Pneumatic tire manufacture
AssigneeDunlop Limited
InventorAnthony Gerald Goodfellow
Life of this patent
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Abstract
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.
Claims5
A method of manufacturing at least a portion of a pneumatic tire, comprising:
- a. locating an annular, substantially inextensible breaker on the radially outer surface of a former, the former including an at least substantially solid annulus which is of greater axial length than radial thickness in radial cross-section and which is of an elastomeric material which yields to permit the diameter of the former to be increased or decreased;
- b. increasing the diameter of the former to stretch the breaker;
- c. locating the former with the breaker in the stretched condition thereon in a mould;
- d. moulding a tire tread portion over the stretched breaker;
- e. moulding a tire sidewall in contact with the tread portion;
- f. curing the moulded tire tread and sidewall;
- and
- g. removing the former from the interior of the cured tire tread and sidewall.
Dependencies are inferred from the claim text.