Abstract: A method of injection molding for use with an injection molding machine includes: a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection molding machine, the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity of a mold in the injection molding machine to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the molten plastic is injected into the cavity, thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity substantially constant as the molten plastic is injected into the cavity.

Abstract: A coextrusion system employs two or more extruders, each with a gear pump at its output connected to a coextrusion die. Different materials are extruded by each extruder. Varying the speed of one or both gear pumps varies the content of the extrudate. The gear pumps permit precise variation of the relative content of the materials extruded by the several extruders lengthwise along the extrudate. A display of a cross sectional dimension of the extrudate along a length of the extrudate permits observation of the lag that occurs between alteration of gear pump speed (or air pressure in the case of tubular or blown sheet extrudates) and the resultant change in dimension, so that a speed correction can be made at the appropriate time to compensate for differing shrinkage and stretching characteristics between the several extruded materials.

Abstract: A method of injection molding for use with an injection molding machine (10) includes: (a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection molding machine (10), the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity (30) of a mold (22) in the injection molding machine (10) to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the molten plastic is injected into the cavity (30), thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity (30) substantially constant as the molten plastic is injected into the cavity (30).

Abstract: A thermoforming process window of a rectangular sheet of a thermoplastic material is determined by calculating its Sag Number during heating. The Sag Number is a function of the sheets length, width and apex depth at the center of sag. Upon the Sag Number being between 10 and 40, preferably 15 and 35, and more preferably 19 and 28, the sheet is ready for forming into an end product.

Abstract: A method for the production of a molded article having a hollow portion by utilizing a gas compression apparatus having a gas source, a compressor composed of a piston and a cylinder, and a discharge valve for controlling the flow of pressurized gas discharged from the cylinder, the method comprising introducing the pressurized gas through the discharge valve into a molten resin injected into a cavity of a mold, under the control of the discharge valve while carrying out, in one molding cycle, the intake step of supplying gas from the gas source to the cylinder and the compression step of compressing the gas by movement of the piston in the cylinder, at least twice each on the basis of predetermined compressor operation conditions, and thereby forming the hollow portion in the molded article.

Abstract: A process and an apparatus for forming a gasket directly on a workpiece having a joining surface which has an annular gasket-fixing groove, wherein a mold having a gasket-forming groove which cooperates with the gasket-fixing groove to define a cavity for forming the gasket is clamped to the joining surface of the workpiece, and a material is injected into the cavity through an injection passage which is formed through the mold and which communicates with the gasket-forming groove. The material is cured into the gasket, and the mold is removed from the workpiece. The mold may have two elastic sealing members disposed on inner and outer sides of the gasket-forming groove, respectively, so as to extend along the gasket-forming groove, and provide pressure-tight sealing of the cavity when the body is placed on the workpiece such that the sealing members are held in elastic pressure-tight contact with the joining surface.

Abstract: The procedure serves the purpose of molding a container from a thermoplastic material. After a temperature treatment a moldable object is fed to a blow station, which has a blow mold that is provided for the purpose of contouring the container. The temperature-treated moldable object is inserted into the blow mold. By feeding in high-pressure blow air, the moldable object is expanded. In addition at least one other pneumatic working step with low-pressure air is carried out, with this air being taken from a low-pressure air supply. The low-pressure air supply has a smaller pressure level than the high-pressure blow-air supply. After the moldable object has been expanded, high-pressure blow air streaming out of the molded container held in the blow mold is fed to the low-pressure air supply during a transition phase. In the region of the low-pressure air supply a pressure monitoring is carried out for the purpose of defining a maximum low-air pressure to be provided.

Abstract: A method for forming an EMI shielding gasket gasket. The gasket is a formed-in-place gasket which is deposited by an extruder. The gasket material is a fluent polymeric material having a conductive particles disposed therein. The fluent polymeric material is supplied to the extruder by a material supply system having several canisters and a mixing chamber. The fluent polymeric material is fed to a chamber in the extruder. Pressure is applied to the fluent polymeric material by a pressure supply system which includes a source of positive pressure and negative pressure, and a control module for selectively supplying positive pressure and negative pressure to the extrusion chamber.

