description
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. Title of the Invention
POLYCARBONATE ROOF PANEL HAVING REINFORCEMENT RECESS FOR COUPLING TO
SANDWICH PANEL
2. Applicant(s)
Name Nationality Address
DAN-PAL ISRAELI Mobile Post Upper Galilee 1224500
Kibbutz Dan, Israel
3. Preamble to the description
The following specification particularly describes the invention and the manner in which it is to be performed
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FIELD OF THE INVENTION
This invention relates to polycarbonate roofs panels adapted for interconnection
with so-called sandwich-type panels having outer metal skins.
BACKGROUND OF THE INVENTION
5 Sandwich-type panels formed by a structure consisting of two sheet metal skins
and a filler material are commonly used as roof and wall coverings. Each panel has at
opposite ends joints of complementary geometries thus allowing multiple panels to be
coupled end to end and fixed to the building structure using screws, which may be
visible or concealed. The metal skins are of course opaque so that such a structure is
10 used where light transmission is not an issue.
Also known are light-transmissive polycarbonate panels that are coupled to
sandwich-type panels for use on roofs and walls of industrial buildings in general,
whereby light can enter the building, while protecting the roof from inclement weather
and providing a degree of insulation to the upper part of the building.
15 EP 3 290 613 discloses a modular polycarbonate panel for roofs of buildings,
comprising a cell structure defining a plurality of chambers, such that a first side has at
least one tab defining a cavity that is suitable for being coupled to a second panel. A
second side of the panel is suitable for being coupled to a third panel and has a projection
defining a geometry complementary to the cavity defined by the tab of the first side. The
20 modular panel can be coupled to successive adjacent panels for covering a surface of a
roof or enclosure rapidly and safely while reducing the installation time.
The need to join polycarbonate panels and sandwich panels is particularly acute
when used for roofing applications since the polycarbonate panels may be transparent or
translucent to light while the sandwich panels are opaque. It is normal therefore to
25 employ a modular construction wherein several sandwich panels are interconnected and
at suitable intervals polycarbonate panels are interposed and must then be joined to the
respective sandwich panels on either side.
Fig. 1 shows a prior art polycarbonate panel 10 corresponding to the teachings
of EP 3 290 613 configured for coupling at opposite ends to respective sandwich-type
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panels (not shown). The polycarbonate panel 10 has a cellular body portion 11, a base
12 of which has an outwardly projecting flange 13 on one end and a depression 14 at the
opposite end. A projection 15 of generally trapezoidal shape projects upwardly from an
upper surface 16 of one end of the panel. The opposite end of the panel supports a jib
5 arm 17 an upper end of which supports a polyhedral tab 18 whose shape may be
complementary to that of the projection 15, and such that the respective base angles 
and  of the projection 15 and jib arm 17 are substantially identical. This allows
multiple panels to be joined end to end, the projection 15 constituting a male connection
and the shaped tab 18 constituting a female connector of complementary shape.
10 Fig. 2a shows a detail of a modular panel system 20 wherein a chain of seriesconnected sandwich panels 21 are coupled at opposite ends of the chain to respective
first and second polycarbonate panels 10, 10 by respective first and second coupling
members 22, 22. Each sandwich panel 21 is fixedly attached to a building structure 23
and has a projection 25 (constituting a male connector) projecting upwardly from an
15 upper surface 26 of the panel toward a first end and a tab 27 (constituting a female
connector) of complementary shape projecting upwardly at its opposite second end. The
tab 27 is shown schematically projecting upwardly from an edge of the panel bounding
the upper surface 26 and the second end of the panel. The tab 27 extends outwardly
away from the upper surface so as overlap the adjacent polycarbonate panel. Each of the
20 polycarbonate panels 10, 10 has at least one joining flange 28 as shown in Fig. 2b
toward each end projecting upwardly from the upper surface of the panel. A U-shaped
support 29 is secured to the building structure 23 by a screw 30 and serves to support an
end of the respective polycarbonate panel, while allowing it to thermally expand or
contract relative to the sandwich panel 21.
25 The first coupling member 22 has a planar support member 31 adapted for
attachment to the upward projection 25 of the sandwich panel 21. Conveniently this is
achieved by means of the same screw 32 that fixes the sandwich panel to the building
structure. The support member 31 may be bent to provide a side portion 33 that fits the
outer contour of the projection 25 thereby impeding water leakage and rotation of the
30 first coupling member 22. Projecting downwardly from the support member 31 is a
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socket 34 adapted for coupling to the upwardly projecting flange 28 of the first
polycarbonate panel 10. A similar arrangement is provided for fastening the tab 27 to
the upwardly projecting flange 28 of the second polycarbonate panel 10.
Fig. 3 shows a modular panel system 40 comprising a pair of juxtaposed
5 sandwich type panels 21, 21 one of which is coupled to a polycarbonate roof panel 10
by a coupling member 41 configured that when fixed to the sandwich panel 21 it
forms an outer contour that is identical to that of the two juxtaposed sandwich panels.
Each of the sandwich panels 21 and 21 is independently affixed to the structure 23 by
respective screws 42, and the seam between the two sandwich panels is covered by a
10 cap 43 that prevents water leakage. Likewise, where the sandwich panel 21 abuts the
polycarbonate panel 10 a cap 43 is mounted over the joint so that when viewed from
above all the seams appear identical. The caps 43 are snap-fitted on to the upward
projection of the sandwich panels and to the upwardly projecting flange of the
polycarbonate panel 10 so as to engage indents 44 formed at the base of the respective
15 projection or flange.
Fig. 4 shows pictorially part of a panel system 45 wherein a juxtaposed polycarbonate panel 10 and sandwich panel 21 are joined using a coupling assembly 50
formed of metal and shaped to engage an indent 51 in an upwardly projecting flange 52
of the polycarbonate panel 10 and fastened to the upward projection 25 of the sandwich
20 panel 10 by a screw 53. The coupling assembly 50 clamps the polycarbonate panel 10 to
the sandwich panel 21 and supports it against downward force applied to the polycarbonate panel 10 near the joint. The resulting joint between each pair of juxtaposed
panels be they sandwich-sandwich or sandwich-polycarbonate is covered by a sealing
cap 54. To this end, indents 55 are formed at the base of the respective projection or
25 flange and serve to engage corresponding shaped lips 56 at the lower rims of the caps
54, thus allowing the caps to be snap-fitted to each of the adjacent panels.
It emerges from the foregoing description that polycarbonate panels are known
having upwardly projecting flanges that have an indent such as shown in Fig. 4 shaped
for accommodating a rigid metal coupling element that is screwed to an adjacent
30 sandwich panel. In this case, the indent 51 is not formed at the base of the flange; nor
can it be since there is formed another indent 55 at its base for engaging the lips 56 of
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the cap 54. The indents 55 are configured to accommodate these lips in a snap-fit
engagement: they provide no structural support for the coupling element.
Likewise, there are known polycarbonate panels as shown in Fig. 1 having at
opposite ends an upwardly projecting trapezoidal flange and a tab or wing coupling
5 element. These are commonly used in the industry to connect to sandwich type panels in
roof structures supporting a plurality of juxtaposed opaque sandwich type panels with
interposed skylights formed of polycarbonate panels.
Furthermore, in all the panel arrangements described above, to the extent that
they provide support for the ends of the polycarbonate panels where they abut an
10 adjacent sandwich panel, the coupling elements are designed to provide this support.
This is true for the arrangements of Figs. 2, 3 and 4. But while the polycarbonate panel
of Fig. 1 is well supported by the polyhedral tab 18 on the upward projection of an
adjacent sandwich panel, which is sufficiently rigid to provide good support, it is
vulnerable at its opposite end where its upward projection 15 merely provides a seating
15 for the wing-type coupling element of an adjacent sandwich panel but is in no way
supported by the sandwich panel. It is to this vulnerability that the present invention is
directed.
