Apparatus for varying pressure within a screw channel
First Claim
1. Apparatus for melting and conveying plasticated material comprising:
- (a) a barrel having a longitudinal axis;
(b) a shaft rotatable within said barrel and having a substantially circular cross-section, said shaft further having a cylindrical bore therethrough, said shaft and said bore being concentric with said axis;
(c) a helical channel defined between successive turns of at least one helical flight formed integrally with said shaft;
(d) at least one radially movable first member slidably disposed within an opening extending from said channel through said shaft to said bore, said first member being located in said channel at a predetermined point at which said material has substantially melted, said first member further having an inner end extending into said bore; and
(e) a reciprocatively movable second member disposed within said bore, said second member having a conical end portion which bears against said inner end of said first member such that said first member is extendable from said opening in response a downstream movement of said second member, and retractable into said opening in response to an upstream movement of said second member.
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Accused Products
Abstract
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.
14 Citations
5 Claims
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1. Apparatus for melting and conveying plasticated material comprising:
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(a) a barrel having a longitudinal axis; (b) a shaft rotatable within said barrel and having a substantially circular cross-section, said shaft further having a cylindrical bore therethrough, said shaft and said bore being concentric with said axis; (c) a helical channel defined between successive turns of at least one helical flight formed integrally with said shaft; (d) at least one radially movable first member slidably disposed within an opening extending from said channel through said shaft to said bore, said first member being located in said channel at a predetermined point at which said material has substantially melted, said first member further having an inner end extending into said bore; and (e) a reciprocatively movable second member disposed within said bore, said second member having a conical end portion which bears against said inner end of said first member such that said first member is extendable from said opening in response a downstream movement of said second member, and retractable into said opening in response to an upstream movement of said second member. - View Dependent Claims (2, 3)
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4. 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:
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(a) a radially movable pin slidably disposed in an opening in said groove at said deepest portion thereof, said opening extending radially from said groove into said bore; and (b) a reciprocatively movable member slidably disposed within said bore, said member having a conical end portion which bears against and co-operates with an inner end of said pin such that said pin is extendable into said groove when said member moves in a downstream direction and recedes from said groove when said member moves in an upstream direction. - View Dependent Claims (5)
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Specification