Note: Descriptions are shown in the official language in which they were submitted.
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_anel, in particular for self-_upporting roof structures
and self-supporting roof structures assembled of such
panels.
The invention relates to a panel, in particular
for self-supporting roof structures and of the type
consisting of extruded, preferably translucent, profile
elements of plastics material, expecially polycarbonate,
5 said el~ments having at least two longitudinal ducts
and coupling members making it possible to assemble the
profile elements side by side to form a continuous
surface, in particular a roof surface, requiring only
to be supported along two opposite ends.
US patent No. 3 886 705 discloses such a hollow
panel having a plurality of ducts mutually bounded by
partitions formed as I-beams and stiffened on both
sides by separate stiffening members. The side walls have
concave outer surfaces.
British patent No. 1 511 189 discloses a single
profile element, the duct of which is divided into two
parts by a partition extending substantially parallel to
the convex outer surfaces. The profile elements can be
assembled to form panels.
Such known panels are used in building structures,
e.g. walls and roofs. The former structure offers the
advantage of requiring less assembling operations for the
erection of a surface of a given dimension, but
drawbacks in connection with manufacture and load
25 carrying capacity have prevented it from gaining ground
in practice.
The second known structure is used to a large
extent but requires a greater number of assembling
operations for the manufacture of, e.g. a roof of the
30 same given dimensions as above. The fact that this known
panel element, owing to the presence of the intermediate
wall, possesses extremely good properties with regard to
heat insulation has resulted in the acceptance in
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practice of the drawback that it is only availa~le as
single profile element and not as a panel proper
comprising a plurality of adjacent ducts.
It is an object of the present invention to
provide a panel having none of the drawbacks of the
- known structures.
According to the invention this is achieved by
providing each of the profile elements with at least
two main ducts lying side by side, separated by an
intermediate secondary duct, each of the main ducts
being divided into two channels by means of a
substantially plane intermediate wall situated
approx;mately halfway between the external convex outer
surfaces of the profile element.
- The two partition walls bounding the secondary
ducts ensure a great stability of the panel during the
manufacture as well as in use. The cross-sectionally
mainly rectangular structure which has these partitions
as constituent parts does not like the known structure
tend to upset and collapse, unless special
stiffening members are used to absorb pressure at right
angles to the outer wall. The panel can therefore be
used as a roof surface in geographical areas where there
is a risk of considerable snow loads. The good
heat-insulating properties of the panel are of special
advantage in such areas.
The outer shape and the appearance of the
secondary duct correspond to the outer shape of that
duct, the ioining duct, which is formed when two panels
are assembled side by side. This constitutes an
advantage from an architectural point of view.
In a suitable embodiment of the panel according
to the invention, the secondary duct is divided into at
least three subducts by walls mainly parallel to, and
having substantially the same thickness as the outer
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walls. These intermediate walls are suitably disposed
in the vicinity of the plane of the outer walls, so as
to form a couple of smaller, mainly rectangular subducts
along the outer and the inner surfaces, separated by a
larger, oblong, rectangular duct. This design prevents
the secondary duct from acting as a heat sink, and
provides an additional strengthening of the structure,
the box-shaped profiles making the panel still more
resistant against a collapse of the wall of the
secondary ducts due to a load on, for instance, the
outer side of a roof surface.
When the panel is to be used in a self-supporting
roof structure, its design shows a curvature in the
longitudinal direction, and it is supported only at
its two extremities. In order to reinforce such
self-supporting structures against pressure loads, metal
bands may, in a manner known per se, be inserted as
reinforcing members in the joining ducts instead of the
usual locking wedges. In the new panel structure,
corresponding reinforcements can be dispensed with
in the secondary ducts, as their stiffness is in itself
sufficient.
It has, however, turned out that self-supporting
roof structures can be subjected to uplift forces on
account of wind loads on the under side, and therefore
one has, for reasons of security, abstained from using
the panels in some free-standing roof constructions.
With a view to avoiding this limitation in the use of
the panel, at least one of the subducts is, according to
the invention, dimensioned so as to allow the insertion
of an anchor bar which is able to absorb the forces
I originating from upwardly directed wind pressure. The
¦ anchor bars are, at their extremities, arranged to
be secured to supports, preferably so that said bars
can be under tensile stress.
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In a further embodiment according to the invention,
thesecondary duct is divided into four subducts by means
of three partition walls, one of which ~es on the same
level as the intermediate wall of the main ducts, while
the two others are spaced, respectively, from the nearest
end wall of the secondary duct so as to form a subduct
of cross-sectional dimensions sufficient to allow the
insertion of a anchor bar in the duct. The provision
of a third intermediate wall on the same level as the
intermediate wall of the main ducts does not, in this
construction, result in a substantial decrease in
thermal loss due to a difference in temperature between
the outer surface and inner surface of the panel,
because two other intermediate walls are already
provided. The presence of the central intermediate wall
which, even in the case of cross loads, is only
subjected to tensile stress and, therefore, can be
thinner than the other walls, results in a substantial
reinforcement of the structure, owing to an important
reduction in the deformation of the side wall of the
secondary duct due to pressure loads on the outer side
of the panel.
One may find it natural to give each of the four
subducts of the secondary duct a rectangular cross-
section. It may, however, prove advantageous to giveonly the two outer suhducts a substantially rectangular
cross section, while the two intermediate subducts are
four-sided in cross section, have one common side on
the same level as the intermediate wall of the main
duct and have each one side parallel thereto and in
common with the two outer subducts, the two other
opposite sides forming an acute angle with each other.
Thereby is achieved a greater resistance to torsions
and skew loads.
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The invention relates furthermore to a self-
supporting roof structure composed of panels each
consisting of at least two, preferably three hollow
profile elements of thermoplastics material extruded in
one piece, said panels being along their sides provided
with assembling members in engagement with each other
to form a loc~ing duct and interlocked by means of
locking members inserted in the locking ducts. Each of
the hollow profile elements of the panels composing
this structure has convex outer surfaces which, together
with two mainly parallel lateral surfaces, form a main
duct of substantially rectangular cross-section, which
main duct is, by means of an intermediate wall extend-
ing in the longitudinal direction, divided into two
parallel ducts, the said lateral surfaces together with
corresponding lateral surfaces of an adjacent profile
forming secondary ducts which, by means of at least two
intermediate walls extending mainly parallel to the
outer surfaces, are divided into subducts of substanti-
ally rectangular cross-section. This roof structure
presents a number of advantages which make it suitable
for various purposes. Said structure is light, solid
and heat insulating, and it is labour-saving as far as
transport to the building site as well as panel
assembling are concerned. One achieves a simplification
already when using panels having two main ducts and an
intermediate secondary duct, but the assembling
operations are, of course, reduced in proportion to the
increase in the number of main ducts composing the paneL
Although it is possible to use panels having more main
ducts, a panel having three is, however, preferred when
the dimensions used are the usual ones, where each main
duct is about 8 x 5 cm, because such a panel is easier
to handle.
In the following, the invention will be explained
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in greater detail with reference to the accompanying
schematic drawing in which
Fig. 1 shows a prespective view of part of an
embodiment of a panel having three main ducts,
Fig. 2 shows an altered embodiment of a panel
according to the invention seen from the end,
Fig. 3 is a side view of part of a panel according
to the invention, with mounting members for securing
the panel to a support, and
Fig. 4 is a side view of part of a panel
according to the invention, with anchor bars for absorb-
ing wind loads on the under side of a roof surface.
The panel of the invention as shown in Fig. 1 is
manufactured in one piece by extrusion and is made of
plastics material, preferably polycarbonate. The
thermoplactics material may be translucent. The panel
may be used for building walls, but it is especially
dimensioned for roof surfaces intended to be
self-supporting, so that the panel only requires
support at its extremities.
The panel is hollow and may be provided with two
or more main ducts generally numbered 1, 2 and 3 but
designated in Fig. 1 as la, lb; 2a, 2b; 3a, 3b, since
each of the main ducts is divided into two channels by
means of an intermediate wall 4, 5 and 6, respectively.
Each of the main ducts 1, 2 and 3 is bounded by outer
walls 7, 8 and 9, respectively, inner walls 10, 11 and
12, respec~ively, and lateral walls 13, 14; 15, 16; and
~17, 18, respectively. The side wall 13 is provided at
the top and the bottom with corresponding coupling
means 19 and 20 of conventional type. The lateral wall
18 is provided with corresponding coupling parts 21 and
22. When assembling two adjacent panels, a part 21 of
one of the panels will engage with a corresponding part
19 on the other panel, while a part 20 will engage with
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a corresponding part 22, so as to form an assembly
which can be designated as an assembling duct and is
adapted to accommodate wedges or bands 38, the panels
being ihereby locked steadily together to form a
surface, e.g. a roof surface.
The lateral walls 14 and 15 form, like the lateral
walls 16 and 17, the walls of a secondary duct providing
a separation between the main ducts 1, 2 and 2, 3,
respectively. Each of the secondary ducts is divided
into four subducts of mainly rectangular cross-section
23, 24, 25 and 26, respectively.
The subducts 23 and 26 are externally bound by
walls having the same shape as the coupling members
20 and 21~ This design has mainly been chosen for
architectural reasons and may be departed from, if
this should prove suitable. The subducts 23 and 26 are,
furthermore, bound by intermediate walls 27 and 28,
respectively. As it will appear from the figure, these
subducts have a mainly rectangular cross-section.
