GB543963A - Balls for games and method for manufacturing same - Google Patents

Abstract

543,963. Moulding balls. ORA HOLDING SOC. ANON. Jan. 9, 1939, Nos. 719, 720 and 721. Convention dates, Aug. 9, 1938, Nov. 24, 1938, and Dec. 2, 1938. [Class 87 (ii)] [Also in Group XV] Balls for games particularly tennis balls, are manufactured by impregnating textile fabric with natural or artificial rubber latex, coagulating the latex, moulding hemispherical segments 4, Fig. 2, from discs of the fabric whilst still wet and at the same time eliminating part of the water through channels 8. drying the cups, cutting off the flanges 5, uniting the two cups along their edges and vulcanizing the so formed ball. The fabric is preferably one wherein the composition of the threads and their tension and degree of twisting are the same in warp and weft. The cups 4 are dried on hemispherical supports and are maintained thereon by means of rings resting on the flanges 5. In uniting two hemispherical cups, the cups are first coated completely with rubber dissolved in a volatile solvent and allowed to dry. After placing the cups together the abutting edges are covered by a band of unvulcanized rubber, the whole being then covered by two pieces of rubberized canvas and vulcanized in a mould 15, 16, Fig. 7. The moulding may have indentations 23. A hollow needle 19 affords communication between the inside of the ball and the inside of the autoclave used for heating the mould. After removal of the ball, the hole left by the needle may be stopped, or reduced in cross-section by a tubular filling.