US4087203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cross beam rotor
Assignee: RTX Corp
•
Filing: 1977-01-07
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Granted: 1978-05-02
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Expires: 1997-01-07
Abstract
Abstract A helicopter rotor having opposed blades interconnected by a common flexible spar which passes across the rotor axis is connected to the drive shaft by clamped hub plates. A spanwise extending torque tube having a pitch horn at its inner end forms a rigid connection with the spar and blade at its outboard end. A centering bearing assembly is positioned at the inner end of the torque tube and spar to react control loads, centralize the torque tube about the spar, and provide pitch, flap, and lead-lag decoupling.
Inventors
- 👤 Donald Leroy Ferris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:44
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/35; B64C27/33
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
107 words
A helicopter cross beam rotor having a pair of opposed blades supported by a common flexible spar for rotation about an axis of rotation, each blade shaped at its inner end to envelope the spar in spaced relation, the inner end of the blade having a pitch horn to receive control inputs, said blade inner end centered about said spar by a bearing assembly including first and second bearing surfaces to produce relative sliding motion between the spar and blade inner end upon blade pitch angle changes, blade lead-lag, and blade flapwise bending, wherein said first bearing surface is spherical and said second bearing surface is flat.
Claim 2
Dependent Claim
107 words
A helicopter cross beam rotor having a pair of opposed blades supported by a common flexible spar for rotation about an axis of rotation, each blade shaped at its inner end to envelope the spar in spaced relation, the inner end of the blade having a pitch horn to receive control inputs, said blade inner end centered about said spar by a bearing assembly including first and second bearing surfaces to produce relative sliding motion between the spar and blade inner end upon blade pitch angle changes, blade lead-lag, and blade flapwise bending, wherein said first bearing surface is spherical and said second bearing surface is flat.
Claim 3
Dependent Claim
33 words
A helicopter rotor according to claim 1 wherein said first bearing surface accommodates motion produced by blade pitch change and flapwise bending, and said second bearing surface accommodates motion produced by blade lead-lag.
Claim 4
Dependent Claim
23 words
A helicopter rotor according to claim 1 wherein said second bearing surface is located closer to the spar than said first bearing surface.
Claim 5
Dependent Claim
46 words
A helicopter rotor according to claim 1 wherein the blade inner end is a rigid, hollow torque tube and enveloping the spar in spaced relation and having an inner end connected to said pitch horn and an outer end connected to the remainder of the blade.
Claim 6
Dependent Claim
75 words
A helicopter rotor according to claim 1 wherein said bearing assembly comprises dual ball halves and mating sockets located on opposite sides of said spar wherein said sockets are each fixedly attached to the blade inner end, the ball and socket mating surfaces forming said first bearing surfaces, and wherein the inner portions of the ball halves form a flat surface to contact the opposite sides of the spar and forms the second bearing surfaces.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-01 | 1981-10-31 | 1982-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-01 | 1985-10-31 | 1986-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-01 | 1989-10-31 | 1990-05-02 | $7700.00 | Window Closed / Lapsed |