US2552864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tandem rotor helicopter
Assignee: Boeing Helicopters Co
•
Filing: 1948-02-05
•
Granted: 1951-05-15
•
Expires: 1968-02-05
Abstract
No abstract record available.
Inventors
- 👤 Frank N Piasecki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:38
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/04; B64C27/12; Y; Y10; Y10T; Y10T74/00; Y10T74/19; Y10T74/19023; Y10T74/19074; Y10T74/19079; Y10T74/19088
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1225202A
Cited
US1849235A
Cited
CH155974A
Cited
US2023105A
Cited
US2233747A
Cited
US2273303A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-05-14 | 1954-11-13 | 1955-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-05-14 | 1958-11-13 | 1959-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-05-14 | 1962-11-13 | 1963-05-15 | $7700.00 | Window Closed / Lapsed |