Abstract: An apparatus for plug-assisted thermoforming of a cup or other hollow article has a concave well or cone region machined into its top with a series of small holes drilled near the deepest part of the well and connected to a port inside the plug which is connected to a specifically sized manifold system. The manifold has a source for positive (pneumatic) and negative (vacuum) pressure air. During the machine cycle, a vacuum is introduced into the plug, which draws the hot plastic sheet into the plug well to stretch it. The vacuum is replaced by compressed air to transfer the pre-stretched sheet into a mold. In a particularly preferred embodiment, the plug is shaped to provide stretching in both the central well and in peripheral regions concentric with the well. Controlled air pressure in the mold may be used to provide the concentric prestretching.

Abstract: A control system for a gas assisted injection molding apparatus which provides precise and reproducible indication of when the injection of plastic is to terminate and when the pressured gas is to be introduced on basis of sensing of the location of the flow front of the injected plastic in the mold cavity. The flow front sensor control system according to the present invention includes: one or more sensors located at one or more predetermined locations of the cavity of a mold of a gas assisted injection molding apparatus, a controller which processes sensed data from the one or more sensors and thereupon sends a signal to the gas assisted plastic injection molding apparatus to discontinue plastic injection and introduce pressured gas. The preferred type of sensor is a temperature sensor; however, other types of sensors, such as a pressure sensor, may be used.

Abstract: A tire vulcanization apparatus in which an encaser 3 makes it possible to introduce a tire into a mold 1 and, by means of inductors 42, transfers to the mold heat energy necessary for vulcanization and in which a chamber 5 receives several molds 1 and makes it possible to maintain each mold insulated from the environment in order to limit heat losses during the time necessary for the vulcanization.

Abstract: Process for forming a dimensionally variable tubular member for use in catheterization procedures. The process includes a mechanism for extruding a tubular member. A variable speed puller pulls the tubular member through or from the extrusion means at a selectively variable speed. A variable air or gas pressure supply supplies pressurized air or gas to the extrusion mechanism at a selectively variable rate. The dimensionally varying tubular member may be cut to desired lengths for use as catheter shafts or catheter soft tips. The process may include forming a tubular member having a dimensionally varying first layer and a dimensionally varying second layer, wherein a portion of the first layer at a distal end of the tubular member is removed.

Abstract: A process for drawing curtain filament bundles comprises the steps of:a) introducing the filament bundles together with aspirated gas into an injector which is rectangular in horizontal section and partially drawing the filament bundles in the injector,b) fully drawing the filament bundles in a drawing shaft which adjoins the injector and consists of two parallel and close-distance plates,c) monitoring the pressure profile in the drawing shaft with a plurality of pressure measuring devices arranged in the form of a grid, andd) setting a desired pressure profile in the drawing shaft by local variation of the geometry and/or the amount of drawing gas in the drawing shaft.

Abstract: A method and apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepregs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: Tooling and method for gas assist injection molding of plastics material into a hollowed part in which a mold chamber formed between stationary and movable mold tools is initially charged with an inert gas to provide a resistance force against the flow front of a short shot of plastics melt subsequently injected into the cavity and supplied with a pressurized assist gas so that the velocity of the flow front of the short shot expanded by the assist gas in the mold chamber is modulated by the controlled release of the retarding chamber charge gas to prevent blow out of the short shot while eliminating flow hesitation lines to improve molded part appearance and uniformity of part wall thickness.

Abstract: A method and apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepregs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: The present invention relates to a flexible tubular conduit with a jacket or tube made of crosslinked polyethylene, specially crosslinked polyethylene, and a method for manufacturing the conduit. A jacket or tube is made from polyethylene crosslinked by hydrolysis.

Abstract: A spun-bond apparatus can be operated with additional high-pressure jets at the outlet gap immediately above the collecting belt and below the intermediate passage connecting that gap with the cooling chamber to establish a higher velocity of the filaments which are collected in the nonwoven fabric on the belt.

Abstract: A tire cure control system and method characterized by a computer-based data acquisition and process control unit that uses non-invasive, direct cure measurements to adjust the length of cure so that all cured articles such as tires will be cured to the same extent in the minimum amount of time, thereby to maximize production while providing uniformly cured products. The unit generally includes at least one microwave probe, although preferably multiple microwave probes, placed in the mold and a processor to process probe data and to initiate a control action principally initiating a mold opening sequence at the optimal time. Initiation of the mold opening sequence at least in part is based upon a measurement of the time rate of change of the attenuation of microwave energy caused by the curing rubber compound in the mold.

