Note: Descriptions are shown in the official language in which they were submitted.
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ELONGATED METAL STRUCTURAL MEMBERS
Eield of the Invention
The present invention relates to elongated metal
structural members and in particular to such members for use as
studs in the framework of buildings.
Re~view of the Prior Art
It is of course extremely well known to construct
walls of a building by use of elongated vertical studs to which are
attached facing materials, such as plasterboard, particle board,
siding, etc. Such studs also provide support for window frames
and door casings and establish a cavity within which thermal in-
sulation may be located. The demand for load bearing steel stud
is growing, and in institutional, commercial and industrial
buildings, where steel studs are already in use, the market share
is growing due to the non-flammability of the studs. In the
residential markat, the increase in cost of wood and above all,
the dimensional stability of steel, has also increased the market~
ability of such studs. Steel studs usually are formed from sheet
material which is roll formed or otherwise bent to provide a C
cross-section. A problem with such studs however, is that the
metal has a much higher thermal conductivity than wood, and
generally they have permitted a greater heat flow from one surface
to the other than the equivalent wood stud. In order to reduce
thermal conductivity as much as possible, and also to reduce the
cost and weight of the steel studs, they are made from the thinnest
possible material that will provide the required structural
strength, and any reduction in thickness that is possible is
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highly desirable.
Definition of the Inven-tion
It is therefore an object of the present invention to
provide a metal structural member which thermal conductivity is
reduced whilst retaining the required structural strength.
According to the present invention there is provided an
elongated metal stud member roll-formed from an elongated metal
strip of uniform thickness comprising:
two spaced flange members extending generally parallel
to the longitudinal axis of the elongated member and to one
another and interconnected by a transverse web member integral
with said two spaced flange members;
said web member comprising a plurality of coplanar
straps traversing said longitudinal axis and inclined thereto to
define a plurality of apertures;
each of said straps having a pair of upturned edges
projecting out of the plane of said web at the perimeter of the
respec-tive apertures, therehy providing a channel of generally
U-shaped cross-section to increase the rigidity of the strap,
each of said strap edges varying in height along the length of
the respective strap, and being of maximum height at a point
located approximately midway between said flange members; and
said stud member elements being of the same uniform
thickness and requiring a minimal amount of metal -to minimise
thermal transmissivi-ty while providing structural strength.
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The use of ~s-traps having the defined channel
cross-section permits them to be thinner so that the heat flow
between the two flange members i9 reduced whilst retaining the
rigidity of the stud. The variation in height of the lips of
the strap, with the maximum height at a point located
approximately midway between the flanges, increases the rigidity
of the web.
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Description of the Drawings
Embodiments of the invention will now be described, by
way of example only, with reference to the accompanying drawings
in which:~
FIGURE 1 is a perspective view of a portion of a
structural stud;
FIGURE 2 is a side elevation of the stud of Figure l;
FIGURE 3 is a cross-section on the line 3-3 of Figure
2, showing surfacing material connected to one flange of the stud;
FIGU~E 4 is a plan view similar to Figure 2 of a blank
from which the member is formed, as it appe~rs prior to the step in
which the web member is finally formed;
FIGURE 5 is an end view showing a pair of the studs
shown in Figure 1 nested together to provide a composite stud; and
FIGURE 6 is a view similar to Figure 2 of an alternative
embodiment of the stud shown in Figure 1.
Referring now to the drawings, an elongated metal
structural stud 10 is formed to have a pair of spaced parallel
flange members or portions 12 and 14 respectively interconnected by
a transverse web member or portion 16. The web member 16 is formed
with a plurality of triangular-shaped apertures 18 which alternate
in their direction of extension, and so that each immediately adja-
cent pair of apertures borders an intervening strap 20, resulting in
a plurality of such straps 20 which traverse the longitudinal axis
indicated by LL in Figure 2 of the stud 10 and are inclined to the
axis. It will be seen that adjacent pairs of the straps 20 converge
toward one another to define with a cooperating one of
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the flange portions at their other en~s the respective generally
triangular aperture 18 in the web portion 16.
Each of the straps 20 is bordered by a pair of up-
turned edqes 22 which project therefrom perpendicular to the plane
of the webportion 16, 50 that each of the straps has a generally
U-shaped channel cross-section. The height of the edges 22 varies
progressively along the length of the straps 20 from each end to a
maximum at a point 24 approximately midway between the flange
portions 12 and 14. Each two immediately adjacent converging
straps merge smoothly together at their junction at the apex of
the respective aperture 18 while their opposite ends have between
them an elongated edge portion 26 parallel to the flange portionsO
The edges 22 of adjacent converging straps 20 merge smoothly with
one ano~her at the respective end where the straps 20 converge,
while the respective edges 22 are interconnected at their other
ends by inturned edges 28 extending from the respective elongate
edge portions 26 of the web member 16.
Each edge portion 26 is connected to an inner perpen
dicular planar portion 30, which forms part o~ the respective
flange portion 12 and 14. Respective outer perpendicular planar
portions 32 extend generally parallel to the respective inner
planar perpendicular portions 30 but are spaced therefrom and
connected thereto by respective planar parallel members 34, the
members 34 extending generally parallel to the plane of the web 16
but laterally spaced therefrom. An inwardly directed edge portion
or member 36 is formed at the opposite end of each of the outer
planar perpendicular portions 32, and serves to increase the
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rigidity of the respective outer planar perpendicular member.
The outer planar perpendicular member 32 of the flange
portion 12 has a greater width than the corresponding planar per-
pendicular member of the flange portion 14; the web portion 16 is
positioned to one side of a plane containing the mid-points of the
two planar perpendicular members 32 with the maximum height of the
lip 22 at the point 24 extending to this plane. This greater width
of flange portion 12 is such that flange portion 14 will fit snugly
wi~n flange portion 12, as shown in Figure 5, when two studs are
turned end-for-end. The inwardly directed edge portions 36 are
therefore offset as are the planar parallel members 34. This
enables a pair of studs 10 to be nested as shown in Figure 5 to
form a composite stud. The resulting composite stud is symmetrical
about the last-mentioned plane and provides a very rigid structural
member. The studs 10 however can be used individually as is shown
in Figures 2 and 3. It will be noted that each flange includes a
stepped portion constituted by connected portions 26 and 30. Each
flange cross-section comprising portions 30, 32 and 36 has a consid-
erable moment of ine ~ a about the major axis, and this moment is
further increased by the presence of the stepped portion. This
effect is particularly important at the end of a stud which can
therefore be cut to any random length. In addition the fact that
the plane of the web 16 is closer to thP central line than in a C
cross-section stud makes the stud more symmetric about the central
line and less prone to rotate under lateral loads, such as wind
loads. The outer surface of the outer perpendicular member 32
provides a support surface for facing material, such as panels 38
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(Fig. 3) which ~ay be secured to the surface by self-tapping
screws, indicated at 40. Facing material can also be attached to
the corresponding surface of the other perpendicular portion 32 to
provide a cavity wall installation. The provision of the apertures
18 in the web reduces the heat transmission between the flanges 12
and 14, whilst the provision of the edges 22 on the straps 20
ensures adequate rigidity and strength for the web portion 16. The
shape of the edges 22 ensures that they employ the minimum of
metal, while providing rigidity at the location where it is specific-
ally needed. It has been found that a web portion formed in this
manner is more rigid than, for example, a web provided with a
plurality of spaced longitudinally extending slots. The planar
parallel portions 34 will also provide support surfaces for window
and door frames or the like, so that the stud may be used with con-
ventional construction techniques.
A preferred method of production of the ~etal structural
members of the invention is by roll forming, a blank of the shape
illustrated by Figure 4 being first produced and thereafter the edges
22 being turned by a drawing operation. Thus, apertures 18 are
punched from the blank after the flange portions 12 and 14 have been
roll formed, the blank being cut so that the edges 22 and 28 are
continuous, the inner limits of the edges being shown in broken
lines in Figure 4. The tapering of the edges 22 from the points 24
towards the opposite ends of the straps 18 reduces the deformation
of material as the edges 22 are drawn to the position shown in
Figures 2 and 3, and thereby reduces the possibility of splitting
of the material. It has also been found that the provision of the
edges 28 enhances the rigidity of the stud even if it is cut
directly through an aperture 18. This again increases the utility
of the stud and makes it sufficiently versatile to be used on a
conventional construction site.
An alternative embodiment of the stud is shown in
Figure 6 in which the straps 20 are spaced further apart so that
the apertures 18 are generally trapezoidal in shape, the location
of the triangular apertures of the previously-described embodiments
being whown in broken lines ~or comparison. This further reduces
the transmission of heat through the stud but still maintains the
structural strength required for general construction purposes.
It will be seen therefore that a longitudinal structure
member has been provided which can readily be formed from sheet
material and in which the transmission of heat between the flanges
thereof is reduced whilst the overall rigidity of the member is
maintained.
