Accessory tile and its manufacturing method

Abstract: An accessory tile and its manufacturing method. The accessory tile is made of preformed tile bodies 10a, 20a, 30a, 40a, 50a, 60a of plate shape which have colored patterns on their surfaces, respectively. The preformed tile bodies are disposed on both sides 113a, 113b, 123a, 123b, 133a, 133b of a press surface of a lower mold 113, 123, 133 of a V-shaped cross section, respectively, while joint end surfaces of the preformed tile bodies are contacted closely with each other. They are pressed between the lower mold and an upper mold 115, 135 into one body. The pressed bodies are burnt to obtain the accessory tile as a final product.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an accessory tile and its manufacturing method, more particularly, to an accessory tile which has a variety of colored patterns on the surfaces and a manufacturing method of such a tile. Such tiles may be angled or curved, and used for stepped parts, e.g. stairs, corners of pavements or roads, corners of gateposts, or any building corner parts. Description of Related Art Conventionally, accessory tiles have been used for corner tiling. Such tiles have a bent plate shape having an angle corresponding to a corner to be tiled. These tiles are generally manufactured by pressure forming of granulated raw materials. Specifically, the process is as follows. First, a press die composed of a lower mold and an upper mold is used. The molds define a forming space of a V-shaped or reversed V-shaped cross-section corresponding to a cross section of an accessory tile. A granulated raw material containing a binder is disposed on a press surface of the lower mold and pressed between the lower mold and the upper mold, thereby forming a tile body of a specific shape corresponding to a shape of the accessory tile. Then, the tile body is burned. Such an art is disclosed in Japanese Utility Model Publication No. 4-30011 or the like. Thus manufatured accessory tiles have unified bodies without any joint lines at anywere including corner portions, so that they present good appearance and sufficient strength. However, the patterns formed on their surfaces are limited to simple ones such as plain-colored or spotted patterns. Recently, demands for colorful tiles are growing, and a variety of patterns of tiles are proposed or practically used. For instance, Japanese Patent Publication No. 2-42323 or the like discloses an inlay tile having a specific pattern embedded in its superficial portion by pressure forming granulated materials. Japanese Patent Publication No. 2-8883 discloses a tile having an irregular pattern formed by disposing a material lump of clay body, mixed with coloring pigment powder, on a press die and pressing the clay body. These patterns are applicable to square tiles of a flat plate shape, because they are formed by plane dies. However, it is difficult to apply them to the above mentioned accessory tiles which are manufactured by the press die having an inclined press surface. Therefore, when corners need to be built with colored pattern tiles, two square tiles are joined at right angles via an adhesive and stuck to the corner. Otherwise, square tiles are cemented to each other and have the joined part reinforced by an angle member made of metal or resin. A specific shape of tiles, namely, corner cap tiles are used as accessory tiles for tiling side corners, of a stepped part, having a triangular pyramid shape where a front plane, an upper plane and a left or right side plane cross with each other. Such side corners are tiled by the same way as above by combining three square tiles. With these ways of tiling, tiling work needs much labor and is troublesome. Moreover, in case of joining tiles by an adhesive, the contacted part is exposed and exhibits poor appearance. In case of cementing the tiles, there is a fear of abrasion. In view of the above situation, it is desirable if a variety of shapes, such as an angle plate, a corner cap or the like, can be obtained even for the accessory tiles having colored patterns. If so, a man-hour or labor for tiling work, durability or appearance could be improved drastically. Thus, it has been longed in the ceramic industry to provide such an improved technique. EP-A-0 591 728 discloses a further known method for manufacturing patterned angular tiles. According to this method, two preformed patterned flat tile bodies are arranged in a V-shaped press mold with a joining bar or a joining granule being arranged in the corner of the mold between the connection surfaces of the two tile bodies. After pressing, a bruning step unifies the two tile bodies with the joining material being interposed between the connection surfaces. SUMMARY OF THE INVENTION It is the object of the invention to provide a simplified method for manufacturing an patterned accessory tile with a sufficient strength at a corner portion thereof. This object is solved with a manufacturing method having the features of claim 1. Further objects and advantages of the invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the invention are clearly shown. BRIEF DESCRIPTION OF THE DRAWING FIG.1 illustrates perspective views of examples of accessory tiles having various colored patterns which are obtained in the first embodiment to the third embodiment of the invention. FIG.2 shows a flowchart showing a manufacturing process of an accessory tile according to each embodiment of the invention. FIG.3 illustrates a perspective view of an outline of a plate tile press machine which is used in a preformed tile body forming step B of FIG.2. FIG.4a and FIG.4b are sectional views of plate tile press machines which is used in the preformed tile body forming step B in the first embodiment of the invention, respectively, wherein FIG.4a illustrates a sectional view of a plate tile press machine which forms a preformed tile body 10a for forming a main plate 10c, and FIG.4b illustrates a sectional view of a plate tile press machine which forms a preformed tile body 20a for forming a bent plate 20c. FIG.5a and FIG.5b illustrate the preformed tile bodies in the first embodiment of the invention, respectively, wherein FIG.5a illustrates a perspective view of the preformed tile body 10a for forming the main plate 10c, and FIG.5b illustrates a perspective view of the preformed tile body 20a for forming the bent plate 20c. FIG.6 illustrates a sectional view of an outline of an accessory tile press machine in operating condition which is used in a tile body forming step D in the first embodiment of the invention. FIG.7 illustrates a sectional view of a plate tile press machine which is used in a preformed tile body forming step B in a second embodiment of the invention. FIG.8 illustrates a perspective view of a preformed tile body in the second embodiment of the invention. FIG.9 illustrates a sectional view of an outline of an accessory tile press machine in operating condition which is used in a tile body forming step D in the second embodiment of the invention. FIG. 10a to FIG. 10c are perspective views, partially cut away, of upper mold ridges of accessory tile press machines of the invention, respectively, wherein FIG. 10a illustrates an upper mold ridge of the accessory tile press machine in the first and second embodiments, FIG. 10b illustrates an upper mold ridge as an example of a first modification and FIG. 10c illustrates an upper mold ridge as an example of a second modification. FIG.11 illustrates a perspective view of an accessory tile in a third embodiment of the invention. FIG.12 illustrates a perspective view of an accessory tile press machine which manufactures the accessory tile in the third embodiment of the invention. FIG. 13a to FIG. 13c respectively illustrate front elevational views of various shapes of accessory tiles of further embodiments which can be manufactured in this invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Several preferred embodiments of the present invention will be described based on the above mentioned drawings, wherein same reference characters in the different views designate identical or corresponding parts throughout several views. FIG.1 illustrates several examples of accessory tiles, obtained in the present invention, which have various colored patterns on their surfaces as designs, respectively. The accessory tiles of an angle plate shape manufactured in the following embodiments have angle shapes, respectively, which are composed of two tile elements of different or same length joined at opposite ends of a perpendicular corner. They may be used for corner tiling of stepped parts of stairs, pavements or stepped parts of roads, and the like. In the following descriptions, a long tile is called a main plate, and a short one is called a bent plate. Referring to an accessory tile in FIG.1a, a long rectangular main plate 10c has four triangle parts 11c, 12c 