Abstract: A venting unit is inserted in a press fit within the air vent of a rubber article forming mold and is comprised of a cylindrical body member with an axial bore having a reduced outer end section forming an air inlet open to the mold cavity. Received for reciprocal axial movement within the bore between an inlet closed position in abutting engagement with the outer end section and an inlet open position removed from the outer end section is a heat absorbing piston or disc. The opposite or inner end section of the bore receives a vented plug in a press fit to form a radially inwardly projected shoulder and a spring is held in compression between the disc and the shoulder of the vented plug. During expansion of the rubber article, pressurized air in the mold cavity urges the disc to its inlet open position and is vented to the atmosphere.

Abstract: A venting unit is inserted in a press fit within the air vent of a rubber article forming mold and is comprised of a cylindrical body member with an axial bore having a reduced outer end section with an air inlet open to the mold cavity. The junction of the reduced outer end section with the main section of the bore is defined by a shoulder that provides a rubber severing member. Any uncured rubber which, during expansion of the rubber article to its final form that may be compressed into the reduced section expands on entering the main bore section and is severed at the shoulder on removal of the formed article from the mold cavity. The diameter of the reduced bore section relative to its axial length provides for the unexpanded rubber that adheres to the removed article being of a relatively minute size so as to form with the exterior surface of the article a substantially smooth and continuous surface.

Abstract: Separable mold sections of a tire forming machine are brought together to form a tire cavity within which a preformed tire band is continuously expandable toward and against the inner surface of the cavity side wall. During the tire shaping operation, air is forced by the expanding tire band from the cavity and into the atmosphere through vents having vent opening and closing valve units. As the expanding tire band moves into conforming engagement with the inner surface of the cavity side wall, the final residual air in the cavity is forced therefrom concurrently with the valve units at the terminal cavity ends of the vents being engaged and moved by the expanding tire band to vent closing positions wherein the velve units form a smooth surface continuous with the inner surface of the tire cavity.This application is a continuation of application Ser. No. 363,037, filed Mar. 29, 1982, now abandoned, which is a continuation-in-part of application Ser. No. 181,461, filed Aug. 20, 1980, now issued as U.S. Pat.

Abstract: Separable mold sections of a tire forming machine are brought together to form a tire cavity within which a preformed tire band is expandable against the inner surface of the cavity side wall. During the tire shaping operation, air is forced by the expanding tire band from the cavity and into the atmosphere, through valve controlled air passages having terminal ends open to the cavity side wall. As the expanding tire band moves into conforming engagement with the inner surface of the cavity side wall, the final residual air in the cavity is forced therefrom concurrently with valves at the passage terminal ends being engaged and moved by the expanding tire band to passage closing positions wherein the valves form a smooth surface continuous with the inner surface of the tire cavity.