Abstract: In a process for the simultaneous manufacturing of a plurality of injection-molded micro parts from thermoplastic or cross-linking polymers in an injection molding tool, an injection device is provided which has injection cylinders, injection pistons and temperable antechambers. The plastic melt coming from a conveyor worm, by way of temperable sprues, first arrives in the antechambers and, in a second step, is supplied by the injection pistons by way of the injection nozzles to the mold cavities. The mold cavities are filled independently of one another. The co-solidifying runners are eliminated, and it is possible to manufacture particularly small parts with a low injection volume at particularly reasonable cost.

Abstract: To avoid generation of air bubbles and silver which otherwise may be caused due to forced retraction of a dwelling plunger after a dwelling cycle is completed. A dwelling cycle is performed at the same time of metering by using an injection machine 1 and a dwelling machine 2. The injection machine 1 comprises an injection screw 11 mounted in a heating cylinder 12. The dwelling machine 2 comprises a dwelling plunger 21 slidably mounted therein and faced to a resin passage 14. An advancing motion of the dwelling plunger 14 is limited to the side surface of the resin passage while a backward movement of the dwelling plunger is limited to a position at which a desired volume of a resin trap 26 is formed for the resin to be packed in the passage between the head of the plunger and the resin passage 14. The dwelling plunger 21 is allowed to be in a free state during an injection cycle or the metering.

Abstract: A back-flow prevention apparatus includes a screw which includes a metering portion and a screw head; a seal ring which is removably disposed on a rear portion of the screw head and which has a first resin passageway formed therein; a back-flow prevention ring which is disposed on a front portion of the screw head in such a manner as to be rotatable with respect to the seal ring and which has a second resin passageway formed therein; and a drive unit for selectively rotating the screw in a regular or reverse direction. A first positioning mechanism is disposed between the screw head and the seal ring and adapted to position the seal ring at a predetermined position with respect to the screw head.

Abstract: A process and apparatus for distributing molten thermoplastic material supplied directly from melt polymerization to a plurality of molding machines operating in timed sequence is disclosed. The invention is particularly applicable to transferring molten polyester (normally polyethylene terephthalate or a copolymer thereof) directly from a melt polymerization reactor to injection molding machines for producing molded plastic articles.

Abstract: An apparatus and method for molding thermosetting polymers onto clothing. The apparatus includes at least one molding device, at least one polymer supply and a control system for controlling the operation of the molding devices and polymer supplies. The molding devices include die sets having an input member and a mold. The polymer supplies supply polymers for injection into the input members of the molding devices for use in molding three dimensional bodies of polymers onto substrates such as clothing.

Abstract: A pre-plasticizing type injection molding machine includes a plasticizing device for plasticizing a molding material supplied from a hopper by a first screw disposed within a first barrel, an injection device 8 for measuring a molten resin supplied from the plasticizing device 5 and for injecting the measured molten resin by a second screw disposed within a second barrel. A switching valve is provided in a resin passage between a resin outlet of the plasticizing device and a resin inlet of the injection device, and an accumulation device is provided for housing a pushing plunger having a stock chamber communicated with the resin passage at a position between the switching valve 10 and the resin outlet of the plasticizing device.

Abstract: An apparatus and method for molding thermosetting polymers onto clothing. The apparatus includes at least one molding device, at least one polymer supply and a control system for controlling the operation of the molding devices and polymer supplies. The molding devices include die sets having an input member and a mold. The polymer supplies supply polymers for injection into the input members of the molding devices for use in molding three dimensional bodies of polymers onto substrates such as clothing.

Abstract: The invention is directed to a two-stage, all-electric injection unit. More specifically, an injection unit in which the feed screw is preferably used only for plastication and the injection of the plasticized material is accomplished by a separate accumulator having an electrically driven linear actuator, such as a ball screw mechanism. The accumulator is configured so that the ratio of the piston stroke to the piston diameter is preferably in the range of ten to fifteen. In the preferred embodiment there are separate motors for rotation of the screw and operation of the accumulator. An alternate embodiment is disclosed wherein the system is driven with a single motor and one-way clutches.

