Abstract: An arrangement is disclosed for independently controlling shutoff and flow to a cavity gate in a multicavity injection mold apparatus, in which a plurality of valve pins are mounted to a movable holder plate, each aligned with a cavity gate and movable thereinto to control shutoff and a plurality of fixed position plunger sleeves are each mounted over a respective valve pin and adjustably positioned with respect to a restriction feature in the supply passage upstream of the associated gate.

Abstract: Apparatus for thermal gated injection molding having a cavity forming insert separate from the heated nozzle. The cavity forming insert has a combination of heating and cooling extending around a central melt bore leading to a gate. The cavity forming insert has an integral electric heating element with an inner portion having a number of adjacent coils near the gate. Power to the heating element is switched on and off during the thermal gated cycle, and the combination of heating and cooling in the cavity forming insert improves the thermal response and shortens the cycle time.

Abstract: An integral heated torpedo for use in injection molding has an internal melt distribution chamber which distributes heated melt through multiple melt flow paths onto the exterior surface of the torpedo. The torpedo is formed from a single piece of metal and has an elongate body portion which extends axially from an enlarged end portion and which terminates in tip. The center of the torpedo body portion contains an axial cavity extending between the torpedo tip and the enlarged end portion. The bore is adapted to receive a heating element which includes a coil of resistance wire and a thermocouple which are surrounded by heat insulative material. A plurality of melt flow passages extend axially through the enlarged end portion and are disposed generally around the torpedo bore to provide a series of melt flow paths through the enlarged end portion onto the heated exterior surface of the torpedo body.

Abstract: To extend the useful life of the elastic seal (6) which is arranged between a base plate (1) and a cover plate (2) of molds for the production of flat moldings of curable casting resins and through the passages (8) of which the mold cavity is charged with the casting resin melt and vented and to accelerate venting and filling, the passages (8) are in the form of fixed capillary tubes (9) which project partly into the seal (6) and which are each adjoined by a channel (10) opening into the mold cavity (3) and closure needles (13) insertable into the channels are provided.

Abstract: An injection molding thermal gated nozzle having a nose portion which extends forwardly to the cavity. The nozzle has a melt channel which extends through the nose portion to form the gate. An integral electric heating element has a forward portion with a generally rectangular cross section and a number of adjacent coils which form an inwardly tapered inner surface. Part of the inner surface of the forward portion of the heating element forms an inwardly tapered portion of the melt channel adjacent the gate. This direct contact of the heating element with the melt reduces considerably the cycle time of the thermal gate. The forward portion of the heating element is shaped by compressing it between tapered dies. It is then mounted between forward and rearward portions of the nozzle, and the assembly is integrally brazed together in a vacuum furnace.

Abstract: A multi-cavity injection mold, for simultaneously injection molding a plurality of multi-layer articles, having a single hot runner manifold system for the sequential supply of first and second molten molding materials to the cavities of the mold with each of the materials being supplied simultaneously to all cavities in equal quantities. The invention also provides a core rod for each cavity in which a concavity is provided, adjacent the entry point of the materials into the cavity, to prevent the first injected material in an injection cycle from being washed from the end of the core rod by the second injected material, a buffer of the first injected material in the neck region of the preform to compensate for variations in temperature of the cavities and material being distributed to different parts of the mold and the use of the first part of the metered quantity of the first to be injected material from the next injection cycle to seal the preform at the end of the injection cycle.

Abstract: A heated manifold, for use in the distribution of heated plastic resins to the various cavities of injection molds for thermoplastic materials. The parts of the manifold interlock with each other and contain the high pressures generated by the injection molding presses. The components of the manifold are fitted with seals of metals dissimilar to the manifold, and with a higher coefficient of expansion than the manifold material. The system includes heated bushings which channel the plastic materials to the individual cavities and are fitted with a removable tip which can be adjusted to change the overall length of the bushing.

Abstract: A pre-wired injection molding assembly to be supplied to the customer for installation in a mold. The assembly includes a number of sub-manifolds connected to a main manifold, a wiring frame having a number of elongated fingers connected to the sub-manifolds, and a number of heated nozzles connected to the sub-manifolds. The fingers of the wiring frame extend from a hollow channel member which leads to a connector box. The assembly is pre-wired by the supplier by running the wires from the nozzles along the fingers and through the channel member to the connector box. The pre-wired assembly is mounted from the rear in a matching mold manifold plate which greatly facilitates installation and disassembly for the customer.

