Flash-free vented tire mold
AssigneeThe Firestone Tire & Rubber Company
InventorLouis W. Shurman
Life of this patent
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Abstract
A tire mold having air and gas venting holes is provided with synthetic resin plugs mounted in enlarged bore portions of the vent holes adjacent the inner forming surface of the mold. The plugs are axially compressible and project a slight distance beyond the inner surface of the mold. The molding pressure of the material within the mold compresses the plug whereby an outer surface of the plug becomes generally flush with the inner surface of the mold cavity to substantially eliminate the formation of runners on the molded tire. The plugs preferably are formed of a PTFE (polytetrafluoroethylene) filter leaf membrane material.
Claims14
A mold having a mold cavity with an inner article forming surface and an outer surface, at least one vent hole extending from said forming surface to said outer surface, and a filter plug mounted in said vent hole for venting air or gases from the mold cavity, said filter plug being formed of a slightly compressible porous synthetic resin and extending along a portion of the vent hole a slight distance beyond the inner forming surface and into the mold cavity so that the plug is compressed slightly during a molding operation and an end surface of the plug is generally flush with said inner forming surface reducing the formation of flash on an article being molded within the cavity.
A mold having a mold cavity with an inner article forming surface and an outer surface, at least one vent hole extending from said forming surface to said outer surface, and a filter plug mounted in said vent hole for venting air or gases from the mold cavity, said filter plug being formed of a compressible porous synthetic resin and extending a predetermined distance beyond the inner forming surface and into the mold cavity so that the plug is compressed by material in the mold cavity during molding and an end surface of the plug generally conforms to the inner forming surface to substantially eliminate the flow of material into the vent hole and resulting flash.
Dependencies are inferred from the claim text.