US Patent 7658607 Cross-over nozzle system for stack molds

A crossover nozzle system for transferring molten plastic from an inlet at the center of the stationary platen of an injection machine to the main manifold of the molding chambers of the stack molds of the injection molding machine. The crossover nozzle system relies on molten plastic pressure within the system to actuate the primary sprue shut-off valve, and thus to open and close the flow of molten plastic to the molds. Therefore, a drool-free valve mechanism is created without needing an external actuation of the shut-off valve like, for instance, a hydraulic or a pneumatic cylinder.