Patent Publication Number: US-6702979-B2

Title: Method for producing special ceramic parts

Description:
This application is a 371 of PCT/ES00/00494 filed Dec. 28, 2000. 
    
    
     OBJECT OF THE INVENTION 
     As expressed in the title of this specification, the present invention refers to a new method for manufacturing special ceramic pieces. 
     It permits the obtainment of ceramic pieces for ceramic coverings with qualities superior to the ones existing at this time. 
     The method basically consists of manufacturing by extrusion a tube-shaped profile from which the different special pieces are obtained and of making some appropriate cuts by means of the appropriate tool. 
     BACKGROUND OF THE INVENTION 
     Nowadays ceramic coating or covering of walls is not only limited to the use of the classic tiles of a uniform format (square, rectangular, etc.) used to cover more or less flat surfaces. 
     Complementary pieces whose purpose is to obtain better finishes have also been developed and the one used to finish corners that have a curved or arched shape preferably stands out. 
     Hence, it is a piece whose section has the approximate shape of a circular crown sector. 
     Normally this piece has a length equal to that of the tiles used in the covering and it is placed on the corner of the wall covering the hollow space left by the facing of the tiles. 
     It is a very narrow piece, for which reason it is not possible to manufacture it by spreading ceramic paste, since from a certain length deformations that would undoubtedly spoil the linearity and continuity thereof would be produced. 
     These technical conditions require the ceramic support of a piece to be manufactured as if it were a ceramic tile, in other words, by pressing and subsequent enameling and baking. 
     On the other hand, the pressing process requires molds whose dimensions will obviously limit the dimensions of the piece to be obtained. 
     This fact also implies another added problem, since the formats of ceramic pieces are ever increasing and this requires new and costly molds to be made in order to obtain this special piece that has the arched shape or other different shapes of flat tiles. 
     DESCRIPTION OF THE INVENTION 
     In order to overcome the problems and inconveniences mentioned in the preceding section, the invention proposes a new method for manufacturing special ceramic pieces in such a way that from a conventional ceramic paste, similar to the one used in the manufacture of ceramic tiles, a preferably cylindrical tube-shaped profile is obtained by extrusion. Subsequently this profile is subjected to firing in order to achieve the vitrification thereof which provides it a hardness similar to the one of a conventional tile. 
     Once we have the baked ceramic bisque tube or profile it is then cut by means of specific tools. 
     Normally four longitudinal cuts will be made in order to obtain four pieces applicable to corners, whose angle is approximately 90°, although the number of cuts can vary in order to obtain different angular measurements larger or smaller than 90°. 
     Once the curved segments are obtained, they will be enameled on one of their surfaces and subjected to the corresponding baking in order to vitrify the enamel, as conventionally done in the manufacture of tiles. 
     In this way, we obtain totally linear pieces of the desired length. 
     The key to the success of this new method or process lies on the fact that extrusion of the tube-shaped body is substantially stabler than that of an open profile in which the inside stresses deform it more easily. 
     Hereinafter to provide a better understanding of this specification and forming an integral part thereof, some figures in which the object of the invention has been represented in an illustrative and non-restrictive manner are attached. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 represents a front view of a tube-shaped body obtained by extrusion that forms part of the method for manufacturing special ceramic pieces. Once said tube-shaped body has been obtained, it will be subjected to firing in order to achieve the vitrification thereof. 
     FIG. 2 represents an arched ceramic piece obtained by means of a cutting tool from the tube-shaped body obtained by extrusion of the preceding figure. This arched piece includes enamel on its visible surface. 
     FIG. 3 represents a view of the arched pieces applied to a corner formed by two walls at 90° that are covered by other conventional flat pieces. 
     FIG. 4 represents a view similar to the preceding one wherein the corner where the two walls converge forms an angle larger than 90°. 
     FIG. 5 represents a perspective view of a cylindrical-tube-shaped body obtained by extrusion like the one represented in FIG.  1 . 
     FIG. 6 represents a perspective view of an elongated piece with a curved shape obtained from the body represented in the preceding figure. 
     FIG. 7 represents a front view of a tube-shaped body obtained by extrusion like in the case of the body of FIG. 1, the body having a polygonal section of four sides. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Making reference to the numbering used in the figures, the method for manufacturing special ceramic pieces comprises the following steps or stages. 
     Initially, starting with a conventional ceramic paste similar to the one used in the manufacture of ceramic tiles ( 1 ), there is a first step in which a tube-shaped profile with a cylindrical ( 2 ) section, hexagonal section ( 3 ) or any other section is obtained by extrusion. 
     A second step wherein the tube-shaped profile obtained by extrusion is subjected to firing in order to achieve the vitrification thereof which provides it with a hardness similar to the hardness of a conventional tile ( 1 ). 
     A third step in which a cut ( 4 ) is made in the tube-shaped profile of the vitrified bisque by means of a specific tool. Normally, longitudinal cuts that section it into corresponding smaller and smaller special parts or pieces will be made. 
     Normally four longitudinal cuts will be made in order to obtain four pieces applicable to corners ( 8 ), whose angle is approximately 90° (FIGS.  1  and  3 ), although the number of cuts can vary in order to obtain different angular measurements (FIG.  4 ). Furthermore, the angle of the corner ( 8 ′) formed by the walls ( 9 ) and ( 10 ) can be different from 90° (FIG.  4 ). 
     Once the special segments or pieces have been obtained, whether they are curved ( 5 ) and ( 6 ), angular ( 7 ) or the like, in a fourth step the visible surfaces of these special pieces will be coated with enamel ( 11 ). 
     In a subsequent step, the special pieces with enamel will be subjected to firing in order to vitrify the enamel, just as it is usually done when tiles are manufactured. 
     In this way, we obtain totally linear homogeneous pieces with the desired continuity on their visible surfaces, wherein the desired length can be obtained.