US3593843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conveying screw
Assignee: PLCV Ltd
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Filing: 1969-03-18
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Granted: 1971-07-20
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Expires: 1989-03-18
Abstract
Abstract An extruder conveying screw comprising a core having two helical flights thereon, the first of which extends between opposite ends of the screw to define a helical channel and the second of which extends generally across the channel over a portion intermediate the length of the screw, and a casing around said screw characterized in that said second flight is terminated at its upstream end in spaced relationship to the wall of the first flight and further in that the second flight is provided with a groove across its peripheral surface adjacent and parallel to a line of junction between the first and second flights at the downstream end of the latter, said groove having a depth such as to provide a clearance of between 0.060 and 0.090 inches between the base of the groove and the casing.
Inventors
- 👤 Alan Harvey Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:13
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/505; B29C48/64; B29C48/65; B29C48/62; B29C48/03
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
140 words
An extruder conveying screw comprising a core having two helical flights thereon, the first of which extends between opposite ends of the screw to define a helical channel and the second of which extends generally across said channel over an intermediate portion of the length of said screw, and a casing around said screw characterized in that said second flight is terminated at its upstream end in spaced Relationship with respect to the wall of said first flight and in that said second flight is provided with a groove across its peripheral surface adjacent and parallel to a line of junction between said first and second flights at the downstream end of the latter, said groove having a depth such as to provide a clearance of between 0.060 and 0.090 inch between the base of the groove and the casing.
Claim 2
Dependent Claim
140 words
An extruder conveying screw comprising a core having two helical flights thereon, the first of which extends between opposite ends of the screw to define a helical channel and the second of which extends generally across said channel over an intermediate portion of the length of said screw, and a casing around said screw characterized in that said second flight is terminated at its upstream end in spaced Relationship with respect to the wall of said first flight and in that said second flight is provided with a groove across its peripheral surface adjacent and parallel to a line of junction between said first and second flights at the downstream end of the latter, said groove having a depth such as to provide a clearance of between 0.060 and 0.090 inch between the base of the groove and the casing.
Claim 3
Dependent Claim
30 words
A conveying screw as claimed in claim 1 in which there is provided a narrow channel between the first and second flights at the upstream end of the second flight.
Claim 4
Dependent Claim
37 words
A conveying screw as claimed in claim 2 in which a narrow channel of between one-sixteenth and one-fourth of an inch is provided between the first and second flights at the upstream end of the second flight.
Claim 5
Dependent Claim
31 words
A conveying screw as claimed in claim 2 in which the minimum depth of the narrow channel at the upstream end of the second flight is between 0.060 and 0.090 inch.
Claim 6
Dependent Claim
48 words
A conveying screw as claimed in claim 1 in which there is provided a narrow channel between the first and second flights at the upstream end of the second flight, said narrow channel having a throat therein which has a minimum width of between 0.060 and 0.090 inch.
Claim 7
Dependent Claim
25 words
A conveying screw as claimed in claim 5 in which the depth of the channel at the throat is somewhat in excess of 0.090 inch.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |