Abstract: This invention relates to an improved valve pin for an injection molding system and a method of making the same. The elongated valve pin has a tip end portion which extends from a larger driven end portion into the flow of melt to the cavity. The elongated tip end portion is provided with a desired combination of strength and thermal conductivity by having a copper core inside a steel casing. The casing is made by brazing a tip end cap member to a hollow sleeve. A predetermined quantity of copper wire is then inserted into the casing and melted in a vacuum furnace to form an integral construction. The excess sleeve is then cut off and the end is brazed into a well in the driven end portion of the valve pin. The tip end cap member is then machined to provide a tip end of a desired shape.

Abstract: The present invention relates to a method and the relative device for the effecting thereof, for eliminating the feeder head portion which results at the end of the injection moulding process for articles of thermoplastic material.

Abstract: A material injection assembly (10) of the type for injecting a resin material into a mold cavity including a body member (12) defining a nozzle (13) for injecting material into a mold (14) and including at least one central channel (16) for conveying a first material through the nozzle (13). The assembly is characterized by an internal purging mechanism for closing the nozzle (13) to the mold (14) while allowing the flow of purging material between the channel (18) supplying resin material to the control channel (16) and a debris channel (22). The purging mechanism further allows flow of purging material between a separate purging material channel (20) and the debris channel (22) to perform a post-purge function.A cooling system is also disclosed which provides a coolant supply channel (70) which bifurcates into two channels (75, 77) about the central channel (16) proximal to the nozzle (13) to provide maximum cooling at the portion of the assembly (13) closest to the mold (14).

Abstract: A gate for a mold comprises a plunger member mounted in the molding compound inlet conduit and adapted to prevent flow through the conduit in a first longitudinal position and to permit flow through the conduit in second longitudinal positions. The plunger defines an enlarged sealing end which is proportioned to prevent flow through the conduit on the first position. The sealing end defines a mold cavity-facing surface which is of larger cross-sectional area than the surface of the plunger opposed to the mold chamber and subject to contact with pressurized molding compound in the compound. The plunger member is longitudinally expansible and contractible so that even though one end may be rigidly mounted in the conduit, the enlarged sealing end is longitudinally movable to open and close the mold gate in a manner purely responsive to pressures therein. Thus, spontaneous gating of a mold may be provided.

Abstract: 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.

Abstract: This invention relates to an integral heated probe for plastic injection molding and a method of making the same. The probe has an elongated steel outer body with a cylindrical well extending to a pointed tip end. An electrical cartridge heater member positioned in the well with the leads extending out the open end. The space adjacent the pointed tip end and all around the cartridge heater is filled with copper to improve heat transfer between the heater member and the outer body. The copper fusing is performed by two-stage heating in a vacuum furnace. First a slug of copper is inserted into the well and heated to melt it into the pointed tip end. Then the heater member is inserted into the well through a sleeve of copper at the top and heated to melt the copper. The copper flows down around the heater member and fuses to it, the outer body and the previously inserted copper.

Abstract: A nozzle for use in an injection molding machine. The nozzle comprises a tripartite body having an inlet, an outlet and an interconnected passageway extending therethrough. A heat pipe is located within the center of the body and portions of the passageway are disposed about the heat pipe. A resistance heating band is mounted on the body to conduct heat therethrough to heat the heat pipe. The heat pipe serves to heat plastic flowing through the surrounding passageway portions to the outlet.

Abstract: The instant invention is directed to an injection nozzle for mixheads for the production of foams or solids from at least two flowable reaction components, comprising a nozzle housing with a nozzle needle guided in it which is provided with a positive control and cooperates with a nozzle opening, wherein a feed pipe and a return pipe end upstream of the nozzle opening in said nozzle housing and wherein said nozzle needle in its closed position connects said feed pipe and said return pipe to each other via a connecting channel, characterized in that said nozzle needle is divided into a needle core and a needle sleeve which surrounds said needle core and is guided on it, wherein said needle core cooperates with said nozzle opening and is pin-less in design and wherein said needle sleeve is provided with said connecting channel; and in that, when switching over from injection to return, said needle core is located in the closed position sooner than said needle sleeve in the return position, and when switching ov

Abstract: An injection molding device for molding shaped bodies of natural or synthetic rubber comprising a heatable mold for shaping and vulcanizing therein the bodies to be molded and an elongated feed duct communicating with the mold via an injection nozzle. Plasticized material is fed into the duct by a plasticizing device and injection is effected by a piston-type injection device, both communicating with the duct. There is provided in the duct a valve which in its closed position blocks ingress of plasticized material into the duct but opens the duct for ingress of the material to be pressed by the injection means into the mold via the nozzle. The valve head is axially displaceable in the duct and mounts a member so dimensioned that in the open position of the valve it fully closes the nozzle opening, thereby pushing any residual plasticized material into the mold and in the closed position is completely withdrawn from the nozzle opening.

Abstract: This invention relates to mechanical double acting mechanism for actuating valve pins in a valve gated injection molding system. A number of valve gate units are aligned with a pneumatically driven toothed rack member. The rack member engages a hollow rotatable pinion member which is secured in each unit against transverse movement. The driven end of the valve pin is fixed in a bushing which extends through the pinion member and threadably engages it. The valve pin is actuated between the open and closed positions by longitudinally driving the rack member which rotates the pinion member and the bushing. In addition to providing a reliable and relatively inexpensive actuating mechanism, provision is made for relative axial adjustment of the valve pins prior to the commencement of operation which provides accurate valve seating without unduly high manufacturing tolerances.

Abstract: Apparatus for the sprueless injection molding of parts from polymers. The apparatus includes an injection mold having a part-forming cavity, and an injection nozzle having a front end cooperating with the mold. A selectively operated closing valve is disposed in the nozzle, the valve having a movable valve member with a valve seat thereon cooperating with a valve seat on the nozzle body. A gate channel or passage is disposed between the valve seat on the body of the nozzle and the inlet opening of the mold cavity. The movable valve member has an elongated forward end portion which is telescoped within the gate passage, the forward end portion sealingly engaging the wall of the gate passage when the valve member is in its forward, closed position, the forward end surface of the elongated forward end portion of the valve member facing the mold cavity lying substantially flush with the wall of the mold when the valve member is in its forward, valve-closed position.

Abstract: This invention relates to an improved valve-gated injection molding system. The hot runner passage through which the melt flows to the cavity is divided into three spiral-shaped channels which converge again immediately before the gate, thereby imparting a curving motion to the melt as it flows outward from the gate in the cavity. This avoids unidirectional molecular orientation of the melt, thereby providing a stronger molded product. In a preferred embodiment of the invention, the melt channels reduce in helical diameter and cross sectional area as they approach the gate, thereby accelerating the swirling motion of the melt.

Abstract: A gate for a mold comprises a molding compound inlet conduit for communication of molding compound to the mold cavity. A plunger member is slidably mounted adjacent the inlet conduit and adapted to prevent flow through the conduit in a first sliding position and to permit flow through the conduit in a second sliding position. The plunger defines a slidable shaft and an enlarged end proportioned to prevent the flow through the conduit in the first position. The enlarged end defines a mold cavity-facing surface of larger area than the opposed surface on the enlarged end, which opposed surface communicates with the conduit. Accordingly, pressurized molding compound presses against the opposed surface, to spontaneously open the plunger into a second sliding position to admit molding compound to the mold cavity. Upon essential equalization of the pressures in the mold cavity at the conduit, the plunger is spontaneously moved hydrostatically to its first closed sliding position.

Abstract: This invention relates to a nozzle seal for valve-gated injection molding. The hollow seal is seated in the nozzle portion of the heater cast and extends across the insulative air gap and into a gate aperture in the cavity plate. The inner bore of the nozzle seal is tapered to form the gate which receives the tip end of the valve pin in the closed position. The nozzle seal is formed of a poor conductive metal such as titanium alloy which conducts sufficient heat to provide a clean closing gate without resulting in unacceptable heat loss to the surrounding cavity plate.

Abstract: A valve nozzle is used at an end of a hot runner or an injection molding machine for an injection molding. The valve nozzle comprises a cylinder as a body of the nozzle, and a piston. The cylinder has a gate and has a larger inner diameter at the rear end and a smaller inner diameter at the front end. The piston has a passage in the piston and has a large outer diameter at the rear end and a smaller outer diameter at the front end.

