US1645810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direction finding and indicating system
Assignee: AT&T Inc
•
Filing: 1921-01-08
•
Granted: 1927-10-18
•
Expires: 1941-01-08
Abstract
No abstract record available.
Inventors
- 👤 Francis A Hubbard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:51
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/72
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1930-10-17 | 1931-04-18 | 1931-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1934-10-17 | 1935-04-18 | 1935-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1938-10-17 | 1939-04-18 | 1939-10-18 | $7700.00 | Window Closed / Lapsed |