Abstract: The invention provides a process and apparatus for producing an injection moulding of plastics material.

Abstract: A nozzle for the injection molding of thermoplastic materials includes a nozzle body having a first bore for establishing a flow path for a molten thermoplastic. A first end of the nozzle body is adapted for fluid connection with a sprue of an associated mold body, and a second end thereof is adapted for fluid connection with an end of an associated injection molding machine. The nozzle body also includes a second bore. A first valve assembly, which is adapted for reciprocating movement in the nozzle body second bore, is provided to control the flow of plastic through the nozzle body. The first valve member includes a body having a tip portion and a fluid passage formed in the body and open at one end through the tip portion. A connection member is provided for communicating the valve body fluid passage with an associated source of pressurized fluid.

Abstract: An apparatus for compressing a gas includes a preferably substantially vertically oriented cylinder body, having a longitudinally extending bore with a wall, and a preferably substantially vertically oriented piston adapted for reciprocating movement in the cylinder bore. The piston includes a piston head preferably having a substantially horizontally oriented top face and a seal groove extending around the periphery of the piston head and spaced from the piston head top face. At least one fluid passage extends in the piston head from the top face thereof to the seal groove. A seal member is positioned in the groove and has an outer face adapted to contact the cylinder inner wall. A layer of a lubricant is provided on the piston head top face. An inlet aperture is provided for allowing a gas to enter the cylinder above the piston head. A movement member is provided to urge the piston upwardly and compress the gas.

Abstract: A method and apparatus for making a twin-wall internally corrugated plastic structural part provided with a smooth, dense, solid, thin walled, non-cellular skin comprising injecting a thermoplastic or resin material into a pair of closed mold members which define a sealed cavity. A small amount of plastic material is initially injected into the cavity with the material impinging upon and being dispersed over the mold members thereby forming a generally continuous thin skin substantially the mold surfaces. Thereafter, successively and intermittently injecting an inert gas under pressure through one mold member during continued injection of the plastic material into the cavity thereby pressurizing the skin against the walls of the mold cavity and progressively commingling the inert gas under pressure and the inwardly flowing plastic material as both enter the cavity until the cavity is filled with an internal corrugated body integral with and bonded to the skin.

Abstract: A method and apparatus for making a twin-wall internally corrugated plastic structural part provided with a smooth, dense, solid, thin walled, non-cellular skin comprising injecting a thermoplastic or resin material into a pair of closed mold members which define a sealed cavity. A small amount of plastic material is initially injected into the cavity with the material impinging upon and being dispersed over the mold members thereby forming a generally continuous thin skin substantially the mold surfaces. Thereafter, successively and intermittently injecting an inert gas under pressure through one mold member during continued injection of the plastic material into the cavity thereby pressurizing the skin against the walls of the mold cavity and progressively commingling the inert gas under pressure and the inwardly flowing plastic material as both enter the cavity until the cavity is filled with an internal corrugated body integral with and bonded to the skin.

Abstract: This apparatus is used to improve the heat distribution on the cavity surface in foam molding dies where a smooth finish on the resin filled foam molded plastic product manufactured by an injection molding process is desired. This invention improves the method for heating the mold cavity using a condensing vapor in a molding die by a channel and slit type orifice means in the mold around a portion of the periphery of the part to be molded. Another channel and slit type orifice means around the remaining periphery is included in the die for removing the condensing vapor or condensate from the mold cavity. During the heating process when condensing vapor is introduced into the mold the sprue opening to the extruder is sealed by a valve means to prevent condensate from collecting therein.

Abstract: The apparatus molds during each cycle homogeneous plastic material and foam plastic material. It includes a barrel member, a main passageway therein in which is located the screw member. A pair of injecting means for filling molds are provided, one having a homogeneous plastic injection chamber and the other having a foam plastic injection chamber. The first injection means is connected to the screw and barrel member upstream of the place where the inert fluid is introduced into the main passageway whereby homogeneous plastic material is discharged from the main passageway into the first injection means. The apparatus includes means for introducing an inert fluid into the main passageway whereby the rotating screw member mixes the gas with the molten plastic as it moves towards the discharge port which is connected to the second injection means whereby foam plastic material is injected into the foam plastic injection chamber. Each injection means has one or more nozzles connected to a mold located in a press.

Abstract: A method and apparatus is provided for making a composite structural homogeneous resinous article having (a) a smooth, shiny non-cellular or homogeneous relatively thin injection compression molded liner on the outer surface and (b) a cellular relatively thicker injection molded core integral with the molded liner. One extruder is connected by valve controlled passages to a pair of injection devices, each device having an injection chamber. One chamber stores the homogeneous plastic resin and the other chamber stores the foam plastic resin. A first mold assembly having a movable upper mold part and a stationary lower mold part form a cavity, with a gap opening, at a first molding station. The cavity is in communication with the first injection chamber.

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 substantially improves the surface finish on resin filled foamed molded plastic products manufactured by injection molding by pre-heating the skin surface of that part of the mold in contact with the part prior to the injection cycle of the machine and then subsequently chilling the mold via internal tube connections to shorten the time needed in the manufacturing cycle for solidifying the part sufficiently for release from the mold.

Abstract: A method for the manufacture by foam molding of plastic products by first injecting into a mold non-cellular plastic resin and then injecting a foamed plastic resin of the same basic composition as the non-cellular plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the non-cellular and foamed plastic resin are extruded from the same extruder and stored in an accumulator until shot into the mold by a hydraulic cylinder. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the final product will be solid resin. By a simple addition, coloring of the resin may be accomplished so that the basic resin, method or apparatus will not require changes.

Abstract: An apparatus for the manufacture by foam molding of plastic products by first injecting into a mold solid plastic resin and then injecting a foamed plastic resin of the same basic composition as the solid plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the solid and foamed plastic resin are extruded and stored until shot into the mold by hydraulic pressure. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the product will be solid resin and by a simple addition, coloring may be added so that the basic resin, method or apparatus will not require changes.

Abstract: Apparatus for making a foamed plastics product. A foamed plastics product is formed by introducing into an at least substantially fully plasticated material a series of discontinuous gaseous bubbles while said plasticating material is under a substantial and often variable pressure, accumulating said material and intermixed bubbles in an injection zone while maintaining said pressure thereon and thereafter injecting said material into a mold whereupon said pressure is sufficiently released to permit expansion of said gas bubbles and the formation of a foam thereby. Said gas is introduced, as aforesaid, by a series of separate injections wherein the pressure on the gas being injected rises from substantially zero to a level potentially in excess of the highest pressure expected to be developed within the plasticating means.

Abstract: This invention embodies an intensifier cylinder assembly within the main hydraulic ram of a plastic molding machine whereby the clamping force holding the mold halves together can be increased during the shot cycle of the machine by at least three times the normal clamp force of the machine. Additionally, the location of the intensifier reduces the number of high pressure hydraulic fittings in the machine improving the safety factor while reducing the overall cost of the intensifier itself since the ram piston now becomes the housing for the intensifier piston.

Abstract: The nozzle manifold assembly of an injection molding machine is infinitely adjustable horizontally perpendicular to the nozzle axis. The nozzles themselves project through slots in the front clamp plate of the machine which give flexibility to the mold designer in his placement of sprues and runners for filling the mold. Additionally this manifold assembly and its associated injection hardware, such as the shot accumulator, hydraulic pressure accumulator and valving, are mounted on a carriage assembly which is capable of moving horizontally in a direction parallel to the axis of the nozzles thereby allowing the nozzles and associated heater bands to be accessed and maintained without the need for removing the mold from the machine.

Abstract: Plastic molding machine, primarily adapted for generating and molding a closed-cell foam thermoplastic material. The foam is generated by introducing a gas inert to the thermoplastic material into a granular mixture of same so that the gas is thoroughly intermixed among the granular particles. The gas is then held under pressure while the granular particles are reduced to a flowable material, said pressure being sufficient to assure that the gas will not be expelled therefrom during such process. In one preferred embodiment, gas is mixed into the granular thermoplastic in a hopper and held therein under pressure as said granular material is fed into a screw and plasticated thereby.The plastic material is then conducted at a relatively low pressure, such as that generated by the extrusion machine used for plasticating the material, through a branched system past a check valve in each branch of said system, to an injection assembly.

Abstract: Plastic molding machine, primarily adapted for generating and molding a closed-cell foam plastic material. The foam is generated by introducing a gas inert to the plastic material into a granular mixture of same so that the gas is thoroughly intermixed among the granular particles. The gas is then held under pressure while the granular particles are reduced to a flowable material, said pressure being sufficient to assure that the gas will not be expelled therefrom during the plasticization process. In one preferred embodiment, gas is mixed into the granular plastic in a hopper and held therein under pressure as said granular material is fed into a screw and plasticized thereby.The plastic material is then conducted at a relatively low pressure, such as that generated by the extrusion machine used for plasticizing the material, through a branched system past a check valve in each branch of said system, to an injection assembly.