Dual feed single cavity injection molding system
AssigneeMold-Masters Limited
InventorHarald H. Schmidt
Life of this patent
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Abstract
This invention relates to a manifold housing for a valve gated single cavity injection molding system. The heated manifold housing has a dome portion and a base portion which is secured to a heated nozzle with aligned central bores through which the valve pin extends. Hydraulic actuating mechanism is mounted inside the manifold housing to reciprocate the valve pin between open and closed positions. The melt duct in the manifold branches from a central inlet into two separate arms with smoothly curved bends which extend to join the central bore on opposite sides of the valve pin. Providing two streams of melt which meet at the valve pin avoids the problem of streaking and slow melt flow on one side of the valve pin.
Claims7
In a valve gated single cavity injection molding system having a heated nozzle seated in a cavity plate with an elongated valve pin having a driven end and a tip end mounted in a central bore in the nozzle, and a melt passage for conveying melt from a central inlet to a gate in a cavity plate leading to a cavity, the melt passage extending around the valve pin in the central bore of the nozzle which is in alignment with the central inlet and the gate, the improvement wherein,
- (a) a heated hollow manifold housing is seated in a mold back plate, the manifold housing having a dome portion and a base portion, the dome portion having the central inlet therein, the base portion extending between the heated nozzle and ths dome portion and having a valve pin bore extending therethrough, the valve pin bore having a first portion and a second portion, the first portion having a substantially uniform diameter to snugly receive the valve pin therethrough, the second portion having a larger diameter than the first portion and extending in alignment from the first portion to an outlet connecting to the central bore of the nozzle, the manifold housing having a melt duct which forms a portion of the melt passage and extends from the central inlet to the join between the first and second portions of the valve pin bore, the melt duct in the manifold housing branching into at least two arms which extend to connect to the valve pin bore on opposite sides thereof, and
- (b) hydraulic valve pin actuating mechanism is mounted inside the manifold housing, the actuating mechanism including a cylinder securely mounted inside the dome portion of the manifold housing with an insulative air space between them, a piston located in the cylinder and operatively connected to the driven end of the valve pin, and hydraulic fluid ducts connected to the cylinder on opposite sides of the piston, whereby the valve pin is reciprocated between a retracted open position and a closed position wherein the tip end of the valve pin is seated in the gate
Dependencies are inferred from the claim text.