Patent ID: 7836915
Filing Date: 2010-11-23
Classification: B29C,Y10T

Abstract:
1. A valve gate apparatus comprising: a plurality of pistons, staggeredly arranged; wherein the plurality of pistons includes at least an upper piston and a lower piston; wherein the upper piston is positioned above the lower piston; a projected area of the upper piston overlapping a projected area of the lower piston; a first valve stem; joined to the upper piston, such that the upper piston and the first valve stem travel operatively, in unison; and a second valve stem, joined to the lower piston, such that the lower piston and the second valve stem travel operatively, in unison, wherein a wall thickness between a piston bore, or a cylinder bore, and a valve stem bore, is sufficient to rigidly support the lower piston or a piston cylinder and house them in an airtight chamber within a cylinder block, further including a cover plate, operatively mounted to a top of the cylinder block, which encloses the piston bore, such that when air is fed via a second passage through said cover plate, above the lower piston, said lower piston moves downward.