| 摘要 |
A method and apparatus for building a closed torus pneumatic tire in which the components of the tire, exclusive of the belt and tread structures, are wrapped about a cylindrical former, inextensible bead rings are positioned about the former in positions spaced axially apart substantially the same as the final desired axial spacing. The former is radially expanded and expands the carcass structure to clampingly engage the bead rings. Each axially outer end portion of the carcass structures is folded over toward the axial centerplane of the drum in a manner in which the carcass is free of internal restraint at the fold. Each axially outer end of the folded over end portion of the carcass structure freely contracts radially into position to be clamped by a pull-over ring and is pulled axially across the former to a predetermined position past the midcircumferential centerplane of the former and released. A sidewall restraint ring moves into position adjacent the fold to prevent roll back of each end portion. The overlapped center portions of the ply structures are stitched together to form a closed envelope construction. A preformed belt and tread structure is disposed circumferentially about the former with the centerplanes of the belt, tread, and carcass coincident. The envelope is inflated into engagement with the preformed belt and tread structure which are in turn stitched to the carcass.
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