13c and 14c divided by two diagonals. The main plate 10c has two pairs of triangle parts of different colors, namely, the first pair 11c and 13c in one color, and the second pair 12c and 14c in another color, while making each pair show symmetry. A short rectangular bent plate 20c is the same color as that of the adjacent triangle part 12c. Referring to an accessory tile in FIG.1b, a long rectangular main plate 30c has a pair of symmetrically arranged semicircular parts 31c and 33c of different colors. The main plate 30c also has a pair of symmetrically arranged triangular parts 32c and 34c which have a different color from that of the semicircular parts 31c and 33c. A short rectangular bent part 40c is the same color as that of the adjacent semicircular part 33c. Referring to an accessory tile in FIG.1c, a main plate 50c and a bent plate 60c have the same length. They have spread mottled patterns thereon, respectively, which are composed of first parts 51c and 61c, second parts 52c and 62c, and third parts 53c and 63c. These colored patterns 11c to 14c, 31c to 34c, 51c to 53c, 61c to 63c go through the tile element thoroughly in its thickness direction, thereby preventing themselves fading out due to abrasion of surfaces of the tiles. It is possible to apply this invention to other various patterns of accessory tiles in accordance with the following process, as long as colored patterns go through the tile in the thickness direction. [FIRST EMBODIMENT] The first embodiment of the invention will be described referring to FIG.2 to FIG.6, taking the accessory tile of FIG.1a as an example. In FIG.1a, the accessory tile has the main plate 10c and the bent plate 20c formed at both sides of the corner 25. The main plate 10c has four triangular parts 11c to 14c. One pair of triangles 11c and 13c are provided with light gray spots on a black background. The other pair 12c and 14c are provided with light blue spots on a white background. The bent plate 20c has light blue spots on a white background like the adjacent triangular part 12c of the main plate 10c. The spots of the bent plate 20c are exposed on its surface so as to be continual to the spot pattern of the triangular part 12c. This accessory tile is manufactured as follows. FIG.2 shows a flowchar of a manufacturing process of the first embodiment of the accessory tile of the invention. The manufacturing process has five steps. First, in a colored raw material preparing step A, a desired number of colored raw materials are prepared. In a next preformed tile body forming step B, preformed tile bodies of plate shape are formed of the colored raw materials so as to have colored patterns on their surfaces. In a preformed tile body disposing step C, the preformed tile bodies are disposed on an inclined surface of a lower mold of V-shape or reversed V-shape in cross-section. In a tile body forming step D, tile bodies of a specific shape are formed by pressing the preformed tile bodies integrally between the lower mold and an upper mold. In a last burning step E, the tile bodies are burnt to obtain accessory tiles as a final product. FIG.3 illustrates a perspective view of an outline of a plate tile press machine 100 which is used in the preformed tile body forming step B of FIG.2. FIG.4a and FIG.4b illustrate sectional views of plate tile press machines 100a and 100b which are used in the preformed tile body forming step B. FIG.4a illustrates a sectional view of the plate tile press machine 100a which forms the preformed tile body 10a for forming the main plate 10c. FIG.4b illustrates a sectional view of the plate tile press machine 100b which forms the preformed tile body 20a for forming the bent plate 20c. FIG.5a and FIG.5b illustrate the preformed tile bodies. FIG.5a illustrates a perspective view of the preformed tile body 10a for forming the main plate 10c. FIG.5b illustrates a perspective view of the preformed tile body 20a for forming the bent plate 20c. In FIG.3, the plate tile press machine 100 has an upper mold 101 and a lower mold 103. At the center of the lower mold 103, a cavity 105 is provided. The cavity 105 has an identical square shape, in plan view, with a profile of side surface of the preformed tile bodies 10a and 20a, which define initial product for forming the main plate 10c and the bent plate 20c. A pusher 107 has the same outline, in plan view, with that of the cavity 105. A shape of an upper surface, used for pressing, of the pusher 107 is identical with a shape of a bottom surface of the preformed tile body 10a, 20a. The pusher 107 is movable up and down inside the cavity 105 by a driving unit such as a hydraulic cylinder (not shown). The upper mold 101 has the same outline, in plan view, as that of the cavity 105. A bottom surface, used for pressing, of the upper mold 101 has an identical shape with the upper surface of the preformed tile body 10a, 20a. The upper mold 101 is movable up and down to adjust an interval to the lower mold 103 or the pusher 107 through the driving shaft 109 by a driving unit such as a hydraulic cylinder (not shown), thereby to define a forming space together with the pusher 107 and the cavity 105 in an appropriate dimension. FIG.3 shows only the outline structure of the plate tile press machine 100, and the sizes and shapes of the upper mold 101, lower mold 103, cavity 105 and pusher 107 are modified in accordance with the size and shape of a preformed tile body. For instance, the sizes and shapes of the main plate 10c and the bent plate 20c are not identical in this embodiment. The structures of the plate tile press machine 100a for forming the preformed tile body 10a and the plate tile press machine 100b for forming the preformed tile body 20a are substantially alike. However, as shown in FIG.4, sizes and shapes of a cavity 105a of a lower mold 103a and a cavity 105b of a lower mold 103b, or pushers 107a and 107b are different. Accordingly, a size and a shape of the upper molds 101 are also different for each of the machines 100a and 100b, though not shown. In FIG.5a and FIG.5b, two kinds of tile bodies 10a and 20a are prepared. Namely, a preformed main plate body 10a forms the main plate 10c, and a preformed bent plate body 20a forms the bent plate 20c. The preformed main plate body 10a has four colored triangular parts 11a, 12a, 13a and 14a which are finally made into the triangular parts 11c, 12c, 13c and 14c of the main plate 10c, respectively. The preformed main plate body 10a and preformed bent plate body 20a has trimmed parts 15 and 21, respectively, in the preformed tile body forming step B. When the preformed tile bodies 10a and 20a are joined to each other and burned to form an accessory tile, the trimmed parts 15 and 21 are cut off along the two-dot chain lines shown in the FIGs. 4a, 4b and 6. Namely, the length of the main plate 10c and the bent plate 20c are not same in this embodiment, so that two types of the cavities 105a and 105b are prepared for forming the preformed main plate body 10a and the preformed bent plate body 20a. A substantially rectangular parallelepiped forming space is defined by the upper mold 101, cavity 105a and the pusher 107a. The forming,space has the same shape as that of the preformed main plate body 10a and has a dimension of 103mm wide, 120mm long and 13mm deep. Also, a substantially rectangular parallelepiped forming space is defined by the upper mold 101, cavity 105b and pusher 107b. The forming space has the same shape as that of the preformed bent plate body 20a or is shorter than the length of the forming space for the preformed main plate body 10a. It has a dimension of 103mm wide, 55mm long and 13mm deep. The bottom surface of the upper mold 101 for forming the preformed main plate body 10a is sized 103mm wide and 120mm long. The bottom surface of the upper mold 101 for forming the preformed bent plate body 20a is sized 103mm wide and 55mm long. Inclined joining surfaces 16 and 22 are provided on one longitudinal ends of the preformed tile bodies 10a and 20a, respectively. Such joining surfaces are to be contacted and joined to each other in following steps. An angle of an upper edge, at the one end, of the preformed tile body 10a, 20a is 45 degrees and an angle of a lower edge, at the one end, of the preformed tile body 10a, 20a is 135 degrees, as shown in FIG.4a and FIG.4b. When the joining surfaces 16 and 22 are joined, the preformed main plate body 10a and the preformed bent plate body 20a cross at right angles. Then, the joining area of the preformed main plate body 10a and the preformed bent plate body 20a are enlarged, therefore, the bonding force and corner strength are increased. One longitudinal ends of the pusher 107a and the pusher 107b is inclined in accordance with such edge angles of the preformed tile bodies 10a and 20a. Namely, an acute edge of 45 degrees is defined between the one end of the pusher 107a, 107b and the upper mold 101. On the