US2521881A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio-frequency recorder
Assignee: Individual
•
Filing: 1944-12-01
•
Granted: 1950-09-12
•
Expires: 1964-12-01
Abstract
No abstract record available.
Inventors
- 👤 Verner E Suomi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:46
CPC Classifications
G; G01; G01W; G01W1/00; G01W1/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1598739A
Cited
US1828944A
Cited
US1818963A
Cited
US1967072A
Cited
US2178225A
Cited
US2228883A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-09-11 | 1954-03-13 | 1954-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-09-11 | 1958-03-13 | 1958-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-09-11 | 1962-03-13 | 1962-09-12 | $7700.00 | Window Closed / Lapsed |