Method and apparatus for forming a tire

Claim 1

Tire forming apparatus for shaping and curing a preformed tire band within separable upper and lower mold members wherein an inflatable shaping mechanism is located axially of the lower mold member comprising: a. means for moving the upper mold member to a closed position relative to the lower mold member, said upper mold member in the closed position therefor forming a tire cavity with the lower mold member, b. fluid passage systems in said mold members including a plurality of passage ways having terminal end portions open to said tire cavity and spaced circumferentially in the side wall of said tire cavity, c. valve units corresponding to said passageways, each valve unit including a stem member reciprocally movable within an associated terminal end portion for movement to a retracted position to open an associated passageway and to an extended position to close said passageway, said stem member having an end face flush with the cavity side wall to form a continuous surface therewith when the stem member is in the extended position therefor, d. means for inflating said shaping mechanism under an initial pressure to provide for the expansion of the tire band to a first position adjacent to but spaced from the side wall of the tire cavity, to form an air chamber about said tire band, e. means for evacuating air from said air chamber through said passageways when the stem members are in the retracted positions therefor to produce a sub-atmospheric pressure in said air chamber, f. means for moving said stem members to the extended positions therefor when the sub-atmospheric pressure in the air chamber is at a predetermined value, g. means for heating and inflating said shaping mechanism to a predeteRmined curing temperature and pressure to expand the tire band into conforming engagement with the cavity side wall, and h. means for moving said upper mold member to the open position therefor when the tire has been cured.