Abstract: A tire mold is described that includes a plurality of tread molding segments having an inner surface for molding the tire tread. The mold further includes a plurality of sidewall plates having an inner surface for molding the tire sidewall. The tread mold segments together with the sidewalls cooperate to form a tire molding cavity. The sidewall plate further comprises a slot that extends from the outer surface of the tread segment to the inner mold surface, and has a piston having a head slidably received in the slot. A pin is positioned between the piston head and an end of the slot. The mold further includes actuating means for actuating the piston in the slot when the mold is closed.

Abstract: A vent for a mold having a mold cavity comprises a valve member housed within a main body sleeve and reciprocally moveable therein in an axial direction between open and closed positions. The sleeve is mounted within a mold wall and contains an expansion agent such as silicon. An increase in mold temperature causes the expansion agent to expand and move the valve member from the closed position into the open position. An external annular groove is provided within the sleeve to receive displaced mold wall material as the sleeve is press inserted into the mold wall. A tight fit of the sleeve within the mold wall results. The sleeve and valve are configured to allow air to escape in the open position. The valve member is moved to the closed position by material within the mold cavity pressing against the valve member.