The present invention also refers to a procedure for obtaining tiles or panels with a base made from material generally consisting of a water, cement and powdered and granulated stone material based mixture and which presents a covering for example in marble, marble agglomerate, ceramic, glass, wood or other facing material on the visible surface.

The invention applies mainly to the manufacturing industry for the processing of marble, stone, granite and the like.

BACKGROUND ART Concrete tiles are particularly suited for the construction of floating or raised floors which normally present a reticular frame designed to maintain the tile in a raised position with respect to the ground in order to create a cavity which can house electrical ducts and/or water pipes.

A procedure is already known for obtaining concrete tiles or panels which foresees: - preparation of a mixture consisting of water, high-

resistance cement and a selection of crushed stone materials in the form of powder or granules of various sizes; batching of this mixture inside a pressing die; high-pressure pressing to form a single layer tile or panel; hardening of the tile or panel, generally by means of steam curing; subsequent dressing, polishing and chamfering operations.

The above-described procedure makes it possible to obtain concrete tiles or panels with predetermined and precise dimensions.

The main disadvantage of the procedure described above consists of the fact that the tiles must be of considerable thickness to resist the loads that are exerted on them. This makes them very heavy, leading to greater difficulties in positioning them and to structural limitations in the construction of raised floors.

In document PCT/IT01/00636, this applicant described a procedure for the production on an industrial scale of concrete tiles or panels or sheets which makes it possible to limit their weight and thickness.

This procedure comprises the following processing stages : - crushing of the inert stone material ; - preparation of a mixture consisting of water, crushed material and inert cement sand binders; - preparation, in a pressing die, of a plastic frame inside which a wire-mesh reinforcement is positioned;

batching of this mixture inside the die; pressing of the mixture in order to obtain a tile presenting a predetermined configuration and predetermined dimensions, this pressing being carried out by means of a punch-holder shaped block, positioned in operation above, the die, designed to support a plurality of punches which penetrate the mixture between the links of the wire-mesh; extraction of the tile from the press and subsequent curing of the tile.

A procedure such as the one described above makes it possible to obtain cement tiles or panels with precisely predetermined lengths, widths and thicknesses, and is performed in a continuous process on a specially designed plant.

The visible surface of these tiles or panels always consists of the same material used in the cement mixture and requires subsequent dressing, polishing and chamfering operations.

Moreover, the imperfections which are often present on the surface are such that the material has to be rejected or classified. as seconds with an obvious disadvantage from the economic point of view.

DE$C TE This invention proposes to provide a tile or panel for the construction of raised or floating floors which allows the end user to determine the structure and the decoration of the visible surface of the tile or panel, it being possible to use any type of covering, for example wood, ceramic, etc.

This is achieved by means of a tile or panel for raised floors, with the features described in claim 1.

The dependent claims describe advantageous embodiments of the invention.

According to another aspect, this invention proposes to provide a procedure for the production of tiles or panels for floating or raised floors which makes it possible to obtain a product with a surface covering in a different material from the material forming the base of the tile, and which has fire-proof features that allow it to be classified as class"zero".

This procedure is characterised by the following stages: - positioning of a frame, for example in plastic material, inside a pressing die; - positioning of at least one element forming the visible surface inside the frame; - preparation of a mixture consisting of water, crushed material, inert cement sand binders and appropriate binding additives; - batching of the mixture inside a pressing die until a the frame is filled, according to a predetermined volume; - pressing of the mixture in order to obtain a tile or panel with a concrete base and a covering forming the visible surface closely joined to the base; - extraction of the tile from the die and its subsequent curing.

This procedure forms the subject of claim 11.

The claims dependent on claim 11 described further advantageous embodiments of the invention.

According to another aspect, this invention proposes a procedure for the production of tiles or panels (10) for floating or raised floors characterised by the following stages: - positioning of a frame, for example in plastic material, inside a pressing die; - positioning inside the die of an appropriate removable mould for the formation of a cavity on the upper surface of the tile; - preparation of a mixture consisting of water, crushed material and inert cement sand binders; batching of the mixture inside a pressing die until the frame is filled, according to a-predetermined volume; - pressing of the mixture in order to obtain a base with a predetermined shape and predetermined dimensions; - extraction of the base from the die and subsequent curing of the base.

- application of at least one element in the cavity of the upper part of the base designed to define the visible surface of the tile or panel.

This procedure is the subject of claim 18.

The claims dependent on claim 18 described further advantageous embodiments of the invention.

According to a particular embodiment of the invention, the procedure can foresee the positioning, inside the pressing die, of a wire-mesh reinforcement which can for example be supported by the frame.

In this case, after the positioning of the frame and the elements forming the visible surface inside the

pressing die, a first batching of the cement mixture is poured into the die until a part of it is filled.

The wire-mesh reinforcement is then positioned on top of the material poured in and then a second batching of the mixture is added to cover the wire-mesh reinforcement. After the pressing stage the frame and the wire-mesh become a single body with the tile.

The coupling according to this invention of covering elements forming only the superficial part of the tile and in particular the visible surface, with the base structure of a characteristic cement-structure tile, makes it possible to obtain a tile or panel with a considerable saving of the more prestigious material while maintaining all the technical features necessary for the construction of raised floors.

For example, if the above-mentioned covering elements are marble tiles or panels, the limited thickness required reduces both the quantity of marble used and the final weight of the tile. Moreover, since the marble panel is supported by the cement structure it can be larger in surface area while maintaining a limited thickness.

