GB810425A - Pneumatic tyres - Google Patents

Abstract

810,425. Pneumatic tyres. DUNLOP RUBBER CO. Ltd. July 20, 1956 [Aug. 11, 1955], No. 23118/55. Class 144 (2). A pneumatic tyre has a tread reinforcement 9 between the tread 12 and the carcase 8 in the form of a double layer of cord with the cord in one layer crossing that in the other layer to form, a lattice, and the cord in each layer extending in a series of loops 13 which progress continuously around the tyre in the same direction and meet and leave diametrically opposite edges of the tread substantially tangentially at each end of a geodesic path across the tyre crown. As shown the tread reinforcement 9 is wound on the bared crown of a carcass 8 of a worn tyre mounted on a collapsible former 2, the bared crown having been coated with rubber cement. The cord used may be rubbercoated steel, cotton, rayon, nylon, &c., either in filament or stranded form and may be wound by an apparatus such as described in Specification 786,162, the former 2 having a part spherical surface and the carcase 8 being stretched to conform thereto, Fig. 6. Rubber tread and side wall stock 12 is applied to the completed winding 9 which latter subsequently becomes embedded in the tread during moulding. In an alternative arrangement, loop 13 of the winding 9 may comprise diametrically opposite arcuate edge portions at each end of the geodesic portions to ensure a tendency to contraction of the edge portions of the reinforcement under the cord tension imposed by tyre inflation.