Abstract: Multi-bladed disc cutter for cutting into pellets thermoplastic material extruded from a die plate of an underwater pelletizer, wherein the blades of the cutter are integrally formed on the periphery of a backplate and radially project therefrom, the sidewalls of the blades being integrally connected by shroud members to provide added strength against bending and twisting of the blades under load. Perforations are provided in the shroud members and backplate to permit passage of water to cool and flush away the cut pellets. Additionally, integrally formed blades may be arranged in concentric circles inwardly of the periphery of the backplate. The integral of the disc cutters avoids weakening and misalignment of the blades, saves space and permits a greater number of cutting edges than is possible in disc cutters wherein the blades are fastened to a hole by bolts. Casting the cutter integrally with its blades permits off-line grinding for final alignment purposes.

Abstract: Apparatus for forming a constructional block in which a lower die is filled with a given and at least substantially excess amount of material after substantially closing the lower die with an upper die for forming a mold by drawing the dies together, the material is highly compressed while, simultaneously with drawing them together under the action of a means for controlling and regulating its passage, in a first stage, the excess material is allowed to escape partly outwardly of the mold and, in a second stage, substantially before obtaining the desired dimension between the two faces of the block through the relative drawing together of the dies, the passage of the material escaping outwardly of the mold is stopped.

Abstract: An injection molding apparatus for forming plastic items employs a mold formed of tool members which mate to form a mold cavity. A mold core assembly includes a pull core adapted to extend into the mold cavity and a core support member from which the pull core depends. A nozzle is provided for introducing liquid plastic into a runner which communicates with the mold cavity. The nozzle has a retracted position and an injection position. The nozzle is attached to the core support member such that movement of the nozzle between the retracted position and the injection position causes movement of the pull core, and such that fluid may pass from the nozzle into the runner. The nozzle may be attached to the core support member in a manner to allow the pull core to move laterally with respect to said nozzle.

Abstract: The present invention has as an object an adjustable mold for the manufacture of concrete elements such as staircases of the type having a straight line extent, of which the treads are perpendicular or not perpendicular to the risers.

Abstract: A screw extruder comprises a barrel including a section that is supported for rotation about the longitudinal axis of the barrel. A screw extends and is supported for rotation in the barrel; and, in use, rotation of the screw rotates and advances plastic material through the barrel. Rotation of the screw also causes the rotatable barrel section to rotate, and a brake is connected to that rotatable section to maintain the rotational speed of the rotatable section less than the rotational speed of the extruder screw. The rotational speed of the screw relative to the rotatable barrel section controls the relative rates at which plastic is mixed, heated, and pressurized in the barrel.

Abstract: The present invention provides a matrix for the production of pellets from powdered, granular, fibrous or pre-compressed loose material, said matrix having a plurality of pressure canals passing therethrough through which the loose material is forced and having cutting means which divides up the pressed material emerging from the pressure canals into pellets of predetermined length, wherein, on the exit side of the matrix, there are present flanges running between the pressure canals with a constant distance from one another, between which flanges sections of the cutting means extend up to the exit ends of the pressure canals.

Abstract: An extruded composite structure consisting essentially of an outer sheath surrounding an inner core, said outer sheath consisting essentially of an extrudable resin which remains thermoplastic after extrusion and said inner core comprising a substance whose melting point or decomposition temperature is lower than the temperature to which said resin must be heated to be extruded and to the apparatus and process for making such composite structure.

Abstract: A method and an apparatus are presented for forming couplings from blanks made from lengths of extruded plastic pipe, to join pipe together. The blank is cut from the length of extruded pipe and heated to the thermoplastic point. The heated blank is mounted between two mandrels which have a slight taper toward the ends, which are beveled. The ends of the mandrels are brought together inside the blank at a uniform rate and force. The pressure between the ends of the mandrels causes a bulge in the blank. A split die clamps around the blank at about the bulge, causing the bulge to collapse and forming a ridge in the inside surface of the blank. Coolant circulates in the mandrels and cools the inside surface of the blank. The mandrels are then withdrawn, leaving the formed blank in the split die.