Foamed plastic molding method and apparatus

Claim 1

A MOLDILNG METHOD FOR MOLDING A CUP FROM EXPANSIBLE PLASTIC BEADS WHICH COMPRISES THE STEPS OF INTERMITTENTLY ESTABLISHING COMMUNICATION BETWEEN A SUPPLY OF BEADS AND THE INTERIOR OF A CUP-SHAPED MOLD CAVITY, INDUCING THE FLOW OF BEADS FROM THE SUPPLY INTO THE CAVITY WHILE COMMUNICATION IS ESTABLISHED BY CONDUCTING FLUID THROUGH A VENTURI ORIFICE TO DRAW BEADS FROM THE SUPPLY, ENTRAIN THE SAME, AND DELIVER THE FLUID AND ENTRAINED BEADS INTO THE MOLD CAVITY WHILE SUCH CAVITY IS VENTED, CREATING A BACKFLOW OF FLUID FROM THE MOLD CAVBITY TO THE SUPPLY UPON FILLING OF THE MOLD CAVITY WITH BEADS TO STOP THE FEEDING OF BEADS TOWARD THE MOLD CAVITY, THEN APPLYING STEAM UNDER PRESSURE TO THE MOLD EXTERIOR AND TO THE MOLD CAVITY TO EXPAND AND UNITE THE BEADS WHILE THE MOLD REMAINS VENTED TO PURGE ALL BEAD-SUPPLY FLUID THEREFROM, THEN CLOSING THE MOLD WHILE THE STEAM IS APPLIED TO COMPLETE UNITING AND EXPANSION OF THE BEADS, THEREAFTER COOLING THE MOLD BY APPLYING COOLANT TO ITS EXTERIOR, AND FINALLY OPENING THE MOLD AND APPLYING FLUID PRESSURE TO THE INTERIOR OF THE FORMED CUP TO EJECT THE SAME FROM THE OPENED MOLD.