Patent US4249862A successfully refreshed from Google Patents.
US4249862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Damper means for helicopter rotors
Assignee: Westland Group PLC
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Filing: 1977-12-05
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Granted: 1981-02-10
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Expires: 1997-12-05
Abstract
Abstract A helicopter rotor includes a rotor head having, for each of a plurality of rotor blades, an elastomeric bearing and a damper that is arranged to provide controlled restraint of rotor blade movement in both the flap and lead/lag planes. The damper can be arranged to exhibit either substantially equal stiffness in both operational planes or any desired stiffness ratio. In a preferred embodiment of the latter arrangement, the desired stiffness in the respective planes are provided by separate components incorporated in the single damper. The damper may be situated either inboard or outboard of the elastomeric bearing.
Inventors
- 👤 Alan Waddington
- 👤 Alfred C. Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:24
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/51; B64C27/32; B64C27/35
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
179 words
A helicopter rotor including a rotor head and a plurality of rotor blades, means for supporting the rotor blades by the rotor head for rotation about an axis, each rotor blade supporting means comprising a spindle attached to the rotor blade, the spindle extending inwardly into the rotor head, a hollow elastomeric bearing for the rotor blade, the hollow bearing having a geometrical centre about which rotor blade flap and lead/lag movements occur during operation, and a generally annular elastomeric damper assembly for the rotor blade, the damper mounted on the rotor head generally transversely of a longitudinal axis of the spindle and being spaced apart axially from the elastomeric bearing, said spindle being operatively connected to said damper so as to be free to rotate about its axis relative the damper in response to feathering movements of the rotor blade and so that lateral movements of the spindle due to rotor blade flap and lead/lag movements are transmitted to the damper, whereby said damper provides controlled restraint of rotor blade movement in both the flap and lead/lag planes.
Claim 2
Dependent Claim
179 words
A helicopter rotor including a rotor head and a plurality of rotor blades, means for supporting the rotor blades by the rotor head for rotation about an axis, each rotor blade supporting means comprising a spindle attached to the rotor blade, the spindle extending inwardly into the rotor head, a hollow elastomeric bearing for the rotor blade, the hollow bearing having a geometrical centre about which rotor blade flap and lead/lag movements occur during operation, and a generally annular elastomeric damper assembly for the rotor blade, the damper mounted on the rotor head generally transversely of a longitudinal axis of the spindle and being spaced apart axially from the elastomeric bearing, said spindle being operatively connected to said damper so as to be free to rotate about its axis relative the damper in response to feathering movements of the rotor blade and so that lateral movements of the spindle due to rotor blade flap and lead/lag movements are transmitted to the damper, whereby said damper provides controlled restraint of rotor blade movement in both the flap and lead/lag planes.
Claim 3
Dependent Claim
47 words
A helicopter rotor according to claim 1 and further including a universal joint interposed between the spindle and damper assembly, a support member attached to the rotor head and said damper including at least one annular elastomer layer disposed between said support member and said universal joint.
Claim 4
Dependent Claim
17 words
A helicopter rotor according to claim 2 wherein said elastomer layers comprises a layer of synthetic rubber.
Claim 5
Dependent Claim
16 words
A helicopter rotor according to claim 1 wherein said damper comprises a plurality of elastomer layers.
Claim 6
Dependent Claim
39 words
A helicopter rotor according to claim 1 and said damper assembly including support members attached to said bearing and said rotor head, said support members having leg portions and a plurality of elastomer layers bonded to said leg portions.
Claim 7
Dependent Claim
31 words
A helicopter rotor according to claim 5 wherein said leg portions are disposed in generally perpendicularly opposed planes corresponding to the flap and lead/lag planes of movement of the rotor blade.
Claim 8
Dependent Claim
52 words
A helicopter rotor according to claim 1 wherein said damper assembly includes a support member and elastomeric layers interposed between the support member and the rotor head at both sides of the longitudinal axis of the spindle, said elastomeric layers being oriented in a plane generally parallel with a blade flap plane.
Claim 9
Dependent Claim
21 words
A helicopter rotor according to claim 7 wherein a plurality of alternate layers of metal are interposed between said elastomeric layers.
Claim 10
Dependent Claim
16 words
A helicopter rotor according to claim 7 wherein said elastomeric layers comprise layers of natural rubber.
Claim 11
Dependent Claim
18 words
A helicopter rotor according to claim 1 wherein said damper assembly is disposed inboard of said elastomeric bearing.
Claim 12
Dependent Claim
18 words
A helicopter rotor according to claim 1 wherein said damper assembly is disposed outboard of said elastomeric bearing.
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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) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |