Retread mold including matrix biasing means

Claim 1

A retread mold comprising a pair of relatively movable platens, means for imparting relative motion to said platens to move the same between a first spaced position and a second more adjacent position, a pair of relatively movable bead aligner wheels, a first of said bead aligner wheels beng carried by a first of said pair of platens, a second of said bead aligner wheels being carried by a second of said pair of platens, means for imparting relative motion to said bead aligner wheels to move the same between a first spaced position at which said platens are in their first position and a second more adjacent position at which said platens are in their second position, first and second matrices movably carried by said first and second platens, respectively, said matrices defining an annular curing chamber in the second position of said platens, said bead aligner wheels being in axial alignment and being disposed radially inboard of said matrices, first and second biasing means between each first platen and first matrix and each second platen and second matrix, respectively, for biasingly urging the first and second matrices toward each other though in axially spaced relationship in the first position of said platens, said spaced relationship being reducible in opposition to the forces of said first and second biasing means upon movement of said platens to the second position thereof thereby defining said annular chamber, an annular bladder having first and second marginal edge portions adapted to rest upon said first and second bead aligner wheels, respectively, said annular bladder being adapted for insertion into a tire adapted to be cured in said annular chamber, first and second mechanical means for gripping first and second beads of a tire to said first and second bead aligner wheels, respectively, at least when said platens and bead aligner wheels are in their first positions whereby the tire is radially foreshortened, and means for controlling the motion imparting means of said platens to move the same to their second position to form said annular chamber prior to the movement of said bead aligner wheels from their first position to their second position whereby the radially foreshortened tire is returned to its normal condition within said annular chamber.