Abstract: A preplasticizing type injection apparatus having an injection cylinder internally provided with an injection plunger and a plasticizing cylinder provided in the inside with a plasticizing screw or plunger, the injection and plasticizing cylinders being arranged in juxtaposition and held in communication with each other by way of a resin conduit connecting an inlet path of the injection cylinder arranged at the front end thereof and defining the limit of advancement of the plunger and an outlet path of the plasticizing cylinder arranged at the front end thereof so that a front end portion of the injection cylinder is charged with resin molten in the plasticizing cylinder and the resin in the front end portion of the injection cylinder is injected into a mold by the plunger, characterized in that the resin conduit is realized in the form of a small metal pipe having an inner diameter between 5 and 10 mm and a length at least five times and preferably twenty to forty times greater than the inner diameter of the

Abstract: A pre-plasticizing injection molding machine includes a plasticizing and flow regulating assembly connected to the tip of an injection chamber or shooting pot having an injection cylinder. A distributor valve allows the transfer of plastic resin into the shooting pot at low pressure and prevents the backward flow of resin to the plasticizing unit when the injection plunger injects the resin. A plurality of distribution channels in communication with either the distributor valve or a separate valve, and having outlets in the shooting pot angularly equispaced in proximity to the perimeter of the conical tip of the plunger uniformly distributes new resin behind resin retained in the shooting pot from the previous injection cycle, thereby obviating stagnation zones.

Abstract: Foam forming techniques are capable of permitting foaming of biodegradable resin to be positively and uniformly accomplished to provide a biodegradable resin foam with satisfactory quality. The biodegradable resin including foam is made of biodegradable resin a main biodegradable resin ingredient of 100.degree. C. or more in melting point and a low-melting biodegradable resin ingredient of 100.degree. C. or less in melting point. The biodegradable resin foam is produced by placing a starting material of at least biodegradable resin and a substantial amount of moisture in a heated and pressurized environment, releasing the starting material from the environment to foam the biodegradable resin, and subjecting the foamed resin to forming by a forming mold. An apparatus for producing the foamed biodegradable resin foam includes a pressure adjusting chamber, an air-permeable forming mold, a pressure reducing tank and an injection machine.

Abstract: An injection molding apparatus for processing thermoplastic materials has at least one plasticizer unit, at least one injection molding cylinder with associated emptying piston, and at least one injection molding mold. The injection molding cylinder is provided with a sleeve which is arranged reciprocally between a position in which communication with the injection molding mold is interrupted and a position in which communication with the injection molding mold exists. In the position in which the communication with the injection molding mold is interrupted, a passage is provided between the sleeve and the housing which is connected between the feed conduit from the plasticizer unit and a storage space defined on the inside by the sleeve. The outside diameter of the ejection piston is slightly smaller than the inside diameter of the sleeve so that remaining between the two is an annular gap through which the plastic material passes into the storage space from one end of the sleeve.

Abstract: An injection molding machine for thermoplastic resin consisting of an accumulator in which a plunger is slidably provided and an injection mold, the sprue of which connects with the nozzle of said accumulator, wherein said plunger consists of a cylinder and a screw rotatably arranged in said cylinder, the tip of said screw protrudes from the front end of said cylinder and the maximum diameter of said tip is larger than the diameter of said screw, and the ratio of the effective volume of said plunger to the effective volume of said accumulator is in the range between 1:4 to 1:10 is provided in the present invention. By using said injection molding machine a large size product can be molded at a low injection pressure.

Abstract: This plant for manufacturing fiber-reinforced thermoplastic structural components, especially for motor vehicles, is characterized in that it includes:means (1) of continuous production of a dough of a fiber-reinforced thermoplastic compound, receiving as input, on the one hand, the thermoplastic (4) and, on the other hand, the reinforcing fibers (6);means (14) of accumulation and of temporary storage of the dough produced; andmeans (26) of removing the dough from the accumulation and temporary-storage means (14) and of introducing this removed dough into a mould (29) for forming the component.

