Abstract: An injection apparatus of a plunger type for injecting reinforced materials such as BMC is of a single barrel type or a double barrel type comprising a rotatable plunger disposed in the barrel. A check valve means for preventing a back flow of the materials in a metering process is provided such that it is closed when the plunger is actuated to move axially for injection.

Abstract: This invention relates to a valve gated single cavity injection molding system wherein the valve pin actuating mechanism is cooled by circulating hydraulic fluid through it. The cylinder is mounted in a cylinder housing inside a dome portion of a heated manifold housing. The cylinder housing has a wing portion extending out openings in each side of the manifold housing. Each wing portion has an inlet duct and an outlet duct for hydraulic fluid across which a pressure differential is applied. The ducts connect to circumferential channels which extend around the outside of the cylinder and lead to respective openings into the cylinder. Thus, the application of hydraulic fluid pressure during operation circulates hydraulic fluid through the actuating mechanism. The cooling which results extends the operating life of the mechanism, particularly the seals and O-rings.

Abstract: In an injection resin machine, runners are provided perpendicular to the runners of the fixed plate in order to force the resin flow toward the sprues into a same direction and to achieve uniform resin pressure in the proceeding direction, thus realizing uniform injection into the runners.

Abstract: The invention relates to a nozzle for mixing at least two flowable (and in particular foam-forming) reaction components comprising a housing; component supply pipes leading into the housing; a housing bore arranged in the housing having a coaxial outlet channel in its end face; at least one needle casing arranged coaxially in the housing bore; an injection needle guided coaxially in the needle casing; a first chamber arranged between the wall of the housing bore and the needle casing with one of the component supply pipes opening into said first chamber; a second chamber arranged between the needle casing and the injection needle, with another component supply pipe opening into said second chamber; wherein in the closed state, said injection needle forms a tight fit with the internal end face of the needle casing, and the external end face of said needle casing forms a tight fit with the internal end face of the housing bore; and wherein in the open state, said injection needle frees a coaxial nozzle opening

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: Injection molding apparatus (10) for processing and transferring molding material from a feed mechanism (30) to a nozzle (75) for discharging into a mold including a bolster (12), an injection head (11) extending through the bolster, an injection barrel (37) in the injection head for containing a predetermined sized shot of the molding material, a plunger (46) movable in the injection barrel for discharging the shot of molding material into the mold, a bore (47) extending longitudinally of the plunger for loading molding material into the barrel, feed mechanism (30) supplying molding material to the bore of the plunger irrespective of the position of the plunger, and a valve (60) closing the bore upon movement of the plunger in one direction for discharging the shot of molding material and opening the bore upon movement of the plunger in the other direction for discharging the barrel with a predetermined shot of molding material.

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: 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 a valve gated injection molding system having an improved rocker arm assembly connected between the valve pin and the actuating mechanism. The rocker arm assembly includes an elongated rocker arm which is pivotally mounted in a groove in a cylindrical support member. The rocker arm assembly is removably received in a bore in the mold bore and the rocker arm is disconnectable from the valve pin, whereby the rocker arm assembly is quickly and easily replaceable without disassembly of the mold.

Abstract: Apparatus for unit cavity and multi-cavity, multi-layer injection molding and injection blow-molding machines are provided, which in preferred embodiments, include one or more co-injection nozzle means each having a central channel, at least two passageways having associated orifices which communicate with the central channel and valve means operative in the central channel and movable to block and unblock the orifices. The valve means preferably comprise an elongated sleeve having an axial central passageway and a port in its side wall and an elongated pin axially-reciprocable within the sleeve central passageway. The sleeve and pin are mounted in close tolerance slip fit relationship to prevent significant accumulation of polymer melt material therebetween.

Abstract: A method and apparatus for cold runner transfer molding. Insulating and/or cooling means are provided so that the mold runnerblock is kept sufficiently cool to prevent curing of the plastic molding compound therein. By the addition of a plunger near the gate of the mold, a quasi-continuous molding operation may be effected. Local preheating of the molding material at the gate locale may be used to liquefy a feedstock which has travelled through the cold-runners in powdered form.

Abstract: This invention relates to an improved valve pin bushing for a multi-cavity, injection molding system. The valve pin bushing has a central bore through which the valve pin extends. The melt duct extends through the bushing to join an enlarged portion of the central bore around the valve pin. In the bushing according to the invention, the melt duct branches into two arms with smoothly curved bends which lead to opposite sides of the valve pin. This avoids the problem of streaking and slow melt flow on the opposite side of the valve pin.

