US3115674A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Backflow restrictor for extruders
Assignee: Dow Chemical Co
•
Filing: 1961-02-15
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Granted: 1963-12-31
•
Expires: 1981-02-15
Abstract
No abstract record available.
Inventors
- 👤 Walter J Schrenk
- 👤 Kenneth J Cleereman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:36
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/505; B29C48/62; B29C48/03
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
116 words
IN AN EXTRUDER ASSEMBLY INCLUDING A FEED SCREW HAVING A SPIRAL THREAD AND AN ADDITIVE INLET PORT NEAR THE DISCHARGE END OF THE EXTRUDER, A BACKFLOW RESTRICTOR COMPRISING, A RIB EXTENDING BETWEEN THE SIDE WALLS OF ADJACENT SCREW THREADS SAID RIB BEING ARRANGED SO THAT THE LEAD END THEREOF IS UPSTREAM FROM SAID INLET PORT, THE OUTERMOST SURFACE OF SAID RIB BEING ARRANGED A UNIFORM DISTANCE FROM THE AXIS OF SAID SCREW AND AT A SLIGHTLY LESS DISTANCE THAN THAT OF THE OUTER PERIPHERY OF THE SPIRAL THREAD, AND BEING FURTHER ARRANGED SO THAT THE LONGITUDINAL AXIS OF SAID RIB IS SUBSTANTIALLY NORMAL TO THE WALLS BETWEEN ADJACENT SCREW THREADS AT THE POINT OF JUNCTURE THEREWITH.
Claim 2
Dependent Claim
116 words
IN AN EXTRUDER ASSEMBLY INCLUDING A FEED SCREW HAVING A SPIRAL THREAD AND AN ADDITIVE INLET PORT NEAR THE DISCHARGE END OF THE EXTRUDER, A BACKFLOW RESTRICTOR COMPRISING, A RIB EXTENDING BETWEEN THE SIDE WALLS OF ADJACENT SCREW THREADS SAID RIB BEING ARRANGED SO THAT THE LEAD END THEREOF IS UPSTREAM FROM SAID INLET PORT, THE OUTERMOST SURFACE OF SAID RIB BEING ARRANGED A UNIFORM DISTANCE FROM THE AXIS OF SAID SCREW AND AT A SLIGHTLY LESS DISTANCE THAN THAT OF THE OUTER PERIPHERY OF THE SPIRAL THREAD, AND BEING FURTHER ARRANGED SO THAT THE LONGITUDINAL AXIS OF SAID RIB IS SUBSTANTIALLY NORMAL TO THE WALLS BETWEEN ADJACENT SCREW THREADS AT THE POINT OF JUNCTURE THEREWITH.
References Cited (Backward Citations)
USRE23948E
Cited
FR809465A
Cited
US2378539A
Cited
DE841643C
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US2662243A
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US2719325A
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US2752633A
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US2810159A
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US2868517A
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US2970341A
Cited
US3026273A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1966-12-30 | 1967-07-01 | 1967-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-12-30 | 1971-07-01 | 1971-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-12-30 | 1975-07-01 | 1975-12-31 | $7700.00 | Window Closed / Lapsed |