Abstract: A multi-cavity valve gates injection molding system. The pneumatic actuating mechanism to reciprocate each elongated valve member includes a piston which reciprocates in a cylindrical opening through a cylinder plate. A sealing bushing which is mounted around each valve member has a flanged portion which bridges an insulative air gap between the manifold and the cylinder plate. Thus, the sealing bushing forms part of the piston cylinder as well as sealing against melt leakage around the reciprocating valve member. The piston has a circumferential outer band formed of a graphite alloy seated in a groove formed between a front portion and a removable rear plate portion.

Abstract: The method and apparatus includes an injection molding assembly including a mold, a core and a mold cavity therebetween wherein said mold cavity has a base, a peripheral area of said base and a central area of said base, at least two injection gates for injecting plastic material into said mold cavity situated adjacent the peripheral area of the mold cavity in a substantially balanced fashion, a source for injecting plastic material through the injection gates whereby molten plastic advances from the injection gates in the mold cavity to force gas in advance of the plastic and to stabilize the core, and means for venting the gas from the mold cavity.

Abstract: A stack molding apparatus wherein the injection nozzles are disposed in pairs of coaxial nozzles in a housing between two sets of injection molds. The reciprocable valving elements of the injection nozzles of each pair are coaxial with each other and are connected with pistons which are reciprocable by compressed air. The pistons are mounted in cylinders of discrete melt supplying members which receive melt from an additional melt supplying member. The housing has two mirror symmetrical sections which can be parted in a plane between pairs of coaxial pistons to afford access to the melt supplying members, to the pistons, to the nozzles and to a device which serves to supply compressed air for reciprocation of the pistons.

Abstract: An injection molding machine for the making of barrels of syringes has first and second mold sections which have confronting surfaces and one of which is movable between operative and retracted positions in which the surfaces respectively abut and are spaced apart from each other. The first section has cylindrical bores each of which is open at the respective surface and extends to an end wall adjacent a nozzle with several uniformly distributed orifices which admit heated plasticized material into the bore when the two surfaces abut. The second section has cores each of which extends into a bore in the operative position of the one section to define with the first section a cavity for reception of plasticized material. The first section has coolant-conveying channels which concentrically surround the bores, and the first section has flow restricting ports which connect the discharge ends of the orifices with the respective cavities.

Abstract: A number of heated injection molding nozzles are mounted along the side surface of a melt conveying manifold. In one embodiment of the invention, a connector collar having a tapered flange portion is bolted to the side surface of the manifold to provide each melt bore outlet. Each nozzle has a matching flange portion with a melt bore inlet extending laterally from a side surface. The nozzle is mounted on the manifold by securing the flange portions together by bolting a wedge clamp having two halves over the aligned flange portions. This accurately aligns the inlet with the outlet and allows the nozzle to be rotated to a particular angular position. In another embodiment, a melt conduit member is mounted between the manifold and each nozzle. The melt conduit member is clamped to the manifold after being rotated to a desired angular position about a first axis.

Abstract: A manifold assembly of the type used for conveying plastic injection molding material from a central injection point or sprue to a number of mold cavities or to multiple points within one large mold cavity. The assembly includes an integral manifold and a plurality of nozzles extending radially outward therefrom. Insulating rings are disposed about the nozzles for inhibiting heat transfer between the nozzle and the core or cavity and a stainless steel locating ring is disposed between the sprue and a support member, which supports the assembly. The locating ring inhibits heat transfer from the sprue to the support member. Aluminum plugs are disposed at the terminal ends of the manifold and inhibit heat transfer from the terminal ends. Preload pads are removably secured to the manifold radially opposite the nozzles for insulating and supporting the manifold under pressure. Heater bands supply the heat to the assembly and the temperature of the plastic injection molding material is monitored by thermocouples.

Abstract: An improved retractable pin mold for golf balls has a gate valve positioned at the pole of the core.

