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This application is the U.S. national phase of International Application No. PCT/IB2006/001675 filed 21 Jun. 2006 which designated the U.S. and claims priority to IT MI2005A001199 filed 24 Jun. 2005, the entire contents of each of which are hereby incorporated herein by reference. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention concerns a tile built applying at least one metallic layer, in stainless steel or other metals, on a substratum like, for example, a sound-deadening or a thermosetting plastic material; a number of such tiles may be used to cover surfaces in the building field. Characteristic of these tiles is that the tile sides are properly shaped to join the tiles together to realize stable, plane and continuous coverings. 
     The surfaces to be covered could be horizontal, as a floor, or tilted, or vertical as building facades or inner walls. The tile structure is normally square or rectangular, even if there aren&#39;t limits to structure type provided that the sides are made to be joined together. The invention concerns also a corresponding method to realize such tiles and the coverings obtained installing the tiles on suitable plane surfaces. Similar tiles are known being made by a metal plate bonded, with various methods, to a substratum of a non metallic material like, but not only, a plastic material. To apply such tiles, multiple methods exists, but all of them are time consuming, need skilled people, and are costly. Moreover, the tile installation to the rough support requires costly adhesives or similar that frequently become a critical factor when exposed to humidity or to wide thermal excursions. 
     An object of the present invention is to propose a new tile of the type and for the applications just described, together with the method to realize it; the tile is carefully designed to make installation easy, fast and cheap without using adhesives to fix it to the basement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the solution, according to the present invention, will be apparent from the description given below of preferred embodiments, given purely as an indicative example without limitations, with reference to the enclosed figures, in which: 
         FIG. 1  illustrates, in a schematic way, a tile in section according to the invention. 
         FIG. 2  is a plane view from the bottom of the tile of  FIG. 1 . 
         FIG. 3  is a section to show the details of the coupling of two tiles of the type represented by  FIGS. 1 and 2 . 
         FIG. 4  shows in a section details of the possible installation of a tile to the basement and reinforced tiles having two metal layers. 
         FIG. 5  shows a different realization of the tile&#39;s coupling. 
         FIG. 6  shows the same coupling of the previous  FIG. 3 , modified to allow the removal of a single tile from a complete pavement. 
         FIGS. 7 and 8  show “jolly” tiles without an inner female edge or with a shorter inner female edge, respectively. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference in particular to  FIGS. 1 and 2 , a tile  10  is illustrated, the tile being composed by a metallic plate  12 , preferably but not exclusively, in stainless steel, and by a suitable plane substratum  14 , made as example by sound-deadening or thermosetting plastic material. The metallic plate  12 , which is the stamping surface or the top external surface of the covering realized assembling these tiles, is coupled to the substratum  14  by any suitable way, like, as example by bonding with adhesive. Moreover, when out of ordinary mechanical performances are required, given that a single metallic layer cannot exceed a certain thickness because of the surface&#39;s shaping process, the tile could be built coupling more than one metallic plate, as example with two of them. 
     The tiles will be installed on a base surface to be covered, normally a plane surface, horizontal in case of floors or tilted as in case of slope coverings, or vertical when covering facades or internal walls. 
     To guide and join together adjacent tiles  10 , each tile shows, on one side, or preferably on two consecutive sides, a female shaped joint; the opposite sides are properly male shaped, these elements being obtained by the edges of the metallic plate of which the tile is composed. It is important to highlight that the tile joints according to the present invention, are made of homogeneous material, in the case metal, folded without soldering or other complex workings. Moreover, as per  FIGS. 1 and 2 , where the tile shown has one metallic plate  12 , the four lateral profiles are external to the substratum  14  and are properly folded to obtain the male and female joints. The method to get the female profile  16  is to make a first fold  18  of the ending side of the plate versus the tile inner, and a second fold  20 , in the opposite direction to obtain an open “Z”, with an externally facing seat  22  parallel to the tile side. The global thickness of the “Z” fold is a bit less of the total tile thickness, to assure planarity. The seat  22  of the female  16  is dimensioned to host a free edge  24  of a contiguous tile, the edge being part of a male element  26  as a result of folding down and then externally as in  28  the metallic side of the tile to obtain a substantially “L” shaped profile, where the free side  24  has a proper quote to perfectly fit inside the “V” seat  22 . 
     With reference to  FIG. 2 , a rectangular tile  10  is illustrated, having two female elements  16  on two contiguous sides, and two male elements  26  on the contiguous opposite sides. To avoid metal interferences during folding and to close the tiles one near to the other during installation, the angles of the rough metal plate  12  are properly cut as per  FIG. 2 , detail  32 . To be noticed that cuts at the angles are made to get a completely continuous and closed tile plane when installed. It&#39;s also possible to build tiles having only two joints, typically on the longest dimension, instead of the four shown and described; this two side insertion tile is preferred for long and tightened tiles and less expensive results. 
