Check valve for injection molding apparatus

Claim 1

IN A MOLD ASSEMBLY COMPRISING A SIDE RING AND SOLE PLATE MOVABLE RELATIVE TO THE BOTTOM OF THE SIDE RING, SAID SOLE PLATE CONTAINING A PASSAGE PROVIDING AT LEAST ONE ENTRANCE THROUGH ITS UPPER SURFACE INTO THE MOLD CAVITY THROUGH WHICH AN ELASTOMER MAY BE INJECTED INTO THE MOLD CAVITY, A VALVE HAVING A PART LOCATED BETWEEN THE PASSAGE AND THE ENTRANCE TO THE MOLD CAVITY MOVABLE BETWEEN A POSITION BLOCKING FLOW FROM THE PASSAGE THROUGH THE ENTRANCE TO A POSITION PERMITTING FLOW FROM THE PASSAGE TO THE ENTRANCE, MEANS NORMALLY HOLDING THE VALVE IN THE POSITION BLOCKING FLOW OF ELASTOMER, SAID VALVE BEING A THIN-WALL TUBE SLIDABLY DISPOSED IN THE PASSAGE, SAID TUBE CONTAINING A HOLE IN ITS WALL MOVABLE RELATIVE TO SAID ENTRANCE TO A POSITION OF ALIGNMENT THEREWITH TO PERMIT FLOW FROM THE INTERIOR OF THE TUBE TO THE ENTRANCE INTO THE MOLD CAVITY, AND MEANS OPERABLE, BY THE PRESSURE OF THE ELASTOMER IN THE INJECTION PASSAGE WHEN INJECTION PRESSURE IS APPLIED, TO MOVE THE VALVE TO THE POSITION PERMITING FLOW FROM THE PASSAGE TO THE ENTRANCE.