Abstract: A vent for a mold having a mold cavity comprising a vent main body, a valve closure member having an upper end face for positioning at the surface of the mold cavity, the valve closure member being moveable with respect to the vent main body for opening and closing the vent, a spring opening mechanism formed integrally with the vent main body for opening the vent, and a valve seat between the valve closure member and the main body wherein the vent is closed by material in the mold cavity contacting the upper end face of the valve closure member.

Abstract: A vent for a mold comprising a valve closure member and integrally formed spring opening mechanism for opening the valve closure member such that when mounted in an air release vent the valve closure member may open or close said vent.