     Moreover, the female joints  16  can be formed by single sub-elements  18 ′ obtained with cuts  18 ″ perpendicular to the tile edge, and folding lines  20  can be previously traced on the tile rear surface to improve the folding precision. 
     With reference to  FIG. 3 , details of a couple of tiles are shown, to highlight the joint of a male element  26 ′ and of a female element  16 , belonging to two adjacent tiles  10 ′ and  10  covering a surface  33 . The female element  16  by the first fold  18  defines an external tile surface  140  and an internal tile surface  141 . As shown, a U-shape is defined by the first fold  18  and the second fold  20 , including a first edge portion  142  and a second edge portion  143 . The first edge portion  142  is parallel to the surface to be covered and contacts the internal tile surface  141 . The second edge portion  143  rests on the surface to be covered  33 . The free edge  24  of the male element  26  is parallel to the surface to be covered  33  and is positioned inside a seat defined by the U-shape of the female element  16 . 
     When the surface  33  is horizontal, it&#39;s normally not necessary to fix the tiles to the surface; anyhow, in case where the fixing is desired or preferable, the female free edge  34  can be foreseen few millimeters longer to accept fixing screws, 38 on holes  36 , as shown in  FIG. 4 .  FIG. 4  illustrates two tiles  10 ″ and  10 ″′, having metal plates  12 ″ a ,  12 ″ b  and  12 ′″ a ,  12 ′″ b  respectively, the male and female profiles being obtained by folding the metal plane of the external plates  12 ″ a  and  12 ″′ a.    
     However, the male and female joints can be obtained by folding the inner plates  12 ″ b  and  12 ′″ b.    
     An even simpler fixing is possible on the “L” shaped side as it happens at the ending lane of the coverings. 
     Due to the characteristics of the present invention, the installation of tiles is simple, fast, and precise; and the covering is aesthetically very clean, without visible screws with the metal tiles quite continuous. The metal joints, as made, allow the recovery of small planarity defects frequently present on the base rough surfaces, and compensate the dimensional changes due to temperature variation. An important advantage of the invention is that the metal tiles are electrically interconnected by a practically infinite number of points, which makes very simple the metal grounding of the complete covering when requested. 
     With reference to  FIG. 5 , a different form of the invention is shown; with reference to two tiles  40  and  40 ′, each having a metal plate  42  and  42 ′, coupled with a substratum  44  and  44 ′, standing on a surface  45 . As per this implementation, the female joint element  46  is built folding the metal edge firstly down and secondly up; this realizes a “V” seat  48 , where to insert a free folded down edge  50 ″ of the male element  52 . Also with this implementation the joints could be two or four on the sides of each tile. 
     It&#39;s a general good practice to simplify the replacement of eventually damaged tiles or to give access to under covering installations, to interpose to normal tiles special easily removable “jolly” tiles without joints ( FIG. 7 ) or with joints of reduced length ( FIG. 8 ) as shown in  FIG. 6  which corresponds to  FIG. 3  with the difference that the joining “Z” profile  16   h  of the tile  10   h  has an inner edge shorter than the equivalent one of the tile  10  in  FIG. 3 . 
     As an alternative (not shown), the “jolly” tiles can be formed without joints and maintained in position on the ground surface by means of magnetic attraction between permanent magnetically attracting elements, embedded in the ground surface and in the bottom surface of the tile substratum. 
     To build the tiles, according to the present invention, a metal plate is properly cut at dimension, and the plate corners are cut with a number of additional cuts made as beneficial to the precision of the folding process; as example, the line of folding can be properly engraved to improve precision. 
     The plate is then folded, in multiple steps, to get the tile metal plate complete with its female and male side profiles. Finally the tile is assembled with an eventual second metal plate and the substratum. The covering made without screws with tiles produced as per the invention, keeps the lower surface exactly as it was before. This is very desirable and allows temporary installations and tile reusability, which are important characteristics for a number of applications, as example like the fair stands floors or the technical floors. 
     In conclusion, the present invention realizes, with limited investments, simple, flexible and cheap metal covering tiles characterized by an easy, adhesive free installation method, and by a very clean aesthetic, without visible screws or other heterogeneous components. The peculiarity of the metal joint is beneficial to recover the small planarity defects of the installation surface, important to compensate dimensional changes due to the thermal excursion and allows easy electrical grounding.

Summary:
A tile is provided for covering surfaces in the form of one or more metallic plates. A substratum is to be placed on the surface to be covered. At least one metal plate has folds forming male and female shaped elements to be connected with those of adjacent tiles to form a substantially continuous coverage.