The visible surface of the tile or panel for raised floors according to the invention can consist of a single element with the same area as the pressing die or of several elements with a smaller area.

For example, several standard size ceramic tiles arranged according to a particular design can be used to form a single panel ready for laying.

The base surface, not visible in use, of the tile or panel for raised floors according to this invention can

present a plurality of cavities, for example.. corresponding to the links in the wire-mesh and formed during the production procedure by means of a shaped punch-holder block, positioned in operation above the die, designed to support a plurality of punches or projections which penetrate the mixture during the pressing stage. These cavities allow a further reduction in weight of the panel.

During the pressing stage, moreover, the mixture can be subjected to vibration compression and suction.

The tile or panel according to the invention can present a sloping wall or flared configuration, designed to guarantee easy laying of the floating floor. This flared shape in fact facilitates the insertion of each panel on the relative framework which is raised above the ground.

A further embodiment of tiles or panels with a visible surface advantageously consisting of different material for the construction of floating or raised floors envisages the formation of the base in cement material according to the procedure described above in which a special mould, for the formation of a cavity designed to accommodate the elements comprising the visible surface, is inserted in place of the initial elements. These are fixed in place after curing of the cement base.

The tile or panel according to the invention can be advantageously produced with the use of an automatic control machine.

DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become evident on reading the following description of one embodiment of the invention, given as a non-binding example, with the help of the enclosed drawings, in which: - figure 1 shows a perspective view, slightly from above, of a tile according to present invention with a single element forming the visible surface of the tile; - figure 2 shows an exploded perspective view, slightly from above, of the tile according to figure 1; - figure 3 shows an exploded perspective view, slightly from above, of a tile according to the invention with several elements forming the visible surface; - figure 4 shows a plan view from below of a tile according to the invention; - figure 5 is a cross-section of a tile according to the invention, showing some internal details of the tile.

DESCRIPTION OF ONE FORM OF EMBODIMENT In the figures, the reference number 10 generally indicates a tile or panel obtained according to the present invention, in the case in question a tile 10 made from inert concrete with at least one covering element 13 situated on the upper part defining the visible surface of the tile or panel 10.

Around the concrete base 14 and the element 13 is a peripheral frame 11 which can be made from various materials, for example plastic or metal.

The base 14 generally consists of a mixture of cement, marble powder or other stone material in granules of various sizes and nature to which appropriate binding additives can be added for a direct grip on the covering elements 13 forming the visible surface.

The tile or panel 10 according to the invention, as shown in figure 4, consists of a frame 11 and inside the base 14 can comprise a wire-mesh reinforcement 12, presenting a plurality of cavities 17 on the lower surface of the base 15, not visible when laid.

The cavities 17, which can present a depth corresponding to a good part of the thickness of the tile, ensure a considerable reduction in weight of the panel or tile 10 without jeopardising the structural features.

These features can be strengthened by the presence of a mesh reinforcement 12 for example in metal and the cavities 17 can correspond to the links of the mesh 12.

An advantageous procedure for the production of tiles or panels 10 for raised floors, with a cement base 14 according to the invention foresees: - positioning of. a frame 11, for example in plastic material or in an appropriate metal or metal alloy, inside a pressing die ; - positioning inside the frame 11 of one or more covering elements 13 forming the visible surface ; - preparation of a mixture consisting of water, crushed material, inert cement sand binders and appropriate binding additives ; - batching of the mixture inside a pressing die until the frame 11 is filled, according to a predetermined

volume; - pressing of the mixture in order to obtain a tile 10 with a predetermined shape and predetermined dimensions, this pressing being achieved by means of a shaped punch-holder block, positioned during operation above the die and designed to support a plurality of projections or punches which penetrate the mixture between the links of a wire-mesh reinforcement 12; during this stage the mixture can also be subjected to vibration compression and suction; - extraction of the tile or panel 10 from the die and subsequent curing of the base.

As mentioned above, the frame 11 can be made from composite plastic material resistant to relatively high temperatures or from a metal alloy.

The embodiment represented in figure 3 shows a tile 10 for raised floors with a cement base 14 and with four elements 13 situated on its upper part, defining the visible surface of the tile 10. These elements are fixed in the cavity 20 to the base 14 for example by means of the use of a layer of binding material 21.

This embodiment makes it possible to obtain great flexibility in the use of the tile or panel according to this invention.

In fact, the tile or panel 10 is moulded in such a way that it consists of a concrete base, surrounded by a frame 11 which projects on one side with respect to the surface of the base, in such a way as to form an appropriate housing for the subsequent positioning of one or more covering elements 13.

These covering elements 13, which can for example consist of blocks of parquet, ceramic tiles, terra cotta, <BR> <BR> carpet, quartz/resin agglomerate tiles, etc. , are inserted and fixed in the housing, by means of appropriate adhesives, after the curing of the cement base 14.

In this way, the end user can choose the covering material of the raised or floating floor, according to technical or decorative requirements.

With reference to the figures from 1 to 5 it can be noted that the tile 10 advantageously presents a slightly prismatic configuration and a quadrangular base with a lower surface 15 and a visible surface with perimeter flaring to ensure easy laying of the panel 10 in the support frame of a raised floor (not shown in the drawings).

As mentioned above, the materials used as covering elements 13 forming the visible surface of the tile can be for example marble, marble agglomerate, ceramic, glass or wood. The surface of these covering elements 13 can already be finished and not require further processing such as for example dressing, polishing and chamfering.

The invention is described above with reference to several preferred embodiments.

It is nevertheless clear that the invention is susceptible to numerous variations, within the framework of technical equivalents.