Pneumatic tire manufacture

摘要

In the moulding of the tread portion of a pneumatic tire the radially inner surface of the mould cavity is defined by the radially outer surface of an annular former of elastomeric material. The former is contracted, a breaker assembly is built onto it and it is allowed to expand to stress the breaker. In the mould the former is further expanded and is held in compression between mould parts and the breaker to withstand moulding pressure. The former may have inflatable pockets to throw the breaker edges into contact with tire sidewall reinforcements.