Retreading stacked tires using inflatable pressure member

Abstract

An improved method and apparatus is shown for simultaneously retreading all of the tires in a stack of rubber tires that have been placed in an autoclave or the like. Each of the tires is covered respectively with a precured tread and enclosing envelope having a U-shaped cross section that surrounds the periphery of the tire to be retreaded, the inner edges of the respective envelopes being pressed to seal against the rims or shoulders of the tires. Proper sealing of the edges of the U-shaped envelopes against the sides of the tires is effected by compressing the stack against a back-up means adjustably supported on and locked in position on a post that extends centrally through the stack. The improved means for producing compression in the tire stack includes an inflatable tire means that surrounds the post to press the stack against the back-up means. The apparatus here shown is particularly adapted to a procedure for first pressurizing the stack and pulling a vacuum on the space inside each envelope prior to placing the stack in the autoclave and then placing the stack in the autoclave and inflating the pressure tire to maintain the seal between the tires and the envelopes. The curing process is then completed in the autoclave for applying the precured tread strips to the tires to effect the recapping of the tires.