US3866415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fan blade actuator using pressurized air
Assignee: General Electric Co
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Filing: 1974-02-25
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Granted: 1975-02-18
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Expires: 1994-02-25
Abstract
Abstract A fan having variable pitch blades is driven by the core engine of a gas turbine. The blades are mounted to a disc for rotation of the blades about their respective axes and the disc is mounted to a fan shaft. The fan shaft is mounted for rotation by a casing. A reversible turbine and an actuation gear are mounted for rotation relative to the fan shaft at opposite ends of a cylindrical portion of the fan shaft. A planetary gear train mounted interiorly of the cylindrical portion transmits rotation of the turbine to the actuation gear at a reduction of 915:1. Pneumatic means, including a pneumatic slip ring, introduces compressor discharge pressure (CDP) air to the turbine to serve as motive fluid. A centrifugal brake means locks the actuation gear in place when CDP air is not being ducted through the pneumatic means.
Inventors
- 👤 John J Ciokajlo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:57
CPC Classifications
F; F01; F01D; F01D7/00; F05; F05D; F05D2220/00; F05D2220/30; F05D2220/36; F05D2260/00; F05D2260/70; F05D2260/74; F05D2260/76
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
164 words
In a fan of the type used in a gas turbine engine having a core engine driving the fan through a fan shaft; a. a plurality of variable pitch fan blades secured to said fan shaft for rotation; b. a pitch change turbine mounted to said fan shaft for rotation relative thereto; c. an actuation gear mounted to said fan shaft for rotation relative thereto wherein said actuation gear cooperates with said variable pitch blades to vary the pitch of said blades in response to rotation of said actuation gear relative to said fan shaft; d. reduction gear means cooperating with said turbine and said actuation gear to rotate said actuation gear relative to said fan shaft in response to rotation of said turbine relative to said fan shaft; e. pneumatic means for introducing air under pressure to said turbine to serve as the motive fluid of said turbine; and f. control means to selectively regulate the flow of motive fluid to said turbine.
Claim 2
Dependent Claim
164 words
In a fan of the type used in a gas turbine engine having a core engine driving the fan through a fan shaft; a. a plurality of variable pitch fan blades secured to said fan shaft for rotation; b. a pitch change turbine mounted to said fan shaft for rotation relative thereto; c. an actuation gear mounted to said fan shaft for rotation relative thereto wherein said actuation gear cooperates with said variable pitch blades to vary the pitch of said blades in response to rotation of said actuation gear relative to said fan shaft; d. reduction gear means cooperating with said turbine and said actuation gear to rotate said actuation gear relative to said fan shaft in response to rotation of said turbine relative to said fan shaft; e. pneumatic means for introducing air under pressure to said turbine to serve as the motive fluid of said turbine; and f. control means to selectively regulate the flow of motive fluid to said turbine.
Claim 3
Dependent Claim
61 words
The fan recited in claim 1 wherein said fan shaft includes: a. a disc for mounting said blades for rotation about their respective axes whereby their pitch is varied; and b. a generally cylindrical portion coaxial with said fan shaft wherein said turbine, said actuation gear and said reduction gear means are mounted to said cylindrical portion for rotation relative thereto.
Claim 4
Dependent Claim
73 words
The fan recited in claim 2 wherein: a. said cylindrical portion of said fan shaft has a downstream end for mounting said turbine, an upstream end for mounting said actuation gear, and an intermediate portion; and b. said reduction gear means comprises a planetary gear train disposed interiorly of and cooperating with said intermediate portion of said cylindrical portion of said fan shaft for transmitting rotation of said turbine to said actuation gear.
Claim 5
Dependent Claim
13 words
The fan recited in claim 1 wherein said turbine is a reversible turbine.
Claim 6
Dependent Claim
75 words
The fan recited in claim 4 wherein said turbine includes: a. a first set of turbine buckets for rotation of said turbine in a first direction in response to the introduction of air under pressure to said first set; and b. a second set of turbine buckets spaced radially from said first set for rotation of said turbine in a second direction in response to the introduction of air under pressure to said second set.
Claim 7
Dependent Claim
48 words
The fan recited in claim 5 wherein said pneumatic means includes: a. a first pneumatic circuit for selectively introducing air under pressure to said first set of turbine buckets; and b. a second pneumatic circuit for selectively introducing air under pressure to said second set of turbine buckets.
Claim 8
Dependent Claim
24 words
The fan recited in claim 6 wherein said core engine includes a compressor, and said air under pressure is air discharged from said compressor.
Claim 9
Dependent Claim
63 words
The fan recited in claim 1 wherein each said blade includes a blade trunnion coaxial with said blade and each said blade trunnion includes a pinion gear and said actuation gear includes circumferentially extending face teeth meshing with said pinions for rotation of said blades about their respective axes in response to rotation of said actuation gear with respect to said fan shaft.
Claim 10
Dependent Claim
76 words
The fan reCited in claim 1 further including centrifugal brake means mounted to said fan shaft and having an operative position wherein said centrifugal brake means restrains said actuation gear against rotation relative to said fan shaft and an inoperative position freeing said actuation gear for rotation relative to said fan shaft wherein said centrifugal brake means cooperates with said pneumatic means so that said inoperative position is occupied when air is introduced to said turbine.
Claim 11
Dependent Claim
85 words
The fan recited in claim 9 wherein said centrifugal brake means comprises at least one braking mechanism including: a. a weight movable radially outwardly under centrifugal force to contact said actuation gear when said centrifugal brake means occupies said operative position; and b. a piston cooperating with said weight and said pneumatic means to move said centrifugal brake means to said inoperative position, wherein said weight is moved radially inwardly and out of contact with said actuation gear when air is introduced to said turbine.
Claim 12
Dependent Claim
81 words
The fan recited in claim 10 further including an annular casing for mounting said fan shaft for rotation wherein said pneumatic means comprises: a. tube means mounted to said annular casing; b. a pneumatic slip ring communicating with said tube means; c. duct means mounted to said fan shaft in communication with said pneumatic slip ring and said turbine for ducting said air under pressure from said pneumatic slip ring to said turbine, wherein said piston cooperates with said duct means.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |