Патент USA US2120742код для вставки
June 14, 1938. F. W. GRUNDY I 2,120,742 TILE OR SLAB MADE FROM CERAMIC OR LIKE MATERIALg Original Filed Feb. 9, 1934 2,120,742 Patented June 14, 1938 UNITED STATES PATENT OFFICE‘ 2,120,742 TILE OR ‘SLAB MADE FROM CERAMIC OR LIKE MATERIALS Francis Wilson Grundy, Rainford, near St. Helens, England, assignor to Rainford Potteries Limited, Rainford, England, a British company Original application February 9, 1934, Serial No. 710,551. Divided and this application August 20, 1936, Serial No. 97,069. In Great Britain April 28, 1933 2 Claims. The present invention relates to new and use ful improvements in tiles or slabs of the type shown in my copending application Serial No. 710,551, ?led February 9, 1934 of which this is a 5 division. The invention relates more particular ly to improvements in tiles or slabs which are made from ceramic earthenware or the like ma terial. It has been heretofore proposed to provide hol 10 low clay bodies of rectangular or substantially rectangular section with longitudinal grooves to form cleavage lines for the baked body. With the exception of hollow cylindrical bodies or pipes it has hitherto not been possible to obtain 15 a tile or slab the surfaces of which wholly con formed to that of the original clay body as def ormation of the sides and surfaces of the body occurred due to the fact that the resultant stresses incident upon drying or baking did not 20 lie wholly within the inner and outer bound ing surfaces of the body. An object of the present invention is to pro vide a hollow clay body wherein the resultant stresses incident to the drying and baking of the 25 clay body are evenly distributed and lie wholly within its material structure so that the re sulting slabs, after the hollow body has been split, have ?at and regular surfaces. A further object of the invention is to provide 30 an extruded hollow polygonal clay body in cluding at least one acute angle which is op posed to an obtuse angle whereby the hollow body can be readily split through the apices of the opposed obtuse and acute angles to form 35 angle slabs having truly ?at surfaces. The above and other objects of the invention will in part be obvious and will be hereinafter more fully pointed out. The invention relates generally to the provi 40 sions of an extruded hollow clay body having at three sides or at most four sides wherein two pairs of the sides are identical and disposed rel ative to one another so that the hollow‘ clay body is provided with at least one acute angle 45 which is directly opposed to a flat surface or to (Cl. 72—41) poses unless completely ?at is useless for aesthet ic reasons. Angular slabs of this character are particu— larly desirable as facing bricks or tiles for form ing corners or angles of a building where two walls join one another so that there is no mortar or cement seam visible down the corner of the building. These slabs may also be used in the making of window-sills or the like. Where two Walls join one another at an angle of nine 10 ty degrees, it is obvious that the angle within each duplicate slab will also be ninety degrees. The invention is more particularly described with reference to the accompanying drawing in Which:—- ' spective. Figure 2 shows an alternative form of clay body in end perspective View. Figure 3 is the same body in side perspective 20 View. ' In one method of construction, plastic clay is forced by mechanical or hydraulic pressure between a central mandrel of substantially tri angular shape in cross-section and an outer die 25 ring having a substantially triangular inner sur face in cross-section. The apices of the hollow prismatic body so extruded as shown in the drawing are provided with grooves I. Any desired grooving, such as 2, may be left on 30 the inside walls. This body is then dried, the drying operation preferably including an initial rapid drying of its surface immediately after ex trusion from the die to convert the surface into a porous state, whereby blisters are avoided 'on 35 subsequent baking. The element is then baked to the biscuit stage. It may then be glazed and re?red, whereupon the element can be broken up into three separate slabs about the cleavage lines 3 at the bottom of the grooves l, thereby forming 40 three slabs of any desired dimensions. Where it is desired to form smaller tiles, the grooves, such as 4 may be cut in. the soft clay prior to baking to form extra cleavage lines subsequent 45 to baking. In another method of construction shown in an obtuse angle. Thus, the hollow clay body is symmetrical about a line intersecting the base Figures 2 and 3 plastic clay is forced by mechani or apex of the opposed obtuse, and apex of the cal or hydraulic pressure between a central man acute angle so that it may be split to provide 50 duplicate angular tiles or slabs which have smooth internal and external surfaces. Hither to it has been found almost impossible to se cure perfectly flat slabs in dimensions larger than a few square inches, due to the stresses set 55 up in drying and baking. A tile for facing pur 15 Figure 1 shows one form of clay body in per drel of prismatic shape in cross-section and an 50 outer die ring of similar shape. Grooves are preferably formed on the inside of the body as shown at 5, by means of inwardly pro jecting knives or the like from the die. These grooves are preferably undercut, and as shown at 6 and 1, may be reversed relatively to one another 55 2 2,120,742 to form a good keying for cement or plaster-work, by which the slabs are attached. It will be found It will be found that the body, when baked, will split readily at the “apex” 9 of the body, and also at the opposing apex l0, thus forming two or to predetermine the width of the ?nished slab. From the foregoing description, it will be ap parent that minor changes in the details of con struction and arrangement of parts may be made Without departing from the scope of the invention 5 as set forth in the appended claims. I declare that what I claim is:- angular slabs H, 12, of unequal sides, which are particularly suitable for ledges or corner-work in polygonal clay body, the inner and outer surfaces that a roughened edge 8 is formed at one side of these grooves, which further assists this. 10 the facing of buildings. In the manufacture of the body, it is preferably dried after extrusion, the drying operation pref erably including an initial rapid drying of its'sur face immediately after extrusion from the die to 15 convert the surface into a porous state, whereby blisters are avoided on subsequent baking. The element is then baked to the biscuit stage. It may then be glazed and re-?red, whereupon the ele ment can be broken up into two separate angular slabs about the cleavage apices 9, l0. Cleavage lines [3 may be formed in the clay prior to baking to facilitate trimming of the slab 1. As a new article of manufacture, a hollow of which are bounded by parallel planes and hav 10 ing acute and obtuse angles directly opposed to one another and including at least two pairs of symmetrical sides. 2. As a new article of manufacture a four-sided hollow clay bodyhaving an acute angle directly 15 opposed to an obtuse angle and being symmetrical about a line intersecting said angles whereby the body may be split through the apices of said angles to form duplicate angular slabs, the inner and outer surfaces of each side of said body lying 20 in parallel planes. ' _ FRANCIS WILSON GRUNDY.