Plastic article or earthenware shaping or treating: apparatus – Control means responsive to or actuated by means sensing or... – Feed control of material en route to shaping area
Patent
1992-08-31
1993-08-31
Bushey, Scott
Plastic article or earthenware shaping or treating: apparatus
Control means responsive to or actuated by means sensing or...
Feed control of material en route to shaping area
425563, B29C 4552
Patent
active
052403980
ABSTRACT:
A screw head is composed of a cone portion, a tapered portion formed behind the cone portion and a narrow portion formed behind the tapered portion. A counter-flow stopper ring is provided around the narrow portion so that an annular resin passage is formed between the counter-flow stopper ring and the narrow portion. The tapered portion of the screw head has a plurality of circumferentially spaced grooves. The sectional area of each groove decreases from the inner circumference toward the outer circumference of the tapered portion. The grooves are so formed that the resin flowing through the grooves creates a force which pushes the counter-flow stopper ring backward, the ring being moved forward by forward flow of resin caused during backward movement of the screw. Thus, the grooves help maintain a gap between the counter-flow stopper ring and the screw head.
REFERENCES:
patent: 3482285 (1969-12-01), Falkenberg
patent: 3501810 (1970-03-01), Powell
patent: 4477242 (1984-10-01), Eichlseder et al.
patent: 5013233 (1991-05-01), Semmekrot
patent: 5153149 (1992-10-01), Naito et al.
patent: 5167971 (1992-12-01), Gill et al.
"What Injection Molders Should Know About Reciprocating Screw-Tip Shutoffs", Plastics Technology, vol. 13, No. 8, Aug., 1967.
Akaguma Nobuyuki
Emoto Atsushi
Suumen Hiroyoshi
Bushey Scott
Sumitomo Heavy Industrie's, Ltd.
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