other hand, an obtuse edge of 135 degrees is defined between the inclined part and the plane part of the pusher 107a, 107b. FIG.6 illustrates a sectional view of the outline of an accessory tile press machine, in operating condition, which is used in the tile body forming step D of FIG.2. The accessory tile press machine has a main mold 111, a lower mold 113 and an upper mold 115. The lower mold 113 has a press surface of a V-shaped cross section composed of a pair of flat sides 113a and 113b which crosses at an angle corresponding to an angle of a corner to be tiled, such as pillars, steps or the like. The upper mold 115 has a press surface of a V-shaped cross section composed of a pair of flat sides 115a and 115b which crosses at an angle corresponding to the edge angle of the press surface 113a and 113b of the lower mold 113. In this embodiment, the flat sides 113a and 113b cross at right angles to form a valley. Also, the flat sides 115a and 115b cross at right angles to form a ridge. The upper mold 115 is movable up and down to adjust the interval to the lower mold 113 by a driving unit such as a hydraulic cylinder and so on. The lower mold 113 is movable up and down inside the main mold 111 by a driving unit such as a hydraulic cylinder and so on (not shown). The process of making accessory tile of this embodiment by using the plate tile press machine and the accessory tile press machine is as follows. To begin with, in the colored raw material preparing step A, colored granules used for making the preformed tile body 10a are prepared as follows. A crashed and mixed raw material consisting of 50% of feldspar, 20% china clay, 10% kaolin and 20% clay is used herein. Three kinds of crashed and mixed raw materials are prepared: a first material adding 5% black pigment (belonging to a group of CoO, Cr 2 O 3 , Fe 2 O 3 ) to the above crashed and mixed raw material; a second material adding 5% blue pigment (belonging to a group of ZrSiO 4 (V) or ZrO 2 -SiO 2 -V 2 O 5 ); and a third material without any pigment added. Water is added to each kind of these materials. They are then mixed and ground by a trommel or the like into a slip, and granulated by a spray drier into granules of a fixed moisture content (granule diameter of about 70um). Thus, black, blue and uncolored (white) granules are prepared. The preformed tile body is prepared using these colored granules (including white ones) as mentioned below. In the preformed tile body forming step B, as shown in FIG.4, the pusher 107a is lowered to a forming position, then the rectangular parallelepiped forming space (size of 103mm wide, 120mm long, 13mm deep) is formed between the cavity 105a of the lower mold 103a and the upper surface of the pusher 107a of the plate tile press machine 100a. A 15mm height partition plate (not shown) is disposed diagonally in a square part, excepting an area of the joining surface 16, 22, of the forming space. Thus, the forming space is divided into four isosceles right triangle spaces corresponding to the triangular parts 11a, 12a, 13a and 14a of the preformed tile body 10a. Then, a mixture of the same quantity of the uncolored (white) granules and the black granules is filled in the laterally facing pair of the triangle spaces for forming the triangular parts 11a and 13a. A mixture of the same quantity of the uncolored (white) granules and the blue granules is filled in the longitudinally facing pair of the triangle spaces for forming the triangle parts 12a and 14a. A mixture of the same quantity of the white granules and the blue granules, which is the same color as the color of the triangle part 12a or 14a, is filled in a rectanglar space adjacent to the triangle space for forming the triangle part 14a (the right area from the two-dot chain line in FIG.4a), thereby to form the trimmed part 15. Thereafter, the partition plate is removed, and the granules are pressed by lowering the upper mold 101 so as to form the preformed main plate body 10a, having a colored pattern shown in FIG.5a, and the trimmed part 15 into one body. The preformed main plate body 10a has the inclined joining surface 16 which is formed by the inclined surface of the pusher 107a at the bottom surface of the joining end. A mixture of the white granules and the blue granules is filled in the forming space (size of 103mm wide, 55mm long, and 13mm deep) of the lower mold 103b, then the granules are pressed to obtain the preformed bent plate body 20a. As shown in FIG.4b, the pusher 107b is lowered to a forming position, then the rectangular parallelepiped forming space (size of 103mm wide, 55mm long, 13mm deep) is formed between the cavity 105b of the lower mold 103b and the upper surface of the pusher 107b of the plate tile press machine 100b. A mixture of the same quantity of the white granules and the blue granules, which is the same color as that of the adjacent triangle part 12a of the preformed main plate body 10a, is filled in the forming space. A mixture of the same quantity of the white granules and the blue granules, which is the same color as that of the square preformed bent plate body 20a, is filled in a narrow rectangular space adjacent to the square forming space for making the preformed tile body 20a (the right area from the two-dot chain line in FIG.4b), thereby to form the trimmed part 21. Thereafter, the granules in the forming space are pressed by lowering the upper mold 101 of the plate tile press machine 100b so as to obtain the preformed bent plate body 20a and the trimmed part 21, which have a single color shown in FIG.5b, in one body. The preformed bent plate body 20a has the inclined joining surface 22, which is formed by the inclined surface of the pusher 107b, at the bottom surface of the joining end. The above mentioned primary pressure forming work, as the preformed tile body forming step B, for forming the preformed tile bodies 10a and 20a is carried out at a pressure of 50 to 100 kg/cm 2 . Each of the preformed tile bodies 10a and 20a after pressing has a thickness of 10± 0.5mm. Here, the pressure is not limited to the above mentioned range. If the shape of preformed tile bodies is not damaged at the time of tranferring them to the accessory tile press machine after the primary pressure forming work, a lower pressure or a higher pressure is admitted vice versa, depending on a kind of clay bodies as raw materials, an adhesive such as CMC or the like, or a mixture percentage of the clay body and adhesive. If the pressure is 50 kg/cm 2 or more, the shape of the preformed tile body 10a, 20a is kept in a desired one more reliably, in case of the pressure forming with commonly used raw material. That is, the primary pressure is high enough, thereby increasing strength of the whole or the corner of the preformed tile bodies, while maintaining accessory tiles in high quality. If the pressure is 100 kg/cm 2 or less, when forming a tile body in a below mentioned secondary pressure forming work, as the tile body forming step D, it is possible to set a difference between the primary pressure and the secondary pressure large, thereby joining more securely the preformed main plate body 10a and the preformed bent plate body 20a. As mentioned above, the preformed tile bodies 10a and 20a have the trimmed parts 15 and 21 of a length of about 20mm provided at one longitudinal ends, respectively, which are unnecessary parts in the final products of tiles. These trimmed parts 15 and 21 are removed by cutting in a following step. Therefore, uncolored or white granules are filled in the forming spaces therefor. Since the trimmed parts 15 and 21 have no influence on an appearance of the final product, any colored or uncolored material may be used therefor. In forming the preformed main plate body 10a, the partition plate is diagonally disposed only in a square part (103mm square) of the forming space defined between the cavity 105b of the lower mold 103a and the pusher 107a, while excepting a part for forming the trimmed part 15 (about 20mm wide). Thus manufactured preformed main plate body 10a and preformed bent plate body 20a are taken out by pushing up the pushers 107a and 107b for facilitating taking-out work of the preformed tile bodies from the cavities 105a and 105b. In the preformed tile body disposing step C, two kinds of preformed tile bodies 10a and 20a, obtained in the preformed tile body forming step B, are respectively disposed on the pressure forming die of a shape corresponding to a shape of a finished accessory tile. As shown in FIG.6, the lower mold 113 of the accessory tile press machine is lowered to a forming position shown by a solid line in FIG. 6. Then, a forming space, which corresponds to a specific shape of a tile body, is formed between the press surface 113a and 113b of the lower mold 113 and the inner side surface of the main mold 111. Then, the preformed main plate body 10a and the preformed bent plate body 20a are