Method and apparatus for injection molding of plastic materials

Claim 1

A METHOD OF CONTROLLING THE FLOW OF PLASTIC MATERIAL INTO A RAM BORE FROM AN INTERSECTING FEED PASSAGE COMPRISING THE STEPS OF LOCATING A RESTRICTION IN SAID PASSAGE AT A POINT SPACED FROM THE INTERSECTION OF SAID PASSAGE WITH SAID BORE, LOCATING AN ELONGATED MEMBER ADAPTED TO SEALINGLY SLIDE IN SAID RESTRICTION WITHIN THAT PORTION OF THE PASSAGE BETWEEN SAID RESTRICTION AND SAID INTERSECTION, FEEDING PLASTIC MATERIAL THROUGH SAID RESTRICTION AND SAID PORTION OF SAID PASSAGE INTO THE RAM BORE AT A RATE SUFFICIENT TO COMPLETELY FILL SAID PORTION OF SAID PASSAGE, ADVANCING A RAM THROUGH SAID BORE PAST THE INTERSECTION OF THE PASSAGE WITH THE BORE TO SEPARATE THE MATERIAL IN SAID BORE FROM THE MATERIAL IN SAID PORTION OF SAID PASSAGE, ADVANCING SAID ELONGATED MEMBER INTO SAID RESTRICTION TO BLOCK SAID PASSAGE, AND CONTINUING TO ADVANCE SAID ELONGATED MEMBER INTO SAID RESTRICTION IN A DIRECTION AWAY FROM SAID PORTION OF SAID PASSAGE TO THEREBY INCREASE THE VOLUME OF SAID PORTION OF SAID PASSAGE TO SUCK PLASTIC MATERIAL IN SAID PORTION OF SAID PASSAGE AWAY FROM SAID RAM BORE.