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US 4,380,426 AGranted
Injection molding valve pin direct pneumatic actuator
OwnerWilliam J. Wilesinventor
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OwnerWilliam J. Wilesinventor
Estimating the term…
This invention relates to a valve gated injection molding system of the type where the melt passage enters the system on general alignment with the valve pin and cavity. The system has a novel valve pin actuating mechanism which is pneumatically operated according to a predetermined timed cycle. A piston which reciprocates in a cylinder has an outer collar portion from which a tongue portion extends inwardly to operatively engage the driven end of the valve pin. The melt passage extends through a portion of the back plate which, in turn, extends through the outer collar portion of the piston and is offset to leave room for the tongue portion of the piston to engage the driven end of the valve pin. Piston rings are located between the piston, back plate and cylinder to prevent excessive air leakage. This center entry system with a pneumatic actuating mechanism provides a more reliable mechanism which may be double acting.
In a valve gated center entry injection molding system comprising a heater cast seated in a cooled cavity plate, a gate through the cavity plate leading to a cavity, an elongated valve pin which reciprocates in a bore in the heater cast between open and closed positions, the valve pin having a driven end and a tip end which seats in the gate in the closed position, valve pin actuating mechanism, and a melt passage which receives pressurized melt from a molding machine at a center entry and extends through the heater cast to the gate, the improvement wherein;
In a valve gated center entry injection molding system comprising a heater cast seated between a back plate and a cooled cavity plate, a gate through the cavity plate leading to a cavity, a melt passage which receives pressurized melt from a molding machine and extends from a center entry in the back plate through an offset portion of the back plate and the heater cast to the gate, an elongated valve pin which reciprocates in a bore in the heater cast with a central longitudinal axis in alignment with the gate and the center entry, the valve pin having a driven end and a tip end which seats in the gate in the closed position and valve pin actuating mechanism, the improvement wherein;
Dependencies are inferred from the claim text.