Abstract: A method and apparatus for multiple cavity injection molding which permits individual variation of gate opening time for mold shut-off bushings. The gate pins for the shut-off bushings are controlled by individual double-acting fluid motor, the bushings being fed by a common manifold. Gate opening is thus not dependent upon attainment of a predetermined injection pressure. Closure of the gate for each cavity will permit material to be fed faster to the other cavities. Novel means is provided for securing each gate pin to its actuating cylinder, which minimizes heat transfer to the motor, accommodates expansion of the material manifold and permits gate opening adjustment. The fluid motors are end-mounted on an actuating fluid manifold, allowing close juxtaposition. A cycle counter may be used to control inventory.

Abstract: An injection molding machine includes complementary mold members which cooperate to present a mold cavity in the shape of a clay pigeon or other articles. An injection passage leading to the mold cavity receives a slidable pin of smaller diameter than the passage. The pin has a tapered tip which, when the pin is extended by a power cylinder, seats in an outlet opening of the passage to block the opening in a manner to prevent the formation of a sprue on the part. The pin is heated along with a surrounding sleeve to maintain the material in the passage in a molten state and to assure proper release of the part from the mold. When the pin is retracted, molding material is able to flow around it, through the injection passage, and into the mold cavity.

Abstract: An injection gate of a mold cavity comprises an elongate valve rod which passes axially through a flow channel for molten plastic material and is guided in an extension of a thin-walled steel cylinder open at its opposite end toward an adjoining manifold plate. The rod extremity remote from the gate is secured to a tubular neck of a piston inside the cylinder whose stroke length is a fraction of the axial height of the cylinder's interior, a clearance around this neck providing space for drooling plastic while the length of the neck and of the peripheral cylinder wall serves for thermally insulating the manifold plate from the flow channel.

Abstract: Apparatus for coating one surface of a molded article that consists of a pair of hot relatively movable die members which when closed, form a cavity for molding the article in a desired configuration. A pin is selectively movable into and out of engagement with the surface of one of the die members. On retraction, the pin is also retracted through the opening in the injector nozzle allowing the injector to force material into the cavity to coat the outer surface of the article while the die members are closed. The barrel of the injector nozzle is cooled.

Abstract: This device injects plastics material into a mould having a plurality of impressions. It comprises a distribution plate pierced with channels for the inlet of the plastics material to be injected and provided with heating means and an impression plate comprising a plurality of impression inserts into which the plastics material is to be injected. Injection nozzles are disposed between the distribution plate and the various impression inserts, each presenting an injection orifice opening into the impression insert associated therewith and being obturated by an obturator needle mounted to slide axially in the nozzle.

Abstract: This invention relates to improved flow control mechanism for valve gated injection molding. The mechanism is of the type where movement of the valve pin is controlled by a pneumatically driven rocker arm. The back plate is cast with an integral pivot pin portion projecting from it and a pivot ball is fixed in a seat on the end of it. The rocker arm has a recess which receives the pivot ball for pivotal motion on the pivot pin portion of the back plate. The back plate is cast of a steel with sufficient strength and flexibility to withstand the repeated lateral loading on it due to the pivotal motion of the rocker arm, while the pivot ball is formed of a significantly harder material to avoid unacceptable wear where it is in moving contact with the rocker arm. Casting the back plate rather than machining it, enables bends in the runner passage extending through it to be smoothly curved, thus avoiding "dead spots".

Abstract: An injection mold assembly wherein moldable material is delivered to a plurality of injection molds through a manifold runner and wherein flow into each mold is controlled by a gate valve. The gate valve is mounted independently of the manifold runner and has a valve stem which extends freely through a valve stem passage in the manifold runner with there being an actuator on the side of the manifold runner remote from the injection mold for reciprocating the valve stem to effect opening and closing of the gate valve.

