US2574475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for calibrating piezoelectric crystal units
Assignee: Individual
•
Filing: 1946-02-27
•
Granted: 1951-11-13
•
Expires: 1966-02-27
Abstract
No abstract record available.
Inventors
- 👤 Charles H Grogan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:55
CPC Classifications
G; G01; G01L; G01L27/00; G01L27/002; G01L27/005
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-11-12 | 1955-05-14 | 1955-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-11-12 | 1959-05-14 | 1959-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-11-12 | 1963-05-14 | 1963-11-13 | $7700.00 | Window Closed / Lapsed |