angle section and the locking member.