Abstract: The accumulator of an extrusion blow molding machine is constructed so that the programming cylinder and die adjustment rod have axially aligned bores to receive a die pin retaining rod. The retaining rod holds the die pin in place by means of a lower split ring that nests inside the die pin and a lock nut combined with an upper split ring associated with the programming cylinder. When the lock nut is loosened and the upper split ring is removed, the retaining rod is moved down (while the die pin is held in place) and the lower split ring is removed. The die pin is then free to slide off the retaining rod and be removed from the accumulator head.

Abstract: An apparatus for heating and blending thermoplastic material prior to delivering the material into the barrel of an extruder has an elongated housing which contains two intermeshing feed screws that are driven to rotate in the same direction. Controlled heating is provided by electric band heaters which encircle the exterior of the housing, and electric cartridge heating elements fitted into aluminum cores that are received by an axial bore in each of the feed screws.

Abstract: An electric drive with hydraulic assist is disclosed for use in an injection molding machine, especially for screw advance during the injection process and/or in the dwell pressure phase. An electric motor is primarily used to produce the axial advance of the injection screw via an appropriate gear train. A piston that is moveable in a cylinder through pressure provided by a hydraulic fluid reservoir, can be used to supplement the axial movement produced by the electric motor. It is proposed according to the invention that pressurization occurs via the hydraulic fluid reservoir upon reaching a defined control quantity which corresponds to a defined load condition on the electric motor, such that the pressure rise in the cylinder is proportional to the load on the electric motor.

Abstract: A method is disclosed for manufacturing ejector sleeves from tubular stock. In particular, the method includes the following steps or operations: (a) cutting the tube stock to length, (b) enlarging a portion of the inside diameter of the sleeve to provide a clearance diameter, (c) rough-sizing a close-fitting inner diameter, (d) optionally semi-finishing the outside diameter of the sleeve, (e) hardening and straightening the sleeve, (f) final sizing of the outside diameter while maintaining concentricity with the inside diameters, (g) finishing the end face of the sleeve adjacent the close-fitting diameter, (h) final sizing of the close-fitting inner diameter while maintaining concentricity with the outside diameter, (i) forming a head on the sleeve by heating and forging to a predetermined size, (j) optional annealing and refinishing of the head for purposes of hardness or dimensional modification, or improving surface finish.

Abstract: The present invention provides a dual flow divider for use on an extruder. The flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as is practically possible. The relative flow in the respective channels can be varied by rotating a diverter valve that extends to a position adjacent the central entry of the flow divider, i.e., where the flow begins to divide. The flow channels and control end of the diverter valve are specially configured to avoid any shape or surface conditions that would impose heat-generating restrictions to material flow, and/or allow areas of stagnation in the flow stream. More specifically, the flow channels are machined to provide smooth, streamlined transitions at all points along the flow path.

Abstract: An electro-mechanical drive apparatus uses a single motor and three one-way clutches to provide both injection and extruder functions in the injection unit of an injection molding machine. When engaged, the first one-way clutch couples the feed screw to the frame of the injection unit, the second clutch couples the drive motor to the feed screw, and the third clutch couples the drive motor to the ball screw mechanism. During rotation of the drive motor in a forward (injection) direction, (a) the third one-way clutch engages, rotating the ball screw mechanism which results in forward movement of the feed screw; (b) the second one-way clutch slips; and (c) the first one-way clutch engages to prevent rotation of the feed screw as it moves forward.

Abstract: An accumulator head for a blow molding machine uses an electromechanical drive assembly for the purging and programming functions. The purging actuator of the drive assembly includes a ball screw and nut assembly in which the ball screw is rotated by an electric motor to move the ball nut assembly vertically and operate the plunger of the accumulator. A second ball screw and nut assembly is included in the programming actuator of the drive assembly for moving the mandrel vertically, thereby controlling the size of the die outlet opening of the accumulator. Preferably, the ball screws of the programming and purging actuators are axially aligned with the nut assemblies each carried by a yoke that travels on guide rods. Four support rods are provided to maintain alignment and provide stationary mounting for the respective motors. The structure has sufficient rigidity to supply the force required for the purging operation, but uses no hydraulic actuators.

Abstract: The present invention provides a barrel venting system for use on an extruder. Gases that are generated during plasticizing are drawn by vacuum through a filter to remove plastic particles before the gas is exhausted to the atmosphere. To enable cleaning of the filter without interrupting extruder operation, a shuttle valve is provided to allow rapid switching of the gas flow to a second filter. The valve itself includes two disc shaped elements with ports that align in two positions to enable flow to either the first or second filter, as desired.

Abstract: A cooling method that involves circulating a liquid coolant through the motor housings and mounting surfaces for electrical/electronic components, such as the electric motors and associated electronic drives, in electric plastic processing machines. Specifically, the motors are provided with a housing having an integral heat exchanger, such as stainless steel tubing cast into a cylindrical aluminum stator housing. The various electrical/electronic components are mounted to the surface of a plate type heat exchanger (chill plate) that is contained within the electrical cabinet for the primary electrical circuitry. In addition, the air within the electrical cabinet is continually circulated over the chill plate to provide a more uniform temperature distribution within the enclosure and minimize condensation on the surface of the plate. The heat generated by the motors and electronics is absorbed from the motor housings and chill plate by the circulating liquid and released through a heat exchanger.

Abstract: The present invention provides a dual flow divider for use on an extruder. The flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as is practically possible. The relative flow in the respective channels can be varied by rotating a diverter valve that extends to a position adjacent the central entry of the flow divider, i.e., where the flow begins to divide. The flow channels and control end of the diverter valve are specially configured to avoid any shape or surface conditions that would impose heat-generating restrictions to material flow, and/or allow areas of stagnation in the flow stream. More specifically, the flow channels are machined to provide smooth, streamlined transitions at all points along the flow path.

Abstract: A pair of injection units and a common co-injection manifold are carried on a slide mounted a machine base. The machine base carries a mold element, and the injection units and manifold are moved in unison with respect to the mold element. The injection units are, in turn, carried on slideways mounted to the machine slide such that the injection units may be separately moved relative to the co-injection manifold.

Abstract: An injection molding machine is provided with an open frame specifically designed to avoid angular displacement of the stationary platen during the molding process. More particularly, the stationary platen and the supporting frame are configured to maintain a constant moment of inertia relative to the line of force acting on the platen during the clamp closed part of the cycle, so that it displaces linearly when force is applied. In addition, the frame is provided with integral support members to connect with the die height adjustment mechanism. The support members are positioned on the frame to minimize the distance of the open frame, thus minimizing the length of frame subject to deflection when the force is applied.

Abstract: A cooling system which circulates a liquid coolant through motor housings and mounting surfaces for electrical/electronic components. This system is particularly cost effective where there are multiple electric motors and associated electronic drives, as in electric plastic processing machines. Specifically, the motors are provided with a housing having an integral heat exchanger, such as stainless steel tubing cast into a cylindrical aluminum stator housing. The various electrical/electronic components are mounted to the surface of a plate type heat exchanger (chill plate) that is contained within the compartment for the primary electrical circuitry. In addition, the air within the electrical enclosure is continually circulated over the chill plate to provide a more uniform temperature distribution within the enclosure and minimize condensation on the surface of the plate.

Abstract: In an apparatus for generating clamping force in injection molding machines having stationary and moving platens, between which an injection molding die is mounted, and a traversing mechanism associated with the moving platen for opening and closing of the injection molding die, the present invention provides means for locking the traversing mechanism after the molding die has been closed. The clamping force required during injection is generated by at least one element made of a magnetostrictive material that is mounted between the traversing mechanism and the moving platen. Each magnetostrictive element is surrounded by a magnetic coil that is controllably energized to produce an alternating magnetic field which causes elongation of the associated element, generating the clamping force.

Abstract: A method for compensating for variations in the operating efficiency of electric motors used in plastic processing machines. The current to the motor is continually monitored during all periods of operation to identify variations in the motor's actual efficiency as it relates to measurable machine performance. Normal operation of the electric motor is monitored to establish baseline current usage for the various periods of the operating cycle under given conditions. With a baseline established, variations in motor efficiency can be detected by monitoring the current during closed loop control of specific parameters and comparing the results to the baseline. Since the parameter is held constant by virtue of the closed loop, a deviation in current from the baseline indicates a change in efficiency. Based on the identified variance, the current to the motor during other (open loop) operations can be adjusted accordingly.

Abstract: A dynamic braking system for the electric motors in an injection molding machine uses the electric heater bands on the barrel of the injection unit as resistors to dissipate the energy generated by the electric motors during an emergency stop. This system includes suitable switching circuitry to disconnect the heaters from their normal power source and connect them to the motor windings for the short term dynamic braking function.

Abstract: The method of the present invention relates to reducing cycle time in injection molding machines that are running large capacity molds, such as multiple cavity preform molds, and require a high volume supply of quality melt. Specifically, the present invention proposes using a continually plasticizing extruder to supply two melt accumulators which will alternately operate to inject the plastic material into the mold. To accomplish this, a rotary valve at the end of the extruder is controlled to fill the pots, and ball check valves are positioned to control flow direction and limit pressure in certain parts of the system. A shuttle valve between the shot pots and before the nozzle facilitates decompression.

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: A device for producing moldings of plastic material having a cavity therein filled with a fluid comprises a mold cavity, an injector for injecting flowable plastic into the mold cavity, an injector for injecting a pressurized fluid into an interior portion of the plastic, and a side cavity connected to the mold to receive flowable plastic melt expelled by the injected pressurized fluid. The side cavity may be randomly lockable and may comprise a closing stuffer which rests flush with respect to the mold cavity interior walls.