Fig. 5 shows a perspective view of part of a roof panel structure. Sandwich
panels are laid lengthwise along purlins of which two are shown spanning the width of
20 the roof structure with an intermediate gap. The sandwich panels are, of course, opaque
and in order to admit light through the roof structure, transparent or translucent
polycarbonate panels are laid across the gaps. The purlins extend along the full widths
of the extruded panels, which can be several meters in length and extend in both
directions perpendicular to the purlins. The purlins are spaced apart at sufficiently close
25 intervals whereby the sandwich panels are rigidly supported between opposing purlins,
such that a person such as a construction worker can stand on the sandwich panels
without them buckling. However, the polycarbonate panels will buckle under a person’s
weight and therefore require additional support to prevent this, as well as to withstand
environmental and climatic loads such as snow and wind.
30 Prior art coupling arrangements are known that prevent or reduce buckling owing
to the different rates of thermal expansion of sandwich panels and polycarbonate panels.
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For example, WO 2020/039423 (corresponding to IL 261363) discloses a modular panel
system that includes adjacent polycarbonate and sandwich type panels, the polycarbonate
panels being fixed to a building structure. Various types of coupling members are
described that are attachable to both panels in such manner as to withstand forces applied
5 to either surface of the panel system while allowing the panels to thermally expand along
their common seams at different rates.
However, there is a need for a coupling arrangement for panels of a geometry
similar to the panel disclosed in EP 3 290 613 as shown in Fig. 1, commonly referred to
as a European-Type panel system, having a generally trapezoidal upward projection at
10 one end, wherein the coupling arrangement offers built-in reinforcement along the seam
between adjacent panels adjacent the trapezoidal projection so that the resulting roof
structure will better withstand a person’s weight without buckling.
Further, and more generally, there is a need, in the European-Type panel system,
as described in EP 3 290 613 to couple the joint between two adjacent panels such that
15 both panels will simultaneously support a downward force exerted on each of the panels
alone or on both together.
This need exist also when both panels are sandwich-type panels with the same
rigidity, so that when coupled, the load will be spread over a larger area, such that the
panels will buckle together, to a lesser extent, and no gap will be opened between them.
20 SUMMARY OF THE INVENTION
It is an object of the present invention to provide such a coupling arrangement.
This object is achieved in accordance with different aspects of the invention by a
panel and a panel system having the features of the respective independent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
25 In order to understand the invention and to see how it may be carried out in
practice, embodiments will now be described, by way of non-limiting example only,
with reference to the accompanying drawings, in which:
Fig. 1 shows pictorially a known polycarbonate roof panel adapted for coupling
to sandwich type panels;
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Figs. 2a and 2b show pictorially another known polycarbonate roof panel
coupled to a sandwich type panel using a coupling assembly;
Fig. 3 shows pictorially the same polycarbonate roof panel of Fig. 2 coupled to a
serial connection of sandwich panels such that all joints have an identical profile;
5 Fig. 4 shows pictorially another prior art polycarbonate roof panel coupled to a
sandwich panel and having a clip-on cap for sealing against rain;
Fig. 5 is a perspective view showing part of a modular panel system according
to the invention;
Fig. 6a is a sectional view in the direction A–A of Fig. 5 between adjacent
10 purlins;
Fig. 6b shows an enlarged detail part of a conventional sandwich panel having a
metal wing fastener along its length;
Fig. 6c shows pictorially a conventional saddle washer that may be used to
reinforce joints between adjacent panels;
15 Figs. 7 and 8 are enlarged details of an extruded projection and a female
connector along a length of an intermediate polycarbonate panel used for securing it to
an adjacent sandwich panel;
Fig. 9 is an enlarged detail of a coupling element; and
Fig. 10 is a sectional view in the direction A–A of Fig. 5 along a purlin showing
20 screws securing the panels to the purlins.
DETAILED DESCRIPTION OF EMBODIMENTS
In the following description of some embodiments, identical components that
appear in more than one figure or that share similar functionality will be referenced by
identical reference symbols.
