U.S. patent application number 17/171245 was filed with the patent office on 2022-08-11 for roof tile and a roof covering.
The applicant listed for this patent is Dal-Tile Corporation. Invention is credited to Terry Adams, Kyle Bartz, Claudio Caselli, Rahul Patki.
Application Number | 20220251841 17/171245 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-11 |
United States Patent
Application |
20220251841 |
Kind Code |
A1 |
Patki; Rahul ; et
al. |
August 11, 2022 |
ROOF TILE AND A ROOF COVERING
Abstract
A roof tile comprising a decorative layer, the decorative layer
comprising a ceramic body, and a support layer disposed below the
decorative layer, wherein the roof tile comprises an upper edge, a
lower edge which is opposite to the upper edge and two opposite
side edges, the opposite side edges being transverse to the upper
edge, wherein the roof tile comprises at least a first coupling
elements configured for being coupled to an adjacent roof tile in a
roof covering, and wherein the first coupling elements are provided
at least at one side edge of the roof tile.
Inventors: |
Patki; Rahul; (Richardson,
TX) ; Adams; Terry; (Dallas, TX) ; Bartz;
Kyle; (Heath, TX) ; Caselli; Claudio; (Dallas,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dal-Tile Corporation |
Dallas |
TX |
US |
|
|
Appl. No.: |
17/171245 |
Filed: |
February 9, 2021 |
International
Class: |
E04D 1/00 20060101
E04D001/00; E04D 1/28 20060101 E04D001/28; E04D 1/26 20060101
E04D001/26 |
Claims
1. A roof tile comprising: a decorative layer comprising a ceramic
body; and a support layer disposed below the decorative layer,
wherein the roof tile further comprises an upper edge, a lower edge
which is opposite to the upper edge and two opposite side edges,
the side edges being transversal to the upper edge, wherein the
roof tile further comprises at least a first coupling elements
configured for being coupled to an adjacent roof tile in a roof
covering, and wherein the first coupling elements are provided at
least on one side edge of the roof tile.
2. The roof tile according to claim 1, wherein the first coupling
elements are at least partially formed in the support layer.
3. The roof tile according to claim 1, wherein the support layer
comprises at least a portion extending beyond at least an edge of
the decorative layer.
4. The roof tile according to claim 3, wherein the first coupling
elements are at least partially formed in one or more of said
extending portions.
5. The roof tile according to claim 1, wherein the first coupling
elements are provided at opposite side edges, and wherein the first
coupling elements at opposite side edges have substantially the
same shape.
6. The roof tile according to claim 1, wherein the coupling
elements comprise an upward concave shape.
7. The roof tile according to claim 1 further comprising at least a
second coupling element that is at least partially formed in the
decorative layer.
8. The roof tile according to claim 7, wherein the second coupling
element in the decorative layer is at least partially formed in an
upper surface of the decorative layer.
9. The roof tile according to claim 7, wherein the second coupling
element is disposed at a predetermined distance from an upper edge
of the decorative layer.
10. The roof tile according to claim 9, wherein the predetermined
distance is less than half of a distance between the upper edge and
the opposite lower edge, preferably less than one-third of the
distance between the upper edge and the opposite lower edge.
11. The roof tile according to claim 7, wherein the second coupling
element in the decorative layer is in the form of a groove.
12. The roof tile according to claim 11, wherein the groove of the
second coupling element runs parallel to an edge of the decorative
layer.
13. The roof tile according to claim 7 further comprising a third
coupling element for coupling with the second coupling element of
an adjacent roof tile in the roof covering.
14. The roof tile according to claim 13, wherein the third coupling
element is provided in the support layer.
15. The roof tile according to claim 1, wherein the first coupling
element is in the form of an adhesive strip.
16. The roof tile according to claim 15, wherein the adhesive strip
comprises a pressure sensitive adhesive.
17. The roof tile according to claim 1, wherein the support layer
comprises a metal plate.
18. The roof tile according to claim 1, wherein the decorative
layer comprises a glaze coating of the ceramic body.
19. The roof tile according to claim 1, wherein the ceramic body
comprises porcelain.
20. The roof tile according to claim 1, wherein the roof tile
comprises a rectangular shape and a top decor imitating a plurality
of roof tiles.
Description
TECHNICAL FIELD
[0001] The invention further relates to a ceramic roof tile, i.e. a
roof tile comprising a ceramic body, preferably made of porcelain,
and to a roof covering comprising porcelain roof tiles.
BACKGROUND
[0002] US 2017/0218632, U.S. Pat. No. 10,618,156 and U.S. Ser. No.
16/100,900 disclose roof tiles having a body made of porcelain.
Such kind of materials improve the weather/frost resistance and
durability of the roof tile with respect to other kinds of ceramic
materials like red body ceramic, for example terracotta.
[0003] In order to improve waterproofness of the roof covering said
roof tile are installed above a polymeric underlayment that is
disposes below each row of roof tiles in the roof covering. In
practice, said row of the roof covering comprises one strip of
underlayment below multiple tiles so to impermeabilize the joint
between roof tiles on the same row. The placement and securing of
said underlayment provides is a time-consuming operation that slows
down the roof covering installation operation.
[0004] The present invention aims in the first place to provide an
alternative roof tile, of the aforementioned type, whereby,
according to various preferred embodiments, solutions are offered
for problems with roof tiles known in the art.
BRIEF SUMMARY OF THE INVENTION
[0005] In one aspect, the present invention provides a roof tile
comprising: a decorative layer comprising a ceramic body; and a
support layer disposed below the decorative layer, wherein the roof
tile further comprises an upper edge, a lower edge which is
opposite to the upper edge and two opposite side edges, the side
edges being transversal to the upper edge, wherein the roof tile
further comprises at least a first coupling elements configured for
being coupled to an adjacent roof tile in a roof covering, and
wherein the first coupling elements are provided at least on one
side edge of the roof tile.
[0006] In an embodiment, the first coupling elements are at least
partially formed in the support layer.
[0007] In an embodiment, the support layer comprises at least a
portion extending beyond at least an edge of the decorative layer.
In an embodiment, the first coupling elements are at least
partially formed in one or more of said extending portions.
[0008] In an embodiment, the first coupling elements are provided
at opposite side edges, and wherein the first coupling elements at
opposite side edges have substantially the same shape.
[0009] In an embodiment, the coupling elements comprise an upward
concave shape.
[0010] In an embodiment, the roof tile further comprises at least a
second coupling element that is at least partially formed in the
decorative layer. In an embodiment, the second coupling element in
the decorative layer is at least partially formed in an upper
surface of the decorative layer. In another embodiment, the second
coupling element is disposed at a predetermined distance from an
upper edge of the decorative layer. In an embodiment, the
predetermined distance is less than half of a distance between the
upper edge and the opposite lower edge, preferably less than
one-third of the distance between the upper edge and the opposite
lower edge, preferably less than one-quarter of the distance
between the upper edge and the opposite lower edge.
[0011] In an embodiment, the second coupling element in the
decorative layer is in the form of a groove. In an embodiment, the
groove of the second coupling element runs parallel to an edge of
the decorative layer.
[0012] In an embodiment, the roof tile further comprises a third
coupling element for coupling with the second coupling element of
an adjacent roof tile in the roof covering. In an embodiment, the
third coupling element is provided in the support layer.
[0013] In an embodiment, the first coupling element is in the form
of an adhesive strip. In an embodiment, the adhesive strip
comprises a pressure sensitive adhesive.
[0014] In an embodiment, the support layer comprises a metal
plate.
[0015] In an embodiment, the decorative layer comprises a glaze
coating of the ceramic body.
[0016] In an embodiment, the ceramic body is made of porcelain.
[0017] In an embodiment, the roof tile comprises a rectangular
shape and a top decor imitating a plurality of roof tiles.
[0018] These and other objects, features and advantages of the
present invention will become more apparent upon reading the
following specification in conjunction with the accompanying
description, claims and drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0019] The accompanying Figures, which are incorporated in and
constitute a part of this specification, illustrate several aspects
described below.
[0020] FIG. 1 represents a perspective view of a roof tile in a
first preferred embodiment, with a view on the front face of the
roof tile;
[0021] FIG. 2 represents an enlarged cross-section according to
line II-II in FIG. 1;
[0022] FIG. 3 represents an enlarged cross-section according to
line III-III in FIG. 1;
[0023] FIG. 4 represents an enlarged view of detail F4 of FIG. 3,
in an alternative of said first embodiment;
[0024] FIG. 5 represents a cross-sectional side view of part of an
installed roof covering with roof tiles of the first
embodiment;
[0025] FIG. 6 represents a perspective view of a roof covering
comprising roof tile according to the first preferred embodiment,
with a view on the front face of the roof tiles;
[0026] FIG. 7 represents an enlarged cross-section according to
line VII-VII in FIG. 6;
[0027] FIG. 8 represents an enlarged cross-section according to
line VIII-VIII in FIG. 6;
[0028] FIG. 9 represents a perspective view of a roof tile in a
second preferred embodiment, with a view on the front face of the
roof tile;
[0029] FIG. 10 represents an enlarged cross-section according to
line X-X in FIG. 9;
[0030] FIG. 11 represents an enlarged cross-section according to
line XI-XI in FIG. 9;
[0031] FIG. 12 represents a perspective view of a roof tile in an
alternative of said second preferred embodiment, with a view on the
front face of the roof tile;
[0032] FIG. 13 represents an enlarged cross-section according to
line XIII-XIII in FIG. 12.
DETAILED DESCRIPTION OF THE INVENTION
[0033] To facilitate an understanding of the principles and
features of the various embodiments of the invention, various
illustrative embodiments are explained below. Although exemplary
embodiments of the invention are explained in detail, it is to be
understood that other embodiments are contemplated. Accordingly, it
is not intended that the invention is limited in its scope to the
details of construction and arrangement of components set forth in
the following description or examples. The invention is capable of
other embodiments and of being practiced or carried out in various
ways. Also, in describing the exemplary embodiments, specific
terminology will be resorted to for the sake of clarity.
[0034] It must also be noted that, as used in the specification and
the appended claims, the singular forms "a," "an" and "the" include
plural references unless the context clearly dictates otherwise.
For example, reference to a component is intended also to include
composition of a plurality of components. References to a
composition containing "a" constituent is intended to include other
constituents in addition to the one named. In other words, the
terms "a," "an," and "the" do not denote a limitation of quantity,
but rather denote the presence of "at least one" of the referenced
item.
[0035] As used herein, the term "and/or" may mean "and," it may
mean "or," it may mean "exclusive-or," it may mean "one," it may
mean "some, but not all," it may mean "neither," and/or it may mean
"both." The term "or" is intended to mean an inclusive "or."