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 hydraulic actuating mechanism for a valve gated injection molding system wherein the enlarged head of the valve pin is removably connected to the piston and a floating seal is provided against the leakage of hydraulic fluid. The actuating mechanism has a piston which is reciprocated in a cylinder between open and closed positions. The valve pin extends through a bore in the piston and has an enlarged head which is retained in a cup in the piston by a circular cap which fits over it. The cap is held in position between a removable resilient retaining ring which snaps into a groove and a compressible O-ring. Thus, both a seal against leakage and an easily releasable connection between the valve pin and the piston are provided by the combination of the resilient retaining ring and the O-ring.

Abstract: An apparatus for cold injection molding of glass fiber reinforced composite materials. The apparatus includes an injection unit for the composite material, a unit for the mixing of said material, the discharge orifice for the mixed material of which is connected directly with the feeder orifice of the injection unit, and a die or the like for injection of the material into the cavity of the heated mold. The unit is designed so as to discharge a sheet of the elongated material from the orifice of the cavity, in the joining plane of the mold. The dimensions of the sheet are smaller than or equal to those of the piece to be molded. The die and the mold are equipped with guillotine blades to cut the sheet at the end of the injection.

Abstract: An injection nozzle assembly is used for molding a plurality of articles having accurate dimensions without causing a sink mark to appear in the molded article. The injection nozzle assembly comprises a body which is heated to a temperature higher than the melting point of thermoplastic material. A cylindrical bore is formed within the body, and an outlet port is formed at one end of said cylindrical bore. A plunger moves within the cylindrical bore between a first position near the outlet port to a second position which is remote from the outlet port. A first feed line supplies the molten thermoplastic material and a second feed line feeds high pressure through passageways that are formed within the body. The plunger is formed within a first passageway connecting the feed line with the outlet port when the plunger is moved to the second position. The pressure at the outlet port is reduced by the movement of the plunger from the first position to the second position.

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 molding valve nozzle comprises a nozzle head with a gate dividing a flow passage into two sections, a spool slidably attached to the gate and including axial grooves in its outer surface and a spring for urging the spool rearward. The valve nozzle is so arranged that the gate is closed by the spool because the grooves do not reach the gate upon lower pressure of resins below a certain level, but that the spool may slide forward to extend the grooves over the gate, communicating a front passage with a rear passage upon higher resin pressure above a certain level and that when the pressure differential between the front and rear passages decreases or the resin pressure descends below a certain level, the spool slides rearward by the spring for closing the gate.Thus, the gate is closed by the spool until the resin pressure rises up to a certain level.

Abstract: This invention relates to an improved method of making nozzles for injection molding. The nozzles are heated by an electrical heating element which is cast in a copper portion between inner and outer stainless steel portions. The method includes making a main rear portion and a steel nose cap portion separately, brazing them together in a vacuum furnace to form an integral unit, and then finishing it by drilling and machining to provide it with a central bore and a particular gating configuration. This method has the advantage that a single inventory of unfinished nozzles can be maintained, from which a requirement for one of several gating configurations can be quickly supplied by finishing the nozzles according to that configuration.

Abstract: A hot-runner mold for injection molding for obtaining a product constructed of a multi-layered body made of two kinds of thermoplastic resinous materials comprises: a first hot-runner which communicates with an outlet formed in a hot-runner block and is provided in an interior of the hot-runner block; an outer stem received in the first hot-runner; a second hot-runner which communicates with an outlet formed in the outer stem and is provided in an interior of the outer stem; and an inner stem which is reciprocally movably received in the second hot-runner so that a front end portion of the inner stem conducts an opening/closing operation of each of the outlets of the hot-runner block and the outer stem.

Abstract: An improved check valve assembly which is mounted on the front end of a feedscrew of an injection molding machine having a check ring which is slidably mounted on the shank of a retainer within the heated barrel of the molding machine. An annular-shaped flow gap is formed between the inner periphery of the check ring and retainer shank for feeding cylindrical-shaped sleeves of heated material into a discharge chamber at the forward end of the barrel. The check ring is movable between a forward material feed position where it is engaged with a front valve seat and a rearward material blocking position where it is engaged with a rear valve seat.

Abstract: An injection molding apparatus including a barrel for holding molten plastic material, a first passage connected at one end with the barrel for receiving hot plastic material from the barrel, a second passage connected with the other end of the first passage for receiving molten material from the first passage for supplying the material to a mold, a cylinder, a third passage connected at one end with the cylinder and connected at its other end with the second passage, a piston in the cylinder, movable by pressure means in one direction to maintain pressure on molten material in the cylinder, the third passage and the second passage, and movable by pressure means in the other direction to exert a suction action in the cylinder, the third passage and the second passage for drawing molten material in the second passage back into the third passage and the cylinder, and a valve means.

