Patent US4437845A successfully refreshed from Google Patents.
Patent US3487623A successfully refreshed from Google Patents.
US3487623A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air filtration system
Assignee: GEORGE EVANS CORP
•
Filing: 1967-11-13
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Granted: 1970-01-06
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Expires: 1987-11-13
Abstract
No abstract record available.
Inventors
- 👤 Howard C Easter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:38
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/10; B01D46/66; B01D46/68; B01D46/681; Y; Y10; Y10T; Y10T74/00; Y10T74/18; Y10T74/18056
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
CA614754A
Cited
US3183647A
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US877580A
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US1475062A
Cited
FR856275A
Cited
GB583445A
Cited
US2671248A
Cited
US2823762A
Cited
US2854086A
Cited
US2994434A
Cited
US3309847A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-01-05 | 1973-07-07 | 1974-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-05 | 1977-07-07 | 1978-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-05 | 1981-07-07 | 1982-01-06 | $7700.00 | Window Closed / Lapsed |