respectively disposed on flat sides 113a and 113b of the press surface of the lower mold 113. Describing this step more specifically, the preformed main plate body 10a (left in FIG. 6) is disposed on the flat side 113a of the press surface, while having a sharp edge side of the joining surface 16 placed downward so that the sharp edge meets with the perpendicular corner or valley defined between the flat sides 113a and 113b of the V-shaped press surface of the lower mold 113. Then, a sharp edge side of the joining surface 22 of the preformed bent plate body 20a (right end in FIG. 6) is disposed on the flat side 113b of the press surface, while having a sharp edge side of the joining surface 22 placed downward so that the sharp edge meets with the perpendicular corner of the V-shaped press surface. Thus, the joining surfaces 16 and 22 contact closely to each other. The thicknesses of the preformed tile bodies 10a and 20a are equal. Both the joining surfaces 16 and 22 have the sharp edges of the equal angles of 45 degrees. Consequently, areas of the joining surface 16 and 22 are equal, so that both the joining surfaces 16 and 22 are closely stuck without any surplus area. When the joining surfaces 16 and 22 are contacted closely, a corner of the angle tile body, which is defined around the joining surfaces 16 and 22, becomes perpendicular. Thus, the corner angle corresponds to the corner angle of the press surface 113a and 113b of the lower mold 113. As a result, the preformed tile bodies 10a and 20a are closely disposed on the press surface 113a and 113b. The trimmed parts 15 and 21 of the preformed tile bodies 10a and 20a are positioned outward on the press surface of the lower mold 113. Accordingly, the preformed tile bodies 10a and 20a on the press surface 113a and 113b take a position as shown in FIG.6. In the accessory tile forming step D, the upper mold 115 is lowered toward the lower mold 113 on which the preformed tile bodies 10a and 20a are disposed. Both of the preformed tile bodies 10a and 20a are pressed between the press surface 113a and 113b of the lower mold 113 and the press surface 115a and 115b of the upper mold 115. The preformed tile bodies 10a and 20a are joined at the joining surfaces 16 and 22. Then, a main plate body element 10b is obtained from the preformed main plate body 10a, and a bent plate body element 20b is obtained from the preformed bent plate body 20a. After this step, as shown in FIG.6, there is produced a tile body of an angle plate shape, which is composed of a pair of tile body elements 10b and 20b and which has smooth upper and lower surfaces without any joint line exposed on the corner. The size of the flat side 113a, for disposing the preformed main plate body 10a, of the lower mold 113 is 105mm wide and 123mm long. The size of the flat side 113b, for disposing the preformed bent plate body 20a, of the lower mold 113 is 105mm wide and 57mm long. The lowering limit of the lower mold 113 is within 10mm from the upper end of the inner surface of the main mold 111. Therefore, the size of the above mentioned accessory tile forming space is: 105mm wide, 123mm long and 10mm deep for the preformed main plate body 10a, and 105mm wide, 57mm long and 10mm deep for the preformed bent body 20a. The depth of the forming space of the accessory tile press machine for the secondary pressure forming work is a little smaller (about a few millimeter) than that of the plate tile press machine for the primary pressure forming work. This is because the performed tile bodies 10a and 20a are to be compressed in the thickness directions, in the secondary pressure forming work, so as to make the joining surfaces 16 and 22 stuck strongly. The width and length of the forming space of the accessory tile press machine for the secondary pressure forming work are set a little wider (about a few millimeter) than those of the plate tile press machine for the primary pressure forming work. This is because some extra space should be given for permitting the materials to spread at the time of compressing the performed tile bodies 10a and 20a in the thickness direction in the secondary pressure forming work. In the accessory tile forming step D of this embodiment, the pressure of the secondary pressure forming step is set at 300 kg/cm 2 , in consideration of the primary pressure of 50 to 100 kg/cm 2 in the preformed tile body forming step B. The accessory tile body elements 10b and 20b are compressed respectively into a thickness of 8mm. Here, the pressure is not restricted to the above mentioned one. If the preformed tile bodies 10a and 20a are completely joined at the corner ends in the secondary pressure forming work, a lower or higher pressure is admitted, depending on a kind of clay bodies as raw materials and an adhesive such as CMC, or a mixture percentage of the clay body and adhesive, or the primary pressure. It is preferable to set the secondary pressure to two or more times as large as the primary pressure. It is more preferable to set it three or more times as large as the primary pressure. This makes it possible to join the preformed tile bodies 10a and 20a more firmly, thereby to provide an accessory tile of higher strength and quality. That is, the larger the pressure difference becomes between the primary pressure and the secondary pressure, the higher the joining force of the preformed tile bodies 10a and 20a becomes. This increases the strength of the whole or the corner of the tile body, and also makes the accessory tile of high quality. The accessory tile body elements 10b and 20b are taken out after pulling up the upper mold 115 to separate it from the lower mold 113, pushing up the lower mold 31 to a taken-up level, and bringing the upper surface of the tile body elements 10b and 20b above the top end of the main mold 111. Such a position is shown by the tow-dot chain line in FIG.6. Thus obtained tile body has the trimmed parts 15 and 21 of approximately 20mm long continuously provided at its outside ends, namely, at outer positions than a necessary part used for the final product. These trimmed parts 15 and 21 are removed by cutting by a cutter along the two-dot chain line shown in FIG.6. Since the accessory tile body elements 10b and 20b are pressed and joined by a sufficient secondary pressing force, which is two or more times as large as that of the primary pressure, the tile body has enough strength to bear any works such as cutting or trimming of the trimmed parts 15 and 21 by hand to a sufficient degree, unless it is intended to destroy them. Moreover, the corner of the tile body is given sufficiently large strength since it is formed by joining surfaces 16 and 22 whose surfaces are larger than those of right angle ends. In the burning step E, the accessory tile bodies obtained in the tile body forming step D are arranged in a chamotte sagger at appropriate intervals therebetween. They are burned four hours at a temperature of 1200°C and sintered. The thickness of the accessory tile which was about 8mm comes into about 7.5mm after burning. Thus, the finished accessory tile is obtained. As shown in FIG.1a, this accessory tile has the main plate 10c, which is 100mm wide, 100mm long and 7.5mm thick, and the bent plate 20c, which is 100mm wide, 35mm long and 7.5mm thick, at opposite sides of the rectangular corner 25. The main plate 10c is diagonally divided into four triangle parts 11c, 12c 13c and 14c. One pair 11c and 13c has the light gray spotted pattern on the black background and the other pair 12c and 14c has the light blue spotted pattern on the white background. The bent plate 20c has the light blue spotted pattern on the white background, which is the same as the pattern of the adjacent triangle part 12c of the main plate 10c. According to the present embodiment, since the plate shaped preformed tile bodies 10a and 20a are given colored patterns on their surfaces beforehand, such patterns appear on the surface of the accessory tile as they are, so that it is possible to obtain various desirable patterns that would be difficult to provide in conventional molds for accessory tiles. Moreover, the plural preformed tile bodies 10a and 20a are joined integrally to each other at the joining ends 16 and 22 into a predetermined shape of , molded body, corresponding to the shape of a tiled corner without any joint line, and then burned for obtaining stronger tiles. Therefore, the finished tile has a good appearance and sufficient corner strength. In this embodiment, an accessory tile can be obtained just by contacting a pair of joining ends 16 and 22 of the preformed tile bodies 10a and 20a, joining them and burning, so that the number of raw material parts used for manufacturing are decreased, and the production costs of the accessory tiles are kept low. Furthermore, the pressure for the tile forming is set larger than that for preformed tile body forming, and both of the preformed tile body 10a, 20a and tile body 10b, 20b are formed by pressure forming. Accordingly, the dry molding method, which is rather simple, can be used for these pressure formings, thereby cutting down the production costs. A desired angle shape of accessory tiles can be provided for the corner of the steps or stairs, pillars or the like, so that tiling becomes easier even if corner shapes have many variations, and work efficiency is improved. Also, a pair of preformed tile bodies 10a and 20a having the inclfned joining ends 16 and 22 are joined, so that the joining area and joining force is increased. It makes it possible to give higher strength and quality to the corner of the tile, thereby endowing the accessory tile corners with more strength. In this embodiment, the angle of joining surface 16, 22 is set at 45 degrees, so that the pressure is uniformly transmitted thereto and stronger joint force is obtained. No part of the joined end surfaces of the preformed tile bodies 10a and 20a appear in a design surface or an exterior surface when tiled. Therefore, the present embodiment can be applied to preformed tile bodies which have a color or pattern on circumferential end surfaces which is different from a general pattern of a design surface, since no such different color or pattern is exposed and affects the appearance of the accessory tile. [SECOND EMBODIMENT] A second embodiment of the invention will be described referring to FIGs.7 to 9, taking the accessory tile of FIG.1c as an example. In FIG.lc, an accessory tile has the main plate 50c and the bent plate 60c at opposite sides of the rectangular corner 65. Each of the main plate 50c and the bent plate 60c is provided with a spread mottled pattern composed of three colors of parts 51c, 52c, 53c, 61c, 62c and 63c, respectively. The colors are white, blue and dark brown. This accessory tile is manufactured as mentioned below, according to a manufacturing method similar to that of the first embodiment shown in FIG.2. FIG.7 illustrates a sectional view of a plate tile press machine which is used in the preformed tile body forming step B in this embodiment. FIG.8 illustrates a perspective view of a preformed tile body 50a. In this embodiment, one plate tile press machine is used for forming preformed tile bodies 50a in the same size and shape. The accessory tile is formed by two pieces of preformed tile bodies 50a in the same size. One of them is used for forming the long rectangular main plate 50c without cutting. The other is used for forming the short rectangular bent plate 60c by cutting a long rectangular preformed tile body into a fixed length. The plate tile press machine has the same structure as that used in the first embodiment. The square space, one side of which is 105mm, is defined between the square cavity 105a of the lower mold 103a and the pusher 107a having an inclined surface at one longitudinal end. FIG. 9 illustrates a sectional view of an outline of an accessory tile press machine, in operating condition, which is used in the tile body forming step D in this embodiment. The accessory tile press machine has a main mold 131, a lower mold 133 and an upper mold 135. The lower mold 133 has a pressing surface composed of a pair of flat sides 133a and 133b, which form a cross section of reversed V-shape corresponding to a corner shape of a pillar, a stepped part or stairs or the like. The upper mold 135 has a pressing surface composed of a pair of flat sides 135a and 135b, which form a cross section of reversed V-shape corresponding to the pressure surface 133a, 133b of the lower mold 133. The flat sides 133a and 133b cross with each other at right angles to form a ridge. Also the flat surfaces 135a and 135b cross with each other at right angles to form a valley. The upper mold 135 is movable up and down so as to adjust an interval to the lower mold 133 by a driving unit such as a hydraulic cylinder and so on. The lower mold 133 is movable up and down inside the main mold 131 by a driving unit such as a hydraulic cylinder and so on(not shown). A manufacturing method of the present embodiment, which uses the plate tile press machine and the accessory tile press machine, is described below. To begin with, in a colored raw material preparing step A, a preformed tile body is obtained in the following way. Three kinds of colored granules (white, dark brown and blue) are prepared by: adding 5% white pigment (a group of ZrO 2 -SiO 2 or zircon), 5% dark brown pigment (a group of Fe 2 O 3 -ZnO) and 5% blue pigment (a group of ZrO 2 -SiO 2 -V 2 O 5 or zircon blue) respectively to three crashed and mixed raw materials similar to those of the first embodiment; further adding water to each of them so that the moisture content becomes 20%; and kneading each of them. The three kinds of colored clay bodies are respectively put into an extruder (not shown). Then, each clay body is extruded from a mouthpiece of 25mm diameter (not shown), thereby molding white, dark brown and blue bars each of which is 1000mm long and 25mm diameter of a circular section. Thereafter, three kinds of colored round bars are gathered and piled in four rows and four lines while arranging the colors at random. Then, the gathered body is vertically cut at 25mm intervals in the longitudinal direction. The cut pieces are half-dried by air drying at a temperature of not more than 50°. The half-dried cut pieces are disposed in the forming space 105a of the lower mold 103a of the plate tile press machine 100a while their cut surfaces being faced above. Then, they are pressed at a pressure of 50 kg/cm 2 thereby forming non-dried body of the preformed tile body 50a, 60a. At the time of pressing, the cut pieces are deformed and spread, thereby providing the non-dried preformed tile body 50a, 60a which has a flowing mottled pattern on its surface. The non dried preformed tile body 50a, 60a is dried at a temperature of 100°C for hours. In this way, the preformed tile body 50a, 60a is obtained as shown in FIG.8. As mentioned above, this preformed tile body 50a, 60a has an inclined joining surface 56 at the bottom surface of the joining end, corresponding to the slope of the pusher 107a. In this embodiment, two pieces of preformed tile bodies 50a and 60a which are 105mm long squares and have the inclined surfaces 56 at an angle of 45 degrees in one end, are used. This is because the patterns on the upper surface and bottom surface of the preformed tile body 50a, 60a after extruding and cutting are similar. It is not necessary to form the preformed tile bodies for main plate 50c and bent plate 60c separately. In this embodiment, one accessory tile is formed of two pieces of preformed tile bodies 50a in the same size and shape. One of them is used for forming the long rectangular main plate 50c without cutting, and the other is used for forming the short rectangular bent plate 60c by cut a long one into a fixed length. As the preformed tile body forming step B, a primary pressure forming work of the preformed tile body 50a, 60a is carried out at a pressure of 50 kg/cm 2 , though the pressure is not restricted to this value in practising the invention. If the extruded bars can be surely formed into a desired three dimensional shape, a lower or higher pressure is admitted, depending on a kind of clay bodies as raw materials, an adhesive such as CMC and so on, or a mixture percentage of the clay body and adhesive, etc. There are provided no trimmed parts on the preformed tile bodies 50a and 60a in this embodiment. In a preformed tile body disposing step C, two pieces of preformed tile bodies 50a and 60a obtained in the preformed tile body forming step B are respectively disposed into an angle shape, corresponding to a shape of a finished accessory tile. As shown in FIG.9, the lower mold 133 of the accessory tile press machine is lowered to a forming position shown by a solid line in FIG. 9. A forming space, which corresponds to a shape of an accessory tile body, is formed between the press surface 133a, 133b of the lower mold 133 and the inner surface of the main mold 131. Then, the preformed tile bodies 50a and 60a are respectively disposed on one flat side 133a for the main plate 50c and on the other flat side 133b for the bent plate 60c. Describing this process more specifically, the preformed main plate body 50a is disposed on the flat side 133a so that an acute edge of the inclined joining surface 56 is placed upward and that an obtuse edge thereof meets with the ridge between the flat sides 133a and 133b. Then, the preformed bent plate body 60a is disposed on the other flat side 133b such that an acute edge of the joining surface 56 is placed upward and that an obtuse edge thereof meets with the ridge. Thereafter, the joining surfaces 56 of the preformed tile bodies 50a and 60a are joined together. The size of them are equal. Since the preformed tile bodies 50a and 60a have the sharp edges of an angle