Injection molding valve member actuating mechanism

In a multi-cavity injection molding apparatus having at least one melt distribution manifold and a plurality of heated nozzles mounted in a mold with an elongated valve pin reciprocating in a first direction in a central bore in each heated nozzle, a valve pin plate mounted in the mold to reciprocate in a first direction, the valve pin plate having the valve pins extending forwardly therefrom and actuator means extending rearwardly therefrom, at least one elongated cam member mounted in the mold adjacent the valve pin plate actuator means to reciprocate in a second direction lateral to the first direction, one of the valve pin plate actuator means and the at least one elongated cam member having a plurality of diagonally extending grooves facing the other of the valve pin plate actuator means and the at least one elongated cam member, the other of the valve pin plate actuator means and the at least one elongated cam member having a plurality of laterally projecting slide means, each of the laterally projecting slide means extending into one of the diagonally extending grooves, whereby movement of the at least one elongated cam member in the second direction moves the valve pin plate actuator means, the valve pin plate and the attached valve pins in the first direction, the improvement comprising;

• actuating mechanism to drive the at least one elongated cam member between at least first, second and third positions in the second direction to drive all the elongated valve pins to stop simultaneously and accurately at least first, second and third corresponding positions the first direction during each injection cycle.