Abstract: The present invention refers to a hot runner manifold composed of two parallel hot runner plates disposed in parallel, one behind the other, to feed at least two different plastic materials along horizontal hot runners to injection nozzles bolted to the front hot runner manifolds.

Abstract: An integral sprue gated injection molding nozzle having a melt bore extending centrally therethrough wherein a circular forward end portion of the electrical heating element encircles the melt bore in the nose portion to provide additional heat adjacent the gate.

Abstract: Injection molding nozzle having electric plate heaters mounted thereon. Insulative air spaces are provided according to a predetermined size, shape and pattern between the outer surfaces of the nozzle and the abutting inner surface of each heater. This provides heat transfer from the heaters to the nozzle according to a desired profile along the melt flow passage through the nozzle, depending upon the system configuration and the application.

Abstract: An injection molding nozzle having a self-supported valve member actuating mechanism. The elongated valve member extends rearwardly into a cylinder assembly which is mounted on the main body of the nozzle. The rear end of the valve member is connected to a pneumatically actuated piston to reciprocate it between the open and closed position. A wedge clamp removably attaches the cylinder assembly to a connector member which is bolted to the rear end of the main body of the nozzle.

Abstract: A valve gated injection molding system having a heated nozzle which is secured to a heated manifold received in a well in a cooled cavity plate. An insulative air space extends around between the heated nozzle and the cooled cavity plate. An locating flange extends outwardly across the insulative air space from either the nozzle or the manifold into contact with the surrounding cavity plate. The locating flange has number of holes extending transversely therethrough according to a predetermined configuration to reduce heat loss from the heated nozzle and manifold to the surrounding cooled cavity plate.

Abstract: A valve gated injection molding apparatus in which the actuating force from a pivotal lever member is transmitted to an elongated valve member through a split ring. The two opposing segments of the split ring are mounted around the neck portion of the valve member when it is in the retracted position. The segments are received in a central opening in the manifold which keeps them in longitudinal engagement with the valve member as they reciprocate. The split ring has a notch which engages the inner end of the lever member. The split ring has a collar portion which extends into the nozzle bore in the forward position and determines the length of travel of the valve member between the open and closed positions.

Abstract: This invention relates to a multi-cavity injection molding system in which a number of nozzles are fixed to a common manifold, and valve gating is provided by actuating the manifold and the nozzles together. A pair of hydraulically actuated pistons are mounted to drive the manifold and nozzles between a retracted open position and a forward closed position. Each nozzle has a truncated tip on the forward end portion which seats in a gate in the closed position. Pressurized melt flows through a melt passage which branches in the manifold and extends through each nozzle to a melt receiving space around the forward end portion. A circumferential sealing and locating flange prevents the leakage of melt from this space as the nozzle reciprocates.

Abstract: This invention relates to an injection molding system in which melt flows in channels in the outer surface of a heated probe seated in the cavity plate on its way to the gate leading to the cavity. The probe has a tip end in alignment with the gate and the probe is reciprocated between open and closed positions to valve gate the flow of melt to the cavity. According to a preferred embodiment, in a multi-cavity system a number of probes are fixed to a manifold which is actuated to valve gate all of the cavities simultaneously. Hydraulic cylinders are provided to drive the manifold to the closed position, and injection melt pressure acting on the tip ends of the probes is utilized to return them to the open position. Valve gating the heated probes provides the advantage of improved temperature control of the melt in the immediate gate area.

Abstract: The invention relates to a single nozzle injection molding system in which the nozzle is reciprocated longitudinally to valve gate the flow of melt to the cavity. The nozzle has a pointed tip which seats in the gate in the forward closed position and is retracted to the open position. The nozzle is secured against rotation, and an inner collar is secured to it. This inner collar threadably engages a surrounding outer collar which is free to rotate, but secured longitudinally. A pneumatic piston is connected to the outer collar to rotate it through a predetermined angle. Thus, when the outer collar is rotated in one direction, the inner collar and nozzle are driven to the forward closed position, and when the outer collar is rotated in the opposite direction the inner collar and nozzle are retracted to the open position.

Abstract: A melt transfer system is provided for a stack mold. The melt transfer system includes first and second transfer bushings arranged in opposing platens of the mold. Each transfer bushing defines a portion of a runner passage communicating at shear gates disposed in a shearing surface that is parallel to the direction of opening and closing movement for said platens in order to shear the melt when the platens are moving from a closed position to an open position. In another aspect, the shearing surfaces are normal to the direction of movement of the platens and at least one of the transfer bushings is rotatable relative to the platen for shearing the melt. In another aspect, a transfer bushing is provided having a core formed of an insulative material and a shell formed of a conductive material. The core defines a channel for conducting melt between a shear gate at one end of the channel and an aperture at another end of the channel.

Abstract: This invention relates to an injection molding system having an axially aligned forward and rearward heated nozzle mounted in tandem. The rearward nozzle is seated in a fixed position, while the forward nozzle reciprocates between a retracted open position and a forward closed position to provide valve gating. The forward nozzle has a rearwardly extending sleeve portion which projects into the rearward nozzle to connect the melt bores of the nozzles as the forward nozzle reciprocates. The forward nozzle has a heated nose portion with a tip which seats in the gate in the closed position. A pneumatically actuated piston bears against the rear end of the forward nozzle to drive it to the closed position. Injection melt pressure around the nose portion drives the forward nozzle back to the open position.

Abstract: A valve gated injection molding system having a novel valve member for large volume applications. The elongated valve member has a ribbed insulative portion between the main steel portion and a conductive portion adajcent the tip end. The conductive portion provides more rapid cooling when the tip end is seated in the gate in the closed position. The adjacent insulative portion provides a thermal barrier to reduce heat flow along the valve member to the conductive portion. This combination avoids sticking of the tip end when the mold opens and thus allows cycle time to be reduced. The conductive portion has an integral beryllium copper plug which is supported by radially extending ribs of the insulative portion to withstand continual repeated impact loading every time the gate is closed.

Abstract: A valve gated injection molding system having a double acting pneumatic rack and pinion valve pin actuating mechanism. The melt passage branches in a manifold from a central inlet and flows along the valve pin in a central bore in the nozzle to the gate. A pneumatically driven piston pivots a toothed pinion member mounted in a slot in the manifold. The pinion member engages a toothed rack member which reciprocates along a straight line in the slot in the manifold and engages an enlarged head of the valve pin in a slot in the rack member. Lateral forces from the pinion member are absorbed by sliding contact of surfaces of the rack member against matching surfaces of the slot and/or a valve pin bushing, and are not transmitted to the valve pin. This avoids uneven wear and buildup of melt deposits around the valve pin which can otherwise result in leakage and malfunction.

Abstract: Valve gated stack injection molding apparatus with an upstream heated nozzle seated in a fixed mold platen and a downstream heated nozzle seated in a movable mold platen. The melt flows through a melt passage across a parting line from an upstream gate to an aligned downstream gate. A first elongated valve member is reciprocated between a retracted open position and a closed position in which the tip of the valve member is seated in the upstream gate. A second elongated valve member is similarly reciprocated between a retracted open position and a closed position in which the tip of the valve member is seated in the downstream gate. In the closed position, the faces of the tips of the valve members abut against each other along the parting line. One of the valve members has a vent bore extending diagonally from its face to avoid a piece of plastic film being formed from melt trapped between them in the closed position.

Abstract: A stack injection molding system for conveying melt from an upstream heated nozzle seated in a fixed mold platen to an aligned downstream heated nozzle in a movable mold platen. The upstream dowstream nozzles each have a nose portion with a forward face which abuts against each other in the parting line in the closed position. The melt passage extends through aligned central melt bores in the nozzles which taper inwardly adjacent the forward faces to form a sprue gate where they join. While both nozzles have an integral electrical heating element, only the heating element of the upstream nozzle has a circular forward portion which is brazed in the nose portion to encircle the melt bore and provide more heat and better control adjacent the sprue gate. Before the mold is opened along the parting line for ejection during the injection cycle, power to the heating elements of the nozzles is turned off to avoid drooling of melt from the open sprue gate.

Abstract: A center entry valve gated injection molding system having a heated nozzle secured in front of a heated manifold with at least a pair of valve member biasing mechanisms extending radially outward from a reciprocating elongated valve member. The melt passage splits into two branches which extend through a manifold outwardly around a rear portion of the valve member. The two branches of the melt passage and the two biasing mechanisms are alternatively evenly angularly spaced around the valve member which considerably reduces the space required. The valve member has an enlarged forward end which opens forwardly into the cavity and is closed in a retracted position in which it seats in the matching mouth of a gate in a nose portion of the nozzle. Each biasing mechanism includes a compression spring which engages a lever member to continuously urge the valve member rearwardly. When injection pressure is applied it overcome the force of the springs and moves the valve member forwardly to the open position.

Abstract: This invention relates to injection molding and particularly to a melt transfer system for stack molding. According to the invention, a novel combination of known melt flow control valve units are arranged and operated to control the flow of pressurized melt from the stationary platen adjacent the molding machine to a manifold in the center moving platen. One control valve unit is located in the stationary platen in alignment with another control valve unit located in the moving platen. When the moving platen is in the closed position adjacent the stationary platen, the gates of the two control valve units abut and when the valve pins of the two control valve units are actuated to the open position, pressurized melt will flow through the gates from the stationary platen to the moving platen. The hot runner passage extends from the molding machine through the control valve unit located in the stationary platen.