of 45 degrees at the joining surfaces 56, the joining areas thereof are equal, too, and both the joining surfaces 56 are closely stuck without any surplus area. When the joining surfaces 56 are contacted closely, the corner of the preformed tile bodies 50a and 60a around the joining surfaces 56 become perpendicular. Such an angle of the corner corresponds to the corner angle of the ridge, which is also 90 degrees, formed between the flat sides 133a and 133b of the lower mold 133. Therefore, the preformed tile bodies 50a and 60a are closely placed on the press surface 133a, 133b. Consequently, a pair of preformed tile bodies 50a and 60a are disposed on the press surface 133a, 133b of the lower mold 133 as shown in FIG.9. In the present embodiment, the bent plate 60c is obtained by cutting the preformed tile body 60a, because the pattern of the preformed tile body 60a is a spread mottled one and it is hard to obtain the same pattern in other shape than the square shape. The cut parts are used for manufacturing another angle tile. In a tile body forming step D, the upper mold 135 is lowered toward the lower mold 133 on which the preformed tile bodies 50a and 60a are disposed. Both the preformed tile bodies 50a and 60a are pressed between the press surfaces 133a, 133b and 135a, 135b. Then, the preformed tile bodies 50a and 60a are joined at the joining surfaces 56, thereby providing an accessory tile body of angle shape. This accessory tile body is dried for a sufficient time at a temperature of not more than 100°C. A main plate body 50b is made of the preformed tile body 50a as it is. A bent plate body 60b is obtained by cutting the preformed tile body 60a at right angles by a cutter at a position 50mm apart from the end of the joint surface 56, corresponding to the length of the bent plate 60c, as shown by the two-dot chain line in FIG.9. Thereafter, an angle shaped tile body, which is composed of a pair of tile body elements 50b and 60b, is obtained. This tile body has its inner and outer surfaces smooth without any joint line at the corner. The size of each flat side 133a and 133b of the lower mold 133 is 107mm wide and 107mm long square. The lowering limit of the lower mold 133 is within 15mm from the upper end of the inner surface of the main mold 111. Therefore, the size of the forming space for each preformed tile body 50a, 60a is 107mm wide, 107mm long and 15mm deep. In the tile body forming step D of this embodiment, the pressure of the secondary pressure forming work is set at 300 kg/cm 2 , in consideration of balance with the primary pressure 50 kg/cm 2 in the preformed tile body forming step B. The main plate body 50b has a size of 100mm wide, 100mm long and 8mm thick square, and the bent plate body 60b has a size of 100mm wide, 50mm long and 8mm thick rectangular. The pressure is not restricted to the above value. If the preformed tile bodies 50a and 60a are completely joined at the corner by the secondary pressure forming work, a lower or higher pressure is admitted, depending on a kind of clay bodies as raw materials, an adhesive such as CMC and so on, a mixture percentage of the clay body and adhesive, or the primary pressure. The larger the pressure difference between the primary pressure and the secondary pressure is, the stronger the joining force of the preformed tile bodies 50a and 60a is. Thus, the corner strength of the finished accessory tile is increased. The accessory tile body 50b, 60b formed in the above mentioned way is taken out from the forming space by pulling up the upper mold 135 to separate from the lower mold 133 and pushing up the lower mold 133 to a take-up level, thereby moving the upper surface of the tile bodies 50b and 60b over the top end of the main mold 131, as shown by the two-dot chain line in FIG.9. Since the accessory tile body 50b, 60b is pressed and molded by the primary pressure forming work after forming a plurality of bars by the wet method and by the sufficient secondary pressing force, which is several times as large as the primary pressure, it has enough strength to bear any works by hand to a sufficient degree, unless it is intended to destroy them. The corner of the accessory tile is formed by sticking the joining surface 56, whose surfaces are larger than those of rectangular ends, so that a stronger corner can be obtained. In a burning step E, the accessory tile bodies obtained in the tile body forming step D are arranged in a chamotte sagger at appropriate intervals therebetween. They are burned four hours at a temperature of 1200°C and sintered. Thus obtained tile is shown in FIG.1c. The accessory tile has the main plate 50c of 100mm wide, 100mm long and 10mm thick and the bent plate 60c of 100mm wide, 50mm long and 10mm thick at opposite sides of the perpendicular corner 65. Each surface of the main plate 50c and the bent plate 60c has three parts 51c and 61c, 52c and 62c, and 53c and 63c with a spread mottled pattern or three colors, white, blue and dark brown arranged successively. In this embodiment, the preformed tile bodies are formed by the wet method, so that interval between particles of raw materials becomes closer. Moreover, the primary pressure is set at 50 kg/cm 2 , and the secondary pressure is set at 300 kg/cm 2 . As a result, tile bodies have enough strength. FIGs. 10a-10d illustrate perspective views, partially cut away, of an upper mold ridge of the accessory tile press machine, respectively. FIG.10a illustrates the upper mold ridge of the accessory tile press machine used in the first and second embodiments. FIG.10b illustrates an upper mold ridge as an example of a first modification. FIG.10c illustrates an upper mold ridge as an example of a second modification. In FIG.10a, a perpendicular ridge is formed between a pair of flat sides 115a and 115b as a press surface of the upper mold 115. In FIG.10b, a ridge is formed between a pair of flat sides 145a and 145b as a press surface of an upper mold 145. The ridge has a pressure assisting projection 145c of a semicircular cross-section, which is bulged downward from a perpendicular corner of the mold 145. In FIG.10c, a ridge is formed between a pair of flat sides 155a and 155b as a pressing surface of an upper mold 155. The ridge has plural pressure assisting projections 155c of a semicircular section, which are bulged downward from a perpendicular corner of the mold 155 and aligned along the ridge at a fixed interval. For instance, if a tile of a standard size of 100mm wide and not more than 10mm thick is produced like the above embodiment, the primary pressure of a preformed tile body is set at 100 kg/cm 2 , and the secondary pressure for forming an accessory tile is set at 400 kg/cm 2 . Thus, the preformed tile bodies can be joined reliably at the corner along the width direction merely by adjusting the pressures. The same is true for the second embodiment. On the other hand, if a larger tile, for example, a larger size over 150mm long and 20mm thick is produced, it is possible that an enough pressure cannot be transmitted from the ridge of the upper mold 115 to the jointed corner portion, particularly to both sides of the corner, of the preformed tile bodies, by merely increasing the secondary pressure. Therefore, the above mentioned press assisting projections 145c and 155c are provided to add a larger pressure to a portion, where a pressure is hard to be transmitted sufficiently, such as both sides of the joint corner of preformed tile bodies, than the rest. In consequence, particle density of the joint corner ie heightened and pressure effect is improved, thereby giving the corner an enough strength. Here, the press assisting projection 145c or the projections 155c should be provided on the ridge of the lower mold 133 in case of the die of FIG. 9. Thus, when a pair of preformed tile bodies are joined by pressing, the press assisting projection 145c or projections 155c increase the pressure for joining the corner portions of the preformed tile bodies. This structure brings some advantageous effects. Especially, it prevents such troubles as deterioration in strength of the corner of the tile, which could be caused by insufficient joining force at the corner in case it is rather longer. The pressure assisting projection 145c or 155c transmits more pressure to the inside surface of the accessory tile, without any influences on the outside surface as a design surface, so that no marks due to the additional pressure appear on the design surface. Thus, a good appearance of the design can be kept on the tile, in spite of the addtional pressure by the projection 145c, 155c. [THIRD EMBODIMENT] A third embodiment of this invention will be described referring to FIGs. 11 to 12, taking the accessory tile (cap corner tile) shown in FIG. 11 as an example. FIG. 11 illustrates a perspective view of an accessory tile in the third embodiment of this invention. Three pieces of plate tiles 201, 202 and 203 form an accessory tile shown in FIG. 11, which has such a shape as takes any three faces out of six faces of a hexahedron with other three faces opened. Such a shape of tile is called a corner cap tile. Each plate tile 201, 202, 203 is made by the method described above. A draining projection 201a is integrally formed on a joint side corner of an outer top surface, as,a design surface, of the plate tile 201. The draining projection 201a is similar to that of the second embodiment. The projection 201a can drain water or the like from the top surface of the plate tile 201. This accessory tile is manufactured by a process similar to the process shown in FIG.2, namely, by the secondary pressure forming of the preformed tile bodies obtained in each embodiment, burning them, and so on. Still, the accessory tile of the present embodiment is different from the beforementioned embodiments in that it has the corner cap shape, as mentioned above, composed of three plate tiles 201-203. FIG. 12 illustrates a perspective view of an accessory tile press machine which manufactures the accessory tiles in the third embodiment of this invention. This accessory tile press machine has a large cubic female die 211 and a small cubic male die 213a. The female die has three flat sides 211a, 211b and 211c and a curved dent 211, as a press surface. The press surface 211a to 211d of the female die 211 defines substantially a cubic concavity corresponding to the outer design surface of the accessory tile, which is composed of three perpendicularly crossing flat surfaces and a bulged surface of the draining projection 201a. Three flat sides 213a to 213c of the male die 213 has plane surfaces, respectively, corresponding to an inner surface of the accessory tile, which is composed of three perpendicularly crossing flat surfaces. The male die 213 is movable toward and away from the female die 211, so as to adjust an interval to the female die 211 by a driving unit (not shown). The male die 213 is entirely put into the cubic concavity, composed of the flat sides 211a-211c, of the female die 211, while having perimeters of the flat sides 213a-213c closely touched with perimeters of the flat sides 211a to 211c. The press surface 213a-213c of the male die 213 and the press surface 211a-211d of the femala die 211 cooperatively define a forming space corresponding to the shape of the accessory tile. An opposite corner of the press surface 213a-213c of the male die 213 is cut away so as to form a driving side surface 213d, which is connected to the above mentioned driving unit. To manufacture the accessory tile of the present embodiment, first, desired colored raw materials are prepared in a colored raw material preparing step A. Then, preformed tile bodies of plate shapes corresponding to the shapes of the plate tiles 201, 202 and 203, respectively, are formed in a preformed tile body forming step B. In a next preformed tile body disposing step C, the three preformed tile bodies are disposed appropriately on the flat sides 211a-211c of the female die 211 shown in FIG. 12. In a tile body forming step D, the male die 213 is driven closely toward the female die 211. Then, the flat sides 213a to 213c of the press surface respectively press the corresponding sides of the inner surface of the preformed tile bodies, disposed in the forming space of the female die 211, toward the press surface 211a-211d of the female die 211 at a predetermined pressure. That is, the preformed tile body go through the primary pressing between the press surfaces 211a-211d and 213a-213c, thereby being formed into the accessory tile body (corner cap body). Thereafter, the tile body is taken out from the female die 211. The accessory tile shown in FIG.11 is finally obtained by burning the tile body in a burning step E. In the above mentioned tile body forming step D, the female die 211 is preferabaly structured such that it is able to move the press surface 211a to 211d between an inner forming position and a take-up position which is set outward from the forming position. If the female die 211 has such a structure, the tile body after the secondary pressure forming can be easily taken out therefrom. Free ends of the tile body are formed aslant in parallel with the moving direction of the press surface 211a to 211d, until the secondary pressure forming is finished. The free ends of the tile body are cut off by a cutter before the burning step E so as to be rectangular. In the present embodiment, manufacturing conditions or the like in each step follow those in the above embodiments. The preformed tile bodies have inclined ends joined like the first embodiment. In this embodiment, corner cap tiles as accessory tiles are obtained. These accessory tiles can be used for such corner parts of buildings as both right and left ends of stairs or stepped parts, both rectangular ends of pillars or the like. As a result, tiling work becomes easier even if corner shapes have many variations, and work efficiency can be improved. [FURTHER EMBODIMENTS] A variety of accessory tiles which can be manufactured by this invention are shown in FIGS. 13a-13c. These accessory tiles are manufactured in a similar way to that of the above embodiments, as shown in FIG.2. An accessory tile of FIG.13a uses four pieces of preformed tile bodies, as primary formed bodies, which is obtained in a similar way to that of the above each embodiment. A forming space, which is defined between upper and lower molds or female and male dies, is made into a shape composed of any four sides of a hexahedron with other two sides opened. These four preformed tile bodies are disposed on corresponding four sides of the press surface of the mold or die, respectively. Then, the preformed tile bodies go through a secondary pressing and are formed into one body by the molds or dies, thereby providing a tile body of a specific shape of the forming space. The tile body is burnt to be made into the accessory tile as a final product. This example can provide an accessory tile coresponding to corners or longitudinally opposite ends of bars or the like as a building material for tiling, so that tiling becomes easier even if corner or end shapes have many variations, and work efficiency is improved. An accessory tile of FIG. 13b uses five pieces of preformed tile bodies, as primary formed bodies, which is obtained in a similar way to that of the above each embodiment. A forming space, which is defined between upper and lower molds or female and male dies, is made into a box shape composed of any five sides of a hexahedron with other one side opened. These five preformed tile bodies are disposed on corresponding five sides of the press surface of the mold or die, respectively. Then, the preformed tile bodies go through a secondary pressing and are formed into one body by the molds or dies, thereby providing a tile body of a specific shape of the forming space. The tile body is burnt to be made into the accessory tile as a final product. This accessory tile has a square or rectangular tube with one end opened and the other end closed. Such a tile can be used for tombstones or the like. It can be manufactured easier and faster than conventional tombstones made of common stone materials. Moreover, the accessory tile has less weight, thereby making its handling easier. Furthermore, the production costs can be cut down. This example can provide an accessory tile coresponding to corners or longitudinally opposite ends of bars or the like as a building material to be tiled, so that the same effects as the above example of FIG.13a are expected. An accessory tile of FIG. 13c uses a preformed tile bodie of plate shape and two preformed tile bodies of semi-quarter circular cross section, as primary formed bodies. The plate shaped body is obtained in a similar way to that of the above each embodiment. The bodies of semi-quarter circular cross section are made by a press machine, which modifies the forming space of the plate tile press machine of the above embodiments into a semi-quarter circular cross section. The forming space, which is defined between upper and lower molds or female and male dies, is made into substantially a V-shaped cross section. These three preformed tile bodies are disposed on corresponding parts in the forming space of the molds or dies, respectively. Then, the preformed tile bodies go through a secondary pressing and are formed into one body, while joined at portions shown by two-dot chain lines of FIG. 13c, thereby providing a tile body of a specific shape of the forming space. The tile body is burnt to be made into the accessory tile as a final product. This accessory tile has substantially a V-shaped cross section. In case of manufacturing the tiles of the examples FIG. 13a to FIG. 13c it is preferable that the female die for forming an outer surface of the tile is split in plurality, e.g. into pieces devided at the positions shown by the two-dot chain lines. With this structure, the accessory tiles can be manufactured with more ease, and work efficiency is improved. Moreover, high quality of accessory tiles can be obtained. In the above mentioned embodiments, the preformed tile bodies or tile body elements, which are joined at the corner, may be any lengths, including the same length. Moreover, the tile body or the accessory tile as a final product may have a corner of any angles, including curved corner. Moreover, the accessory tile may have any shapes, e.g. a polygonal tube such as a triangular tube, pentagonal tube, hexagonal tube or octagonal tube, a eight figure cross section, etc. Furthermore, the accessory tile may have a bottomed tubular shape, which is made by closing one end of the above shape of tubes. Otherwise, a desired side or a desired part of these shapes may be opened. The accessory tile may be applied to those which are made by joining a plurality of plates or curved tiles. In addition, the size of the final product is not restricted to that described in the above embodiments. Thus, this invention can be used for manufacturing a large plate shape of accessory tile such as a large table or the like. The manufacturing apparatus used in this invention is not restricted to those described in the above embodiments. Any type of apparatus which has been already used in the ceramic industry can be used as they are, or can be modified to form the above mentioned accessory tiles. The manufacturing method of the accessory tiles according to the above mentioned embodiments are composed of the colored raw material preparing step A, the preformed tile body forming step B, the preformed tile body disposing step C, the tile body forming step D and the burning step E. The top surface and bottom surface of the accessory tile manufactured by these processes show unique designs, while made by an unglazed natural material. The surfaces is nonskid and may be available for flooring or the like. A grinding step may be added after the burning step E, and at least the design surface of the accessory tile may be ground to exhibit more shine. Since thus ground design surface of the accessory tile gets luster and water repellency similar to those obtained by glazing, it is preferable that the accessory tile is used for the places where not only good design but also waterproofing capacity are required, such as a kitchen, bathroom or the like. In the grinding step, a conventional multi-stage grinding apparatus (three stages or five stages) may be used so as to give a desired surface roughness to the tile by means of each stage of of grinder by making the surface roughness smaller stepp by step. In this case, the accessory tile has its surface ground usually in a thickness of 1 to 2 mm. Still, sice the accessory tile of this invention is made of colored materials, as a predetermined pattern, which go through the tile in all the thickness direction, the predetermined pattern is not lost and good appearance is kept even after the grinding. In addition, in case the accessory tile of this invention is applied to a place where it is used for a time, such as a table, pillar, floor or the like, its surface can be ground to remove dirts on the surface. Thus, the tile restores good appearance and prolongs its life. The upper mold and lower mold of the above mentioned embodiments can be used vice versa. That is, the word "upper and lower" is for convenience sake, and the upper mold may be used as a lower mold and the lower mold may be used as an upper mold. The preferred embodiments described herein are therefor illustrative and not restrictive, the scope of the invention being indicated in the appended claims and all variations which come within the meaning of the claims are intended to be embraced therein.

Claims: A manufacturing method of an accessory tile made by pressing and burning a clay body into a predetermined shape, comprising the steps of: forming a plurality of preformed tile bodies (10a, 20a, 50a, 60a, 251 to 254, 261 to 265, 301; 302) of a clay body, the preformed tile body having a plate shape with a colored pattern provided on its surface, the preformed tile body being plastic and deformable; placing the preformed tile bodies on a press surface (113a, 113b, 133a, 133b, 211a to 211d) of a first mold (113, 133, 211) while having first ends (16; 22; 56) of the preformed tile bodies directly contacted with each other, the press surface of the first mold having a shape corresponding to a shape of a corner portion of a building base material so that the preformed tile bodies placed on the press surface have a shape corresponding to the shape of the corner portion, wherein the first ends of the preformed tile bodies (10a, 20a, 50a, 60a) have inclined surfaces (16, 22, 56), respectively, the inclined surfaces dividing the angle of the corner portion substantially by half; moving a press surface (115a, 115b, 135a, 135b, 145a to 145c, 155a to 155c, 213a to 213c) of a second mold (115, 135, 145, 155, 213) toward the press surface of the first mold, the press surface of the second mold having a shape corresponding to the shape of the press surface of the first mold; pressing the preformed tile bodies between the press surfaces of the first and second molds so as to join the preformed tile bodies with the first ends thereof, thereby obtaining a tile body (10b, 20b, 30b, 40b, 50b, 60b) of a shape corresponding to the shape of the corner portion of the building base material; and burning the tile body. A manufacturing method of an accessory tile according to claim 1, in which the tile body (10b, 20b, 50b, 60b) is composed of two preformed tile bodies (10a, 20a, 50a, 60a), the press surface of the first mold (113, 133) is composed of a pair of flat sides (113a, 113b, 133a, 133b) crossing angularly, and the tile body is formed into an angle shape. A manufacturing method of an accessory tile according to claim 1, in which the tile body is composed of three preformed tile bodies, the press surface of the first mold (211) is composed of three flat sides (211a to 211c) selected from six sides of a hexahedron, and the tile body is formed into a shape composed of three flat sides selected from six sides of a hexahedron with other three sides opened. A manufacturing method of an accessory tile according to claim 1, in which the tile body is composed of four preformed tile bodies (251 to 254), the press surface of the first mold is composed of four flat sides selected from six sides of a hexahedron, and the tile body is formed into a shape composed of four flat sides selected from six sides of a hexahedron with other two sides opened. A manufacturing method of an accessory tile according to claim 1, in which the tile body is composed of five preformed tile bodies (261 to 265), the press surface of the first mold is composed of five flat sides selected from six sides of a hexahedron, and the tile body is formed into a shape composed of five flat sides selected from six sides of a hexahedron with other one side opened. A manufacturing method of an accessory tile according to claim 1, in which the tile body (301, 302, 303) has an arc cross section. A manufacturing method of an accessory tile according to claim 1, in which the first end of one of the preformed tile bodies has a draining projection extending longitudinally on an exterior side thereof. A manufacturing method of an accessory tile according to claim 1, in which one of the first and second molds presses an exterior side of the tile body and the other (145, 155) of the first and second molds presses an interior side of the tile body, and the other of the first and second molds has a press assisting projection (145c, 155c) at an edge thereof, the press assisting projection protruding in such a direction as to divide an angle of the edge substantially into two. A manufacturing method of an accessory tile according to any of the claims 1 to 8, in which the preformed tile bodies (10a, 20a, 50a, 60a, 251 to 254, 261 to 265, 301; 302) are formed by pressing a clay body at a first pressure and pressing the preformed tile bodies between the press surfaces of the first and the second molds at a second pressure larger than the first pressure. A manufacturing method of an accessory tile according to claim 9, in which the second pressure is approximately two or more times as large as the first pressure. A manufacturing method of an accessory tile according to claim 9 or 10, in which the first pressure is not less than 50 kg/cm 2 . An accessory tile characterized by being obtainable by the methods of any of claims 1 to 11.

Inventors: KAKAMU SHINICHI, KAKAMU SHUKICHI, KAKAMU YOSHINORI, KAKAMU, SHINICHI, KAKAMU, SHUKICHI, KAKAMU, YOSHINORI
Applicants: MINO GANRYO KAGAKU CORP, MINO GANRYO KAGAKU CORPORATION
Application year: 1995
Main classification: B28B1
IPC codes: B28B3, E04D1, E04F13, B28B1