25 Referring to Figs. 5 to 10 there are shown details of a modular panel system 60,
comprising at least one triad 61 of mutually juxtaposed panels, of which two outer
panels 62, 63 have a high rigidity relative to a third intermediate panel 65. Typically,
the outer panels 62, 63 are sandwich-type panels consisting of two sheet metal skins and
a filler material. Owing to the outer metal skins these panels are opaque and, in order to
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transmit ambient light, the intermediate panel is formed of light-transmissive
polycarbonate and is mounted edge to edge between the two outer panels.
The panels are supported on a roof structure comprising purlins 70, 70 that
extend along a width of the panels. The panels are typically extruded and are laid
5 lengthwise across the purlins, which are spaced apart at intervals that provide sufficient
rigidity to the sandwich-type panels to allow a person to stand on them without causing
damage or buckling. In Fig. 5 one of the sandwich panels 62 is elongated in both
directions to show more clearly that the drawing shows only that portion of the panels
supported between adjacent purlins. It also serves to distinguish between the width of
10 the panels along the length of the purlin and the length of the panels which extend
across multiple purlins.
As shown in Figs. 6a, 7 and 8, the polycarbonate panel 65 has a trapezoidal
projection 71 projecting upwardly from an upper surface 72 of the panel and extending
along a length of the panel toward a first side thereof 73 constituting a proximal side 74
15 of the projection 71. The projection 71 has an undercut 75 defining an internal recess
extending along a length of the panel on a distal side 76 of the projection. Although in
the figures the undercut 75 forms an overhang with the upper surface of the panel such
that the recess is located between the overhang and the panel surface, the recess may be
formed in the side wall of the projection at a higher location than the panel surface. At a
20 second side 77 of the polycarbonate panel 65 and extending along its length, there is
provided a wing-type female connector 78 projecting upwardly from an edge of the
panel bounding the upper surface 72 of the panel 65 and extending outwardly away
from the upper surface. It is to be noted that the female connector 78 is similar in form
and function to what is described in above-mentioned EP 3 290 613.
25 The polycarbonate panel 65 has an outwardly projecting flange 79 and a
depression 80 each extending along a length of the panel at a lower surface thereof on
the first side 73 and the second side 77 of the panel, respectively. It will be appreciated
that Fig. 6a shows only the coupling of each side of the polycarbonate panel 65 to
respective sandwich panels. In practice on both sides of the polycarbonate panel there
30 are multiple sandwich panels whose interconnection is conventional and not a feature of
the present invention. Likewise, the manner of coupling the polycarbonate panel 65 at
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its second side 77 to the sandwich panel 62 is conventional. The novelty of the
invention thus resides only in the modification of the first side 73 of the polycarbonate
panel 65 that allows it to be coupled to existing sandwich panels while providing greater
rigidity.
5 All of the sandwich panels 62, 63 are identical and have at one end a trapezoidal
projection 90 and at the opposite end a wing-type coupling element 91 (Fig. 6b) of
complementary shape both of which extend along the full length of the panel. Multiple
sandwich panels can therefore be juxtaposed with the wing-type coupling element 91 of
one panel overlaying the trapezoidal projection 90 of an adjacent panel, the two then
10 being secured to the purlins by screws that pass through both the wing-type coupling
element and the trapezoidal projection of the two adjacent panels. Optionally, each of
the sandwich panels 62, 63 may also have a depression 92 and an outwardly projecting
flange 93 each extending along a length of the panel at a lower surface thereof for
engaging the complementary flange 79 and depression 80 on the first side 73 and the
15 second side 77 of the polycarbonate panel 65, respectively.
Conventional coupling of the sandwich panel 63 to the polycarbonate panel 65
at its first side 73 requires only that the wing-type coupling element 91 of the sandwich
panel be mounted over the trapezoidal projection 90 of the adjacent polycarbonate panel
65 after which sufficiently long self-tapping screws 94 shown in Fig. 10 are used to
20 screw the resulting assembly to the purlins below. The joint is reinforced by interposing
between the screw 94 and the wing-type coupling element 91 a saddle washer 95, such
as shown in enlarged detail in Fig. 6c and sold, for example, under the name Baltic
Fasteners®, which is a trademark of Eurofast. The saddle washer 95 has a generally
trapezoidal aluminum profile lined with a foam layer, which adapts to the outer contour
25 of the wing-type coupling element 91 and prevents leakage. The result is that while the
second side 77 of the polycarbonate panel 65 is uniformly supported by the flange 93
and projection 90 of the sandwich panel 62, this is not the case at the first side 73 of the
polycarbonate panel 65, where the polycarbonate panel is vertically supported only at
the purlins and a worker standing on the polycarbonate panel 65 towards its first side 73
30 between purlins will cause the polycarbonate panel 65 to deform if not even break under
the weight. The same might also occur under the weight of heavy snow.
