US3601499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gear drive for variable pitch aerofoil assembly
Assignee: Rolls Royce PLC
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Filing: 1969-06-17
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Granted: 1971-08-24
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Expires: 1989-06-17
Abstract
Abstract A gear drive for variable pitch aerofoil comprises a common gear wheel adapted to drive the aerofoils to vary their pitch, a plurality of compound epicyclic wheels engaging with the common wheel and the drive shaft of the aerofoil, a carrier from which are carried the epicyclic wheel and drive means for the carrier adapted in one mode to hold the carrier stationary and in another mode to cause the carrier to rotate with the drive shaft.
Inventors
- 👤 John H Ellinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:48
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/54; F02K1/64; F02K1/66; F01; F01D; F01D7/00; F05; F05D; F05D2260/00; F05D2260/70; F05D2260/74; F05D2260/76; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
219 words
A variable pitch aerofoil assembly comprising: a plurality of aerofoil blades, a main drive shaft means having said plurality of aerofoil blades operatively attached thereto so that the blades can be rotated about the axis of said main drive shaft means, drive means for rotating the aerofoil blades about their own axes, said drive means including a. pinion means which are constrained to rotate with rotation of said main drive shaft means, b. bevel gear wheel means meshing with said pinion means, c. a ring of gear teeth carried from the bevel gear wheel means, d. a plurality of compound epicyclic wheels each having a first and a second set of teeth, the first sets meshing with the ring of gear teeth of the bevel gear wheel means, e. a gear track on the main drive sHaft means meshing with the second sets of teeth on the epicyclic wheels, f. a rotatable carrier means carrying the plurality of epicyclic wheels and g. interconnection means which normally interconnect the carrier means and the main drive shaft means so that the carrier means and the main drive shaft means rotate at the same speed in a first mode of operation, and arresting means for arresting the carrier means when feathering of the blades is required for a second mode of operation.
Claim 2
Dependent Claim
219 words
A variable pitch aerofoil assembly comprising: a plurality of aerofoil blades, a main drive shaft means having said plurality of aerofoil blades operatively attached thereto so that the blades can be rotated about the axis of said main drive shaft means, drive means for rotating the aerofoil blades about their own axes, said drive means including a. pinion means which are constrained to rotate with rotation of said main drive shaft means, b. bevel gear wheel means meshing with said pinion means, c. a ring of gear teeth carried from the bevel gear wheel means, d. a plurality of compound epicyclic wheels each having a first and a second set of teeth, the first sets meshing with the ring of gear teeth of the bevel gear wheel means, e. a gear track on the main drive sHaft means meshing with the second sets of teeth on the epicyclic wheels, f. a rotatable carrier means carrying the plurality of epicyclic wheels and g. interconnection means which normally interconnect the carrier means and the main drive shaft means so that the carrier means and the main drive shaft means rotate at the same speed in a first mode of operation, and arresting means for arresting the carrier means when feathering of the blades is required for a second mode of operation.
Claim 3
Dependent Claim
46 words
A variable pitch aerofoil assembly as claimed in claim 1 and in which said drive means includes means to cause said carrier means to rotate, in a third mode of operation, at a speed different from that caused in either of the first and second modes.
Claim 4
Dependent Claim
21 words
A variable pitch aerofoil assembly as claimed in claim 2 and in which said interconnection means includes an electrical stepping motor.
Claim 5
Dependent Claim
53 words
A variable pitch aerofoil assembly as claimed in claim 3 and in which said stepping motor comprises two pairs of pole rings, one pole ring of each pair being mounted on the carrier means while the other members of the pair are mounted on the drive shaft means and on fixed structure respectively.
Claim 6
Dependent Claim
38 words
A variable pitch aerofoil assembly as claimed in claim 4 and in which electrical supply means to said poles comprises brushes and slip rings adapted to supply electricity to the rings of poles on the carrier means only.
Claim 7
Dependent Claim
61 words
A variable pitch aerofoil assembly as claimed in claim 5 and in which said brushes are spring loaded radially inwards to such an extent as to overcome centrifugal force tending to lift the brushes from the slip rings only at low rotational speeds of the fan, thus allowing the brushes to lift clear of the slip rings at high rotational speeds.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |