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US 5,004,352 AGranted
Plasticizing screw
AssigneeMitsubishi Jukogyo Kabushiki Kaisha
InventorsYukio Tamura, Kiyoshi Kinoshita, Tetsuo Uwaji, Takashi Mizuno
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AssigneeMitsubishi Jukogyo Kabushiki Kaisha
InventorsYukio Tamura, Kiyoshi Kinoshita, Tetsuo Uwaji, Takashi Mizuno
Estimating the term…
A plasticizing screw for an injection molding machine or the like having one or more lands in a crest portion of a screw flight to prevent the screw flight from coming into contact with a cylinder wall surface when the plasticizing screw is rotated during a molding operation. The land has a smaller diameter than that of a crest portion of the screw flight and is provided at the screw flight crest portion either between leading and trailing surfaces of the screw flight or extending from the leading edge of the screw flight. The land can also be provided as a plurality of circumferentially spaced-apart lands on the side of a front surface of the screw flight, or provided at a central portion between the leading and trailing surfaces of the screw flight.
A plasticizing screw having means for generating lubricating pressure between a screw flight and a cylinder comprising a land formed in a crest portion of a screw flight of the plasticizing screw, the crest portion having a radially outermost peripheral portion extending continuously along the entire trailing edge of the screw flight, a helical line passing along the land lying in a cylinder having a diameter which is less than that of said radially outermost peripheral portion, the land having a width taken in a plane perpendicular to a rotation axis of the screw which is greater than one-half the overall circumferential width between leading and trailing surfaces of the crest portion of the screw flight, the land having a moderate inclination with respect to the outer diameter of the screw flight, a helical line passing along a terminal end of the land lying in a cylinder having a diameter equal to the outer diameter of the screw flight, the terminal end of the land being located between the leading and trailing surfaces of the screw flight, and the greatest depth to which said land extends in the crest portion being about 0.5 mm as measured radially inwardly from a radially outermost peripheral portion of the screw flight whereby the screw flight crest portion can be prevented from coming into contact with a cylinder wall surface upon rotation of the screw.
A barrier type plasticizing screw having a main flight and a barrier flight having a somewhat smaller diameter than the main flight, said main flight having a land formed in a crest portion of the main flight, said land having a diameter which is less than that of the crest portion of the main flight, a helical line passing along the land over at least one pitch of the main flight lying in a cylinder having a constant diameter that is somewhat smaller than the diameter of the main flight whereby the main flight crest portion can be prevented from coming into contact with a cylinder wall surface upon rotation of the screw.
A plasticizing screw having means for generating lubricating pressure between a screw flight and a cylinder comprising a land formed in a crest portion of a screw flight of the plasticizing screw, the crest portion having a radially outermost peripheral portion extending continuously along the entire trailing edge of the screw flight, the land having a diameter which is less than an outer diameter of the screw flight taken at said radially outermost peripheral portion, the land having a width taken in a plane perpendicular to a rotation axis of the screw which is greater than one-half the overall width between leading and trailing surfaces of the crest portion of the screw flight, a helical line passing along the land over at least one pitch of the screw flight lying in a cylinder having a constant diameter that is somewhat smaller than the outer diameter of said radially outermost peripheral portion, and the greatest depth of each said at least one recess in the crest portion being about 0.5 mm as measured radially inwardly from said radially outermost peripheral portion.
A plasticizing apparatus comprising a cylinder and a plasticizing screw having a screw flight disposed within said cylinder, said plasticizing screw having means for causing lubricating pressure to be generated between the screw flight and the cylinder that is sufficient to inhibit said screw from coming in contact with said cylinder when material to be plasticized is disposed in said cylinder and said screw is rotated, said means for causing lubricating pressure to be generated comprising a land formed in a crest portion of the screw flight of the plasticizing screw, the crest portion having a radially outermost peripheral portion extending continuously along the entire trailing edge of the screw flight, the land having a diameter which is less than an outer diameter of the screw flight taken at said radially outermost peripheral portion, the land having a width taken in a plane perpendicular to a rotation axis of the screw which is greater than one-half the overall width between leading and trailing surfaces of the crest portion of the screw flight, a helical line passing along the land over at least one pitch of the screw flight lying in a cylinder having a constant diameter that is somewhat smaller than the outer diameter of said radially outermost peripheral portion, and the greatest depth of each said at least one recess in the crest portion being about 0.5 mm as measured radially inwardly from said radially outermost peripheral portion.
A plasticizing apparatus comprising a cylinder and a plasticizing screw having a screw flight disposed within said cylinder, said plasticizing screw having means for causing lubricating pressure to be generated between the screw flight and the cylinder that is sufficient to inhibit said screw from coming in contact with said cylinder when material to be plasticized is disposed in said cylinder and said screw is rotated, said means for causing lubricating pressure to be generated comprising a land formed in a crest portion of the screw flight of the plasticizing screw, the crest portion having a radially outermost peripheral portion extending continuously along the entire trailing edge of the screw flight, a helical line passing along the land lying in a cylinder having a diameter which is less than that of said radially outermost peripheral portion, the land having a width taken in a plane perpendicular to a rotation axis of the screw which is greater than one-half the overall width between leading and trailing surfaces of the crest portion of the screw flight, the land having a moderate inclination with respect to the outer diameter of the screw flight, a helical line passing along a terminal end of the land lying in a cylinder having a diameter equal to the outer diameter of the screw flight, and the greatest depth to which said land extends in the crest portion being about 0.5 mm as measured radially inwardly from said radially outermost peripheral portion of the screw flight.
A plasticizing apparatus comprising a cylinder and a barrier type plasticizing screw disposed in said cylinder, said screw having a main flight, a barrier flight having a somewhat smaller diameter than the main flight, and means for causing lubricating pressure to be generated between said main flight and said cylinder that is sufficient to inhibit said screw from coming in contact with said cylinder when material to be plasticized is disposed in said cylinder and said screw is rotated, said means for causing lubricating pressure to be generated comprising a land formed in a crest portion of the main flight, said land having a diameter which is less than that of the crest portion of the main flight, and a helical line passing along the land over at least one pitch of the main flight lying in a cylinder having a constant diameter that is somewhat smaller than that of the main flight.
Dependencies are inferred from the claim text.