Title: "Composite cladding panel"

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The present invention relates to a composite cladding panel, comprising a pair of opposite plate-like elements in spaced relationship to form a gap therebetween, a layer of filling material within said gap, said layer extending crosswise between said plate-like elements that form the gap, and being in contact therewith, a laminar natural stone element lying on one of said plate- like elements and attached to the surface thereof that faces away from the gap, and a plurality of crosswise connector devices.

Particularly, but without limitation, the panels which the present invention is referring to, are designed for covering exterior walls of buildings, using appropriate means for fastening it to the underlying masonry substrate.

A variety of wall cladding panel structures are known in the art including, in addition to thermal and/or acoustical insulating elements, also surface decorative elements consisting of natural stone or marble plates of various natures and colors. These panels conventionally have four-sided shapes that can be arranged in side-by-side relationship to cover the whole surface to be cladded.

In prior art, the laminar natural stone element which is designed to be exposed in the cladding is previously attached to the underlying plate-like element of the pair of elements that form the gap mainly by means of an adhesive. Such fastening arrangement is sometimes complemented by hooks holding together the edges of the stone element and the underlying plate-like element, which conventionally consists of a metal sheet having various shapes or corrugations to increase bending resistance.

In either case, prior art panel structures feature no stable and secure connection between the natural stone element and the other plate-like element that contains the gap and that, by facing towards the wall to be cladded, is designed to be engaged with the devices for attachment

thereto for cladding.

In fact, while crosswise connection devices are provided between the two plate-like elements that both form the gap in which the filling material is held, the connection of the laminar stone element to the wall to be cladded, in prior art structure, is mainly committed to its gluing to the outermost plate-like element.

Therefore, prior art panels of the above type have the drawback of low reliability in holding the laminar stone element against the wall to be cladded, which leads to inadequate safety in terms of overall structural resistance.

The object of the present invention is to obviate the above drawbacks. Such object is fulfilled by a cladding panel as defined in claim 1 below.

The characteristics and advantages of the present invention will appear more clearly from the following detailed description of a few practical embodiments, which are illustrated without limitation in the annexed drawings, in which:

Figure 1 is a schematically perspective partly sectional view of a panel of the invention;

Figure 2 is a sectional view of the panel at a crosswise connector device of the invention, according to a first embodiment;

Figure 3 is a sectional view of the panel at the crosswise connector device of the invention, according to a second embodiment; - Figure 4 is a sectional view of the panel as shown in Figure 3, with the crosswise connector device in its mounted condition.

Referring to the above figures, numeral 1 generally designates the panel of the invention which, when conventionally arranged in side-by-side relationship with other panels of the same type, is adapted to provide cladding for a wall, such as the exterior wall of a building. The panel has a four-sided shape and comprises a pair of opposite plate-like elements 2

and 3 in spaced relationship to form a gap 4. The latter is preferably filled with a material having thermal and/or acoustical insulation properties, such as polyurethane foam, which forms a layer, generally designated by numeral 5, that extends from the element 2 to the element 3 and attaches to the surfaces thereof that face towards the gap. Crosswise connector devices, generally designated with numeral 6, are disposed between the plate-like elements 2 and 3 and extend through the layer 3 of filling material and the plate- like elements 2 and 3.

Figure 1 shows only one crosswise connector device 6, but it shall be understood that a plurality of devices are provided all over the panel 1 , and in such a number as required by the size of the latter which may conventionally be up to 310 x 170 cm and more. A laminar natural stone element 7 is attached to the plate-like element 3, i.e. to the surface facing away from the gap 4, and its surface size is substantially the same as the panel 1 or slightly larger.

Such element 7 may be a thin marble slab of any type and is designed to be the exposed side of the panel 1 in a wall cladding. The laminar natural stone element 7 may be advantageously provided with a glass or carbon fiber-based reinforcement layer attached to the panel surface designed to be unexposed, which layer is fixed to the body of the element 7 by means of particular resins, well known in the art, which possibly allows its thickness to be reduced up to five or six millimeters.

This reinforcement layer is not shown in the drawings because it is of conventional construction and known per se. The natural stone element 7 is attached to the plate-like element 3 with the interposition of a layer of glue 8 spread all over its surface.

The plate-like elements 2 and 3 are particularly formed of thin metal sheets embossed with conventional ribs such as those designated by 2a and 3a in Figure 1, to improve the bending strength of the panel. Particularly referring to Figure 2, it can be seen that the crosswise connector device 6 is a

rod-like member with an externally threaded cylindrical shank 9. At the end 9a, it engages with the laminar natural stone element 7 via an expansion device, generally designated by numeral 10, which fits into a recess 1 1 formed in the thickness of the element 7.

The recess 11, of substantially circular contour, has a closed bottom 12 and an opening 13 facing towards the element 3.

The recess 1 1 has at least one undercut 14 along at least part of its contour, against which the expansion members of the device 10 are designed to engage when driven, e.g. by a nut 16 on the threads of the shank 9.

A conventional expansion device 10 is the one sold under the name of "Keil" joint. It will be appreciated from the above that the laminar natural stone element 7 is firmly attached to the expandable device 10 and is thereby stably attached to the shank 9 of the crosswise connector device 6.

Still with reference to Figure 2, it can be seen that a threaded bushing 17 is fitted onto the shank 9 and extends through the plate-like element 2 in the hole 18 thereof, abutting against the outer surface of the element 2 via an end flange 19 which, in the illustrated embodiment, is provided in the form of a hex nut that can be used for tightening and loosening the bushing 17 on the threaded shank 9, thereby adjusting the length of the rod-like member composed of the shank 9 and the bushing 17.

This bushing 17 has an end opening 20 for access to its threaded hollow inside. Such opening 20 may be used, for instance, to attach the panel 1 to the means for fixation to the wall to be covered if the type of means allows to do so.

Referring to Figures 3 and 4, it can be noted that the crosswise connector device 6, in the second embodiment, differs from the embodiment of Figure 2 in that the bushing 17a has an end flange 19a having no axial opening. Thus, in this case, the panel fixation to the wall to be covered can be effected by different type of means different from those as mentioned above.

It can be appreciated from the above that, according to the invention, the laminar natural stone element is not only attached to the plate-like element 3 by gluing, but is also mechanically fixed to the expansion device 10 and thence to the end 9a of the shank 9. The latter is engaged via the flange 19 or 19a with the metal plate-like element 2, which in the panel structure forms the side facing towards the wall to be covered, whereby the natural stone element which is of considerable weight, in spite of its small thickness, is directly supported thereby and very close to the wall.

Therefore, according to the invention a composite wall cladding panel is obtained, which exhibits both a sturdy structure per se but also a considerably reliable fixation to the wall to be covered.

The invention is susceptible of being implemented in many other variant embodiments, in addition to those expressly illustrated above, according to the requirements of each application, within the scope of the annexed claims.