Abstract: The closing unit of a three-plate injection-molding machine comprises a die plate (1), a movable mold-clamping plate (2) and an end plate (3). Therein the die plate (1) and the end plate (3) are connected to one another via tie bars (4) on which the movable mold-clamping plate (2) is displaceably guided, and a toggle-lever arrangement (5), on which a drive unit (6) acts is provided between the end plate (3) and the movable mold-clamping plate (2). An encasing element (13) of variable length extends between the end plate (3) and the movable mold-clamping plate (2).

Abstract: An injection molding apparatus capable of producing injection molded articles from at least two plastic melts, includes an additional mold mounting device between a fixed mold mounting plate and a movable mold mounting plate that is traversed along four essentially horizontal tie rods. The additional mold mounting device is also pivotable around a rotational axis aligned perpendicular to the longitudinal axis of the tie rods, and carries additional mold halves that cooperate with the mold halves mounted on the mold mounting plates on at least two side surfaces that are aligned with a spacing parallel to each other and relative to the rotational axis. The additional mold mounting device comprises upper and lower support blocks that are arranged at a spacing relative to each other in an essentially vertically aligned plane, with each support block being guided on at least of the two tie rods. A friction or pivot bearing is provided for vertically aligned pivots of a prismatic mold core support.

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: 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 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.

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.