Abstract: To provide a thermodynamic pinpoint gate nozzle which will permit a so-called cosmetic gate without stringing, and during which the plastic material to be processed is not subjected to high viscous or shear stress by the heating elements placed inside the nozzle channel, it is provided that the pinpoint gate nozzle on the side facing the mold cavity exhibits a low-mass inside nozzle (7) and that inside nozzle (7) can be heated by an ohmic resistance wire either inductively or by inside nozzle (7) formed as a Peltier element.

Abstract: An injection molding method and nozzle for use therein wherein first and second variable pressures are applied to a piston of a valve mechanism of the nozzle so that a differential fluid pressure on the piston causes a tip portion of the valve mechanism to alternately open and close. In this way, the tip portion communicates the flow of resin from a nozzle body of the nozzle to an injection aperture of a mold. Differential pressure on the piston prevents a fluid which distributes the molten resin over the interior surfaces of the mold from entering the flow path of the molten resin in the nozzle body. The fluid preferably is a gas, such as nitrogen. Preferably, the piston is mounted for reciprocating movement within the nozzle body and the first pressure is provided by the resin during resin injection and the second pressure is partially applied by the nitrogen gas.

Abstract: A multi-cavity valve gated injection molding system having an elongated manifold through which a melt passage to a number of heated nozzles. A separate valve member bushing is seated in an opening through the manifold in alignment with each nozzle. The bushing is in bearing contact between the back plate and the rear face of each nozzle. The bushing has a melt duct with two smoothly curved arms which connect between the melt passage in the manifold and the melt passage around the valve member. The bushing provides a seal around the reciprocating valve member and has an outer flange which forms a combination insulative air space and containment chamber for melt which does escape.

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: 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: A plastic injection molding system having a plurality of multiple tip torpedo heaters which each have a casing with a pair of opposed tips disposed in respective sprue passageways in a mold. An unsheathed electrical heating element is disposed in an internal bore of the casing at each tip and heat transmitting material is compacted in the bore in surrounding relation to the heating element for electrically insulating each heating element from the casing and filling all air voids between the casing and heating element to effect direct heat transfer to the casing. Electrical leads couple the plurality of heating elements to a power source to permit independent temperature control of the individual heating elements and the exposed surfaces of the respective casing tips over which fluid plastic material is directed.

Abstract: An injection molding heater assembly for use in multi-gate injection molding includes an elongate heating member extending within a mold bore in heating communication with the mold bore mold gates. The heating member has an elongate body portion extending between an inlet portion and an outlet portion. A melt injection passage extends through the inlet portion to convey melt along the body portion to an enlarged portion having a nozzle face. Extending down from the nozzle face are a series of members which include gate tips at their lower ends. Radial channels present in the gate tips serve as extensions to the mold bore mold gates. The gate tips are peripherally spaced apart around the nozzle face and define a recess between the gate tips, the nozzle face and the mold bore for initially injected melt to accumulate in and solidify to form a melt plug. The melt plug serves to insulate the subsequently injected melt from the mold bore and maintain the injected melt in a third condition.

Abstract: A multi-coinjection nozzle injection molding machine and nozzle for co-injecting at least three streams of melt materials to form a multi-layer article. The nozzle includes at least two interfitting shells and a nozzle cap. At least one of the shells has a feed flow channel for flow of melt material which leads to an associated annular flow passageway. The shells have a symmetrical furstoconical shape and and form a fixed tapered, symmetrical, frustoconical portion of an annular passageway which terminates at a fixed, annular orifice for the flow of melt material therethrough.

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: This invention relates to an injection molding nozzle having an improved heating element configuration in the tapered nose portion and a method of making it. A longitudinal portion of the heating element which is integrally brazed centrally into the nose portion is bent back upon itself at least once to provide a multiple thickness part. The type and length of the multiple thickness part which is selected to provide additional heat depends upon the application which the nozzle is to be used for. The multiple thickness part of the heating element is swaged to provide a more circular cross-section before being brazed into a larger diameter part of the heating element bore through the nose portion of the nozzle.

Abstract: An injection molding system having a heated nozzle seated in a well in the mold with an insulative air space therebetween. The nozzle has a resilient sealing and locating flange which extends outward to bridge the air space rearward of a nose portion of the nozzle. The flange abuts against a cylindrical insulating ring which is seated in the mold. The insulating ring is made of a titanium alloy and has grooves in its outer surface which form air spaces to reduce heat loss from the nozzle through the sealing and locating flange.

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: In a vent type injection molding machine of the type comprising a heating cylinder, injection nozzle means having a vent port and connected to the front end of the heating cylinder and a reciprocatable screw for metering a predetermined quantity of resin to be injected, the injection nozzle means comprises a first injection nozzle connected to the heating cylinder, a second injection nozzle coaxial with the first injection nozzle, a spring for urging the second injection nozzle against a stationary metal mold and a housing surrounding the first and second injection nozzles. The vent port is provided through the housing at a point communicating with a space in the housing between the first and second injection nozzles.

Abstract: This invention relates to an injection molding system having two heated nozzles mounted in tandem. The rearward nozzle is considerably longer than the forward nozzle and has a melt bore which is considerably larger in diameter than the melt bore of the forward nozzle. The smaller forward nozzle has a backplate secured to its rear end with a thin flanged portion which extends outwardly and rearwardly into bearing contact against a rearward mold core to secure the forward nozzle in position in a well in a forward mold core. The rear face of the backplate has a seat extending around the melt bore to receive a cylindrical forward portion of a gate insert mounted on the forward end of the rearward nozzle. Thus thermal expansion of the larger rearward nozzle is taken up by the forward portion of the gate insert sliding in the seat.

Abstract: This invention relates to an injection molding system having a number of nozzles conveying melt from an elongated manifold to a common cavity. In the preferred embodiment, each heated nozzle has a melt channel which is offset from a central valve pin bore for conveying the melt to the gate. The melt channel extends through a side portion of the nozzle which is bolted to the side surface of the manifold. The bolts provide a seal against leakage of the pressurized melt, while at the same time allow slight lateral movement between the manifold and the nozzle. This provides for thermal expansion of the manifold relative to the nozzle which is accurately located in a well in the core. The system is used for large cavities which require large flow volumes and avoids the difficulty of accurate machining of the large molds to provide sealing.

Abstract: This invention relates to a valve gated injection molding system in which a number of melt conveying nozzles leading to a common cavity are releasably clamped to the side surface of an elongated manifold. A cylindrical collar around the inlet to each nozzle is received in a recessed seat around each outlet from the manifold. This structure facilitates assembly and ensures alignment of the inlets and outlets, while permitting for some rotational movement between the nozzles and the manifold due to thermal expansion. The integral nozzles are made by vacuum casting a heating element and vacuum brazing a side member with a sidewards projecting face into a steel main body.

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: Apparatus for coinjecting a plurality of thermoplastic materials to mold an article having a layered wall structure using thermoplastic material having different optimum processing temperatures including the maintenance of the optimum temperatures in flow paths individual to each material from its source to a mold cavity.

Abstract: This invention relates to an improved injection molding nozzle having an integral electrical heating element. The nozzle has an elongated nose portion extending to a forward end from a cylindrical central portion. The heating element is brazed in a spiral channel around a central melt bore in the central portion of the nozzle, and extends into the nose portion to a forward end which is grounded by brazing it in nickel adjacent a high speed steel insert portion at the forward end of the nozzle. This forms a pointed tip at the forward end of the nozzle which is corrosion and wear resistant and can be heated to a predetermined temperature. In alternative embodiments, the forward end of the heating element can be brazed in nickel adjacent the forward end without the high speed steel insert portion and/or the nose portion can be inclined with the forward end of the heating element being grounded adjacent an end gate rather than a separate gate.

Abstract: This invention relates to an improved manifold system for a multi-cavity injection molding system. The manifold system has one elongated bridging manifold which extends transversely across a number of spaced elongated support manifolds. Each of the support manifolds, in turn, extend across a number of heated probes or nozzles, each of which leads to a gate to a cavity. The bridging manifold has a portion of the hot runner passage extending through it from a single inlet to receive melt from the molding machine to a number of spaced outlets. Each of the support manifolds also has an inlet which is in alignment with one of the outlets from the bridging manifold and a number of spaced outlets. Each of the outlets of the support manifolds is in alignment with an inlet to one of the probes or nozzles. Each of the manifold has two way junctions at which a larger diameter portion of the hot runner passage joins two smaller diameter downstream portions.

