Plasticizer apparatus for ball agitator along screw flights
OwnerJohn J. Farrellinventor
Life of this patent
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Abstract
This plasticizer screw, for advancing molten plastic to an injection mold, has a row of balls behind the flights of the screw for agitating the plastic to promote better mixing and to eliminate dead regions along the screw. The balls in a continuous row run in a groove in the shank portion of the screw and extend radially beyond the circumference of the shank portion for substantially the same distance as the helical flights of the screw thread. The raceway groove, in which the balls are held, terminates at an abutment where the balls move into a passage within the shank portion of the screw, and they travel back through this passage to an outlet end where they pass back into the other end of the raceway groove.
Claims12
Plasticizer apparatus for injection molding machines including in combination a plasticizer screw having a generally cylindrical shank portion and a helical thread portion that extends radially beyond the circumference of the shank portion and that forms flights for propelling plastic material lengthwise of the screw in a forward direction as the screw rotates, a helical groove in the cylindrical surface of the shank portion immediately adjacent to the rearward side of the thread portion, the successive convolutions of the helical thread portion being axially spaced from one another with generally cylindrical sections of the shank portions between them, balls in the groove, the balls being in a continuous helical line and located in the groove adjacent to one another whereby the balls form a substantially continuous line of balls and movement of any ball along the length of the groove can move the next ball by contact therewith, and said balls being movable in the groove to agitate plastic material which is adjacent to the rearward surfaces of the flights when the plasticizer apparatus is in operation.
Plasticizer apparatus for injection molding machines including in combination a plasticizer screw having a shank portion and a helical thread portion that extends radially beyond the circumference of the shank portion and that forms flights for propelling plastic material lengthwise of the screw in a forward direction as the screw rotates, a helical groove in the surface of the shank portion adjacent to the rearward side of the thread portion, balls in the groove and movable in the groove to agitate plastic material which is adjacent to the rearward surfaces of the flights when the plasticizer apparatus is in operation, characterized by the balls being located in the groove adjacent to one another whereby the balls form a substantially continuous line of balls and movement of any ball along the length of the groove can move the next ball by contact therewith, further characterized by an abutment surface at the forward end of the groove, a passageway extending lengthwise of the screw and having an entrance end at said abutment surface so that balls moving up to the abutment surface can enter the passageway, said passageway being of sufficient cross section for balls to travel through the passageway, and an outlet end of the passageway located adjacent to the rearward end of the line of balls and from which balls can re-enter the groove.
Dependencies are inferred from the claim text.