Abstract: An apparatus for proportioning reaction mixtures, particularly for the manufacture of hard polyurethane foam. The apparatus includes two proportioning cylinders each for proportioning one of the components to a mixing head. The pistons of the two proportioning cylinders can be operated alternatingly for filling the cylinders with the compound and subsequently ejecting the component from the cylinders. Double-acting hydraulic cylinders driven by a common hydraulic pump operate independently from each other the proportioning pistons of the two proportioning cylinders. A servo-controlled proportional valve is provided in each of the connecting lines between the hydraulic cylinders and the hydraulic pump. The control cycles of the proportional valves determining the ejection of the two cooperating proportioning cylinders are adjusted relative to each other so as to temporarily overlap.

Abstract: An apparatus for removing injection molded articles from an opened injection mold of an injection molding machine. The apparatus has a low structural weight and provides exact control of the movements of a grasping member for grasping the injection molded articles. The apparatus has a guide bed and a carriage movably mounted on the guide bed. The guide bed is aligned parallel to the direction of operation of the closing unit of the injection mold. The carriage includes a cantilever which extends transversely of the guide bed. The cantilever carries a slide member longitudinally movable on the cantilever. An adjustable support member is mounted on the slide member. The grasping member is mounted at the lower end of the support member. The grasping member is adjustable relative to the support member about at least two joints extending perpendicularly to each other.

Abstract: An agitator device for charging gas into PUR-components and for the homogenization of the PUR-components and the gas for the production of a foam material includes a pressure vessel for containing the mixture of components and gas with a stirring device extending into the body of the mixture. The stirring device includes a shaft which can be driven in opposite directions. First and second stirring elements are located on the shaft. In one direction of rotation only the first stirring elements operate to charge gas into the PUR-components and when the shaft is driven in the other direction both the first and second stirring elements operate to homogenize the mixture. In one arrangement, due to the direction of rotation, the second stirring elements can be pivotally displaced between a stirring position and an inactive position.

Abstract: There is disclosed an injection molding assembly comprised of a tool unit and two extruder units each including a drive unit spatially-disposed from one another and mounted for transverse movement with respect to the tool unit. In one embodiment of the present invention, if the extruder units are provided with hydraulic drive units, the extruder unit which is not coupled to the tool unit may be placed in fluid communication via a switching device with a low capacity hydraulic pump.

Abstract: A hard outer member generally centered on an axis and having a concave inner surface is injection molded of a relatively hard synthetic resin to have on its inner surface at one end a recess formed with a radially throughgoing passage. Parts of the mold in which this member is molded are then displaced before the resin has time to cure and another softer synthetic resin injected through this radially throughgoing passage to form in the recess a relatively soft seal having a sprue extending through the passage. The seal therefore adheres in surface contact with the inner surface at the recess and the sprue further ensures excellent holding of the seal on the member.

Abstract: A rapid-change system for injection-molding machine has a pair of adapter plates secured to the respective mold parts which engage in guides of the mold-carrying plates of the machine so that nothing projects outwardly beyond these adapter plates. Locks on the mold-carrying plates hold the adapter plates in position and the plates can be provided with service fittings which interconnect and disconnect upon insertion and removal of the molds together with the respective adapter plates.

Abstract: An injection-molding machine whose mold-carrying plates are provided with quick-release locking devices for engagement with adapter plates on respective halves on the mold, also has at least one of the plates provided with a horizontal transverse guide for the mold whereby the mold can be inserted laterally and removed laterally. A carriage is displaceable along the machine and has roller conveyors and a device for drawing a mold from the machine onto the roller conveyor or pushing a mold from a roller conveyor onto the machine.

Abstract: A hard outer member generally centered on an axis and having a concave inner surface is injection molded of a relatively hard synthetic resin to have on its inner surface at one end a recess formed with a radially throughgoing passage. Parts of the mold in which this member is molded are then displaced before the resin has time to cure and another softer synthetic resin is injected through this radially throughgoing passage to form in the recess a relatively soft seal having a sprue extending through the passage. The seal therefore adheres in surface contact with the inner surface at the recess and the sprue further ensures excellent holding of the seal on the member.

Abstract: An extrusion head for the manufacture of a hollow string of thermoplastic material whereby the resulting product consists of two concentric layers of the material whose weld seams are staggered in relation to one another, and whose union is accomplished without the two materials being formed into separate tubular layers. Provisions are made to maintain the layers' ratio of wall thickness.