Patent US5681539A successfully refreshed from Google Patents.
US2523399A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Null-balance frequency meter
Assignee: Boeing Co
•
Filing: 1946-01-19
•
Granted: 1950-09-26
•
Expires: 1966-01-19
Abstract
No abstract record available.
Inventors
- 👤 George H Stoner
- 👤 Cecil K Stedman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:24
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/02; G01R23/06; G01R23/09
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1665857A
Cited
US1601070A
Cited
US1809683A
Cited
US2026421A
Cited
US2260933A
Cited
US2366076A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-09-25 | 1954-03-27 | 1954-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-09-25 | 1958-03-27 | 1958-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-09-25 | 1962-03-27 | 1962-09-26 | $7700.00 | Window Closed / Lapsed |