Patent US1997412A successfully refreshed from Google Patents.
US1997412A
Expired / Lapsed
US
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Regulating the altitude of aircraft
Assignee: Siemens and Halske AG
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Filing: 1933-11-23
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Granted: 1935-04-09
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Expires: 1953-11-23
Abstract
No abstract record available.
Inventors
- 👤 Fischel Eduard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:42
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/04; G05D1/042; Y; Y10; Y10S; Y10S200/00; Y10S200/08; Y10S200/09; Y10T; Y10T74/00; Y10T74/12; Y10T74/1229
Claims Analysis
Total Claims: 0
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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) | 1938-04-08 | 1938-10-08 | 1939-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-04-08 | 1942-10-08 | 1943-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-04-08 | 1946-10-08 | 1947-04-09 | $7700.00 | Window Closed / Lapsed |