Abstract: An apparatus for charge-wise dosing a metered volume quantity of liquid medium to be supplied continuously under delivery pressure, comprising a pair of serially connected cylinder-and-piston assemblies of different diameters the cylinder blocks being arranged axially relatively to each other, forming a composite housing; a supply conduit for the flowing medium connected to the smaller diameter cylinder block and a filling nozzle connected to the larger diameter cylinder block and containing a discharge opening; a tube operating as a piston member for reciprocation in the composite housing, which tube is in direct communication with the smaller diameter cylinder block and connected to the larger diameter cylinder block via a passage provided in the larger diameter piston.

Abstract: An injection mold apparatus for forming molded plastic articles comprising a polymer supply source; a mold cavity; conduit connecting the mold cavity and the supply source; an injection assembly for injecting molten polymer into the mold cavity and a gate valve associated with the conduit and having an elongate central passage terminating in an outlet orifice and a needle positioned in skewed relationship with the elongate central passage and selectively insertable into the orifice in a closed position and retractable from the orifice and the elongate central passage to provide an unrestricted polymer flow in an open position.

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: A method of producing capsules of a moldable hydrophilic polymer composition, preferably gelatin, using a combination of an injection molding device with a microprocessor to precisely control the conditions of time, temperature, pressure and water content of the hydrophilic polymer composition, in a cyclic molding process.

Abstract: A molding machine for producing footwear soles includes a frame carrying a pair of extruders for thermoplastic material at one end; a pair of bottom molds mounted on hot runner systems on the other end of the frame; a pair of vertically movable top molds mounted above and cooperating with the bottom molds to define mold cavities for receiving the thermoplastic material from the hot runner systems; a swing out system for swinging each top mold from a horizontal molding position to an unloading position; gripper jaws for gripping the soles and removing them from the top molds; and swing arm assemblies carrying the gripper jaws for carrying the soles away from the molds to conveyor or packaging locations.

Abstract: A check valve at the end of a plastifying worm for an extrusion or injection molding machine comprises a valve ring whose inner diameter is greater than that of a tip at the end of the head of the worm and which surrounds the neck connecting this tip with the valve seat of the worm. Spacers, preferably balls, are disposed between the ring and the tip and the surfaces of the ring and the tip flanking the balls are oriented to allow radial removal of the balls when the valve projects from the cylinder.

Abstract: This invention relates to a pointed heat-generating device for molds of injection molding machines. It comprises a metal casing, a pointed projectile heat-generating means fixed with the metal casing, and a gate formed at the pointed heat-generating means and communicated to a cavity of the molds, characterized in that a heat-generating wire is penetrated wholly into a passage which is bored in a non-processed cylindrical material and an alloy portion is formed in an inert gas between an end of the heat-generating wire and the non-processed cylindrical material, thereby the alloy portion being formed as a pointed part of the heat-generating means by machining.

Abstract: Apparatus for unit cavity and multi-cavity, multi-layer injection molding and injection blow molding machines are provided, which, in preferred embodiments, include:Coinjection nozzle means, each for plural polymers, valve means for each nozzle, the valve means being adapted to move through a nozzle central channel to clear the nozzle channel of melt, a feed-block for each nozzle, polymer melt splitters, drive means for each valve means, a free floating runner system and a force compensation system to provide an effective pressure seal between the nozzles and the cavity block.

Abstract: A backflow preventer at the end of an injection molding worm has a pressure ring which abuts directly upon the worm and serves a shank of the valvehead which also bottoms in a bore upon the worm so that force transmission to the worm is over its entire cross section. The shank is surrounded by a blocking ring which can shift in its axial stroke between a position in which it abuts the head and a position in which it abuts the pressure ring, the axial stroke being adjustable by shims forming the floor against which the shank abuts within the bore of the worm.

Abstract: A device for preventing the leakage of a molten material remaining in the mold through the gate, the device including a specially designed valve members movable in opposite directions so as to effect the communication of the sprue with the mold and to form a negative pressure chamber therebetween, the negative pressure chamber being adapted to suck a molten material remaining in the mold whereby the internal pressure is vacated from the passageways in the mold. This prevents the molten material from leaking through the gate. When the negative pressure chamber is closed, the sucked molten material therein is expelled into the passageways.

Abstract: This invention relates to an injection molding system having a valve pin which is hydraulically actuated between an open and a closed position in which its tip end is seated in a gate leading to the cavity. The actuating mechanism includes a piston secured to the driven end of the valve pin which reciprocates in a cylinder. The cylinder has an inner cylindrical member which is brazed in an outer member with a flanged portion. Separate hydraulic fluid ducts extend from the flanged portion through the outer member, along grooves in the outer wall of the inner member and then through holes through the inner member to conduct hydraulic fluid to opposite sides of the piston. The flanged portion of the outer member has a pair of passages extending through it, each connected to one of the ducts. Alternate ends of the passages are sealed off so that hydraulic fluid may be received either from supply lines drilled through the back plate in which the cylinder is seated or an abutting top plate.

Abstract: Known apparatuses to inject liquids, in particular plastics into injection moulds have closure rods which remain in the gating when the closure system is opened. In the present apparatus the liquid passage always is completely free when the closure system is opened, because the closure rod can be totally retracted from the liquid passage. This can be accomplished in two ways: either the liquid passage extends in a bended manner or the closure rod has a side view in the configuration of a sector or a circle.

Abstract: A valve nozzle device provided between a heating cylinder of an injection molding machine and at least one metal mold, includes at least one nozzle combined with at least one needle valve for injecting plastic resin melted in the heating cylinder into the metal mold. The device is further provided with a first passage connected with the heating cylinder, third passages each provided around the needle valve to be merged into the nozzle, and second passages interconnecting the first and the third passages. The second passage has a central axis extending in a plane other than a plane including a central axis of the needle valve, and is connected with the third passage in a positional relation such that the plastic resin in the second passage flows into the third passage from one side thereof followed by a helical path around the needle valve.

Abstract: Injection apparatus suitable for supplying in-mold thermoset coating material into a compression molding tool is provided, which injection apparatus comprises a housing (10) the forward end of which comprises an outlet nozzle (11) and an outlet channel (12) extending through the outlet nozzle, the forward terminus of the outlet channel being an outlet port (13). First and second material supply channels (14 and 15) extend within the housing from first and second supply inlet ports (16 and 17) in the housing, respectively, to a single common junction with the outlet channel. A shut-off rod (26) is slideably disposed within the outlet channel, being adapted to provide a sealing closure of the outlet port in a first, forward position and being retractable from the forward position to a second position in the outlet channel rearward of the junction of the material supply channels with the outlet channel.

Abstract: A mold apparatus for liquid injection molding machine which mold is dripless comprising a frame, four support posts mounted on the frame; a conduit for a liquid molding composition slightly mounted on the forward end of the frame having a front end and a rear end; a first plate means having passage means therein for the passage of the liquid molding composition and fixedly mounted on the forward end of said conduit and adapted to slide within support means and within said mold frame means located adjacent to the forward end of said frame, nozzle means at the end of said passage means of said first plate means at the rear end of said mold frame means and away from said conduit means and pin means slidably mounted in said mold frame means adapted to open and close said nozzle means and mold cavity means slidably mounted on said support means adapted to move toward and away from said nozzle means.

Abstract: A shut-off nozzle for injecting molten resin into a mould cavity comprises a cylinder to be connected to a moulding machine, a nozzle head attached to the front end of the cylinder to be connected to a mould, a flow path for molten resin through the cylinder and the nozzle head, a torpedo disposed in the flow path, and a shut-off pin protruding from the front end of the torpedo. The torpedo is of a streamline shape and is divided into a front portion having a hole and a rear portion having a cavity. A spring is disposed in the cavity applying forward force onto the shut-off pin. The cross sectional area of the shut-off pin to accept pressure of molten resin and the force of the spring are adjusted so that the shut-off pin is in the front position until the pressure of molten resin becomes a predetermined value.

Abstract: This relates to an injection nozzle which is provided with a valve gate pin for selectively interrupting plastic flow therethrough. The internal construction of the nozzle is such that the plastic flowing therethrough for injection into an injection mold is uninterrupted and in no way divided so that there will be a separation of the plastic and a rejoining in a manner which will provide for a welded interface. The valve gate pin, notwithstanding the uninterrupted flow passage, is fully supported throughout its length.

Abstract: A plunger injection molding machine for utilizing a liquid composition and in addition to the other usual features, a valve for allowing liquid composition to enter a barrel means; sealing means on the plunger which operates on the barrel of the machine so as not to allow the liquid composition to leak pass the sealing means out of the rear of the barrel means; and stop means to regulate or control the rear work movement of the plunger means out of the barrel means which results in accurate control of the amount of liquid composition forced into the mold. A preferable composition for use with this type of machine is a silicone composition and more specifically a SiH olefin platinum catalyst silicone composition.