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The present invention allows the joint at the first side 73 to be reinforced
between purlins by clamping wing-type fasteners 96 over the wing-type female
coupling element 91. The fastener 96 may be formed of sheet material such as
aluminum, of generally complementary shape to the projection 71 of the intermediate
5 panel 65 and having a hook shaped lip 97 along a distal edge 98 of the fastener. The
wing-type female coupling element 91 is shown in enlarged detail in Fig. 6b. As shown
in Fig. 6a, showing a sectional view between adjacent purlins, the wing-type female
coupling element 91 fits over the projection 71 of the polycarbonate panel 65 and is
secured thereto using the fasteners 96 as described in further detail below. The wing-type
10 female coupling element 91 provides a waterproof seal between the adjacent panels
regardless of whether they are sandwich-sandwich or sandwich-polycarbonate. To this
end, it will be appreciated that the trapezoidal projections 71 and 90 of the polycarbonate
and sandwich panels 65 and 62, respectively, have similar if not identical contours.
Optionally, wing-type fasteners 96 may also be clamped over the wing-type female
15 coupling element 91 at the purlins using long screws that penetrate all the way through to
the purlins. However, as noted above, the panels are in any case supported at the purlins
so such reinforcement is not essential.
Fig. 9 is an enlarged detail of the coupling element 96 also showing part of the
underlying wing-type female coupling element 91, which projects from the sandwich
20 panels in known manner.
The depression 80 of the polycarbonate panel 65 accommodates the flange 93 of
the adjacent sandwich panel 62 and the flange 79 of the polycarbonate panel 65 is
accommodated within the depression 92 of the adjacent sandwich panel 63. As best
seen in Figs. 5 and 6a, at least one fastener 96 is affixed at its proximal edge 99 to the
25 upper surface 100 of the panel 63 at a location intermediate the purlins 70, 70 and is
resiliently mounted over the wing-type female coupling element 91 and the trapezoidal
projection 71 of the polycarbonate panel 65 so that its hook shaped lip 97 engages the
undercut 75 of the projection 71. As shown in Figs. 6a and 10 each of the fasteners 96 is
secured to the projection 71 of the polycarbonate panel by respective screws 94 and may
30 also be secured to the sandwich panel 63 by a screw 94 passing through a proximal
surface 101 of the fastener (see Fig. 9) into the sandwich panel 63. Optionally, fasteners
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96 may be similarly affixed at their respective proximal edges 99 to the upper surface
100 of the outer panel 63 at locations along its length coincident with respective spaced
apart purlins 70, 70 as shown in Fig. 10. However, this will not be absolutely necessary
if saddle washers are employed as described above. Likewise, the female connector of
5 the polycarbonate panel 65 accommodates the second projection 90 of an adjacent
sandwich panel and is secured thereto by respective screws 94, typically on top of a
saddle washer 95. Preferably, where the fasteners 96 are located directly above the
purlins 70, 70, the screws 94, are sufficiently long to penetrate the respective purlins
70, 70 thus allowing the panels to be secured to each other as well as to the building
10 structure with the same screws. In contrast, the screws securing the additional fastener
or fasteners located intermediate the purlins 70, 70 are short so that they do not
completely penetrate through the intermediate polycarbonate panel 65, since they would
then be visible.
Depending on the rigidity of the fastener 96, it may either be slid from the side
15 into the undercut 75 and then moved along to where it is anchored to the underlying
purlin or to a desired location intermediate the purlins; or, and preferably, it may be
snap-fitted on to the wing-type coupling element 91 and the underlying trapezoidal
projection 71 simply by pressing down whereby the hook shaped lip 97 splays apart
slightly and then springs back into the undercut 75. In either case, the fastener 96 must
20 be sufficiently rigid that when clamped to the trapezoidal projection 71, it supports the
polycarbonate panel 65. To this end, the wing-type female coupling element 91 of the
sandwich panel supports the fastener 96 as seen in Fig. 9 since the sandwich panel is
rigidly supported on the underlying purlins. Therefore, since the fastener 96 is mounted
on top of the wing-type female coupling element 91 it, too, is supported against any
25 tendency to sink owing to force applied to the polycarbonate panel near the trapezoidal
projection 71. So, in effect, the fastener 96 serves as a fixed anchor in space that
supports the hook shaped lip 97, whose upper surface rigidly engages the exposed edge
of the trapezoidal projection 71 within the undercut 75. Consequently, the
polycarbonate panel 65 is retained by the fastener 96 even when force is applied
30 vertically close to the seam between adjacent panels.
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During construction of a roof using these panels, the first sandwich panel 62 is
laid across the purlins as shown in Fig. 5. The polycarbonate panel 65 may then be laid
across the purlins with its depression 80 overlaying the flange 93 of the already laid
sandwich panel 62 and with its wing-type female connector 78 over the trapezoidal
5 projection 90 of the panel 62. Screws 94' are then employed to secure the two panels,
preferably on top of the saddle washers 95. The second sandwich panel 63 may then be
laid across the purlins so that its depression 92 overlays the flange 79 of the
polycarbonate panel 65. The respective hook shaped lip 97 of each of the fasteners 96 is
then clicked (or slid) into engagement with the undercut 75, and moved if necessary to
10 its desired location along the length of the panel relative to the adjacent purlins. It is
secured by the screws 94, 94'. The act of securing the fasteners 96 results in its
proximal surface 101 resting flush on the upper surface 100 of the sandwich panel 63. A
screw 94 may then be used to secure the proximal surface 101 of the fastener to the
panel 63.
15 Although the invention has been described with reference to both ends of the
panel structure, in fact the coupling of the second side 77 of the polycarbonate panel to
the adjacent first sandwich panel 62 is known per se from EP 3 290 613. The invention
resides in the manner of reinforcing the coupling of the first side 73 of the
polycarbonate panel to the adjacent second sandwich panel 63 and in a novel poly20 carbonate panel having an undercut and a fastener that cooperate to facilitate the
required reinforcement.
However, although the benefit of the invention is particularly pronounced for
polycarbonate panels whose rigidity is lower than sandwich panels, it is to be noted that
the same principle may also be applied to sandwich panels, which are provided with
25 similar projections that may be advantageously provided with an undercut recess and
whose interconnection may be reinforced using fasteners in like manner. Further, the
undercut recess may be also situated in the proximal side of the projection rather than in
the distal. And further, the undercut recesses may be formed at desired discrete
locations along the projection, rather than being continuous.
30 In this connection if we consider the seam between the two panels 62 and 65
shown in Fig. 6a, it will be appreciated that regardless of the material from which they
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are formed and whether they are formed of the same or different materials, the panel 65
is supported toward its second (i.e. right) side at both its upper and lower surfaces by
the lower flange 93 and the trapezoidal projection 90 of the panel 62. Consequently, a
downward force applied to the panel 65 near the seam between two adjacent panels will
5 be restrained by the flange 93 and the connection between the trapezoidal projection 90
and the wing-type female connector 78. However, a downward force applied to the
panel 62 at its left side will not be supported by the panel 65. Therefore, it may be
beneficial to provide an undercut recess such as 75 also to the trapezoidal projection 90
of the panel 62 so as to facilitate reinforcement also of the joint between the panels 65,
10 62, using fasteners such as 96. In such case, there will be provided a roof structure
comprising a European-Type panel system, all of whose panels have an undercut recess
in their trapezoidal projections and all of whose joints are reinforced using fasteners
such as 96