However, an enlargment is provided which is sufficient
to allow the insertion of an anchor bar 29 so
dimensioned as to be able to neutralize the forces
arising from the wind load on the under side of a
self-supporting roof surface. The number of required
anchor bars depends upon the wind load in each
individual case. Fig. 4 shows how the anchor bar 29 by
means of a nut 30 abutting against an angle profile
31 can be set under tensile stress. The angle profile
31 is secured to a support 32, and between the angle
profile and the panels forming the roof surface a
profiled sealing strip 33 is inserted. The external,
lower part of the panel has been cut away so as to
provide a projecting part 34 preventing rain water from
reaching the angle profile.
The panel is shown as plane in Fig. 4 but when
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intended for use in a self-supporting structure, it will
be arcuate, so that it only requires support at each
extremity, for instance as shown in Fig. 4.
The anchoring proper of the roof surface
composed of the panels appears from Fig. 3 showing the
right end of a roof surface, the left end of which is
shown in Fig. 4. In Fig. 3, 35 is an angle profile
corresponding to the angle profile 31 of Fig. 4. An
anchor member 36 having substantially the shape of a
closed U is connected with the angle profile by means
of a screw 36a fastened in a threaded hole in the anchor
member 36. Along the angle profile 35 provision is made
of a suitable number of anchor members 36, and through
all of them is carried a tube 37, preferably of
aluminium, passing through holes in the lateral walls
of the panel. In cases where, as shown in Fig. 1,
provision is made of a combined strengthening and
locking member 38, said member is also provided with
holes 40 in both ends for the tube 37. The under side of
the panel rests on the angle leg of the angle profile
secured to the support. As the roof surface is
self-supporting and is only supported at each extremity,
no special measures are necessary in order to counteract
extensions and contractions due to temperature
variations.
In the embodiment of Fig. 1, the lateral walls of
the secondary ducts are parallel. It may, however, be
advantageous to choose other designs, one of which is
shown in Fig. 2. In this latter embodiment, two parts
30 14a and 14b of the lateral wall 14 form a small angle
with the other parts of the lateral wall 14. The lateral
wall 17 is provided with similar parts 17a and 17b. The
lateral walls 15 and 16 may be designed in the same or
a similar manner.
A structure of this type is adapted to absorb
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torsional forces resulting from irregular loads which
may occur if the snow accumulates at different places
on the roof surface.
The box profiles constituting the secondary ducts
give a great compressive strength and the intermediate
wall flush with the intermediate walls 4, 5 and 6 of the
main ducts prevents an outward bending of the vertical
lateral walls of the secondary ducts. The distance
between the secondary ducts is chosen so that it will
be natural, when walking on the roof, to step only on
the projecting, less yielding walls of the secondary
ducts. The wall thickness will normally be uniform
throughout the profile and be chosen in view of the
nature of the material and of the desired strength of
the product. The continuous intermediate wall 4, 5 and
6 extending through the main ducts and the secondary
ducts may, however, be substantially thinner, e.g.
less than half the wall thickness of the rest of the
panel, which saves a non negligible amount of material.
In the eJnbodiments shown, the continuous intermediate
wall is placed in the middle of the panel, which
results in no difference in the properties of the
panel, whether it is subjected to pressure loads on one
of the two outer walls or the other. In a plane
condition, it is therefore of no consequence whether
the panel is turned one way or the other.
In a suitable construction of the panel, one
lateral wall of each secondary duct is plane and
vertical, when the panel is mounted as part of a roof
surface, so that these lateral walls in particular
absorb the vertical pressure forces, while the opposite,
non plane lateral walls which are kept in place by the
intermediate walls are particularly active when skew
loads and torsional forces occur.
As it will appear from Fig. 2, the intermediate
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wall 27 is nearer the horizontal central plane of the
profile passing through the intermediate walls 4, 5 and
6 than the outer walls 7 and 8. This results in the
oblique lateral walls 14a of the secondary duct
absorbing a greater part of the tension occurring in
the intermediate wall 4, when the outer wall 7 is
subjected to a downwardly directed pressure.
Owing to the structure of the secondary ducts, it
is not necessary to insert reinforcing bars in these
ducts, which is both material- and labour-saving.
Building structures made of the panels according to
the invention are therefore cheaper and better than the
known structures, whether these are composed of profile
elements having only one main duct or panels having
three main ducts.
For the sake of clarity, Fig. 1 shows only a hole
40 in the locking member 38 but not corresponding
openings made in the lateral walls 13, 14, 15, 16, 17
and 18 of the panel. Further, the intermediate walls
are shown before they have been cut to give space for
the continuous tubular anchoring member 36, shown in
Fig. 3, and a closing member (not shown) inserted at
the extremity of each main duct with a view to
preventing free passage of air and penetratlon of
impurities.
Fig. 3 illustrates the anchoring of the panels at
one extremity by means of the anchoring members 35, 36,
36a and 37. A corresponding anchoring is provided for
absorbing pressure loads at the other extremity.
Likewise, Fig. 4 shows one end of the special anchoring
29, 30 intended for absorbing upwardly directed forces
occur~ing as tractive forces. The anchor bar 29 is
secured correspondingly at the other extremity~