[0036] Throughout this disclosure, various aspects of the invention
can be presented in a range format. It should be understood that
the description in range format is merely for convenience and
brevity and should not be construed as an inflexible limitation on
the scope of the invention. Accordingly, the description of a range
should be considered to have specifically disclosed all the
possible subranges as well as individual numerical values within
that range. For example, description of a range such as from 1 to 6
should be considered to have specifically disclosed subranges such
as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6,
from 3 to 6 etc., as well as individual numbers within that range,
for example, 1, 2, 2.7, 3, 4, 5, 5.3, and 6. This applies
regardless of the breadth of the range.
[0037] Also, in describing the exemplary embodiments, terminology
will be resorted to for the sake of clarity. It is intended that
each term contemplates its broadest meaning as understood by those
skilled in the art and includes all technical equivalents which
operate in a similar manner to accomplish a similar purpose. It is
to be understood that embodiments of the disclosed technology may
be practiced without these specific details. In other instances,
well-known methods, structures, and techniques have not been shown
in detail in order not to obscure an understanding of this
description. References to "one embodiment," "an embodiment,"
"example embodiment," "some embodiments," "certain embodiments,"
"various embodiments," etc., indicate that the embodiment(s) of the
disclosed technology so described may include a particular feature,
structure, or characteristic, but not every embodiment necessarily
includes the particular feature, structure, or characteristic.
Further, repeated use of the phrase "in one embodiment" does not
necessarily refer to the same embodiment, although it may.
[0038] Thereto, the present invention, according to its first
independent aspect, relates to a roof tile comprising a decorative
layer, having at least a ceramic body, and a support layer disposed
below the decorative layer, wherein the roof tile comprises an
upper edge, a lower edge which is opposite to the upper edge and
two opposite side edges, said side edges being transversal to the
upper edge, wherein said roof tile comprises at least one first
coupling element configured for being coupled to an adjacent roof
tile in a roof covering and wherein said first coupling element is
provided at least at one side edge of the roof tile. Preferably
said roof tile comprises first coupling elements provided at
opposite side edges. Since the first coupling elements are provided
at side edges of the roof tile, they are directed of coupling each
other roof tiles on the same row of roof tiles in the roof
covering. In this way the joint between multiple tiles on the same
row in the roof covering can be reduced or deleted thereby
improving the waterproofness of the roof covering. Moreover, said
impermeabilization is obtained during the installation of the roof
tile without the need of any previous operation thereby improving
the speed of the roof covering installation. As another advantage,
easy installation is obtained, since the coupling elements may hold
the roof tile in place for attaching or fastening it to the
framework of the roof. Other advantages that may be obtained are
improved walking resistance, improved uplift wind resistance and/or
improved thermal insulation. Moreover, it is to be noted that by
installing the roof tile to the supporting structure of the roof
solely with the nails can cause leveling defects between roof tiles
of the same row. This leveling issue can cause aesthetic defects in
the roof covering and even expose the roof tiles to wind lift up.
The coupling between roof tiles cause the roof tiles to be properly
leveled each other.
[0039] Within the context of the present application, the term
"upper edge" refers to the edge that in use is directed to be
disposed in an upper position compared to the other edges. Said
upper row is intended to be disposed substantially horizontally in
the roof covering. The term "row of roof tiles" in the roof
covering refers to a succession of roof tiles that are placed one
beside the other along a substantially horizontal line.
[0040] Preferably, the first coupling elements can be partially or
completely formed in the support layer. In this way, in case said
coupling elements are destined to forming a mechanical coupling, it
may be possible to manufacture and shape said coupling elements in
a material that is tougher and/or more elastic or in general
showing properties that are more suitable for forming the coupling
element than the ceramic material of the body. In this way it may
also be simplified the manufacturing of the roof tile.
[0041] It is noted that the upper and lower edges as well as the
opposite side edges of the roof tile may be provided with coupling
elements. In particular in a preferred embodiment, the roof tile
can comprise at least one second coupling element and/or at least
one third coupling element. Said second coupling element and/or at
least one third coupling element may be, preferably, adapted to
couple an adjacent roof tile on a different row in a roof covering,
more preferably and overlapping or overlapped roof tile. In
particular said second coupling element is configured for being
coupled with a third coupling element of an adjacent roof tile.
Preferably said second and third coupling elements are disposed
close to, and preferably parallel to, the lower and the upper edges
of the roof tile respectively. Said second and third coupling
elements can provide for a simplified installation of the roof tile
since they can provide for an immediate and precise overlapping
between tiles belonging to different rows in the roof covering and
can help maintaining this position before fixing the roof tile to
the roof structure.
[0042] In a preferred embodiment said second coupling element can
be at least partially provide on, more preferably formed in, the
decorative layer, for example in the upper surface of the
decorative layer. More preferably, said second coupling can be made
in the ceramic body. In this way the second coupling element can
provide for a very precise overlapping between roof tiles of
different rows in the roof covering. For example, said coupling
element can be in the form of a groove realized in the decorative
layer.
[0043] Said second coupling element can be provided at a
predetermined distance from the upper edge, of the roof tile,
preferably of the decorative layer. In this way said predetermined
position can be selected in order to minimize or maximize the
overlapping the between the roof tiles. It is to be noted that
large overlapping provides for higher wind uplift resistance and
better impermeability of the roof covering, whereas reduced
overlapping provides for lower weight on the roof covering and a
reduced number of roof tile thereby reducing the cost of the roof
covering and speeding up the installation. Since due to the
coupling the wind uplift can be reduced and impermeability can be
improved it is generally possible, due to the invention to minimize
the overlapping. Preferably, said predetermined distance is less
than one half, more preferably less than one third, for example
equal to or less than 26% of the width of the roof tile, wherein
the width is defined as the dimension in a direction parallel to
the side edge.
[0044] It is also possible that the roof tile comprises a further
second coupling element that is substantially parallel to the side
edges. In this case, said further second coupling element is
configured for being coupled with one of the firsts coupling
element of an overlapping roof tile. This is preferably the case
when the overlapping tiles, i.e. belonging to different rows in the
roof covering, are disposed offset each other. In this way a
precise offset positioning of overlapping tile can be achieved
together with an improved impermeability. Preferably, the further
second coupling element runs along a limited portion of the width
of the tile, for example it runs substantially from the second
coupling element to the upper edge of the decorative layer.
[0045] Said third coupling element can be provided close, and
preferably parallel, to the lower edge of the roof tile. The third
coupling element can be adapted for coupling with an overlapped
roof tile, i.e. with a roof tile on a different row in the roof
covering that is disposed partially below the roof tile. In a
preferred embodiment the third coupling element is disposed
substantially in correspondence of said lower edge. In this way the
coupling of the third coupling element with the second coupling
element of an adjacent tile can provide for an extremely precise
positioning of overlapping roof tile. Moreover, said coupling can
further limit open interspaces between overlapping roof tiles
thereby improving impermeability. In a preferred embodiment, said
third coupling element can be at least partially, preferably
completely disposed below said decorative layer, in such a way to
be hidden from external view once coupled.
[0046] In an embodiment, at least one of the opposite side edges of
the support layer may extend beyond the ceramic body, for example
in such a way that its associated coupling element is situated,
partially or completely, beyond the ceramic body. In a preferred
embodiment, both the side edges of the support layer can extend,
partially or completely, beyond the ceramic body for example in
such a way that their associated coupling elements are situated,
partially or completely, beyond the ceramic body. In this way,
during installation, coupling is simplified since the coupling
elements are at least partially visible and not hidden by the
ceramic body. In the most preferred embodiment, the at least one of
said coupling element extend only partially beyond the edge of the
decorative layer. In this way in a coupled condition, the
decorative layers can be closer each other thereby reducing a gap
between said decorative layers and improving waterproofness of the
roof covering.
[0047] The roof tile can be such that in a coupled configuration of
two roof tiles in the same row, an interspace is established at
least between the decorative layers, preferably such that the
decorative layers are placed at a determined distance each other.
In this case, it is preferable that said determined distance
between the decorative layer is less than 5 mm, more preferably
less than 3 mm so as to not be visible from the outside. It is to
be noted that said determined distance is a consequence of the
configuration of the coupling element.
[0048] The aforementioned coupling elements may be performed
according to one or more of the following possibilities, inasmuch
these are not contradictory: [0049] the coupling elements are
provided with a locking system, which, in the coupled condition of
two of such roof tiles, is only active in a direction parallel to
the plane of the roof covering, preferably perpendicular to the
coupled edges, which means that the moving apart of two of such
coupled roof tiles in said direction is limited and possibly
prevented. In an example, the coupling elements concern hook-shaped
parts. [0050] the coupling elements are provided with a locking
system, which, in the coupled condition of two of such roof tiles,
is only active in the direction perpendicular to the plane of the
roof covering, which means that the mutual moving apart of two of
such coupled roof tiles in said direction is limited and possibly
prevented. In an example, the coupling elements concern a tongue
and groove coupling. [0051] the coupling elements are provided with
a locking system, which, in the coupled condition of two of such
roof tiles, is active in the direction parallel to the plane of the
roof covering and perpendicular to the coupled edges as well as in
the direction perpendicular to the plane of the roof covering,
which means that the moving apart of two of such coupled roof tiles
in said directions is limited and possibly prevented; [0052] the
coupling elements are free from locking systems. In an example,
these coupling elements define an overlap between the respective
layers of two of such coupled roof tiles. [0053] the coupling
elements provide for a click-type or snap-type coupling; [0054] the
coupling elements are configured such that they allow to couple two
of such roof tiles by means of a downward movement of one roof tile
with respect to the other, wherein with downward is meant a
movement in a direction that is substantially perpendicular to the
plane of the roof covering; [0055] the coupling elements are
configured such that they allow to couple two of such roof tiles by
means of a sliding movement of one roof tile with respect to the
other along a direction that is substantially parallel to the plane
of the roof covering, such as coupling parts of the dove-tail or
tongue and groove type; [0056] the coupling elements can comprise
adhesive adapted to fix a portion of an adjacent roof tile so that
moving apart of two of such coupled roof tiles in a direction that
is parallel and/or perpendicular to the plane of the roof covering
is limited and possibly prevented; in this case the adhesive can be
provided in form of a pressure sensitive adhesive; the adhesive
strip can be covered by a peelable sheet that is peeled off just
before installation of the tile.
[0057] In a first preferred embodiment, the coupling elements are
provided with a locking system, which, in the coupled condition of
two of such roof tiles, is only active in the direction parallel to
the plane of the roof covering and perpendicular to the coupled
edges, which means that the mutual moving apart of two of such
coupled roof tiles in said direction is limited and possibly
prevented, and wherein the coupling elements are configured such
that they allow to couple two of such roof tiles by means of a
downward movement of one roof tile with respect to the other. In
particular at least one of said coupling elements can be, for
example, upward concave shaped, for example in form of an upward
V-notch, or upward hook shaped, and being adapted to receive at
least a portion of the coupling element of the adjacent tile by a
downward movement. In this way, when they are coupled, locking
surfaces are formed between the coupling elements that limit or
prevent mutual moving apart of two of such coupled roof tiles a
direction parallel to the plane of the roof covering.
[0058] In a first preferred embodiment, the coupling elements on
opposite sides of the roof tile can have a similar shape,
preferably they both have an upward concave shape, for example in
form of an upward V-notch. This shape is relatively simple to
manufacture and provides for a sufficient locking. Moreover,
especially in case of the V-notch shape, the coupling elements can
be very easy to being coupled since the inclined wall of the
concave part can help insertion of one coupling element into the
other.
[0059] In the most preferred configuration of the first preferred
embodiment, the coupling elements on opposite sides of the roof
tile can be slightly different, especially in dimension, to
simplify coupling. For example, one of the two opposite coupling
element can show a deeper concavity than the other. Moreover, at
least one of said coupling element can extend only partially beyond
the edge of the decorative layer, so that the said decorative layer
partially overlaps the upward concave shape. In this way in a
coupled condition, the decorative layers can be closer each other
thereby reducing a gap between said decorative layers and improving
waterproofness of the roof covering. In this way it is also
possible that the portion of the lower surface of the decorative
layer that partially overlap the coupling element, in the coupling
condition, can form a locking surface that limit or prevent a
mutual movement of the rooftile in a direction that is
perpendicular to the plane of the roof covering.
[0060] In a second preferred embodiment the coupling elements are
in form of an adhesive strip. Said adhesive is adapted to fix a
portion, preferably a portion of a lower surface, of an adjacent
roof tile. In this case the coupling element of one roof tile does
not necessarily have to cooperate with coupling element of another
roof tile. For example, the adhesive can be thermosetting adhesive
or thermoplastic adhesive. In a preferred embodiment, said adhesive
can be a pressure sensitive adhesive, examples of pressure
sensitive adhesive are natural rubber PSA, synthetic rubber PSA,
acrylic PSA, silicone PSA, blends of different polymers etc. In a
preferred embodiment the adhesive is synthetic rubber based PSA.
Preferably, the adhesive can be covered by a peelable sheet or
lining that is adapted to be peeled off at the moment of
installation. In some examples the adhesive can be a low tack
adhesive to allow easy removal or substitution of a roof tile. For
example adhesive can show a tensile strength less than 1000 N/m,
preferably less than 700 N/m, even more preferably less than 30
N/m, for example comprised between 80 N/m and 270 N/m. Said
adhesive may be preferably directed upward, for example it can be
provided on an upper surface of the roof tile, in particular of the
support layer and/or of the decorative layer. This can be
especially the case when the first coupling element and/or the
second coupling element are in form of the adhesive strip. In some
embodiments said adhesive strip may be directed downward, for
example it is provided on a lower surface of the roof tile, in
particular of the support layer and/or of the decorative layer.
This can be especially the case when the first coupling element
and/or the third coupling element are in form of the adhesive
strip.
[0061] In this second embodiment, the extending portions of the
support layer provided with the adhesive strip can be substantially
flat.
[0062] Preferably said coupling elements can run, continuously or
discontinuously, substantially along the whole edge of the roof
tile. In this way, relative positioning of the coupling elements
and installation of the roof tile can further be simplified and a
water-tight seal obtained between adjacent tiles.
[0063] In case of coupling elements being present at the upper and
lower edges as well as at the opposite side edges of the support
layer situated below the ceramic body, the coupling elements at the
upper and lower edges may be of a different type than the coupling
parts at the side edges. However, in a preferred case, the coupling
elements on opposite sides may show substantially the same shape
and dimension, more preferably they can be slightly different,
especially in dimension, to simplify coupling. For example,
coupling elements on opposite side in the form of upward concave
shape can be one slightly smaller than the other for being easily
coupled together.
[0064] In some embodiments, the roof tile can comprise the coupling
elements adapted to form a mechanical coupling as well as coupling
element provided with the adhesive strip, for sake of example first
coupling element for mechanical coupling and second or third
coupling element in form of adhesive strip. It is also possible
that in some embodiments the coupling elements are provided by a
combination of mechanical coupling and adhesive strip. For example,
the coupling elements can be in form of an upward concave shape
wherein an adhesive strip is provided on surface of the upward
concave shape.
[0065] In a preferred embodiment, the support layer comprises a
portion extending beyond the upper edge of the decorative layer.
Said extending portion provide for a tough portion of the roof tile
that can be nailed or screwed to the roof structure so as not to
cause breakage of the ceramic body. In a preferred embodiment said
extending portion is free from any attachment hole and during
installation the nail or screw is forced through the support layer.
In this case, as it will be explained also below, the support layer
is made in a material and/or has a thickness that can be easily
perforated by the nail or screw. Moreover, by attaching the nail in
the support layer is also possible to reduce the overlapping
between the ceramic bodies of roof tile, thereby reducing the load
in the roof structure.
[0066] According to a preferred embodiment, said upper edge
corresponds to the length, i.e. the longest edge of the roof tile.
The inventors have found that by attaching the roof tile to the
roof structure close to the longest edge, the roof covering may be
composed of a relatively small amount of roof tiles, thereby
minimizing the number of joints present in the roof covering, in
particular between roof tiles in the same row, and consequently the
risk at water penetration.
[0067] According to an alternative embodiment, the roof tile is
provided with at least one attachment hole. Such attachment hole is
used to attach or fasten the roof tile to a roof structure or
framework of the roof, said framework for instance being formed by
battens. The attachment hole may be preferably a through hole. As
an advantage, the attachment hole allows a safe and secure
installation of the roof tile, for example by using nails, screws
or wires. Moreover, the attachment hole allows a simple and
efficient way to install the roof tile.
[0068] The attachment hole can be situated closer to the upper edge
of the roof tile than to the lower edge of the roof tile.
Preferably, the attachment hole can be situated at a distance from
the upper edge of the roof tile, as measured in the width direction
of the roof tile, which is smaller than 0.25 times the width of the
roof tile. As an advantage, the extent of overlap between adjacent
roof tiles in subsequent rows of the roof covering may be
minimized.
[0069] In this alternative embodiment, the roof tile can be
provided with a multiplicity of attachment holes, for example more
than 2, preferably less than 6. The inventors have found that three
attachment holes provide for a good balance between the desired
wind lift up resistance and speed of installation. The attachment
holes of said plurality can be aligned parallel to the upper edge
of the roof tile.
[0070] If the roof tile comprises attachment holes, it is
preferable that they are provided in the portion of the support
layer that extend beyond an upper edge of the ceramic body. In this
way the risk of breaking the tile during installation with nails
and or screws is reduced.
[0071] In an alternative embodiment, the attachment hole may be
present at least in the ceramic body of the roof tile. Accordingly,
for example when using nails or screws, pressure is exerted onto
the ceramic body for attaching it to the roof framework. Due to the
ceramic body being made of porcelain, the risk at any damage or
breakage of the roof tile, resulting from that pressure, may be
reduced. In this case the attachment can comprise a first portion
in the ceramic body and a second portion in the support layer.
[0072] In a further alternative embodiment, said support layer may
be offset with respect to the decorative layer in the length
direction of the roof tile and/or in the width direction of the
roof tile. In this further alternative embodiment, the support
layer comprises portions that extend beyond one side edge and/or
beyond the upper edge (or the lower edge) of the decorative layer,
whereas the decorative layer comprises portions that extend beyond
the opposite side edge and/or beyond the lower edge (or the upper
edge) of the support layer. In the coupled condition the extending
portion of the decorative layer is intended to overlap the
extending portion of the support layer. Preferably, in this further
alternative embodiment the coupling elements are in the form of the
adhesive strip. Alternatively, in this alternative embodiment, the
roof tile can be free from coupling elements, in this case the
support layer can be nailed to a supporting structure, but the
extending portion may provide for sufficient impermeability.
[0073] Preferably, said support layer is made of a material
different from ceramic or porcelain. The support layer may provide
additional functionalities to the roof tile. As an advantage, it
may be tailored, irrespective of the properties of the ceramic
body. Still another advantage is that such layer may hold pieces or
parts of the roof tile, which are damaged or broken off, due to
heavy wind or hailstorm for example, together. Said layer may thus
function as a safety layer to prevent shards from falling from the
roof. In a preferred embodiment the support layer can act as a
reinforcing layer or comprise a reinforcing element or being
attached to the decorative layer through a reinforcing element.
Said reinforcing element is preferably adapted to improve the
toughness, or impact resistance, of the ceramic body in this way
the thickness of the decorative layer can be reduced thereby
obtaining the best hail resistance performances while reducing the
weight of the roof tile and of the roof covering.
[0074] According to preferred embodiments, the reinforcing layer
may comprise a metal sheet, for example a steel or aluminum sheet
attached to the lower surface of the decorative layer. Preferably,
the ceramic body is compressed by the metal sheet. In this way,
since the ceramic body is in a compressive state, the impact
resistance is strongly improved, because the compression blocks the
propagation of cracks. Moreover, even in case of breakage, the
compressive state helps in disguising the visual effect of
superficial cracks. To achieve this goal, the metal sheet is first
stretched, for example by means of a mechanical or, preferably,
thermal stretching, and then is bonded to the ceramic body while
the metal sheet is still in the stretched state. Subsequently, the
stretch is released, by interrupting the mechanical solicitation or
by cooling the metal sheet itself, thereby establishing a
compressive state in the ceramic body. For example, the metal sheet
has a coefficient of thermal expansion higher than the coefficient
of thermal expansion of the ceramic body. Due to this solution, the
reinforcing element can be heated to a stretched state, and then it
is bonded to the ceramic body while it is still in the stretched
state and subsequently it is cooled down to retract and put the
ceramic body in compression.
[0075] Preferably the metal sheet can comprise an anticorrosion
alloy, like stainless steel, or comprise an anticorrosion coating,
for example of zinc, chrome, paint, glaze or a plastic film.
[0076] The metal sheet can be attached to the decorative layer with
an adhesive layer. Said adhesive layer can comprise one or more
glue. The resin can be a thermosetting adhesive or thermoplastic
adhesive. Examples of thermosetting adhesive are epoxy,
polyurethane, unsaturated polyester, vinyl ester, cyanoacrylate,
reactive hot melt. Examples of thermoplastic adhesive are hot melt,
polyester thermoplastic, acrylic resin, vinyl etc. in a preferred
embodiment the adhesive is a reactive hot melt polyurethane glue.