Abstract: This invention relates to a multi-cavity valve gated injection molding system wherein a continuous flow of hydraulic fluid through the actuating mechanism provides additional cooling. A pair of hydraulic fluid lines are drilled in the mold back plate to apply a minimum pressure differential across the cylinder chamber on one side of the piston. In the preferred embodiment, this pressure differential is also applied to opposite sides of a circular cooling chamber extending through the cylinder to provide additional cooling near a high pressure seal. Additional cooling is very advantageous to avoid system malfunctions and inferior product, particularly when molding high performance engineering resins at a high temperature.

Abstract: This invention relates to sealing and support bushings which are located between the manifold and the mold back plate to encircle each valve pin in a multi-cavity valve gated injection molding system. Each bushing is bolted through the manifold to a respective heated nozzle with central bores in alignment to receive the valve pin therethrough. The bushing has an outer flanged portion which extends to contact the mold back plate and forms a leakage containment chamber between them. Thus, the bushings retain the manifold in place, seal against substantial melt leakage around the reciprocating valve pins and collect any melt which does escape to prevent it entering the insulative air space between the hot manifold and the cooled mold back plate. Location of the bushing between the manifold and the mold back plate also enables the use of a standard manifold having longitudinal and transverse bores without requiring diagonal bores.

Abstract: An injection mold assembly for formation of thin walled multi-partitioned plastic containers. An array of cantileveredly mounted and spaced apart cores are extendable into a female mold assembly which includes a pair of side cavity cams and end cavity cams closeable upon the array, but spaced therefrom to form the plastic container therebetween. A plurality of side locking wedge shaped fingers are extendable into the slots spacing the cores apart. The fingers are arranged to extend into the opposite sides of the array of cores in a direction perpendicular to the longitudinal axis of the array spacing the cores apart while plastic is injected into the assembly by injectors mounted to the female mold. A pair of end pushers contact the two outermost cores in the array limiting outward movement of the cores during the injection step. The end pushers likewise extend in a direction perpendicular to the longitudinal axis of the array.

Abstract: This invention relates to a valve gated injection molding system in which melt flows through an elongated manifold to a number of spaced nozzles to fill a single non-linear cavity. Each nozzle is mounted against a manifold offset block which is bolted to the side of the manifold. Pressurized melt from the manifold flows through a melt duct in each manifold block and through the central bore of the respective nozzle to a gate into the cavity. Actuating mechanism is mounted to reciprocate a valve pin extending through each manifold block and nozzle. Each manifold offset block can be mounted with a different orientation on the side of the manifold to properly space the gates along the non-linear cavity to ensure it completely fills as quickly as possible. Slight lateral movement of each manifold block relative to the manifold is permitted to avoid melt leakage due to misalignment of the nozzles as a result of thermal expansion of the manifold.

Abstract: This invention relates to an injection molding process for synthetic resin and its apparatus which enables the production of highly precise molded articles and a shortening of the molding time. More particularly, by actuating a forcible cooling means mounted in a mold part constituting a gate, the synthetic resin fused by local heating of the gate is cooled and solidified forcibly, thereby closing the gate. On the other hand, by stopping the forcible cooling means, the solidified resin in the gate is heated and fused by a heater mounted either inwardly of a runner or outwardly thereof.

Abstract: A telescoped assembly of sleeves for supporting, sealing and insulating a floating manifold between mold plates or other abutments in an injection molding machine.

Abstract: An injection mold assembly for formation of thin walled multi-partitioned plastic containers. An Array of cantileveredly mounted and spaced apart cores are extendable into a female mold assembly which includes a pair of side cavity cams and end cavity cams closeable upon the array, but spaced therefrom to form the plastic container therebetween. A plurality of side locking wedge shaped fingers are extendable into the slots spacing the cores apart. The fingers are arranged to extend into the opposite sides of the array of cores in a direction perpendicular to the longitudinal axis of the array spacing the cores apart while plastic is injected into the assembly by injectors mounted to the female mold. A pair of end pushers contact the two outermost cores in the array limiting outward movement of the cores during the injection step. The end pushers likewise extend in a direction perpendicular to the longitudinal axis of the array.

