Patent US2400076A successfully refreshed from Google Patents.
US2400076A
Expired / Lapsed
US
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Air purifying and filtering apparatus
Assignee: MSA Safety Inc
•
Filing: 1939-08-12
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Granted: 1946-05-14
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Expires: 1959-08-12
Abstract
No abstract record available.
Inventors
- 👤 John F Dauster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:00
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/24; B01D46/30; B01D50/00; B01D50/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1949-05-13 | 1949-11-12 | 1950-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1953-05-13 | 1953-11-12 | 1954-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1957-05-13 | 1957-11-12 | 1958-05-14 | $7700.00 | Window Closed / Lapsed |