Tyre cast in mould with inflatable diaphragm - using mould for carcass then substitute shell in tread zone for second elastomer filling

摘要

Method of casting a tyre of castable elastomer in a mould uses an inflatable diaphragm, which is initially expanded to fit into the mould, and then deflated or contacted progressively as the elastomer is introduced. The elastomer for the tyre carcass is first introduced through a first duct (24) into the mould, then the tread zone mould part (20) is replaced by one of a different form (28) containing the tread shape, and then further elastomer for the tread zone is introduced through a second duct. The separating diaphragm (4) is thus pref. stretched across the surface of the main diaphragm in the tread zone. The arrangement enables two different materials to be used for the carcass and the tread region.