Abstract: A hot sprue valve assembly is provided for controlling flow of molten material into the mold cavity of an injection molding machine. The valve assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The valve assembly includes a hot sprue bushing defining a heated flow path for passage of molten material toward a stationary dispersion head positioned centrally within the mold cavity. The dispersion head directs the molten material to flow in a generally radially outward direction with substantially uniform radial distribution into the mold cavity.

Abstract: A hot sprue valve assembly is provided for controlling flow of molten material into the mold cavity of an injection molding machine. The valve assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The valve assembly comprises a stationary valve body supporting a movable valve member for sliding motion toward and away from the mold cavity. The valve member includes a hot sprue bushing defining a heated flow path for passage of molten material toward the mold cavity, and a dispersion head carried by the bushing for directing the molten material to flow in a generally radially outward direction through gate passages with substantially uniform radial distribution into the mold cavity. In one position, the valve member is advanced into the mold cavity to align the gate passages with the mold cavity and thereby permit flow of the molten material into the mold cavity.

Abstract: A stationary platen of an injection-molding machine, carrying a mold portion with a sprue leading to one or more cavities, is connected by a set of metallic tie bars with a fixed part of the machine frame containing the mold drive and is limitedly slidable on the machine bed to an extent corresponding to the stretch of the tie bars under a mold-clamping force exerted by that drive upon another platen moving along the tie bars. An injection unit behind the stationary platen has a precompression chamber which communicates with a channel leading to an injection nozzle, this nozzle being received in a cutout of that platen and confronting the sprue through the head of a hollow gating plunger slidable in the nozzle orifice.

Abstract: The invention relates to an injection mechanism for molding plastics, comprising at least one injection bushing, at least one lower needle valve, which is supplied by the injection bushing with molten plastics and opened by the pressure of the molten plastics during injection, further comprising heating means and cooling means adjacent to the flow path of the plastics, control means for maintaining the plastics at an adjusted temperature, further control means for injecting the molten plastics into at least one mold cavity via a corresponding injection aperture, and for the closing off the mold cavity after finishing the injection, wherein for improving this mechanism, especially for facilitating very small distances between injection openings, only one plunger within a heated distributor block is provided, which actuates several needle valves, situated at different locations within the distributor block, for supplying the molten plastics to the mold cavity via one single injection bushing, an injection nozzl

Abstract: An injection-molding apparatus has a nozzle extending along an axis and formed with an axially forwardly opening outlet, an annular port fixed immediately axially behind or upstream of the outlet, and a central axially forwardly opening port axially fixed behind the annular outlet. Respective plastifiers for feeding respective plastified synthetic resins, normally thermoplastics, are connected to the respective ports. An axially displaceable valve body in the nozzle is displaceable from a fully forward position blocking both of the ports, through a partially back position blocking only the central port, to a fully back position clear of both of the ports. Thus in the fully forward position no resin can enter the nozzle, in the partially back position resin can enter the nozzle only from the annular port, and in the fully back position resins can enter the nozzle through both of the ports.

Abstract: A injection molding nozzle with an automatic shut-off valve is disclosed. The present invention is intended for use with injection molding machines employing a screw plasticizer and an injection plunger. The nozzle, as a conversion unit, fits any in-line screw injection machine. The nozzle can, also, be employed as part of a two-stage injection molding machine capable of injection molding, conventional, semi-foam or structural foam. The nozzle of the present invention has smooth flow passages and a few parts which are of simple construction allowing the nozzle to be easily cleaned for conversion to different materials.

Abstract: This invention is an improved injection molding nozzle whereby the shut-off plunger is operated by a fluid and the opening of the nozzle is accomplished by the flow of plasticized material through the nozzle. A control rod internal to the nozzle controls the movement of the plunger shut-off member and is adjustable so that the amount of plasticized resin flowing through the nozzle can be accurately controlled.

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: A nozzle for the introduction of liquefied plastic material into a mold has a channel terminating at one end in an injection orifice and adjoining at its other end a reduced bore serving for the guidance of a valve pin slidable with all-around clearance in that channel, the pin having a rear extremity projecting from its guide bore. A passage for the admission of liquefied molding material under pressure enters the channel at its junction with the reduced guide bore, rearwardly of a set of skew fins of the pin serving for additional guidance thereof in the channel and for imparting relative rotary motion to the flow and the pin. The orifice is blocked at the end of an injection operation by a pusher acting upon the projecting rear extremity; it is unblocked, upon withdrawal of the pusher, by the pressure of the molding material in the channel upon a forwardly facing annular shoulder of the pin.