It is preferred that the adhesive is provided in an amount below
150 g/sqm, preferably below 50 g/sqm.
[0077] It is noted that in some embodiments, said adhesive for
fixing the support layer to the decorative layer can be the same of
the adhesive strip. Preferably, said adhesive for fixing the
support layer to the decorative layer can be different from the
adhesive strip.
[0078] In an alternative embodiment, said support layer may be made
of one or more of the materials selected from the group consisting
of: a thermoplastic polymer, such as polyvinylchloride,
polyethylene, polypropylene and/or polyethylene terephthalate, a
thermosetting polymer, such as polyurethane, and/or an elastomer,
such as rubber or a thermoplastic elastomer. In case polyethylene
is used as a material for said layer, high-density polyethylene or
HDPE is preferred, although the use of low-density polyethylene or
LDPE is not excluded. Another preferred material for the support
layer is PVC, in particular rigid PVC. The support layer may also
comprise a high amount of filler materials, preferably mineral
fillers such as calcium carbonate, talc, chalk, e.g. more than 30
wt % or more than 60% wt of such filler materials. The content of
filler should be preferably limited to less than 75 wt %,
preferably less than 65 wt % in order to avoid excessively
increasing the brittleness of the support layer. Thereto, the
support layer may preferably be made of SPC (solid polymer
composite) that relates to a polymeric board, preferably in PVC,
comprising solid particle filler, like limestone. If said support
layer is made of a polymer, the layer may comprise one or more
plasticizers. The one or more plasticizers may be present in an
amount of less than 20 phr and, in this case, preferably in an
amount between 5 phr and 15 phr. In this case, the support layer is
of the so-called rigid type. In an alternative, the one or more
plasticizers may be present in an amount of minimal 15 phr and, in
this case, preferably in an amount of minimal 20 phr. In this case,
the support layer is of the so-called soft type. It is to be noted
that a rigid polymeric support layer is preferable above a flexible
or soft polymeric support layer since it provides two main
advantages. The first advantage is that due to its rigidity the
support layer interacts with a reinforcing element, if any, thereby
enhancing the reinforcing effect thereof. The second advantage is
that a rigid support shows a limited thermal expansion coefficient
that is closer to that of the ceramic body, thereby providing a
higher stability to the ceramic body.
[0079] Preferably, the support layer is made a material having a
flexural modulus above 1.5 GPa, preferably above 3 GPa, more
preferably above 5 GPa, for example, approximately 8 GPa. Said
flexural modulus is preferably below 15, more preferably below 10
GPa. The support layer may also comprise a flexural strength
between 20 and 90 MPa, for example between 30 and 50 MPa. In fact,
the inventors have found that the rigidity of the support layer
helps absorbing the impact energy thereby improving the impact
strength.
[0080] In a particular embodiment, said support layer may be
foamed.
[0081] According to a further alternative embodiment the support
layer may be made of an inorganic material. For example, the
support layer may be made of cement, for example a Portland cement
board, preferably a fiber cement board. The support layer may be
also made of mineral board, like mica, magnesium oxide or other
mineral boards.
[0082] Preferably the thickness of the support layer is less than
10 mm, even more preferably less than 4 mm. In a preferred
embodiment of the invention wherein the support layer comprises a
metal sheet, it can show a thickness less than 1 mm, preferably
less than 0.7 mm even more preferably less than 0.5 mm. The metal
sheet may have a thickness greater than 0.1 mm, preferably greater
than 0.3 mm.
[0083] In a particular embodiment, the upper and lower surface of
said support layer may converge towards each other. As advantage,
the risk at breakage or damage of the roof tile, e.g. when walking
over it, may be significantly reduced. For example, the upper
surface of said support layer may be substantially parallel to the
lower surface of the ceramic body, whereas the lower surface of
said support layer may be configured such that, in the installed
condition of the roof tile, it is substantially parallel to the
slope of the roof. In particular, they may converge towards each
other in the direction towards the upper edge of said layer. In a
particularly preferred embodiment, the lower surface of said
support layer is arranged such that, in the installed condition of
two of such roof tiles in subsequent rows of the roof covering, the
lower surfaces of the respective layers of these two roof tiles
form a generally flat surface. In other words, the transition from
the lower surface of the support layer of one roof tile of these
two roof tiles to the lower surface of the support layer of the
other roof tile is flush or substantially flush. It is noted that
in case of such converging surfaces the thickness of said support
layer varies. In this case, where reference is made to the
thickness of said support layer, this thickness should be
interpreted as the average thickness of said support layer. The
same applies to the thickness of the roof tile.
[0084] Alternatively, the support layer can comprise a supporting
element that protrudes from the lower surface of the support layer,
or that protrudes from the plane of the support layer. Said
supporting element is configured to rest on the roof structure
adjusting the inclination of the roof tile in the roof covering so
that the risk of breakage or damage of the roof tile, e.g. when
walking over it, may be significantly reduced. Said supporting
element is preferably disposed closer to the upper edge of the roof
tile than to the lower edge. Preferably said supporting element is
disposed below the decorative layer. In a preferred embodiment, the
supporting element runs substantially along the entire length of
the roof tile. The supporting element is preferred above a support
layer with converging surfaces in an attempt of reducing cost and
weight. Further, the support element is more adapted than the
converging surfaces solution for support layer with low thickness
like, for example, in the case of the support layer made of a metal
sheet.
[0085] As mentioned above the support layer, can be fixed to the
decorative layer through a reinforcing element. In a preferred
embodiment, the reinforcing element comprises a resin, for example
can be constituted by a resin. The resin can be a thermosetting
resin or thermoplastic resin. Examples of thermosetting resin are
epoxy, polyurethane, unsaturated polyester, vinyl ester,
cyanoacrylate. Examples of thermoplastic resin are hot melt,
reactive hot melt, polyester thermoplastic, acrylic resin, vinyl
etc. Preferably the resin is a rigid resin. In fact, the inventors
have found that a rigid resin, rather than flexible resin, shows a
higher absorption of the energy rather than flexible resin. In
particular, according to a preferred embodiment of the invention
the reinforcing element comprises an epoxy resin. In some
embodiment of the invention, the resin is a bicomponent resin, i.e.
a thermosetting resin obtained by curing at low temperature (for
example at room temperature) a mixture of two components, namely a
resin and a hardener. When the two components of the resin are
mixed together the curing reaction starts so that it is not
necessary to activate the cure by providing external energy, like
heat, UV or EB radiation. Said external energy could be optionally
provided in order to accelerate the curing process.
[0086] Moreover, according to a preferred embodiment, the resin
material permeates a lower surface of the decorative layer, in
particular of the ceramic body, and in particular an open porosity
thereof. The inventors have found that, due to this solution, the
impact resistance of the roof tile, is highly increased. Moreover,
in this way it is possible to improve the impact resistance of the
roof tile without the necessity to add further rigid or resilient
reinforcing elements like rubber layer, fiberglass or metal sheets.
In fact, the resin permeating the pores of the decorative layer
substantially improves the transmission and dissipation of the
impact stress through the roof tile so that a lower portion of said
energy is absorbed by the decorative layer improving the impact
resistance thereof. Since it is not necessary to add rigid
reinforcing elements, the resulting roof tile is lighter and
thinner. Moreover, the resin constitutes a hindrance to the
propagation of cracks in the decorative layer. Furthermore, in case
of superficial cracks of the ceramic body, the reinforcing layer
keeps the ceramic body itself coherent, and preferably compacted,
thereby disguising the visual appearance of the superficial
cracks.
[0087] According to a preferred aspect of the invention the resin
comprises a viscosity at 20.degree. C. less than 1000 mPas,
preferably less than 800 mPas, more preferably less than 600 mPas,
for example approximately 400 mPas. Within the scope of the
invention viscosity means the viscosity of the uncured resin, for
example the viscosity of the mixture of the two components before
the completion of the curing, i.e. during the so-called pot life.
In fact, the inventors have found that if the resin is sufficiently
fluid, during its application onto the back of the decorative
layer, it can permeate the pores thereof. In practice, when the
resin permeates the pores of the ceramic body it substantially
forms a "composite polymer-ceramic layer" that significantly
improves the impact strength of the decorative layer. Moreover, due
to the reinforcing layer here described it is possible improve the
impact resistance and fatigue behavior of relatively thin ceramic
body, thereby reducing the weight of the roof tile and improving
the maneuverability. It is noted that, according to a preferred
solution the resin is in a substantially liquid state during the
manufacturing process of the roof tile. It is possible that the
resin is in a pasty or gel state during the manufacturing process,
for example showing a thixotropic behavior in order to reach a
sufficient fluidity to permeate the pores of the decorative layer
under predetermined process conditions, for example during a
pressing step.
[0088] In some embodiments the resin may also show a shrinkage,
after curing, comprised between 0.5 and 15% for example between 1
and 10%. The inventors have surprisingly found that a resin showing
this characteristic during its curing retires significantly. Since
during curing the resin is the only component of the roof tile that
shrinks, it compresses the decorative layer disposed above thereby
reinforcing the ceramic body itself. This effect can be further
enhanced if the resin permeates the lower surface of the decorative
layer. In fact, if the resin of the intermediate layer permeates
the lower surface of the decorative layer the strong bonding within
the two layers helps the compressive action of the resin. Moreover,
this reinforcing mechanism due to the compressive action of the
resin may join the reinforcing action due to the filling of the
pores and the improved stress transfer mechanism.
[0089] This compressive effect is evident by measuring the bowing
of the roof tile, i.e. the planarity deviation thereof. Usually,
the planarity deviation of the ceramic body is reflected into the
bowing of the whole roof tile. The inventors have found that after
curing of the resin the roof tile shows a planarity deviation which
is higher than the planarity deviation of the sole decorative layer
before application of the resin. This means that the ceramic body
is compressed and reinforced. Therefore, according to a preferred
embodiment, after gluing the ceramic body a planarity deviation
less than 1.5 mm, preferably less than 1 mm, more preferably less
than 0.8 mm. Within the context of the present application, the
planarity deviation is defined as the height difference between the
extremal portion and the central portion of an edge of the
decorative layer. In particular within the scope of the present
invention the planarity deviation is measured by placing the
extremes of one edge of the decorative layer, on a horizontal plane
and measuring the distance between the middle of the edge from that
horizontal plane. According to an embodiment of the invention, upon
this compressive effect the planarity deviation of the roof tile
after gluing is at least 1%, preferably at least 5%, for example at
least 10% higher than the planarity deviation of the ceramic body
before gluing.
