Patent US2139289A successfully refreshed from Google Patents.
Patent US2688694A successfully refreshed from Google Patents.
US2688694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency detector
Assignee: Hartford National Bank and Trust Co
•
Filing: 1952-04-12
•
Granted: 1954-09-07
•
Expires: 1972-04-12
Abstract
No abstract record available.
Inventors
- 👤 Evertsz Hendrik Co Bennebroeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:02
CPC Classifications
H; H03; H03D; H03D9/00; H03D9/02; H03D9/04; H03J; H03J7/00; H03J7/02; H03J7/04
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2091271A
Cited
US2402421A
Cited
US2436828A
Cited
US2415468A
Cited
GB619864A
Cited
US2479208A
Cited
US2499742A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-09-06 | 1958-03-08 | 1958-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-09-06 | 1962-03-08 | 1962-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-09-06 | 1966-03-08 | 1966-09-07 | $7700.00 | Window Closed / Lapsed |