Abstract: This invention relates to an edge gated injection molding system. An electrically heated sprue bushing is seated in a well in the cavity plate with a centrally extending melt runner passage which branches radially outward with separate channels leading to a number of edge gates in the cavity plate. An air gap is provided to insulate the hot sprue bushing from the surrounding cooled cavity plate and a hollow seal is provided at each gate to convey the melt across the air gap. Each seal is in alignment with one of the channels and one of the gates, and has its inner end seated in a recess in the sprue bushing and its outer end abutting against the curved wall of the cavity plate. The outer ends of the seals are dome shaped so that they are slightly resiliently deformable. A portion of the wall of the cavity plate is slightly inwardly tapered so that at the gates, the effective combined diameter of the sprue bushing and the seals is slightly larger than that of the well.

Abstract: A novel method and device for precision injection molding is disclosed providing controlled cooling of a portion of the mold cavity surface during the molding cycle, or several such portions independently, and also, in the preferred embodiment controlled heating of a portion of the mold cavity surface during the molding cycle or several such portions independently, whereby high quality, high precision parts having close dimensional tolerances may be produced. Another aspect of the invention, a volume-controlled variable conductance heat pipe is disclosed, which novel heat pipe comprises housing means forming a sealed chamber, fluid, such as water or ammonia, within the chamber, wicking means and control means for controlling the thermal conductance of the heat pipe comprising means for controlling the volume of fluid in the liquid phase in the chamber.

Abstract: Apparatus for producing hollow plastic articles in a hollow die with a relatively smaller reciprocating punch therein. Plastic material is fed from a nozzle aligned with the die, into the die about the punch, the punch being initially advanced into the opening of the die and retracting as the plastic is introduced from the nozzle. When the plastic introduction is completed, then the nozzle is slid laterally on the die until the duct of the nozzle is out of registry with the die and the nozzle thus closes the die. Then the punch is advanced within the closed die to compress the plastic material into the space between the die and the punch.

Abstract: An improved injection molding apparatus for molding parts of thermosetting plastic material. First and second mold portions which together form a mold cavity at their molding surfaces are heated to allow thermosetting plastic material to set within the mold cavity when under pressure. A fluid distribution member comprises a manifold having an inlet port, two or more spaced outlet ports and a passage interconnecting the inlet port with the outlet ports guides the flow of plastic material therein. The manifold is cooled and includes a first manifold section disposed within a channel formed at the upper surface of a second manifold section such that the interconnecting passage is formed by a first wall portion of the first manifold section and a second wall portion of a second manifold section within the channel. The first and second manifold sections are separable to permit access to the passage to permit cleaning thereof.

Abstract: An apparatus and method for mounting thermoplastic materials directly upon a string medium. A hot runner system or three-plate mold provides the cavities for integrating the molten thermoplastic material and string medium. Molten thermoplastic is injected at a plurality of input apertures along a bifurcated mold, the bifurcated mold having complementary cavities joined by subrunners to transmit the molten thermoplastic material into each cavity. Each cavity is adapted to form a member which is to be permanently affixed on the string medium and includes aligned channels for receiving the stringed medium prior to injection of the molten thermoplastic material. The stringed medium is disposed within the channels prior to injection of the molten thermoplastic material. Under appropriate temperature and pressure conditions, the injected thermoplastic runner flows into subrunners filling each cavity of the bifurcated mold, thermoplastic bodies forming about the stringed medium in a permanent manner.

Abstract: Methods and apparatus for making cheese topping for a pizza pie use a mold assembly providing a cavity for receiving a solidifiable fluid mass of topping cheese. The mold cavity has an outline corresponding to at least part of the outline of the peripheral region of the pizza pie. A number of mutually spaced rods is movable relative to the mold cavity. The relatively movable rods are inserted into the mold cavity to provide for apertures in the molded piece of cheese. The rods are withdrawn from the poured cheese which is removed from the mold after the poured cheese has become sufficiently solidified in the mold to be self-supporting; containing a number of elongate holes corresponding to the mentioned rods. Slices are cut from the solidified piece of cheese to provide cheese topping slices having apertures through which vapor and juice can rise from the food items on the pizza pie shell during baking of the pie.

Abstract: A method and system for cooling a mold, including the steps of providing fluid flow connectors insertable into a mold for conducting the coolant into the mold. One of the connectors is made in one-piece and includes a threaded stem which threads into a mold opening, and that one-piece also includes two threaded openings which are disclosed transverse to the length of the stem and which align with passageways in the mold for attaching to two tubes extending in the passageways. The system in method is arranged for the alignment of the threaded openings with the passageways while the stem is fluid tightly threaded into the mold opening, and all of these connections are made on the interior of the mold.

Abstract: An injection molding arrangement and process for producing regularly shaped pieces of gasified candy which effect a pleasant sizzling sensation in the mouth. A confectionary solution, which may be a sugar melt, is subjected to a superatmospheric carbonating pressure in a carbonating vessel to cause absorption therein of carbon dioxide. An injection mold for forming the solution into suitably shaped pieces of candy is prepressurized at a superatmospheric carbonation pressure prior to the injection therein of the confectionary solution. The solution is then injected into the mold at a pressure substantially above the superatmospheric pressure in the carbonation vessel. The solution is then allowed to cool and solidify in the pressurized mold, producing regularly shaped pieces of carbonated candy.

Abstract: Heated material is injected into an annular cavity, defined by a pair of mold halves, through a sprue passage, defined by a sprue bushing and an end portion of a punch. The annular cavity and the sprue passage form, respectively the centrally apertured part and a sprue. After partial cooling of the heated material, the punch is locked in place while the annular cavity is displaced relative to the sprue passage so that the sprue is severed from the part along the peripheral surface of the punch end portion. The mold halves are separated to open the annular cavity while the sprue is resting on the punch end portion, and while the part is held by the punch end peripheral surface. After the mold halves are separated, a sprue ejector member is actuated to eject the sprue from the punch end portion. The finished video disc is then removed, carried by the moving platen of the moving mold assembly.

Abstract: An improved nozzle feed assembly is described. The assembly includes temperature-controlled member, preferably cylindrical in shape, having a closed end and an open end. The open end is fitted with standard threads to facilitate attachment of the nozzle member to the feed barrel of a conventional screw-type molding machine. The nozzle member has an internal temperature controlling means and a plurality of feed outlets positioned on the periphery of the nozzle member near the closed end. The temperature maintained in the nozzle member is sufficiently high to maintain the thermosetting molding material within the nozzle member in a plasticized state and sufficiently low that no substantial curing of the thermosetting molding material takes place. In an alternate mode, the assembly includes a sleeve member positioned around the periphery of the nozzle member and moveable to cover and uncover the feed outlets in the periphery of the nozzle member.

Abstract: An apparatus and method for molding articles of manufacture of resinous materials whereby, the surface of the molded article contains a pile-like texture or structure. The pile-like structure is composed of material of the surface stratum of the article and is formed by the adherence of such material to the surface of the mold cavity wall in which the article is molded and by pulling the article away from the mold cavity wall while at least the surface stratum thereof is in a deformable condition such as a semimolten or plastic state resulting from the elevated temperature thereof caused either by the manner in which it is cooled or by applying heat thereto through the mold cavity wall.

Abstract: Molten synthetic resin material containing foaming agent in an amount of 0.05 to 5 percent by weight is injected into a pre-pressurized mold cavity in a mold which is closed by a relatively low clamping force having a coefficient in the range of 10 to 40, said coefficient being represented as a ratio of clamping force to maximum injection shot volume. The above injection step is carried out for at least 3 seconds. After the injection step has been initiated, the pre-pressurized mold is released to atmosphere during the injection step at the soonest. At least two molds may be used to be alternately charged with said material.

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

Abstract: A method and system for cooling an injection molded plastic article by forming a portion of a mold cavity of fluid permeable porous material that communicates with a cooling liquid passageway and subjecting the cooling liquid to different pressures to vary the flow of fluid through the porous plug.

Abstract: Synthetic-resin articles are injection molded with at least one stationary mold cavity on the stationary mold plate being alternately aligned with carriers on the mold-closure plate so that each article is entrainable by this plate into a working station in which, for example, it can be cooled. During the injection molding of one article in the mold cavity defined between the stationary mold half and one of these carriers, a previously molded article is solidified on the other carrier in a working station offset from the stationary mold half. The newly injected mass is retained in the mold cavity only until the surface regions have cooled and set and the plate is then laterally shifted perpendicular to the mold closing direction to carry the article having the set surface regions and still fluid core into a working station while the other carrier, from which the cooled article has been ejected, is aligned with the stationary mold cavity.

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 molding apparatus, using raw material substantially comprised of crumbed rubber tires, and producing end products of durability and structural integrity. Products such as fence posts and dimensioned pieces like dimension-lumber products, have a hardened, dense outer wall structure surrounding a comparatively less dense and relatively porous central core, with the attendent structure integrity advantages of tubular and hollow-walled products. Heat fused raw material is fed under pressure, as from a screw extruder mechanism, through selectively controlled input valves to mold bodies, with the mold bodies carried in a chilled environment to establish fluid flow paths and hardening sequences leading to the desired end product body structure.

Abstract: Unitary molded plastic hinged article and method of making in which a fluid molten mixture of heat softenable resin and a blowing agent in substantially unfoamed condition is introduced into an expandable mold cavity to fill the cavity and the mold is expanded to allow foaming of the resin to form at least one foam cored article section while the resin adjacent the mold surface is still fluid and in which the hinge structure is formed by a member adapted to form a thin, flex portion and portions transitional from the thickness of the flex portion to the thickness of a cored article section, the shaping member being slidably disposed in an aperture in the mold with portions of the walls of the aperture exposed within the mold cavity at the time the molten mixture is introduced and the exposed portions of the walls being wiped by the shaping member when the mold is expanded.

Abstract: Shaped synthetic-resin bodies are made in a separable mold by injecting a flowable mass of a synthetic-resin material into the mold cavity. To precool the mass and cause an initial setting at least of the surface thereof, a liquefied gas, i.e. a low-boiling liquid which is in a gaseous state at room temperature and atmospheric pressure, is introduced between the mass and the walls of the cavity. The coolant is discharged from the cavity through at least one controllable cross-section outlet to regulate the contact time between the coolant and the mass. The initially set precooled body is injected from the mold and is subjected to final cooling and temperature homogenization (tempering), e.g. in a liquid bath.

Abstract: Air that becomes entrapped in a closed mold cavity during the injection of liquid plastic material into the cavity is vented into the flowing liquid coolant of the mold to be exhausted therewith while leakage of coolant into the mold cavity during nonventing is prevented by maintaining the coolant at less than atmospheric pressure.

Abstract: The invention pertains to a device for the fabrication of hollow plastic bodies, of the type comprising a core carrying plate, a double mould plate, means to inject plastic material into said mould plate and means to press said three plates against each other at the proper time, characterized in that it further comprises a metering plate fixed to one of said mould plates, as well as a hydraulic metering control plate facing said metering plate, said metering plate and hydraulic control plate being so conditioned to introduce, in a first step, a metered quantity of material in said metering plate and to transfer, in a second step, this quantity of material from the metering plate into the mould carrying plate, before the force-dieing resulting from pressing said plates together.