[0090] The inventors have also found that preferably the resin may
be free from fillers, like mineral fillers. In fact, the inventors
have found that the presence of fillers if on one hand improves
mechanical properties of the resin as such, on the other hand
increases the viscosity of the resin thereby forming an obstacle to
the permeation of the decorative layer. In case of presence of said
fillers, it is preferable that they are limited to less than the
10% wt of the resin.
[0091] The resin preferably comprises a tensile strength between 50
and 90 MPa, more preferably between 60 and 80 MPa, for example 75
MPa. It is noted that the resin preferably comprises a compressive
strength between 90 and 130 MPa, more preferably between 100 and
120 MPa, for example 110 MPa. The inventors have found that such
strength is sufficient to provide a rigid matrix for the composite
polymer-ceramic layer that allows dissipation of the impact energy.
It is also noted that the resin may preferably show a hardness
value of at least 50 measured on a Shore D scale. Preferably the
resin may comprise a Young modulus comprised above 0.5 GPa, more
preferably above 1 GPa. It may also be preferable that the Young
modulus is below 3 GPa, more preferably below 2 GPa. For example,
the Young modulus can be comprised between 1 GPa and 1.5 GPa,
preferably around 1.3 GPa.
[0092] Preferably the resin covers at least a portion of the lower
surface of the decorative layer, for example the majority, i.e. at
least 50 percent, of the lower surface of said decorative layer.
More preferably the resin covers 80 percent or more of the lower
surface of the decorative layer, for example it covers the 100
percent of the lower surface of the decorative layer so that the
effect of distribution and dissipation of the impact energy is
obtained for an impact occurring in any point of the decorative
layer. The resin is preferably provided onto the lower surface of
the decorative layer in an amount greater than 50 g/sqm, more
preferably greater than 100 g/sqm, even more preferably greater
than 150 g/sqm for example 220 g/sqm so that the resin is present
in an amount that is sufficient to fully permeate the open pores of
the lower surface of the decorative layer. It is also preferable
that the resin is provided in an amount less than 300 g/sqm, more
preferably less than 250 g/sqm.
[0093] It is also preferable that the resin is provided in an
amount sufficient to overflow from said open porosity in order to
act as a glue for the support layer. In other words, it is
preferable that the resin partially permeates the open porosity of
the decorative layer and partially coats the lower surface thereof
for forming an intermediate layer between the decorative layer and
the support layer and improving the transfer of energy. Said effect
of transfer of energy is further improved if the support layer is
directly fixed to the intermediate layer and, in particular, to
said portion of the resin that coats the lower surface of the
decorative layer, so that the intermediate layer acts as an
adhesive layer that bonds together the decorative layer and the
support.
[0094] Although according to a preferred embodiment of the first
possibility the reinforcing element is free from any filler or
rigid element, it is not excluded that according to some
alternative embodiments the reinforcing element can comprise a
rigid element for example at least partially embedded into the
resin material. The rigid element may comprise fibers like glass
fibers carbon fibers, polymeric fibers, for example aramid or
polyamide fibers, or ceramic fibers, for example boron or silicate
fibers. The fibers may be woven or non-woven fibers, for example
with fibers disposed at different orientations, and may be in in
form of mat, fleece or cloth. Fillers can also comprise mineral
such as calcium carbonate, talc, silica, mica, wollastonite, ash
and others. It is to be noted that in case of presence of rigid
element the reinforcing effect of the reinforcing layer can be
caused by the sole presence of the rigid element or by a
combination of the effects provided by the rigid element and the
resin.
[0095] According to a preferred embodiment of the present invention
the ceramic body is made of porcelain since porcelain provides for
a better frost and mechanical resistance with respect to other
ceramic material.
[0096] Although a ceramic body made of porcelain is a preferred
embodiment, it is noted that the system may alternatively comprise
a roof tile having a body of a red ceramic material, clay ceramic
or any other material used for roof covering, especially brittle
material like, for example, natural stone or slate.
[0097] According to a preferred aspect of the invention the ceramic
body may comprise, at least in correspondence of its lower surface,
an open porosity adapted to allow the resin to permeate the ceramic
body itself. Thus, according to a preferred embodiment of the
invention, the ceramic body may comprise an apparent porosity
between 0.1% and 10% determined according to ASTM C373, more
preferably between 2% and 8%, for example 6%. Since, the pores of
the material, especially the closed pores may represent weak points
of the material itself, it is preferable that the ceramic body
comprises an apparent porosity lower than 15%, preferably lower
than 10% measured according to ASTM C373. Furthermore, the ceramic
body may preferably have a volume of the open pores comprised
between 0.01 cc (cubic centimeter) and 1 cc, more preferably
between 0.10 cc and 0.90 cc, for example 0.60 cc. The
abovementioned ranges and values of apparent porosity provide the
optimum balance between intrinsic mechanical properties of the
ceramic body and the resin permeability thereof thereby providing
the best bonding between the resin without affecting the intrinsic
mechanical properties of the ceramic body. In this way the pores
are big enough to be filled by the resin while at the same time
they are sufficiently small to avoid compromising the mechanical
properties of the ceramic body
[0098] Preferably the roof tile further comprises a glaze coating,
which is situated above said ceramic body, i.e. at least on the
upper surface of the ceramic body. Hereby, it is noted that the
glaze coating is not necessarily situated directly above the
ceramic body, however, this is preferably the case. The glaze
coating contributes to the overall weather and frost resistance of
the roof tile, since water can mainly only be absorbed via the
edges of the roof tile. Another advantage is that the roof tile,
due to the presence of the glaze coating, may be provided with a
variety of textures, designs and colors. Other advantages that may
be obtained by the presence of the glaze coating are the prevention
or at least the minimization of moss grow, easy cleanability and/or
UV-resistance.
[0099] Further, according to an embodiment of the invention, the
glaze coating may cover at least one edge of the roof tile, for
example three edges of the roof tile. In particular, since the roof
tiles are destined to be installed partially overlapping
each-other, there can be always one edge, namely an upper edge,
that in use can be placed below another roof tile and that
consequently may not be exposed to weather and water. On the
contrary the other three edges can be exposed to weather and water.
By providing a glaze coating on said exposed edges the overall
weather and frost resistance of the roof tile is improved.
Preferably said exposed and glaze edges may be rounded or chamfered
edges, for example they may be bullnose edges.
[0100] In a preferred embodiment, the glaze coating comprises a
glaze layer of uniform color, which, in case of said glaze coating
comprising a print, is situated below said print. As advantage, the
glaze layer of uniform color may hide imperfections in the upper
surface of the ceramic body. Although the glaze layer of uniform
color is preferably of a white, beige or grey color, the glaze
layer may be of another color as well. In the latter case, the
advantage may be obtained that the ink lay-up, which is needed for
obtaining the desired colors in the aforementioned print, can be
lowered.
[0101] Preferably, the glaze coating comprises a transparent or
translucent glaze layer, which, in case of said glaze coating
comprising a print, is arranged over said print. By having such
glaze layer, the advantage may be obtained that the print can be
protected from wear. Other advantages that may be obtained by the
use of such transparent or translucent glaze layer are the
minimization of moss grow, easy cleanability and/or UV-resistance.
It is noted that the aforementioned glaze coating may be a
so-called wet or dry glaze. In a particular embodiment, the color
or appearance of the ceramic body substantially matches the color
or appearance of the front face of the roof tile. As advantage, no
major color or appearance differences are visible between for
example the edges of the ceramic body and the front face of the
roof tile.
[0102] In a preferred embodiment, said glaze coating comprises a
decor, which may simulate a natural product such as stone, natural
slate or wood. In the latter case, the decor may show wood grains
or wood nerves. As advantage, the roof tile may have the look of a
natural product such as natural slate or wood, while being provided
with better weather and frost resistance than roof elements that
are actually made of such materials. In a particular embodiment,
said decor comprises a print. In other words, the decor, or at
least part of the decor, is provided by means of a printer or
printing machine. Various techniques may be used to provide said
print, such as screen printing, rotary serigraphy or digital
printing, the latter technique being the preferred one. In case of
digital printing, an inkjet printer may be used, which may be of
the single pass type. In particular, a device similar to the one
disclosed in EP 1 038 689 A1 may be used, wherein each roof tile is
printed separately with a single pass of the roof tile underneath
the fixed print heads of the device. With such device, the
possibility is offered to print in certain areas of the upper
surface of the roof tile. For example, the device may be used to
print multiple images, each of these images being present in
respective areas of the upper surface of the roof tile. These
images may be separated from each other by means of intermediate
lines, transitions or edges, which are not necessarily provided by
means of printing, although this is not excluded.
[0103] Preferably, the front face of the roof tile represents or
forms an image of a plurality of roof tiles. In such case, the roof
covering may have the appearance of a conventional one, however,
with the advantage of being composed of fewer roof tiles. That the
roof covering is composed of fewer roof tiles allows reducing the
overall risk at water penetration. Indeed, the number of joints,
present between the roof tiles in the roof covering, in which water
might penetrate, may be minimized. For forming such kind of front
face, a decor with multiple images may be applied, e.g. with each
image representing a single roof tile. These multiple images may be
provided by respectively printing in certain areas of the upper
surface of the roof tile, as previously described. Thereto, a
device such as the device known from EP 1 038 689 A1 may be
applied. In such front face, the borders or transitions between
adjacent images of roof tiles may be represented by means of a
print or of a relief.
[0104] In case of the glaze coating being provided with a print, it
is advantageous that the ceramic body substantially matches the
general color or appearance of that print. Indeed, in that way, any
substantial contrast between the edges of the ceramic body and the
print may be excluded. For accomplishing that goal, the ceramic
body may be provided with one or more color pigments. The pigments
may then be chosen such that they provide the ceramic body with a
color or appearance that substantially matches the color or
appearance of the front face of the roof tile. It is noted that, in
general, the ceramic body may be provided with one or more color
pigments, irrespective of the ceramic body substantially matching
the color or appearance of the front face of the roof tile.
[0105] According to an alternative embodiment wherein the roof tile
comprises a ceramic body, the roof tile may be free from said glaze
coating and the body may comprise a body decor. For accomplishing
that goal, the ceramic body may be provided with one or more color
pigments. The pigments may then be provided into the body randomly
or according to a predetermined pattern or drawing. In this way the
body decor may represent a natural product such as natural slate or
wood. The body decor may also represent multiple images
substantially in the same manner described above with reference to
the glaze coating.
[0106] In an embodiment, the upper surface of the roof tile is
provided with a relief, which preferably is formed by a plurality
of excavations present in said upper surface of the roof tile. By
the relief, the texture of the roof tile, at the upper surface
thereof, may simulate the texture of a natural product such as
stone, natural slate or wood. In the latter case, the relief may
for example simulate the texture of wood grains or wood pores.
