US3528753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helicopter blade with non-homogeneous structural spar
Assignee: RTX Corp
•
Filing: 1968-06-14
•
Granted: 1970-09-15
•
Expires: 1988-06-14
Abstract
No abstract record available.
Inventors
- 👤 Walter J Dutton
- 👤 Walter Gerstenberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:03
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/46; B64C27/473; B64C2027/4733; B64C2027/4736
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2482936A
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US2467031A
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US2588570A
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US2609883A
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US3105557A
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US3237697A
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US3372757A
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US3333642A
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US3321019A
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US3310117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-09-14 | 1974-03-16 | 1974-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-09-14 | 1978-03-16 | 1978-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-09-14 | 1982-03-16 | 1982-09-15 | $7700.00 | Window Closed / Lapsed |