Abstract: An injection molding process for forming high strength, long fiber-reinforced thermoplastic resin, and for holding damage to the pellet-shaped thermoplastic resin to a minimum even when being plasticized, and maintaining the fiber length of pellet-shaped fiber bundles while unwinding the fibers and melting the resin. After the long fiber-reinforced thermoplastic resin has been heated and melted, pressure is applied to unwind the long fiber-reinforced thermoplastic resin while melted, and injection molding then performed.

Abstract: There is provided a preplasticizing injection machine including a resin vent formed in the injection cylinder behind the plunger stroke wherein said resin vent is connected to a pressure reducing device and/or an inert gas feeding machine. The resin entrapped in the clearance prevents gases generated within the cylinder from being exhausted and it may be blackened due to the oxidation thereof. According to the present invention, these problems can be solved by the above construction. Furthermore, a band heater is provided on the outer surface of the cylinder behind the injection plunger stroke over the resin vent to prevent the entrapped resin from being solidified.

Abstract: An injection molding machine having an injection plunger (21) capable of moving back and forth within an injection chamber (22) includes a scraper ring (23) attached to one end of an injection cylinder (2) having a hole penetrated by the injection plunger. A protuberance (23a), which forms the smallest diameter portion of the hole penetrating the scraper ring and extends to the surface of the injection plunger, is formed on the inside wall of that scraper ring. The perimeters (23e, 23h) of this protuberance scrape off any molding material which adheres to the injection plunger. The scraper ring has windows (23f, 23g) for the purpose of dropping scraped-off material outside thereof. Preferably, the injection plunger has a shank (21b) and a head (21a) which forms the tip of the injection plunger and which has a diameter larger than the shank and slightly smaller than the injection chamber; the protuberance of the scraper ring has a diameter which is slightly larger than the shank and smaller than the head.

Abstract: An arrangement of oil cylinders of a plastic injecting machine is provided which positions a large oil cylinder and a small oil cylinder respectively on both the left and right sides of an oil cylinder base and a bearing base. The large and small oil cylinders are located at such a distance away from a material injecting cylinder that the oil seals of the four oil cylinders are not heated by the electric heaters that heat the material injecting cylinder. By this arrangement, the oil seals have a normal service life. In addition, an oil route plate is located on the bearing base to secure oil pipes formed of hard steel connected between the four oil cylinders and an oil pump, to keep oil flowing smoothly.

Abstract: The invention pertains to an apparatus and method of using the same. This apparatus includes a mold defining a mold cavity and an inlet through which molten material can pass. Also included is at least one feeder for preparing a molten material. This feeder has an outlet through which molten material can pass. There is also at least one accumulator spaced from the feeder and the mold. This accumulator has an inlet through which molten material can enter, and an outlet through which molten material pass. The accumulator also is designed such that it can introduce a molten material through its outlet into the mold cavity and exert a shear stress, compressive force or stress tensor on the molten material contained within the accumulator and/or within the mold cavity. The apparatus also includes a flow control mechanism is designed to prevent the flow of molten material from the accumulator back into the feeder.

Abstract: An apparatus for the manufacture of plastic pellets including an extruder, a chiller positioned to receive and solidify extruded strands from the extruder and, a pelletizer for converting such strands to pellets. The apparatus includes a quality testing device having a valve connected to the extruder, an injector having a sample receiving position operably connected to the valve, and a sample mold for forming solidified test samples of the material for analysis. The injector also has an ejection position operably connected to a mold inlet for injecting such samples into the mold.

Abstract: A method and apparatus for producing a molded polyurethane foam without using low-boiling solvents such as Freon and methylene chloride which present problems when used as a blowing agent. The polyurethane foam has the same good appearance and soft feeling as that produced with low-boiling solvents. A polyurethane foam is produced by injecting a polyurethane material into an evacuated cavity and permitting it to expand so that it flows and fills the cavity, said polyurethane material being composed of 100 parts by weight of polyol component and 0.1-0.6 part by weight of water as a blowing agent. The cavity pressure may be maintained high spontaneously or low while the polyurethane material is flowing in the cavity. When the polyurethane material has reached the final fill position in the cavity, the fore-end of the polyurethane material is discharged from the cavity.

Abstract: A system for injection molding a hollow plastic article utilizing a secondary resin flow path which communicates one portion of an article-defining cavity with a second portion of the article-defining cavity. The second portion of the article-defining cavity is typically the hardest-to-fill area of the article-defining cavity. The secondary resin flow path is outside of the article-defining cavity and the normal flow of plastic resin.

Abstract: Equipment, in particular pressure gelling equipment, is provided to fill one or more casting molds with castable, liquid materials of which the components are fed by pumps through closable conduits to at least one plunger-cylinder system from where the components are moved to a mixing chamber and from there to the particular casting mold. In order to process especially abrasive casting materials of high viscosity and short pot life, the invention provides that at least one plunger-cylinder system be operated at a pressure substantially higher than are the pumps and that the mixing-chamber volume be comparatively slight.

Abstract: An injection apparatus having a pressure holding device of a novel constitution, capable of preventing flow-out and decrease of resin when holding pressure, and eliminating instability in pressure holding due to volume changes, by forming the front end of the pressure holding plunger obliquely disposed between front and rear resin paths or penetrating a passage between the resin paths.

Abstract: Molten resin flows from the opening of a path and washes a closed space of an injection chamber to prevent molten resin from being retained therein. Resin leaking from between a peripheral wall of a cylinder and a head of an injection plunger is quickly exhausted. When a screw retreats, molten resin is delivered from the opening to the injection chamber through the path. Resin from the opening causes a flow that washes and agitates resin remaining in the closed space opposite a nozzle hole, since a front face of the plunger is conical in shape with a protruding or higher center. There is a slight step between the plunger head and a shank of the plunger. The step scrapes resin which adheres on the cylinder peripheral wall to quickly exhaust such resin through a narrow clearance between the peripheral wall and the shank. The plunger head is coated with a ceramic.

Abstract: A mixing head for a molding machine includes a mixing chamber into which reaction materials are injected from nozzles communicating therewith, toward a closed end of the chamber and at acute angles with respect to the longitudinal axis of the chamber, the angles' apexes lying toward the closed end. The streams of injected material impact and mix, before entering an area of turbulence between the closed end of the specifically dimensioned chamber, and the points of communication where they are preliminarily reacted. Subsequently the material leaves the chamber by passing back through the point of impact, effecting further mixing. The doubly mixed material thereafter proceeds to a discharge passageway prior to entering a mold.

Abstract: A method and an apparatus for applying afterpressure on injection molding compounds, particularly PET compounds in an injection molding machine including an injection mold and a screw connected to the injection mold through supply ducts. The injection molding material is conducted to the mold cavity by the screw in order to fill the injection mold. After the filling procedure has been concluded, the material flow is cutoff in the vicinity of the screw opening. During the phase of material shrinkage, the loss of volume is compensated by additionally conveying material present in the supply duct between the screw and the mold cavity. After cooling of the injection molding material, the continuous material flow of injection molding material into the mold cavity is separated from the material flow in the supply duct.

Abstract: A standard injection molding machine is combined with an auxiliary plasticizing unit having a hot runner manifold that can be alternately connected with or disconnected from the main injection unit of the molding machine to perform sandwich molding. The injection unit retracts from the mold to connect with a hot runner and receive skin material from a non-reciprocating screw extruder directly into the barrel of the injection unit. The injection unit then disconnects from the hot runner and moves back into position for injection into the mold. Simultaneously with this movement, the injection unit plasticizes sufficient core material to complete the stacked arrangement of skin and core material necessary for sandwich molding. In an alternate embodiment, the sandwich molding apparatus includes an accumulator with a suitable valve and connections to the other components to supply a final shot of skin material into the mold, as well as provide the pack and hold functions of the injection cycle.

Abstract: The invention relates to a hollow injection-molding method of forming a hollow portion in molten resin in a mold cavity by introducing a pressurized fluid, and also to a pressurized fluid introducing and discharging apparatus therefor, and has an object of eliminating the backflow of the molten resin into a pressurized fluid passage. A gap between a cylindrical sleeve and a shaft core inserted into the sleeve is used as the pressurized fluid passage. The front end of the shaft core is projected into a mold beyond the sleeve front end to serve as a guide face. By sliding the shaft core, the state of an opening portion of the pressurized fluid passage in the side of the mold is changed between a narrowed state where the pressurized fluid can pass through the opening portion but the molten resin cannot enter the opening portion and a widened state allowing the pressurized fluid to rapidly discharge. The guide face allows the pressurized fluid to be reliably introduced into the mold cavity.

Abstract: An injection unit (1) for injection molding machines used in the manufacture of plastic objects has a nozzle element (2), a material feed system (7), a cylinder-piston unit (3, 4) arranged between the nozzle element (2) and the material feed system (7), a valve (10) arranged between the cylinder (4) and the material feed system (7), and a device (21) for pressing the nozzle element (2) to the edge of the gate of an injection mold. The nozzle element (2), and the piston (3) guided in the cylinder (4), may be integrally formed. The nozzle element has a channel (11) in alignment with an axial bore (13) in the piston (3). The channel (11) and bore (13) are in communication with the interior of the cylinder. The cylinder (4) can be moved in the direction of the longitudinal axis of the piston while the piston (3) does not move.

Abstract: A molding apparatus for injection-molding a hemispherical hollow body formed of a thermoplastic elastomer and having a valve formed integrally therewith. The apparatus includes a first mold having a hemispherical convex molding surface, a second mold having a hemispherical concave molding surface larger in size than the convex molding surface. The second mold is superposed on the first mold to form a molding cavity for the hollow body. A first valve mold is removably mounted at the center of the hemispherical convex molding surface of the first mold, for forming the valve and an inside and small-diameter portion of a valve rubber insertion hole of the valve. A second valve mold is removably mounted at the center of the hemispherical concave molding surface, for forming an intermediate and large-diameter portion of the valve rubber insertion hole and an outside and small-diameter portion thereof while forming a cavity for the valve in cooperation with the first valve mold.

Abstract: A flow regulating assembly for restricting plastic material from flowing directly from a central chamber of an injection piston to an accumulator cavity of a plastic injection machine and instead directing the plastic material towards the wall of the accumulator cavity thereby providing a scouring effect and reducing build-up of the plastic material on the wall of the accumulator cavity. The flow regulating assembly includes a valve member having a central opening located proximate to and in corresponding alignment with the central chamber of the injection piston and four branch passageways extended from the central opening of the valve member to external openings in a circumferential groove in an outer edge of the valve member, the outer edge of the valve member which is concentric with and proximate to the wall of the accumulator cavity. Four channels are located on a conical-shaped head portion of the valve member proximate to the circumferential groove.

Abstract: Flanges are provided on a screw casing and a cylinder member of a screw driving unit in opposition to each other, and coupled with each other with fastening bolts. An adjusting ring is screwed onto the outer circumference of one of the flanges. The screw member is moved together with the ring in a backward direction until the end of the screw hits. The ring is rotated thereafter to bring it into contact with a side of the other flange, where a datum position is established. The cylinder member is then retreated an adequate amount in this state, and the ring is moved by a specified quantity. The specified quantity, represents the stroke quantity and bolts are fastened so that the ring comes into contact with the side of the other flange. The screw is thereby adjusted in its stroke.

Abstract: A product, such as an optical disk substrate, having a minute surface pattern and a central hole is suitably obtained by an injection molding, wherein a resin is injected into a cavity defined by a mold including a movable half and a fixed half. The movable half is provided with an ejector ring reciprocally movable in a mold opening-and-closing direction and a gate cutter reciprocally movable at two strokes in the mold opening-and-closing direction. After the resin is injected into the cavity to form a product accompanied with a gate, the gate cutter is moved at a first stroke to cut the gate. Then the mold is opened, and substantially simultaneously with commencement of the mold opening, the product is released from the stamper and the gate cutter is moved at a second stage stroke in a direction causing the release of the product from the stamper.

