US3870434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gear arrangement for variable pitch fan
Assignee: General Electric Co
•
Filing: 1973-12-21
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Granted: 1975-03-11
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Expires: 1993-12-21
Abstract
Abstract A variable pitch fan having a plurality of circumferentially spaced apart variable pitch fan blades journalled for rotation about their longitudinal axes in a hub member, further includes a plurality of sector gears drivably connected to the rotor blades and simultaneously actuated by a unison bevel gear wherein each sector gear operates to apply its highest torque to the blades during the cruise mode of engine operation when the inherent turning moments from the centrifugal forces operating on the blades are at their peak.
Inventors
- 👤 Elmir Edward Paulson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:39
CPC Classifications
F; F01; F01D; F01D7/00; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/321; F04D29/322; F04D29/323; F05; F05D; F05D2220/00; F05D2220/30; F05D2220/36; F05D2260/00; F05D2260/70; F05D2260/74; F05D2260/76; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
In a turbomachine of the type having plurality of spaced apart variable pitch blades, journalled in a rotable hub member, a gear arrangement comprising: a plurality of spaced apart sector gears in respective driving engagement with the blades wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear having a plurality of circumferentially spaced apart teeth in simultaneous driving engagement with the teeth of the seCtor gears.
Claim 2
Dependent Claim
104 words
In a turbomachine of the type having plurality of spaced apart variable pitch blades, journalled in a rotable hub member, a gear arrangement comprising: a plurality of spaced apart sector gears in respective driving engagement with the blades wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear having a plurality of circumferentially spaced apart teeth in simultaneous driving engagement with the teeth of the seCtor gears.
Claim 3
Dependent Claim
104 words
In a turbomachine of the type having plurality of spaced apart variable pitch blades, journalled in a rotable hub member, a gear arrangement comprising: a plurality of spaced apart sector gears in respective driving engagement with the blades wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear having a plurality of circumferentially spaced apart teeth in simultaneous driving engagement with the teeth of the seCtor gears.
Claim 4
Dependent Claim
104 words
In a turbomachine of the type having plurality of spaced apart variable pitch blades, journalled in a rotable hub member, a gear arrangement comprising: a plurality of spaced apart sector gears in respective driving engagement with the blades wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear having a plurality of circumferentially spaced apart teeth in simultaneous driving engagement with the teeth of the seCtor gears.
Claim 5
Dependent Claim
42 words
The turbomachine of claim 1 wherein the angle at which the conical surface of revolution intersects the center axis of hub rotation coincides with the angle at which the teeth of the unison bevel gear would intersect the center axis of rotation.
Claim 6
Dependent Claim
52 words
The turbomachine of claim 2 wherein the teeth of the sector gears evolve in a spiraling helix and are of shorter longitudinal length than the teeth of the unison bevel gear and thus engage the bevel gear at varying radial distances from the center axis of rotation with changes in blade pitch.
Claim 7
Dependent Claim
144 words
In a gas turbine engine having a variable pitch fan with a plurality of circumferentially spaced apart variable pitch fan blades, each of which includes an airfoil vane portion together with a root journalled about an inner hub member for rotatable adjustment, an actuating gear arrangement comprising: a plurality of circumferentially spaced apart sector gears in respective driving engagement with the blade roots wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear disposed for rotation about the longitudinal engine center axis and having a plurality circumferentially spaced apart teeth disposed about the outer periphery thereof for simultaneous driving engagement with the teeth of the sector gears.
Claim 8
Dependent Claim
144 words
In a gas turbine engine having a variable pitch fan with a plurality of circumferentially spaced apart variable pitch fan blades, each of which includes an airfoil vane portion together with a root journalled about an inner hub member for rotatable adjustment, an actuating gear arrangement comprising: a plurality of circumferentially spaced apart sector gears in respective driving engagement with the blade roots wherein each gear has a plurality of teeth spaced apart at varying distances along the length of a conical surface of revolution, said sector gears arranged such that the spaced apart teeth of any two adjacent gears overlap without engaging each other, and a unison bevel gear disposed for rotation about the longitudinal engine center axis and having a plurality circumferentially spaced apart teeth disposed about the outer periphery thereof for simultaneous driving engagement with the teeth of the sector gears.
Claim 9
Dependent Claim
41 words
The gear arrangement of claim 4 wherein the angle at which the conical surface of revolution intersects the longitudinal engine center axis coincides with the angle at which the teeth of the unison bevel gear would intersect the engine center axis.
Claim 10
Dependent Claim
54 words
The gear arrangement of claim 5 wherein the teeth of the sector gears evolve in a spiraling helix and are of shorter longitudinal length than the teeth of the unison bevel gear and thus engage the bevel gear at varying radial distances from the center axis of the engine with changes in blade pitch.
References Cited (Backward Citations)
US32733A
Cited
US1802648A
Cited
US2460559A
Cited
US2697365A
Cited
US2711105A
Cited
US2844303A
Cited
US3018668A
Cited
US3601499A
Cited
US3687569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |