Nozzle closure for injection moulding press

Claim 1

IN AN INJECTION MOULDING PRESS PROVIDED WITH AN INJECTION CYLINDER MOVABLE TO AND FROM A MOULD BETWEEN AN INJECTION POSITION AND A RETRACTED POSITION AND WITH AN INJECTION NOZZLE CARRIED BY THIS CYLINDER, A CLOSURE FOR SAID NOZZLE, SUCH CLOSURE COMPRISING A VALVE SLIDABLY MOUNTED IN SAID NOZZLE FOR LIMITED MOVEMENT RELATIVELY THERETO AND HAVING AN INJECTED CHANNEL FOR THE PASSAGE OF MATERIAL TO BE INJECTED FROM THE INTERIOR OF THE CYLINDER THROUGH THE VALVE AND OUTWARDLY THEREOF INTO THE MOULD, MEANS DEFINING A CHAMBER WITHIN SAID VALVE IMMEDIATELY UPSTREAM OF SAID INJECTION CHANNEL, THE SAID VALVE HAVING DUCTS LEADING INTO SAID CHAMBER AND POSITIONED SO THAT, WHEN THE CYLINDER IS IN ITS INJECTION POSITION, THE VALVE IS IN SUCH A POSITION IN THE NOZZLE THE THE SAID DUCTS PROVIDE COMMUNICATION BETWEEN THE INTERIOR OF THE INJECTION CYLINDER AND THE SAID CHAMBER WHILE WHEN THE CYLINDER IS IN ITS RETRACTED POSITION AND RELATIVE MOVEMENT BETWEEN THE NOZZLE AND VALVE HAVING OCCURRED, THE SAID NOZZLE CLOSES THIS COMMUNICATION, AND A PLUNGER MOVABLE WITH THE SAID INJECTION CYLINDER AND SO RESILIENTLY CONNECTED TO THE SAID VALVE THAT, WHEN THE CYLINDER MOVES AWAY FROM ITS INJECTION POSITION, THE SAID PLUNGER MOVES RELATIVELY TO THE VALVE AND CREATES A SUCTION IN SAID CHAMBER.