Patent US4568244A successfully refreshed from Google Patents.
US4568244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber reinforced/epoxy matrix composite helicopter rotor main hub plate
Assignee: RTX Corp
•
Filing: 1983-03-22
•
Granted: 1986-02-04
•
Expires: 2003-03-22
Abstract
Abstract A helicopter hub main retention plate is described made up of graphite and glass fiber reinforced epoxy resin. The graphite fiber reinforcement is in-plane isotropically laid continuous graphite fibers and the glass fiber reinforcement comprises segments of fiberglass continuously and circumferentially wound around the areas of retention. Such materials and configuration provide crack resistance, damage tolerance, and integrity inspectability to the retention plate.
Inventors
- 👤 George J. Wehnert
- 👤 Francis E. Byrnes, Jr.
- 👤 Peter C. Ogle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:19
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
85 words
A helicopter hub main retention plate comprising a fiber reinforced epoxy resin matrix having a plurality of layers of: a. graphite fiber reinforcement comprising in-plane isotropically laid continuous graphite fibers, b. glass fiber reinforcement comprising a plurality of glass fiber segments circumferentially wound around a central axis in a plane substantially parallel to the plane of the graphite fiber reinforcement, said layers of graphite and glass fiber reinforcement symmetrically interleaved so as to produce crack resistance, damage tolerance, and integrity inspectability to the retention plate.
Claim 2
Dependent Claim
85 words
A helicopter hub main retention plate comprising a fiber reinforced epoxy resin matrix having a plurality of layers of: a. graphite fiber reinforcement comprising in-plane isotropically laid continuous graphite fibers, b. glass fiber reinforcement comprising a plurality of glass fiber segments circumferentially wound around a central axis in a plane substantially parallel to the plane of the graphite fiber reinforcement, said layers of graphite and glass fiber reinforcement symmetrically interleaved so as to produce crack resistance, damage tolerance, and integrity inspectability to the retention plate.
References Cited (Backward Citations)
US4195967A
Cited
US4257738A
Cited
DE3037824A1
Cited
US4156583A
Cited
US4293276A
Cited
US4342540A
Cited
US4321013A
Cited
US4352632A
Cited
US4425082A
Cited
US4427340A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |