Patent US3138443A successfully refreshed from Google Patents.
US3138443A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter
Assignee: CAMBRIDGE FILTER Manufacturing CORP
•
Filing: 1962-04-30
•
Granted: 1964-06-23
•
Expires: 1982-04-30
Abstract
No abstract record available.
Inventors
- 👤 Paul M Engle
- 👤 Carl J Bauder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:27
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/10; B01D46/52; B01D46/521; B01D46/523
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1830096A
Cited
GB569458A
Cited
US2681155A
Cited
US2814355A
Cited
US2857017A
Cited
US2907408A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-06-23 | 1967-12-23 | 1968-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-06-23 | 1971-12-23 | 1972-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-06-23 | 1975-12-23 | 1976-06-23 | $7700.00 | Window Closed / Lapsed |