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 process and apparatus includes a die assembly having a die cavity defined therein and an inlet port in the die assembly communicating with the die cavity. An injection nozzle is provided for delivering molten synthetic resin to the die cavity through the inlet port having an opening aligned with the inlet port and a thermally insulating sleeve positioned around the injection nozzle having an elastically yieldable component and a rigid component.

Abstract: An injection mold nozzle is disclosed of the "bodyless" type, with a tip insert surrounding a needle in a central flow passage, each extending forwardly to protrude from the main body of the nozzle into a sprue cavity adjacent the mold cavity and communicating with an injection port. The tip insert conducts heat into the needle and material in the sprue cavity to maintain temperature of the material while eliminating the impression on the part of a full body nozzle design. The nozzle is also provided with a stepped diameter heater cover forming a shoulder to provide a locating feature which may be shifted by machining to adapt a single nozzle configuration to mold plate thicknesses.

Abstract: Disclosed herein is a hot nozzle for use with a mold for runnerless injection molding of plastic material. The hot nozzle includes a body formed of a conductive metal having a predetermined electrical resistance. The body has a nozzle portion and a base portion, and has a pair of diametrically disposed longitudinal slits extending substantially over the length thereof except at least a portion of the forward end of the nozzle portion in such a manner as to divide the nozzle portion substantially into two sections. The base portion has on opposite ends separated by the slits a pair of power receiving mechanisms for connection to an external source of power. With this arrangement, the nozzle portion itself, particularly at the front end thereof, is heated by voltage applied across the opposite ends of the base portion.

Abstract: An injection molding machine includes a platen having a plurality of regularly spaced mold element-receiving chambers adapted to receive any of a number of various mold elements substantially wholly within the stationary platen. A hot manifold system is included between the stationary platen and a plastics injector unit, which includes a plurality of blocks independently coupled to the fixed platen, each block having channels through which the plastics material can flow, the channels of adjacent blocks being coupled by a coupling unit. The machine is particularly designed for quick inexpensive mold changes, and has particular utility in laboratory testing of mold designs and small low-capacity production in satellite plants.

Abstract: Apparatus for forming objects from molten material includes a mold frame and a movable mold side having complementary faces that define molding cavities. The mold frame includes a mold housing having an internally heated manifold which has a molten plastic distribution channel system for conducting molten plastic to injection nozzle passageways, each having a restricted discharge nozzle that discharges the plastic into a molding cavity. Within each injection nozzle passageway is a heater probe which has an internal heater, preferably an electrical cartridge heater. The probe is secured by an integral seating flange to the mold housing to hold the probe coaxially aligned in the injection nozzle passageway and to hold the probe against shifting with thermal expansion and contraction of the manifold. The integral rear flange is positioned in front of manifold block and has a connecting passageway that communicates the manifold distribution channel with the injection nozzle passageway.

Abstract: Apparatus for injection molding plastic parts. The method includes the step of melting and pressurizing plastic material, directing the molten pressurized plastic material into passages leading to a mold, a selectively opening shut-off valve disposed along the passages, selectively closing the shut-off valve after a predetermined amount of molten pressurized plastic material has entered the mold and cooling the predetermined amount of molten pressurized plastic material in the mold to form a part. The apparatus includes an extruder providing pressurized molten plastic material, a mold adjacent the extruder, passages interconnecting the extruder with the mold, and a selectively operable shut-off valve disposed along the passage.

Abstract: This invention relates to an improved heated nozzle probe for injection molding and an improved stack molding system in which it is used. Each nozzle probe has an inner helical shaped heating element which extends into the pointed tip, and a separate outer one which does not. In addition to providing more heat to the pointed tip, this has the advantage that a standard unit can be used for various applications. In the stack molding system, two heated nozzles are arranged in alignment to bridge the parting line and the pointed tip of only the downstream one is heated. Combined with tapering the aligned gates to gradually increase in diameter in a downstream direction, this has been found to considerably reduce stringing and drooling problems as the mold opens for ejection.