Note: Descriptions are shown in the official language in which they were submitted.
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A Lintel
Background and Field
The invention relates to a lintel.
A typical channel lintel comprises a horizontal base with upright side legs
along
both sides of the horizontal base. Masonry being supported sits within the
channel i.e. between the side legs and on the horizontal base. However, such
ict an arrangement is structurally not efficient.
Thus, it is desirable to provide a lintel which addresses at least one of the
disadvantages of the prior art and/or to provide the public with a useful
choice.
is Summary
In a first aspect, there is provided a lintel for spanning across an opening
defined by support structures, the lintel comprising an elongate lintel body
including an elongate base member; side legs extending from the elongate
20 base to define an elongate channel therebetween; a load bearing element
projecting from at least one of the side legs for supporting masonry elements;
end portions at ends of the lintel body for engaging with the support
structures,
and a plurality of protrusions disposed at least at the end portions.
25 The described embodiment is able to strengthen the lintel in view of the
protrusions. Further, the load bearing element is able to support masonry
elements and thus, no masonry is needed to fill up the channel leading to
material savings.
30 Preferably, the protrusions may be spaced apart from each other and
disposed
along the lintel body's length. Some of the plurality of protrusions may be
disposed on the base member and the others on the side legs.
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Preferably, each of the protrusions may be elongate and may have a protrusion
longitudinal axis which traverses a longitudinal axis of the lintel body.
Advantageously, each of the protrusions may be arranged to face inwardly
towards the channel.
Preferably, the load bearing element may include lip members projecting from
respective edges of the side legs and along the longitudinal axis of the
channel,
with the lip members arranged to support the masonry elements.
lo The
lintel may include a plurality of perforations and the plurality of
perforations
may be interleaved with respective ones of the plurality of protrusions. The
perforations may be circular or other shapes.
Other aspects may relate to a method of making the lintel of the first aspect
(for
example, making the protrusions of the lintel by embossing) or constructing a
masonry wall using the lintel of the first aspect.
It should be appreciated that features relevant to one aspect may also be
relevant to the other aspects.
Brief Description of the Drawings
Exemplary embodiments will now be described with reference to the
accompanying drawings, in which:
Figure 1 is a simplified view of a lintel spanning an opening according to
a first embodiment;
Figure 2 is an closed up perspective view of part A of Figure 1 to show a
section of the lintel more closely;
Figure 3 is perspective view of the section of the lintel of Figure 2 without
showing the masonry;
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Figure 4 is a cross-sectional view of the lintel of Figure 3 in a direction B-
B, and
Figure 5 is a partial sectional view of the lintel of Figure 3 in a direction
C.
Detailed Description of Preferred Embodiment
Figure 1 show a lintel 100 according to a preferred embodiment for spanning an
opening 200. The lintel 100 has end portions 102,104 which are supported by
support structures 202,204 defining the opening 200. As it can be appreciated,
the lintel 100 is arranged to bear load 206 above the opening 200 and in this
embodiment, the load 206 and the support structures 202,204 are formed from
masonry such as bricks, concrete units, building stones etc.
Figure 2 is a closed up view of part A of Figure 1 to show a section of the
lintel
100 more closely and Figure 3 is a perspective view of the section of Figure 2
without showing the support structures. Figure 4 is a cross-sectional view of
the
lintel of Figure 3 in the direction B-B, whereas Figure 5 is a partial
sectional
view of the lintel 100 in the direction C of Figure 3.
The lintel 100 is normally prefabricated and preferably made of steel or other
metal. The lintel 100 comprises an elongate lintel body 106 having a
longitudinal axis 108 which spans the opening 200 and the lintel body 106
includes an elongate base member 110 which is generally flat. The lintel body
106 further includes side legs 112,114 projecting uprightly along respective
sides of the base member 110 to define a generally U-shaped channel 116 (see
Figure 4).
The lintel 100 further includes a load bearing element for supporting masonry
and the load bearing element is arranged to project from at least one of the
side
legs 112,114. In this embodiment, the load bearing element includes lip
members 118,120 projecting inwardly and toward each other at approximately
right angles to the side legs 112,114. Each of the opposing lip members
118,120 has a width 'W' of about lOmm.
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The lintel 100 further comprises a plurality of protrusions 122 arranged to
strengthen or reinforce the structural strength of the lintel body 106. The
protrusions 122 are formed on the lintel body 106 and regularly spaced along
the longitudinal axis 108 of the lintel body 106 and centre-to-centre distance
between adjacent protrusions is about 30mm. The protrusions 122 are formed
on the base member 100 as well as the side legs 112,114 to form sets of
protrusions with each set 122a having one protrusion 122 on each of the base
member 100 and side legs 112,114 aligned along a common plane.
Each protrusion 122 is elongate, has a finite strip of length and a
longitudinal
protrusion axis 124 and in this embodiment, the protrusions 122 are arranged
such that the longitudinal protrusion axis 124 traverses the length or
longitudinal
axis 108 of the lintel body 106. The protrusion 122 has a protrusion width Pw'
of about 8mm (see Figure 5) with end radius of about 4mm to form the semi-
circular ends. As shown in Figures 4 and 5, the protrusions 122 are formed
inwardly facing the channel 116, preferably by embossing to create the concave
indentation of about 1 or 2mm depth. Needless to say, other dimensions are
possible.