Abstract: Method and apparatus for pulsating gas-assisted injection molding hollow tubular plastic parts includes the injection of a molten plastic into a mold cavity in an amount less than the cavity volume and in separate molten plastic flows that flow along the cavity and ultimately unite in a solidifying fusion welding state at an interface. A pressurized gas is injected into the molten plastic to form a central void in the molten plastic extending to opposite sides of the interface leaving a voidless solidifying fusion weld section encompassing the interface. The gas pressure acting on the opposite sides of the interface is trapped and then alternately increased and decreased by a separate gas injection that creates gas pulsations that effect shifting of the molten weld section in opposite directions to force intermingling of the plastic molecules therein and across the interface to enhance the strength of the fusion weld section on solidification and eliminate appearance knit lines.

Abstract: A spun-filament nonwoven web is deposited on a sieve belt from a spinning head producing a curtain of thermoplastic filaments which traverse a cooling chamber by drawing the filaments in a drawing nozzle separate from the cooling chamber and passing the filaments through a delivery unit and in the form of a jet pump, air flow through which is controlled at least in part by a suction blower below that sieve belt.

Abstract: A device which is capable of measuring both the viscous injection/casting operation and the shrinkage during the solidification phase, using a suitable measuring device. For this a sensor is fitted in the mould at the critical point expected, with a measuring surface that is flush with the inner wall and is able to measure shear and compressive stresses, so that for the first time the shrinkage phenomenon becomes measurable. With this, a new dimension of quality monitoring becomes possible.

Abstract: A toroidal semifinished product (5) made of raw elastomeric material is semivulcanized in a semivulcanization chamber (4) defined between two half-molds (2, 3) disposed close to each other. A pressure, preferably equal to the pressure exerted by the gases generated in the semifinished product (5), is created in the mold (1a). The half-molds (2, 3) are moved apart from each other and pressure in the mold is gradually reduced, thereby giving rise to the expansion and consequent transferring of the semifinished product (5) from the semivulcanization chamber (4) to a surrounding final vulcanization chamber (6). When the inner diameter of the semifinished product (5) is larger than the inner diameter of the final vulcanization chamber (6), said chamber is closed at its inner circumferential edge and then, after possible pressure increase in the mold, at its outer circumferential edge, in order to integrally enclose the semifinished product and enable completion of the vulcanization process.

Abstract: A resin extruder for supplying resin to flaws in laminated glass includes a casing forming a resin reservoir from which resin is dispensed through a nozzle by screwing inward a ram partially received in the casing and carrying a pressure gauge communicating with the reservoir.

Abstract: The improved electrofusion joint and header for supplying hot water that perform satisfactorily at elevated temperatures as evidenced by high heat resistance, that exhibit good sealing property and that can be handled efficiently in mounting and various other operations have a crosslinked thermoplastic resin layer and at least one joining portion which comprises a non-crosslinked thermoplastic resin layer that is formed a as an integral part of said crosslinked thermoplastic resin layer in the area where it contacts a tubular member to be joined, and a heating electric wire provided either within or on the outer or inner surface of said non-crosslinked thermoplastic resin layer. Such electrofusion joint and header are applicable to any part of a piping system for supplying hot water and they will withstand use for a prolonged period.

Abstract: A method of forming in a mould an article using a thermoplastic sandwich material, which material has a core of a thermoplastic foam and one or two, optionally fiber-reinforced, covering layers of a thermoplastic resin, the method having the steps of providing in the mould a foamable thermoplastic synthetic material and said one or two fiber-reinforced covering layers, supplying a liquid to the mould at an elevated pressure and temperature, whereby the temperature of the thermoplastic synthetic material is raised to a temperature above the temperature at which the material foams, followed by lowering the pressure of the liquid and removing the liquid from the mould with foaming of the thermoplastic synthetic material.

Abstract: The improved electrofusion joint and header for supplying hot water that perform satisfactorily at elevated temperatures as evidenced by high heat resistance, that exhibit good sealing property and that can be handled efficiently in mounting and various other operations have a crosslinked thermoplastic resin layer and at least one joining portion which comprises a non-crosslinked thermoplastic resin layer that is formed a as an integral part of the crosslinked thermoplastic resin layer in the area where it contacts a tubular member to be joined, and a heating electric wire provided either within or on the outer or inner surface of the non-crosslinked thermoplastic resin layer. Such electrofusion joint and header are applicable to any part of a piping system for supplying hot water and they will withstand use for a prolonged period.

Abstract: An injection molding machine utilizing vector controlled AC induction motors in its servomechanism drive systems. Vector controlled AC induction motors provide a cost effective high power drive system which superior performance capabilities. Further system efficiencies are realized when the control is configured to run multiple motors by multiplexing the computer controller circuits for the power sections of each motor.

Abstract: A method for installing a pipe liner in a pipe includes the steps of reducing the diameter of the liner, so that it can be positioned within the pipe, installing the liner in the pipe, enlarging an upstream end of the liner, disposing a liner expander within the upstream end of the liner, pressurizing the upstream end of the liner with a heated fluid, the temperature of the heated fluid being sufficient to soften the liner, and the pressure of the heated fluid being sufficient to propel the liner expander from the upstream end of the liner to a downstream end, allowing a portion of the heated fluid to bypass the liner expander for heating and softening the liner ahead of the expander, and reducing the temperature of the pressurizing fluid to cool the liner below the softening temperature, to allow it to stiffen and form a liner within the pipe.

Abstract: A mold apparatus and method is used to form a solid injection molded plastic part having no internal voids, a Class A finish, a sink-free exterior appearance surface, and unevenly distributed structural detail extending from the opposite surface, the detail including free-standing reinforcement ribs, attachment bosses, and the like. In the method the mold portions of the mold apparatus are closed, charges of molten thermoplastic and pressurized gas are sequentially injected into a mold cavity defining the shape of the desired part, and the mold portions are sequentially separated and closed. The pressurized gas forces the hot plastic away from one mold half and against the other mold half, and separation of the mold portions ensures uniform distribution of the pressurized gas behind the hot plastic, which pressure is maintained during cooling.

Abstract: A vacuum sizing apparatus with a controlled vacuum is provided. The vacuum is precisely controlled by the use of a variable speed motor driven vacuum pump and a step motor controlled vent valve. An electrical circuit containing a microprocessor coordinates the speed of the motor driven vacuum pump with the position of the vent valve to give precise vacuum control within the vacuum chambers of the sizing apparatus. A closed sump tank contains water for the water system of the apparatus and is maintained at the same vacuum level as the vacuum chambers within the sizing apparatus.

Abstract: For the continuous manufacture of a compound pipe with a pipe socket including a smooth internal tube and an external tube provided with transverse grooves and welded together with the latter, an external tube and an internal tube are extruded, the latter into the external tube. While the normal compound pipe is manufactured, gas is blown at a slight overpressure into the space beteen the external tube and the internal tube. When the pipe socket is produced, this space is vented so that a full-surface bearing of the internal tube against the external tube is achieved, to which end the internal tube is acted upon from its inside by gas under pressure.

Abstract: A system for monitoring and controlling the output of extruder apparatus for producing a blown synthetic resin film. An infrared imaging system provides for measuring the temperature of the blown film simultaneously at multiple points on the film between the blowing head and the frost line of the film bubble. The multi-dimensional temperature profile measured by an infrared camera is processed in a computer controller in order to provide control inputs to various components of the extruder apparatus. The extruder apparatus is controlled so as to maintain a desired temperature profile substantially at that which is known to provide a high quality end product.

Abstract: Methods to create hollow spheres and spheres produced according to such methods, such methods including suspending in a chamber at zero gravity a gas-generating pellet in a resin material which gas-generating pellet is caused to produce gas expanding the resin into a spherical mass; methods of coating sphere-forming material on a spherical liquid mass, hardening the coating and removing the liquid mass leaving the thus formed hollow sphere and methods of blowing bubbles of resin to form spheres.

Abstract: The invention relates to a process for the film correction of the thickness profile of a blown portion in the production of bubble film in which the flow of cooling air is varied in individual peripheral regions of the film bubble. According to the invention, at least part of the cooling air is taken via an exit slot which is divided into individual separately fed segments in the peripheral direction of the film bubble and the supply of additional cooling air via the exit slot is, for example, controlled per segment using radial blowers. In this manner it is possible accurately to regulate the cooling action and thus the film thickness in the individual peripheral regions of the film bubble.

Abstract: An article conformity discriminating apparatus for an injection molding machine is capable of automatically discriminating the conformity of articles with accuracy without using a conforming article sample. In molding cycles for mass production of articles executed according to optimum molding conditions of a mold file read from a shared memory (105), an actual resin pressure detected by a pressure sensor (4) is periodically sampled according to an output of an address generator (118), while a reference resin pressure sampled in the same sampling period or a corresponding sampling period on a pressure transition pattern, in a conforming article molding process for determining the optimum molding conditions made before the mass production of the articles, is read from the shared memory, (105) by a processor (114), and the actual resin pressure is compared with the reference resin pressure.

Abstract: To determine and/or automatically control the degree of orientation of tubular films which have been made in a film-blowing plant including an extruder having a film-blowing head and apparatus for internal cooling and also including flattening and take-off apparatus, the rate of exchange of the air for internal cooling, the speed of the extruder, the temperature of the plastic composition being extruded and/or the take-off velocity are controlled. To ensure that the degree of orientation can be determined and/or automatically controlled in a simple manner and without an occurrence of trouble, that shape of the flaring portion of the bubble which corresponds to the desired degree of orientation is determined and/or adjusted and is recorded as the desired shape of the bubble. The actual shape of the flaring portion of the bubble is detected and compared with and adapted to the desired shape.

Abstract: A process and apparatus for producing an elongated body changing in elastic modulus longitudinally thereof with use of polymers without resulting in variations in the outside and inside diameters of the body even when the polymers are different in extrusion characteristics or swelling characteristics. The apparatus may include a feeder 1 for extruding a first polymer in a molten state and a feeder 2 for extruding a second polymer, which is different from the first polymer in elastic modulus and similarly in a molten state. The feeders alternately discharge the respective polymers, which are continuously fed to a long-land die 5 along with a lubricant supplied from a lubricant applicator 4. The polymers are formed into the desired shape and cooled in the die 5, and thereafter extruded.

Abstract: A method and apparatus for making a plastic injection molded part with a smooth surface or skin and a hollow core wherein thermoplastic material is injected as a molten stream into the mold cavity through a sprue bushing fixed in the mold. Simultaneously, an unmeasured quantity of inert gas is introduced through an adapter into the molten stream at the sprue bushing substantially coaxially with the melt stream and at a pressure sufficient to penetrate the thermoplastic material to form a gas cavity in the molten material in the mold. For retrofitting an existing mold, an adapter can be added to the exisiting sprue bushing. During plastic injection and cooling in the mold the gas is maintained at a high pressure, preset, constant and adequate to maintain the plastic against the mold surface until it is self-supporting. The gas is exhausted from the mold, back through the sprue bushing and adapter, before the mold is opened.

Abstract: A rotary plastic blow molding machine (20) including a base (22), a wheel (24) mounted for rotation on the base about a rotational axis A and a programmable logic controller (PLC) (100) mounted on the wheel for rotation therewith to control operation of a plurality of mold stations (40) on the wheel. The blow molding machine (20) as disclosed also has at least one sensor (62) mounted on the wheel (24) for rotation therewith to sense an operating parameter of each mold station and to generate an associated operation signal. The PLC (100) is coupled to the at least one sensor (62), processes the sensed operation signal and controls the machine (20) operation in response to the signal.

Abstract: A method for vulcanizing an elastomeric product placed in a vulcanizing apparatus includes one step of supplying heating medium into the elastomeric product and another step of supplying pressurizing medium into the elastomeric product at a higher pressure than the heating medium, the two steps being performed one after another at least two times. This method can produce an elastomeric product having no bareness without increasing the vulcanizing time.

Abstract: A method of vulcanizing an elastomer product such as a tire including placing the product in a mould, supplying a heating medium to the interior of the product to effect vulcanization, then supplying a pressurizing medium to the interior of the product. In this method the heating medium or the heated fluid mixture is exhausted or removed from the interior of the product at least once by opening an exhaust and simultaneously supplying a cooling pressurizing medium to cool the product to a required temperature level. The heating medium may be exhausted immediately after the completion of the heating medium supply process. The heated fluid mixture may be exhausted in and/or after the pressurizing medium supply process. Preferably the rate of exhaustion is limited by a control orifice. As a result the product is cooled without giving temperature differences in different parts of the product and avoiding unfavorable pressure drop so that efficient vulcanization with good homogeneity in the product results.

Abstract: A molding compound metering system meters a molding compound in supplying the molding compound from a molding compound stocker into the injection chamber of an injection barrel by detecting the backward stroke of the injection plunger of an injection cylinder, axially slidably fitted in the injection chamber and detecting the pressure of the molding compound in the injection chamber of the injection barrel. When the injection plunger is moved backward by the pressure of the molding compound supplied into the injection chamber, the discharge of the working fluid from the back working chamber of the injection cylinder is regulated to apply back pressure to the injection plunger by an adjustable-pressure relief valve, and a regulated pressure is applied to the front working chamber of the injection cylinder.

Abstract: Apparatus and method for cooling an extruded blown film in which the interior surface of the thin film bubble is contacted with a gas which does not contain water vapor to thereby cool the extruded film. The apparatus and method may employ an enclosed circulation system to provide for the reuse of the gas through cooling with a liquid coolant such as liquid cryogen.

Abstract: A process for installing a liner in a generally horizontal pipe section includes the steps of: providing a hollow generally cylindrical folded pipe liner; pulling the folded liner through the pipe section leaving end sections of the liner extending from the upstream end and the downstream end of the pipe; pulling an air hose and a steam hose through the folded liner from the downstream end to the upstream end; providing a floating plug assembly including at least two disk shaped expanders; attaching the steam hose to the floating plug assembly downstream of the disk shaped expanders; attaching the air hose to the floating plug assembly upstream of the disk shaped expanders; inserting the floating plug assembly into the liner at the upstream end; and providing steam to the steam hose and cooling air to the air hose, while pulling the floating plug assembly through the liner to progressively heat the liner to a softening point downstream of the disk shaped expanders, and expand the liner to fill the pipe and co

Abstract: An injection molding machine including a guide coupling for transmitting linear movement to a screw, a screw coupling for transmitting a rotary movement to the screw, a washer-type load cell, disposed between the guide coupling and the screw coupling, for detecting a pressure applied to the screw coupling, and a transmission link having one end thereof coupled to the screw coupling so as to be rotatable relative thereto and axially fixed relative there. The transmission link rotationally fixed relative to the guide coupling.

Abstract: An apparatus for use in gas assisted injection molding of plastic material so as to form an injection molded product includes a pair of mold members defining when closed a sealed cavity. A first opening is provided in one of the mold members for allowing the injection of a plastic material into the cavity. A device is provided to supply a pressurized gas and a second opening is provided in one of the mold members for allowing the injection of the pressurized gas into the cavity. A probe is located in the second opening and is adapted to be reciprocated therein from a retracted position to an extended position. The probe has a first end adapted to selectively extend into the cavity, a second end, and a longitudinally extending bore which terminates in a port located adjacent the first end. The bore is used to guide the gas into the cavity. A device is provided for reciprocating the probe in relation to the cavity.

Abstract: An improved system and method for effectively controlling the operation of a continuous mixer/melter having an adjustable exit opening and connected to a melt pump is provided. The melt pump, which is preferably a gear pump, is operatively connected to an extruder/pelletizer. Operation of the gear pump is controlled in proportional relation to the energy requirements of the mixer/melter motor, the energy applied to adjust and maintain the exit opening of the mixer/melter, and the suction pressure measured at the interface between the mixer/melter and the gear pump. A microprocessor unit which receives and processes the input signals, calculates the energy requirements of the gear pump motor and compares these requirements with the actual torque, makes the necessary adjustments to the gear pump.

Abstract: A method and an apparatus of injection molding articles of thermoplastic material. The method includes initially forcing molten plastics material into an injection mold in an amount sufficient for forming the article. Subsequently, a flowable medium is forced into the injection mold with a pressure which distributes the plastics material uniformly over the surface of the mold cavity of the injection mold so as to form a hollow body. The hollow body is then cooled while the pressure of the medium is maintained. Finally, the pressure of the medium is released and the molded article is removed from the injection mold. The pressure of the medium in the mold cavity is controlled and/or varied at least temporarily until the plastics material has cooled. The apparatus for carrying out the method includes a pressure reservoir for the medium which is connectible to the injection mold through lines. The lines include control and/or regulating elements.

Abstract: An injection/hold pressure control apparatus which permits the production of high-quality molded articles without the need of using an expensive internal mold pressure sensor. When a plurality of points specifying a target injection/hold pressure curve represented as a function of the time period elapsed after the start of injection are manually input in succession, a processor (109) of a numerical control unit (100) calculates a group of target injection/hold pressure data on the basis of the target pressure curve drawn on a screen of a display unit (113), and stores them in a lookup table in a shared memory (102). Upon start of the injection, a comparator (11), connected to a pressure sensor (4) mounted on an injection screw (1) for detecting an actual injection/hold pressure, is connected to the numerical control unit through a first changeover switch (6).