Abstract: An injector for molding machine capable of operation with a simple mold having few cavities at a total cycle of as little as one to five seconds, thereby accomplishing high speed production with a minimum number of mold cavities; the injector having a nozzle structure so arranged as to minimize heat transfer to the mold whereby the mold may be maintained at a temperature to effect rapid cooling and ejection of the molded part, while the molding material in the nozzle is maintained in a fluid condition; the rapid cycle of operation serving to maintain the desired nozzle temperature, also.

Abstract: This invention relates to improved mechanism for actuating injection molding valve pins. In one embodiment, the mechanism is located between two parallel rows of valve pins located in a common plane with their driven ends adjacent the mechanism. The mechanism includes a central elongated member which is longitudinally reciprocable and two parallel elongated transversely reciprocable side members, each located between the central member and one of the rows of valve pins. Each of the side members is connected to the central member by a number of spaced pairs of pivotally connected pins and the central member is secured against transverse motion, while the side members are secured against longitudinal motion. Therefore, the side members are reciprocated transversely when the central member is reciprocated longitudinally by a hydraulic cylinder.

Abstract: An injection gate of a mold cavity comprises an elongate valve rod which passes axially through a flow channel for molten plastic material and is guided in an extension of a thin-walled steel cylinder open at its opposite end toward an adjoining manifold plate. The rod extremity remote from the gate is secured to a tubular neck of a piston inside the cylinder whose stroke length is a fraction of the axial height of the cylinder's interior, a clearance around this neck providing space for drooling plastic while the length of the neck and of the peripheral cylinder wall serves for thermally insulating the manifold plate from the flow channel.

Abstract: A gate of a mold for an injection molding machine comprises a valve cone having a circular cone shape or a pyramid shape and a valve seat corresponding to the valve cone wherein the valve cone is pushed toward the valve seat by a spring in the direction reverse to the injecting direction.

Abstract: This invention relates to an improved valve pin for a valve gating injection molding system. Heat transfer to the gate area is extremely critical in valve gating systems and this is even more so when new high density glass filled materials are being molded. Thus it is necessary to provide substantially increased and more uniform heat transfer to the gate area. Accordingly, the invention provides an improved valve pin having at least a portion of the valve pin adjacent the tip end being formed of an elongated hollow sealed tube which contains a vaporizable fluid under a partial vacuum. The back end of the tube receives heat from the surrounding heater cast to vaporize the fluid in the area. The vapor pressure establishes circulation of the vapor towards the cooler tip end of the tube. The energy required to evaporate a liquid is the latent heat of vaporization and this energy is released by the vapor when it condenses upon encountering a cooler portion of the tube as it moves towards the tip end.

Abstract: The invention relates to a porous electrode for a chemo-electric cell, wh electrode comprises sintered porous grains which in turn are sintered together to a porous, coherent electrode body having a double structure, i.e. a well defined difference as to pore size between and within the grains, respectively. The invention also relates to a method of preparing said electrode as well as to a chemo-electric cell containing the electrode.

Abstract: An apparatus for injection molding synthetic resin materials comprises means for injecting the material to be molded, mold means having a cavity for receiving the material from said injecting means, entrance passage means connecting said injecting means with the cavity of said mold means and valve means disposed in said entrance passage means for closing it to shut off the flow of material in said entrance passage means, said valve means having a fluid passage communicating at its one end with only the cavity of said mold means when said valve means is closed, said fluid passage having the opposite end thereof adapted to connect with another source of pressurized fluid.

Abstract: This invention relates to a nozzle seal to be used in multi-cavity valve-gated injection molding. A heater cast with a lower nozzle portion is spaced from a cavity plate by an insulating air space and the valve pin reciprocates vertically in the heater cast bore into a gate in the cavity plate. A hollow generally cylindrical nozzle seal is provided across the air space between the lower tip of the nozzle portion and the cavity plate around the gate. The cylindrical seal provides additional heat transfer from the heater to the area of the gate to facilitate operation of the valve pin, particularly seating of the valve pin in the gate, during molding of certain plastic materials with high temperature characteristics. The nozzle seal is formed of a high yield strength titanium alloy and structured to avoid leakage or breakage in this critical area due to high injection pressure and both vertical and lateral relative movement between the nozzle and the cavity plate due to thermal expansion and contraction.