GB648998A - Improvements in or relating to tire tubes and method of making same - Google Patents

Abstract

648,998. Pneumatic tyres. FIRESTONE TIRE & RUBBER CO. April 6, 1948, No 9601. Convention date, June 16, 1947. [Classes 144 (i) and 144 (ii)] Double air-tubes of the kind comprising an emergency chamber fitted inside a main tube of larger cross-section are made by preforming both tubes in unvulcanized condition, assembling the tubes for jointing along the rimseating portions, and then vulcanizing the composite structure. As shown in Figs. 1 and 4, the inner emergency tube is first builtup by laying on a drum 10 successive plies 11, 12 of rubberized cord fabric, the cords in the two layers crossing, and a top rubber layer 13, the edges of these layers being stepped as shown. A. marginal strip of rubber 14 is then applied to overlap one edge of the assembled plies and a flutter-valve 15 fitted over a hole adjacent that edge. The structure is then folded, as shown in Figs. 2 and 4, to complete the tube formation. This is temporarily removed from the drum over which a rubber band 30 is laid to form the outer (main) tube. The pre-built tube 1 is then laid on the band 30 the edges of which are then folded over and seamed to the exposed periphery of the tube 1, as seen in Fig. 7. A main inflating-valve 33 leading to the tube 1 is then fitted. The completed tube is finally placed in an ordinary jacketed vulcanizing-mould, steam being admitted intermittently to the inside of the inner tube to effect its partial vulcanization before the jacket is heated to effect vulcanization of the outer tube and the juncture of the tube bases.