[0107] The relief or at least part of the relief may also concern
one or more chamfers present at the upper surface of the roof tile,
which may be provided at one or more edges of the roof tile. For
example, the relief or at least part thereof may concern a
chamfered perimeter of the roof tile, for example in the form of a
bullnose edge. In case of a decor with multiple images, the relief
may also be used to represent lines or transitions between these
images. For example, these lines or transitions may be represented
in the form of depressions in the upper surface of the roof tile,
situated between the images. Various possibilities may be applied
for providing the relief. Preferably, the relief is formed in the
upper surface of the ceramic body, in which case the relief
manifests itself through the glaze coating up to the upper surface
of the roof tile. Alternatively, the relief or at least part of the
relief may be formed in the glaze coating, such that it is situated
substantially or completely above the ceramic body. In case of said
glaze coating being provided with a print, said relief may be
performed "in register" with said print, which means that the
relief is in alignment with the print. By having the relief "in
register" with the print, the natural look or appearance of natural
products such as wood or natural slate is better simulated. For
example, in case the print is a wood pattern with lines simulating
wood grains, the relief may be formed by lines following the course
of said lines of the printed wood pattern or by a plurality of
successive dashes having a configuration following the lines of the
printed wood pattern.
[0108] For having the relief being performed "in register" with the
print, the techniques known from WO 2015/092745 A1 may be used.
[0109] In a particular embodiment, the lower surface of the roof
tile, and in particular of the ceramic body, is flat. More in
detail said lower surface is free from any structure or comprises a
relief structure having a depth or an height below less than mm,
preferably less than 0.5 mm, more preferably less than 0.2 mm. Due
to this feature the adhesion between the ceramic body and the
reinforcing layer is significantly increased.
[0110] Preferably, the thickness of the roof tile is less than 10
mm, for example less than 8 mm, more preferably less than 6 mm. The
thickness can be greater than 1 mm, preferably greater than 3 mm.
In fact, due to the reinforcing layer, it is possible to reduce the
thickness of the ceramic body and thus reduce the weight of the
roof tile itself.
[0111] In a preferred embodiment, the ceramic body forms at least
50%, more preferably at least 75%, and still more preferably at
least 90% of the thickness of the roof tile. In that way, the roof
tile has optimal advantage of the beneficial characteristics of
porcelain.
[0112] Preferably the roof tile, may have a weight expressed in
kg/sqm less than 20 kg/sqm, more preferably less than 15 kg/sqm,
even more preferably less than 10 kg/sqm.
[0113] The inventors have found that the roof tile may be made
relatively wide. For example, the length of the roof tile may be
larger than its width. Also, not necessarily combined with the
previous, the roof tile may be at least 350 mm wide and preferably
at least 500 mm long. That the roof tile may be made relatively
long, offers the advantage that the roof or roof covering may be
composed of a relatively small amount of roof tiles, thereby
minimizing the number of joints present in the roof covering and
consequently the risk at water penetration. Within the scope of the
present application the width of a roof tile is that dimension that
in use is intended to be disposed horizontal, i.e. parallel to the
roof ridge, whereas the length is that dimension that in use is
intended to be disposed inclined according to the slope of the
roof. It is to be noted that since due to the presence of the
reinforcing layer, the thickness of the ceramic body as well as the
weight thereof can be reduced, it is possible to further increase
the dimensions of the roof tile, in particular of width and/or
length, preferably length in such a way to further reduce the
number of joints between the tiles.
[0114] It is to be noted that a roof covering comprising a
plurality of roof tile forms an independent aspect of the
invention. Said roof tile can comprise one or more of the features
described in relation to the first aspect.
[0115] With the intention of better showing the characteristics of
the invention, in the following, as an example without any
limitative character, several preferred forms of embodiments are
described with reference to the accompanying drawings, wherein:
[0116] FIG. 1 represents a perspective view of a roof tile in a
first preferred embodiment, with a view on the front face of the
roof tile;
[0117] FIG. 2 represents an enlarged cross-section according to
line II-II in FIG. 1;
[0118] FIG. 3 represents an enlarged cross-section according to
line III-III in FIG. 1;
[0119] FIG. 4 represents an enlarged view of detail F4 of FIG. 3,
in an alternative of said first embodiment;
[0120] FIG. 5 represents a cross-sectional side view of part of an
installed roof covering with roof tiles of the first
embodiment;
[0121] FIG. 6 represents a perspective view of a roof covering
comprising roof tile according to the first preferred embodiment,
with a view on the front face of the roof tiles;
[0122] FIG. 7 represents an enlarged cross-section according to
line VII-VII in FIG. 6;
[0123] FIG. 8 represents an enlarged cross-section according to
line VIII-VIII in FIG. 6;
[0124] FIG. 9 represents a perspective view of a roof tile in a
second preferred embodiment, with a view on the front face of the
roof tile;
[0125] FIG. 10 represents an enlarged cross-section according to
line X-X in FIG. 9;
[0126] FIG. 11 represents an enlarged cross-section according to
line XI-XI in FIG. 9;
[0127] FIG. 12 represents a perspective view of a roof tile in an
alternative of said second preferred embodiment, with a view on the
front face of the roof tile;
[0128] FIG. 13 represents an enlarged cross-section according to
line XIII-XIII in FIG. 12.
[0129] FIG. 1 represents a perspective view of a roof tile 1
according to a first preferred embodiment of the present invention,
with a view on the front face of the roof tile 1.
[0130] The roof tile 1 is mainly rectangular and, in the
represented example, rectangular and oblong. Furthermore, the roof
tile 1 has an upper edge 2 and a lower edge 3, whereby, in the
installed condition of the roof tile 1, the upper edge 2 is
directed towards the top of the roof, whereas the lower edge 3 is
directed towards the bottom of the roof. Also, the roof tile 1 has
two opposite side edges 4-5. The length L of the roof tile 1 is
larger than its width W. The length L of the roof tile 1 may be at
least 250 mm and preferably at least 500 mm. It is to be noted that
the length L of the roof tile 1 correspond to an upper edge 2 and
the lower edge 3, and defines that dimension that is destined to be
placed horizontally in use. Consequently, the width W correspond to
the side edges 4-5.
[0131] The roof tile 1 comprises a decorative layer 6 and a support
layer 7 disposed below the decorative layer 6. The decorative layer
6 comprises a ceramic body 8, preferably made of porcelain, and has
an upper surface 9 provided with a decor 10. In the illustrated
example, said decor 10 represent a wood pattern. It is noted that
the decor 10 can represent stone, slate pattern or any other kind
of desired image. It is to be noted that the decor 10 is printed,
more preferably digitally inkjet printed using ceramic pigments.
Advantageously, the decor 10 represents or forms an image of a
plurality of roof tiles 1A-1B-1C-1D. In the example the borders or
transitions 11 between the roof tiles 1A-1B-1C-1D are simulated by
printed decor. Alternatively, said transition can be formed by
excavations, which form part of the relief at the upper surface 2
of the roof tile 1.
[0132] In the example shown in FIG. 1, the roof tile 1 comprises
attachment holes 12 for fixing the roof tile 1 to a roof structure.
In the example the attachment holes are advantageously made in the
support layer 7, in particular in an extending portion 13 of the
support layer that extends beyond an upper edge 14 of the
decorative layer 6. Said attachment holes are aligned parallel to
the upper edge 2 of the roof tile 1.
[0133] Furthermore, the roof tile 1 comprises first coupling
elements 15, for coupling with coupling elements of an adjacent
roof tiles, which are provided at the side edges 4-5 of the roof
tiles 1 itself. Preferably, said first coupling elements 15 are
provided in extending portions 16 of the support layer which extend
beyond side edges 17 of the decorative layer. Said first coupling
elements 15 extend substantially along the whole side edge 5 of the
roof tile 1. In the example both the side edges 4 and 5 of the roof
tile are provided with said first coupling elements 15.
[0134] FIG. 1 further shows that the roof tile 1 comprises a second
coupling element 18 that is provided in the upper surface 9 of the
decorative layer 6. In the example said second coupling element 18
is parallel to the upper edge 14 of the decorative layer 6 and runs
substantially along the entire length of the decorative layer 6
itself. The second coupling element 18 is disposed at a distance
from the upper edge 2 of the roof tile, that is less than one
fourth of the width W of the roof tile 1. The roof tile 1 comprise
also a further second coupling element 19 which is provided in the
upper surface 9 of the decorative layer 6 and that is disposed
parallel to the side edges 4-5 of the roof tile. Preferably, the
further second coupling element 19 runs substantially from the
upper edge 14 of the decorative layer 6 to the second coupling
element 18. The further second coupling element is intended to be
coupled with on first coupling element of an overlapping roof tile
1 when the roof tiles are disposed offset each other.
[0135] FIG. 2 shows, in an enlarged view, the section along plane
II-II of FIG. 1.
[0136] As shown in FIG. 2, the decorative layer 6 comprises a glaze
coating 20 of the ceramic body 8. The decor 10 is made in the glaze
coating 20. The glaze coating 20 comprises a background glaze layer
21 of uniform color, which is situated below the printed decor 10,
and a transparent or translucent glaze layer 2, which is arranged
over said printed decor 10. It is noted that according to
alternative examples the glaze coating 20 may be free from said
transparent or translucent glaze layer 22 and/or from said printed
decor 10.
[0137] The upper surface 9 of the decorative layer 6 is provided
with a relief, which, in the represented example, is formed by a
plurality of excavations 23 present in said upper surface 9.
According to the present embodiment the relief is formed in the
ceramic body 8 and manifest itself through the glaze coating 20,
although according to alternative embodiments (not shown) the
relief may be at least partially formed directly in the glaze
coating 20.
[0138] The thickness T of the decorative layer 6 is less than 12
mm, for example less than 8 mm, more preferably less than 6 mm. The
thickness T is greater than 1 mm, preferably greater than 3 mm.
[0139] The support layer 7 is in the form of a metal sheet 23.
Preferably, the metal sheet (or plate) 23 is made of steel. The
metal sheet 23 compresses the ceramic body 8 starting from the
lower surface thereof. In this way, since the ceramic body 8 is in
a compressive state, a major improvement in the impact resistance
is obtained. In order to achieve this goal, the metal sheet 23 is
firstly tensioned (stretched or elongated) by means of a mechanical
or thermal stretching action and is then arranged underneath the
ceramic body 8 while it is still in the elongated state. Then the
stretched condition is released, by interrupting the mechanical
stress or cooling the metal sheet 23, so as to cause compression of
the ceramic body 8.
[0140] According to a first preferred embodiment, the metal sheet
23 has a thermal expansion coefficient greater than the thermal
expansion coefficient of the ceramic body 8. Owing to this solution
the metal plate 22 may be stretched by means of heating so as to
expand in a substantially uniform manner in every direction. After
the metal sheet 23 has been arranged underneath the ceramic body 8
it may be cooled down so as to contract and cause compression of
the ceramic body 8.
[0141] The metal sheet 23 has a thickness less than 1 mm,
preferably less than 0.5 mm even more preferably less than 0.2 mm.
The metal sheet 23 has a thickness A greater than 0.05 mm,
preferably greater than 0.1 mm.
[0142] The metal plate 22 is attached to the lower surface of the
ceramic body 8 by means of an adhesive. Said adhesive is preferably
a reactive hotmelt polyurethane glue.
[0143] Preferably the metal sheet 23 is made in stainless steel,
galvanized steel or comprises a coating that protects the sheet
against corrosion.
[0144] As shown in FIG. 2, the first coupling elements 15 shows an
upward concave shape, preferably a V-notch. The first coupling
elements 15 on opposite side edges 4-5 have substantially the same
shapes, preferably are substantially the same. Due to this shape
the first coupling elements 15 can perform a locking according to a
downward movement.
[0145] FIG. 2 shows the most preferred configuration of a first
preferred embodiment, wherein the firsts coupling elements 15 on
opposite sides 4,5 of the roof tile 1 are slightly different,
especially in dimension, to simplify coupling. In fact the coupling
element 14 on the left side edge 4 of the roof tile shows a less
deep concavity of the upward concave shape compared to the opposite
first coupling element 15. Moreover, the first coupling element 15
on the right side edge 5 extends only partially beyond the edge 17
of the decorative layer 6, so that the said decorative layer 6
partially overlaps the upward concave shape.
[0146] In this way in a coupled condition, the decorative layers
can be closer each other thereby reducing a gap between said
decorative layers and improving waterproofness of the roof
covering. In this way it is also possible that the portion of the
lower surface of the decorative layer that partially overlap the
coupling element, in the coupling condition, can form a locking
surface that limit or prevent a mutual movement of the rooftile in
a direction that is perpendicular to the plane of the roof
covering.
[0147] FIG. 3 shows, in an enlarged view, the section along plane
of FIG. 1.
[0148] As shown in FIG. 3, the roof tile comprises a third locking
element 24 that is provided in the support layer 7 and that is
disposed below the decorative layer 6. In particular, the third
locking element 24 is disposed close to, preferably substantial in
correspondence of, the lower edge 3 of the roof tile 1. The third
coupling element 24 is adapted for boing coupled in the second
locking element 18 of an adjacent roof tile 1 that is partially
overlapping the roof tile 1. The third locking element 24 has an
upward concave shape to perform a locking in a downward
movement.
[0149] The second locking element 28 is in form of an upwards
concave groove open on the upper surface 9 of the decorative layer
6 to receive the third locking element 24 of an overlapping tile by
a downward movement.
[0150] FIG. 3 further shows that the roof tile 1 comprises a
supporting element 25 that is provided below the support layer 7.
In the example the supporting element 25 is disposed below the
decorative layer 6 so that it identifies the point of maximum
thickness of the roof tile 1. In the example, the supporting
element 25 is made directly in the support layer 7 by bending the
metal sheet 23. It is noted that in alternative embodiment the
supporting element 25 can be attached or fixed to the support layer
7. The supporting element 25 has the scope of supporting the roof
tile 1 on the roof structure to adjust its inclination on the roof
covering. In fact, because of overlapping between roof tiles 1,
each tile can be slightly inclined with respect to the roof slope.
Therefore, the supporting element 25 provides a support that
improves strength of the tile against walking load.
[0151] FIG. 4 represents an enlarged view of detail F4 of FIG. 3,
in a variation of said first preferred embodiment of the invention
wherein the support layer 7 is attached to the decorative layer 6
via a reinforcing element 26.
[0152] In this variation, reinforcing element 26 comprises,
preferably consists of, a resin material, for example a
thermosetting resin or thermoplastic resin. Examples of
thermosetting resin are epoxy, polyurethane, cyanoacrylate,
unsaturated polyester, vinyl ester or acrylic resin. It is to be
noted that in this example the reinforcing element 26 is
constituted by the resin. Examples of thermoplastic resin are
reactive hot melt, hot melt, polyester thermoplastic, vinyl etc.
Preferably the resin is a rigid resin. In particular, according to
a preferred embodiment of the invention the reinforcing element 26
comprises an epoxy resin. It is also preferred that the epoxy is a
bicomponent resin, i.e. a thermosetting resin obtained by curing at
low temperature (for example at room temperature) a mixture of two
components, namely a resin and a hardener.
[0153] The resin preferably comprises a tensile strength between 50
and 90 MPa, more preferably between 60 and 80 MPa, for example 75
MPa. Moreover, the resin preferably comprises a compressive
strength between 90 and 130 MPa, more preferably between 100 and
120 MPa, for example 110 MPa. It is also preferable that the resin
shows a hardness value of at least 50 measured on a Shore D
scale.
[0154] As illustrated the reinforcing element 26 covers the 100
percent of the lower surface of the ceramic body 8. The resin is
preferably provided onto the lower surface of the ceramic body 8 in
an amount greater than 150 g/sqm, more preferably greater than 200
g/sqm, for example 220 g/sqm.
[0155] As illustrated in FIG. 4 the ceramic body 8 comprises, at
least in correspondence of its lower surface, an open porosity 7
adapted to be permeated by the resin of the reinforcing element
26.
[0156] Thus, according to this second embodiment of the invention,
the ceramic body 8 comprises an apparent porosity between 0.1% and
10% determined according to ASTM C373, more preferably between 2%
and 8%, for example 6%. Furthermore, the ceramic body 8 may
preferably have a volume of the open pores 27 comprised between
0.01 cc (cubic centimeter) and 1 cc, more preferably between 0.10
cc and 0.90 cc, for example 0.60 cc.
[0157] Preferably, in order to properly flow into said open pores
27 the resin of the reinforcing element 26 comprises a viscosity at
20.degree. C. less than 1000 mPas, preferably less than 800 mPas,
more preferably less than 600 mPas, for example approximately 400
mPas. Within the scope of the invention "viscosity" means the
viscosity of the uncured resin, for example the viscosity of the
mixture of the two components before the completion of the curing,
i.e. during the so-called pot life.
[0158] In the variation of FIG. 4 said support layer 7 is made of
one or more of the materials selected from the group consisting of:
a thermoplastic polymer, such as polyvinylchloride, polyethylene,
polypropylene and/or polyethylene terephthalate, a thermosetting
polymer, such as polyurethane, and/or an elastomer, such as rubber
or a thermoplastic elastomer.
[0159] In the variation of FIG. 4, the support layer 7 is made of
PVC, in particular rigid PVC. The support layer 7 may also comprise
a high amount of filler materials, such as talc, limestone, chalk,
e.g. more than 30 wt % or more than 60% wt
[0160] Preferably the rigid PVC may comprise a flexural modulus
between 1.5 and 3.5 GPa, for example, approximately 2.6 GPa. The
support layer 30 may also comprise a flexural strength between 60
and 90 MPa, for example approximately 76 MPa.
[0161] In this alternative of a first preferred embodiment the
support layer 7 can comprise a thickness less than 10 mm, even more
preferably less than 4 mm.
[0162] It is to be noted that in this alternative of a first
preferred embodiment the resin of the reinforcing element 26 acts
as an adhesive that bonds together the ceramic body 8 and the
support layer 7.
[0163] It is to be noted that the support layer 7 of this
alternative of a first preferred embodiment can be made of
cement-based board or mineral based board like magnesium oxide
board. Moreover, the support layer 7 in the alternative can be a
metal sheet as in the example of FIG. 2, wherein because of the
presence of the reinforcing element 26, it is not necessary to
compress the ceramic body 8.
[0164] FIG. 5 represents a cross-sectional side view of part of an
installed roof covering 28 with roof tiles 1 according to FIG.
1.
[0165] The roof tiles 1 are attached or fastened to a framework (or
roof structure) 29 by means of nails 30, which are put in the
attachment holes 12.
[0166] The roof tiles 1 are installed in subsequent rows, of which
only a few are represented in FIG. 5, namely the subsequent rows
31A-31B-31C. In particular, the roof tiles 1 are installed such
that the roof tiles 1 of one row partially overlap the roof tiles 1
of a previous row. For example, the roof tiles 1 of row 31C and 31B
respectively overlap the roof tiles 1 of previous row 31B and 31A
respectively.
[0167] The overlap O between the roof tiles 1 of the respective
rows is less than 50%, preferably less than 35%. Or, in other
words, the roof tiles 1 of row 31C and 31B respectively overlap the
roof tiles 1 of previous row 31B and 31A, whereby the overlap O is
such that less than 35% of the roof tiles 1 of row 31A and 31B is
covered by the roof tiles 1 of row 31B and 31C respectively.
[0168] It is to be noted that due to the coupling elements 15, 18,
19, 24 the impermeability of the roof covering is improved so that
it is not necessary to place any underlayment below the roof tiles
1, thereby accelerating the installation of the roof covering
28.
[0169] FIG. 6 represents a perspective view of a portion of a roof
covering 28 according to the present invention, with a view on the
front face of the roof tiles 1.
[0170] FIG. 6 shows that in the roof covering 28 the roof tile 1 on
the same row 31A are coupled each other on the side edges 4-5 via
the firsts coupling elements 15. The roof tile 1 of the overlapping
row 31B are coupled to the roof tiles 1 of the row 31A, via the
firsts coupling elements 15 coupled to the further second coupling
elements 19, and the third coupling element 24 coupled to the
second coupling element 18.
[0171] Said couplings are shown in FIGS. 7 and 8 showing enlarged
views of sections along planes VII-VII and VIII-VIII
respectively.
[0172] As shown in FIG. 7 the coupling between first coupling
elements 15 of the two roof tiles 1 form first locking surfaces 32
that limit, preferably prevent, mutual movement of the roof tiles 1
in a direction substantially parallel to the plane of the roof
covering 28, i.e. the slope of the roof, and substantially
perpendicular to the side edges 4-5 of the roof tiles 1. As it is
shown, since one first coupling element 15 is partially overlapped
by the decorative layer 6 in this coupled condition is formed a
second locking surface 33 that limit or prevent a mutual movement
of the roof tiles 1 in a direction that is perpendicular to the
plane of the roof covering 28.
[0173] FIG. 7 further shows that in the coupled condition of the
roof tiles 1 in the same row 31A and intermediate space I is
established between side edges 17 of the decorative layers 6.
Preferably said intermediate space I is less than 5 mm, more
preferably less than 3 mm so to not be visible from the outside. As
it is shown the fact that one first coupling element 15 is
partially overlapped by the decorative layer 6 allows to reduce
said intermediate space I and to improve waterproofness of the roof
covering 28.
[0174] As it is visible from FIG. 7 the coupling between the first
coupling elements 15 may provide for an improved impermeability of
the roof covering 28 since there is no gap between the roof tiles 1
of the same row 31A. Due to the upward concave shape the first
coupling elements 15 in the coupled condition may also form a
draining channel for the draining of water to a gutter.
[0175] As shown in FIG. 8 the coupling between the third coupling
element 24 of the roof tile on the upper row 31B and the second
coupling element 18 of the roof tile 1 in the lower row 31A, allows
for precisely determine the relative position of the roof tiles 1.
In the coupled condition third locking surfaces 34 are formed
between the coupling element that limit, preferably prevent, mutual
movement of the roof tiles 1 in a direction substantially parallel
to the plane of the roof covering 28, i.e. the slope of the roof,
and substantially perpendicular to the upper and lower edges 2-3 of
the roof tiles 1.
[0176] It is noted that the limitation of said movement is
particularly useful during installation before the roof tiles 1 are
nailed to the framework 29.
[0177] FIG. 9 shows the roof tile 1 according to a second preferred
embodiment of the invention. The roof tile 1 in said second
preferred embodiment differs from that shown in FIG. 1 in that the
first coupling elements 15 are in the form of an adhesive strip 32
provided on the upper surface of the support layer 7 in
correspondence of the extending portions 16 of the support layer 7
that extend beyond side edges 17 of the decorative layer 6. The
adhesive strips 35 are configured to fix a lower surface of an
adjacent roof tile, preferably the lower surface of the support
layer 7 of an adjacent roof tile 1. In the example of FIG. 9
adhesive strips 35 are provided on both said extending portions 16
The roof tile 1 in this second preferred embodiment further differs
from the embodiment of FIG. 1 in that it is free from attachment
holes. A first preferred embodiment can be free from attachment
holes, as well as the second preferred embodiment roof tile 1 can
comprise attachment holes 12.
[0178] FIG. 10 shows that preferably the adhesive strip 35 is
covered by a peelable sheet 36 that ca be removed just before
installation. The adhesive in the adhesive strip is preferably a
pressure sensitive adhesive, for example natural rubber PSA,
synthetic rubber PSA, acrylic PSA, silicone PSA, blends of
different polymers etc.
[0179] FIG. 11 shows that in a second preferred embodiment, both
the second coupling element and the third coupling element are
absent. According to alternatives of said second preferred
embodiment that are not shown herein, the roof tile 1 can comprise
the second coupling element and the third coupling element which
can be as described in FIGS. 1 to 8 or in form of adhesive strip as
the first coupling elements 15.
[0180] FIGS. 12 and 13 shows an alternative of the second preferred
embodiment wherein the support layer comprises only one extending
portion 16 that extend beyond the side edge 17 of the decorative
layer 6. This alternative is particularly preferred since the
support layer 7 extends below substantially the entire lower
surface of the decorative layer 6 thereby reinforcing the entire
ceramic body 8, while at the same time it is possible to reduce the
intermediate distance I between the side edges 17 of the decorative
layers 6 of two adjacent roof tiles.
[0181] It is to be noted that in the second preferred embodiment of
the invention illustrated in FIGS. 9 to 11 and its alternative
illustrated in FIGS. 12 and 13, the support layer 7 can also be
made according to the alternative of the first embodiment
illustrated in Figure, and can comprise the reinforcing element
26.
[0182] It is to be noted that the drawings are merely schematic in
order to better explain the invention and they are not drawn in
scale.
[0183] Further, as is clear from the content of the description,
the present invention relates to one or more of the items as listed
below, numbered from 1 to 44:
1.--Roof tile comprising a decorative layer, having at least a
ceramic body, and a support layer disposed below the decorative
layer, wherein the roof tile comprises an upper edge, a lower edge
which is opposite to the upper edge and two opposite side edges,
said side edges being transversal to the upper edge, wherein said
roof tile comprises at least a first coupling element configured
for being coupled to an adjacent roof tile in a roof covering and
wherein said first coupling elements is provided at least at one
side edge of the roof tile. 2.--The roof tile according to item 1,
wherein said first coupling elements are at least partially formed
in the support layer. 3.--The roof tile according to any of the
preceding items, wherein the support layer comprises at least a
portion extending beyond at least an edge of the decorative layer.
4.--The roof tile according to item 3, wherein said first coupling
elements are at least partially formed in one or more of said
extending portions. 5.--The roof tile according to any of the
preceding items, wherein said first coupling elements are provided
at opposite side edges, wherein said first coupling elements at
opposite side edges have substantially the same shape, preferably
are the same. 6.--The roof tile roof tile according to any of the
preceding items, wherein said first coupling elements are
configured to limit, preferably prevent, mutual movement between
the roof tiles in a direction that is substantially parallel and/or
perpendicular to the plane of the roof covering. 7.--The roof tile
according to any of the preceding items, wherein said first
coupling element is in form of an adhesive strip. 8.--The roof tile
according to item 7, wherein said adhesive strip comprises a
pressure sensitive adhesive. 9.--The roof tile according to item 7
or 8, wherein said adhesive strip comprise natural rubber PSA,
synthetic rubber PSA, acrylic PSA, silicone PSA, blends of
different polymers. 10.--The roof tile according to any of the
items from 7 to 9, wherein said adhesive strip is covered by a
peelable sheet. 11.--The roof tile according to any of the items
from 1 to 6, wherein first coupling element is configured for
forming a mechanical coupling with the coupling element of an
adjacent roof tile. 12.--The roof tile according to any of the
preceding items, wherein said firsts coupling elements comprise an
upward concave shape. 13.--The roof tile according to any of the
preceding items, wherein it comprises at least a second coupling
element that is at least partially provided on, preferably formed
in, the decorative layer 14.--The roof tile according to item 13,
wherein the second coupling element in the decorative layer is at
least partially provided on, preferably formed in, an upper surface
of the decorative layer. 15.--Roof tile according to item 13 or 14,
wherein said second coupling element is disposed at a predetermined
distance from an upper edge of the decorative layer. 16.--Roof tile
according to any of the items from 13 to 15, wherein said
predetermined distance is less than 1/2 of the distance between the
upper edge and the opposite lower edge, preferably less than 1/3.
17.--Roof tile according to any of the items from 13 to 16, wherein
said second coupling element in the decorative layer is in form of
a groove. 18.--Roof tile according to any of the items from 13 to
16, wherein said second coupling element is in form of an adhesive
strip, preferably according to any of the items from 7 to 10.
19.--Roof tile according to item 17 or 18, wherein said groove or
strip of the second coupling element runs parallel to an edge of
the decorative layer. 20.--Roof tile according to any of the
preceding items, wherein it comprises a third coupling element,
preferably configured for coupling with the second coupling element
according to any of the items from 13 to 19 of an adjacent roof
tile in the roof covering. 21.--Roof tile according to item 20,
wherein said third coupling element is provided in the support
layer. 22.--Roof tile according to item 20 or 21, wherein said
third coupling element is in the form of a downward projection that
protrudes form a lower surface of the roof tile. 23.--The roof tile
according to 20 to 21, wherein said first coupling element is in
form of an adhesive strip, preferably according to any of the items
from 7 to 10. 24.--The roof tile according to any of the preceding
items, that comprises a supporting element that protrudes from the
lower surface of the support layer, or that protrudes from the
plane of the support layer. 25.--The roof tile according to item
24, wherein the supporting element is disposed closer to the upper
edge of the roof tile than to the lower edge thereof. 26.--The roof
tile according to item 24 or 25, wherein said supporting element is
disposed below the decorative layer. 27.--The roof tile according
to any of the item from 24 to 26, wherein the supporting element
runs substantially along the entire length of the roof tile.
28.--The roof tile according to any of the preceding item, wherein
the decorative layer is compressed by the support layer. 29.--The
roof tile according to any of the preceding item, wherein the
support layer comprises a metal sheet, preferably made of steel.
30.--The roof tile according to item 29, wherein the metal sheet
shows a thickness less than 1 mm, preferably less than 0.7 mm, even
more preferably less than 0.5 mm; for example the metal sheet may
have a thickness greater than 0.1 mm, preferably greater than 0.3
mm 31.--The roof tile according to any of the preceding item,
wherein the support layer is made of a thermoplastic material,
preferably PVC or PP. 32.--The roof tile according to any of the
preceding item, wherein the support layer comprises a filler,
preferably a mineral filler. 33.--The roof tile according to any of
the preceding items, wherein the support layer comprises a
thickness less than 10 mm, even more preferably less than 4 mm.
34.--The roof tile according to any of the preceding items, wherein
the support layer is attached to the decorative layer via a
reinforcing element that preferably acts as the adhesive bonding
together the decorative layer and the support layer. 35.--The roof
tile according to item 34, wherein the reinforcing element
comprises, preferably consists of, a resin, preferably permeating
an open porosity of the ceramic body. 36.--The roof tile according
to any of the preceding items, wherein the support layer comprises
an extending portion that extends beyond an upper edge of the
decorative layer. 37.--The roof tile according to any of the
preceding items, comprising one or more attachment holes,
preferably provided in the extending portion of item 36. 38.--The
roof tile according item 37, wherein the attachment holes are
aligned along the upper edge of the roof tile. 39.--The roof tile
according to any of the preceding items, wherein the upper edge
defines the length of the roof tile, preferably wherein the length
is longer that the width. 40.--The roof tile according to any of
the preceding items, wherein the decorative layer comprises a glaze
coating of the ceramic body. 41.--The roof tile according to any of
the preceding items, wherein the ceramic body is made of porcelain.
42.--The roof tile according to any of the preceding items, wherein
the decorative layer comprises a decor, preferably a digitally
printed decor. 43.--The roof tile according to item 42, wherein
said decor imitates a plurality of roof tiles. 44.--A roof covering
comprising a plurality of roof tiles according to the preceding
items.
[0184] While several possible embodiments are disclosed above,
embodiments of the present invention are not so limited. These
exemplary embodiments are not intended to be exhaustive or to
unnecessarily limit the scope of the invention, but instead were
chosen and described in order to explain the principles of the
present invention so that others skilled in the art may practice
the invention. Indeed, various modifications of the invention in
addition to those described herein will become apparent to those
skilled in the art from the foregoing description. Such
modifications are intended to fall within the scope of the appended
claims.
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