The lintel body 106 further includes a series of perforations and in this
embodiment, the perforations are circular apertures 126 arranged as rows and
interleaved between the plurality of elongate perforations. Each row has two
circular apertures 126 on each of the base member 110 and the side legs
112,114. These circular apertures 126 are arranged to receive mortar to allow
greater bonding between the lintel 100 and sand-cement plaster finish applied
to the lintel 100.
In use, the lintel 100 is arranged to span the opening 200 as shown in Figure
1.
However, instead of masonry arranged within the channel 116, the masonry (or
load) 206 rests on the lip members 118,120 and thus, the lip members 118,120
are arranged to support the weight of the load 206 on top of the lintel 100.
The
load 206 acting on the lip members 118,120 is progressively transferred to the
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support structures 202,204 via the lintel body 106 (via the side legs 112,114
and the base member 110) and the ends 102,104 of the lintel body.
It has been found that the presence of protrusions 122 strengthens the base
5 member 110 and the side legs 112,114 to reduce the possibility of the
base
member 110 warping and/or the side legs 112,114 bowing or bending due to
the load at the base member 110 in contact with the support structures 202,204
and this results in a more efficient load transfer. The use of the protrusions
122
also obviates a need to increase the thickness of the lintel 100 or
fabrication
material stress grade in order to address these failure modes and thus, a more
economical use of materials may be achieved.
Indeed, the protrusions 122 enable the lintel 100 to support more load,
especially in situations with narrower openings 200 (and thus, the lintel 100
would be correspondingly shorter).
With the lintel 100 supporting the load 206 at the lip members 118,120 (and
not
within the channel 116), this offers further advantages:
i) indirect savings in weight and use of (or less use of) masonry since no
masonry needs to be used within the channel 116; and
ii) plaster as thin as 3mm (eg. skim coat situations) may be used for the
masonry units. This is not possible with conventional channel lintels
because side legs of such lintels would be located outside of the
masonry.
The lip members 118,120 may increase the load capacity of the lintel 100. For
example, the stiffness of a 60mm by 60mm (i.e. width and height) lintel 100
with
the 10mm lip members 118,120 is about 30% greater than a similarly sized
lintel with no lip members.
As explained above, the protrusions 122 on the side legs 112,114 helps to
increase the load capacity for shorter spans, and also help in plaster keying
or
bonding. The protrusions 122 may not be as superior as the perforations 126
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(since the protrusions 122 are "blind holes" and not through holes) which
allow
more mortar to penetrate and bond better but the protrusions still helps in
the
bonding process since mortar can fill (outside of) the protrusions 122.
The described embodiment should not be construed as limitative. For example,
in the described embodiment, the protrusions 122 are shaped as elongate finite
strips but other shapes are envisaged. Further, the protrusions 122 are
arranged with their longitudinal protrusion axis 124 running across the width
of
the base member 110 and up the side legs 112,114 to obtain maximum benefit,
but the protrusions 122 may be arranged in other orientations or directions,
such as parallel to the length or longitudinal axis 108 of the lintel body
106,
although this is not preferred.
In the described embodiment, the protrusions 122 are spaced from each other
and are disposed along the entire length of the lintel body 106 for ease of
manufacturing. This is also beneficial since the amount of end portions
102,104
of the lintel 100 which bear or rest on the support structures 202,204 is
usually
determined on site, based on the length of the lintel and the opening 200 etc.
However, it is envisaged that the protrusions 122 need only be formed at or
near the end portions 102,104 of lintel body 106 which rest on the support
structures 202,204 to achieve the advantage of load transfer efficiency and
thus, the protrusions 122 may not be formed throughout the entire length of
the
lintel body 106. Likewise, while it is preferred to form the protrusions 122
at both
the side legs 112,114, this may not be necessary, and in certain applications,
the protrusions 122 may only be formed on just one of the side legs 122,144 or
not on the side legs 122,144 and just at the base member 110.
In the described embodiment, the protrusions 122 are formed to face inwardly
toward the channel 116 but it is envisaged that the protrusions 122 may face
outwardly i.e. away from the channel 116.
The lip member's 118,120 shape and dimensions may change. For example,
while the described embodiment illustrates continuous lip members 118,120
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extending along the length of the lintel body which makes manufacturing
easier,
it is envisaged that the lip members 118,120 may include a series of discrete
members spaced from each other. The dimension of the lip members 118,120
may vary depending on size of the lintel 100 and application. There is no
.. specific limit on the lip member dimensions but if the lip members 118,120
are
too small, the effect and benefit may be limited, whereas if the lip members
118,120 are too large, the load transfer may not be efficient. Indeed, it has
been
found that the width W of the lip members 118,120 may be varied as a function
of the steel thickness and size of side legs 112,114 in order to achieve a
.. particular load transfer efficiency. For example, for 10mm wide lip members
118,120 may be useful for thickness of about 1mm of the lintel body 106 to
achieve optimum load transfer efficiency.
The lip members 118,120 project towards each other in the described
embodiment, but it is envisaged that the lip members 118,120 may face
outwards and away from each other.
The lintel 100 of the described embodiment includes the generally U-shaped
channel 116 but the shape of the channel 116 may vary. Indeed, it is envisaged
that aspects of the described embodiment may also be used for a "box lintel"
where the load bearing element may occlude the channel 116. For example, the
load bearing element may project from one edge of one of the side legs
112,114 and extend across to the other side leg 112,114 to create a box-like
lintel where load would still rest on the load bearing element.
Having now fully described the invention, it should be apparent to one of
ordinary skill in the art that many modifications can be made hereto without
departing from the scope as claimed.
