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US 4,723,847 AGranted
Apparatus for varying pressure within a screw channel
OwnerRobert F. Drayinventor
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OwnerRobert F. Drayinventor
Estimating the term…
This invention relates to apparatus for continuously varying the pressure within a screw channel of a plasticating machine by way of a variable restriction in the screw channel. The apparatus includes a cylindrical barrel, a shaft rotatable within said barrel having a substantially circular cross-section and a longitudinal axis for rotation concentric with the barrel. The shaft is provided with a helical screw channel which is defined between successive turns of at least one helical flight integrally formed with the shaft. At least one radially movable first member is disposed at a right angle to said axis within the channel at a location along the axis and is located within the channel at a location along the axis at which the material being processed is substantially melted. A reciprocatively movable second member is disposed within a cylindrical bore through said shaft along the axis of rotation, the second member having a conical end portion which cooperates with an inner end of said first member such that said first member is movable in a radially inward or outward direction in response to the reciprocating movement of the second member. The inward or outward location of the first member provides a continuously variable restriction in the screw channel which increases or decreases pressure in an upstream direction within the channel.
Apparatus for melting and conveying plasticated material comprising:
An improved plasticizing screw of the type having a shaft and a longitudinal axis concentric with said shaft about which said shaft can rotate within a barrel, said screw having a helical flight formed integrally with said shaft, said flight and shaft defining a helical channel for melting and conveying plasticated material in a downstream direction, said flight having a pushing side oriented downstream from a trailing side thereof, said screw further having a cylindrical bore therethrough concentric with said axis and at least one groove in said shaft disposed along said pushing side of said flight in the vicinity of a metering section of said screw, which groove co-operates with a triangular diverting means having an apex and extending across a portion of said channel from a trailing side of a preceeding flight to a deepest portion of said groove, such that said apex is adjacent to said deepest portion of said groove wherein said improvement comprises:
Dependencies are inferred from the claim text.