Abstract: An injection molding machine in which a support on a base carries oppositely facing stationary mold portions which, when joined by movable mold portions, form a pair of mold cavities, one of which can be injected with a moldable material having a long solidification time, while the other contains a previously injected article which is solidifying and can be released as soon as the injection of the first cavity is completed. One of the movable mold portions is connected to a movable plate in a fixed spaced relationship, with a wedge-type locking mechanism between the plate and the other movable mold portion for the locking of both mold cavities simultaneously with a single locking mechanism.

Abstract: An apparatus for casting a molten material in which the mold is received in one chamber and the molten material is received in another chamber, the two chambers being subject to different pressures so that a tube connecting them can deliver the molten material from the second chamber to the first under a pressure differential. Signal-producing apparatus connected to the mold chambers produce signals representing the two pressures and the pressure differential, the signal-producing apparatus being connected to differentiating apparatus whose output produces time derivatives of the pressures and pressure differential. The time derivatives can be used to control the pressures via a comparator to which a reference value or set point signal is applied thereby varying the rate of filling of the mold in accordance with a predetermined program.

Abstract: A method of controlling the rate of filling of a casting mold wherein a pressure P.sub.1 is applied to a chamber containing a crucible holding the molten material to be cast, a pressure P.sub.2 is provided in a chamber containing the mold, the mold is connected with the crucible by a tube conveying the molten material to the mold, and the molten material is displaced through the tube by a pressure differential .DELTA.p equal to P.sub.1 -P.sub.2, which comprises detecting the time derivatives dP.sub.2 /dt and d.DELTA.P/dt of the pressure in the chamber containing the mold and the pressure differential, respectively. The rate of variation of the pressure in the chamber of the mold is monitored to regulate the process while one of the other derivatives is compared with a set point value to control one of the pressures as a function of time to vary the rate of filling of the mold in accordance with a predetermined program.

Abstract: An apparatus for the production of articles with a compact smooth skin and a cellular core from polymer materials, which contain blowing agents, by injection molding or extrusion wherein the apparatus contains an electric heating element within a channel through which the polymeric material is passed.