Abstract: A machine for molding a starting crystalline saturated polyester resin such as polyethylene terephthalate includes a device for first drying and then preheating the starting resin to a temperature above its melting point to lower the viscosity of the resin to such an extent that the resin is not substantially degraded in the compression section of the molding machine. A feed section is provided for quantitatively feeding the molten starting resin to the main body of the molding machine. Accordingly, the starting resin is molded into a desired shape in a molding machine under conditions such that the crystallization temperature of the resulting molded article is within 20.degree. C. of the crystallization temperature of the starting saturated crystalline polyester resin.

Abstract: An articulated core blade assembly provides improved release of undercuts and similar structures in mold cavities. The articulated core blade assembly includes a retainer secured to an ejector plate, a lifter which moves the product and releases the undercut and a pivot arm which couples the lifter to the retainer. A first knuckle joint couples one end of the pivot arm to the retainer and a second knuckle joint couples the other end of the pivot arm to the lifter. The knuckle joints provide limited pivoting motion about parallel, spaced-apart axes. The articulated core blade assembly may be utilized in a broad range of injection molding machines utilizing plastics, metals and other injection molded materials.

Abstract: An improved method for injection molding including the steps of plasticizing a shot of molding material with the extruder running at a high rpm, transferring the shot to an accumulator means with the extruder running at a low rpm, and injecting the shot into a mold cavity.

Abstract: A mixing head for a mold can receive two or more reactive synthetic resin components in a mixing chamber in which a mixing-chamber piston is displaceable to drive the residues into a first calming chamber communicating with the outlet of the mixing chamber. The first calming chamber also has a piston or plunger which can be advanced to drive the residues into a second calming chamber connected to the outlet of the first calming chamber. The second calming chamber has a second piston displacing the mixture into the mold cavity. Because the pistons of the first and second calming chambers can be retracted as the mixture flows through these chambers, a highly effective calming effect can be obtained for the turbulent mixture of the mixing chamber without throttling.

Abstract: An improved injection blow molding machine has an melt accumulator or melt metering chamber and a vertically extending oval type die communicating therewith for injecting an elliptical annular parison through the die, which is to be blow molded to produce a hollow double wall type article. The oval type die includes a die housing and a mandrel mounted therein to define a melt passage therebetween having a die lip or opening of a four sided elliptical annular profile at a free lower end of the die. The accumulator is in direct contact with the mandrel, and/or the die housing is enlarged in a horizontal direction at a lower end portion thereof. Preferably the enlarged lower end portion is formed by a plate part fixed to a block part forming an upper portion of the die housing.

Abstract: A method and device for manufacturing tire forming bladders (2), whereby a curing mold (3) defines, via first and second half molds (4, 5) and an inner core (6), an inner molding chamber (7) inside which a precured reinforcing ply (72) is optionally inserted; the mold (3) having an outer injection chamber (34) communicating with the inner chamber (7) and consisting of a variable-volume chamber of an injection cylinder (65); the outer chamber (34) being provided with a mass (35) of heated uncured rubber, which is injected into the inner chamber (7) with the mold (3) closed and, when cured, is extracted from the mold (3) by opening the inner chamber (7) and extracting the inner core (6).

Abstract: Apparatus for injection of fluids as, for instance, into a mold for the making of parts out of plastic or the like wherein the apparatus is self-aligning with the opening of the mold, a nozzle being moveable substantially automatically as the injection apparatus is moved into the inlet of the mold. The apparatus further includes a device for injecting a precise volume of such fluid, there being means for quickly and easily disassembling the entire injection apparatus for purposes of cleaning or repair.

Abstract: Cold-stretchable sheet material is isostatically formed at an operating temperature beneath the softening temperature of the sheet material by means of a fluid pressure medium at a pressure of more than 20 bars so as to produce a deep-drawn formed plastics piece. Forming may take place abruptly. The sheet to be formed may be provided with a coating such as an ink imprint. The resulting thin-walled deep-drawn piece may be backed and reinforced by injecting further plastics material.

Abstract: A hot runner system for injecting precise quantities of at least one resin advancing under pressure from a resin source wherein the system includes a shooting pot having a piston with opposed working surfaces which divide the shooting pot into at least two reservoirs. Resin under pressure is switched cyclically from one reservoir to the other whereby the piston is driven by resin under pressure to purge one reservoir while the other reservoir is loaded.

Abstract: Apparatus and method for molding plastic articles including oscillating the molten plastic in the mold cavity. The method and apparatus is particularly suitable for use with a plurality of mold cavities supplied from a single feeding means or extruder. The disclosure teaches alternately feeding molten plastic to the mold cavity from at least one shooting pot while the flow of molten plastic to the mold cavity from the feeding means is discontinued.

Abstract: A resin transfer molding apparatus includes a single-shot metering pump which feeds a predetermined amount of resin material to the mold with a single stroke of the pump via an injector assembly which is mounted on the mold. A closed-loop hydraulic control of the metering pump enables the injection rate and pressure of the resin to be varied during the injection cycle to produce a more consistent fill of the mold and eliminate part waviness caused by pressure rise and fall. The mold-mounted injector assembly and placement of a plurality of valves in the apparatus enables recirculation of unused resin material back to the supply tank at a temperature sufficiently cool to prevent curing, so that solvent flushing of the apparatus can be eliminated in most cases. The apparatus is automatically controlled by a computer resulting in an integrated automatic apparatus.

Abstract: An injection molding machine and method of operation having a plurality of accessory arrangements for molding a plurality of piece parts in efficient overlapping time cycle using primary and secondary molten plastic injection units, primary and secondary clamping units, a plurality of injection units in various arrays including molding piece parts in reverse or uniform orientation.

Abstract: A device for dosing a plastic, perishable mass into moulds has a pressing chamber for receiving a dose of the mass from a feed vessel and a piston operable in the chamber to push and compress the dose into a mould. The device includes a valve for shutting off feed of the mass from the feed vessel and is particularly constructed to avoid spaces into which the mass can collect and spoil, while preventing reentry of the mass from the pressing chamber into the feed vessel.

Abstract: In the injection molding of a hollow shaped article by the injection of not only molten synthetic resin but also compressed gas into a die, a method is provided by this invention which effects the supply of the compressed gas with a multistage compressor and the injected compressed gas is recovered in a recovery container connected to the suction side of the multistage compressor. For the injection molding of a hollow shaped article by the injection of not only molten synthetic resin but also compressed gas into a die, an apparatus is provided by this invention which has a gas nozzle for injecting the compressed gas into the die connected through a first switching valve to the discharge side of the multistage compressor and, at the same time, has the gas nozzle connected through a second switching valve to a recovery container connected to the suction side of the multistage compressor.

Abstract: Apparatus for forming multilayered articles including a nozzle communicating with the mold cavity. The nozzle includes a first nozzle channel for feeding a first thermoplastic material to the mold cavity and a second nozzle channel communicating with the first nozzle channel for feeding a second thermoplastic material to the mold cavity. A metered amount of second material is fed from the second nozzle channel to the first nozzle channel and subsequently to the mold cavity by the first material from the first nozzle channel.

Abstract: A fast cycle plasticator/injector unit for plastic molding machines having a screw type plasticating extruder for feeding thermoplastic material through a sealed fluid flow path to an accumulator which periodically feeds the thermoplastic material through a sealed fluid flow path to an injector that comprises a cylinder with an inlet and an outlet port and a powered piston valve element disposed for reciprocating axial and rotary motion within said cylinder and having a fluid flow channel along a portion of its length in cooperative structural relationship with said inlet port to provide an open fluid flow channel between the inlet port and the charge chamber of said cylinder when the piston is in a first rotational orientation and to block fluid flow from the inlet port to the cylinder when the piston is in a second rotational orientation.