Patent US3924404A successfully refreshed from Google Patents.
US3924404A
Expired / Lapsed
US
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Apparatus for adjusting fan blades in a turbojet engine
Assignee: MTU Aero Engines AG
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Filing: 1973-04-19
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Granted: 1975-12-09
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Expires: 1993-04-19
Abstract
Abstract Apparatus for adjusting fan blades in a turbojet engine of the type which has a primary duct for conducting air to an engine compressor rotor and a secondary bypass duct with the fan blades extending there-across to form part of an axial flow fan of the engine. The adjusting apparatus is positioned substantially within an annulus arranged between the primary and secondary ducts. The adjusting apparatus includes an annular piston attached to toothed adjusting racks which engage teeth on said fan blades to adjust the fan blade angle of attack upon movement of the annular piston. An arresting or locking mechanism actuable by an auxiliary piston serves to lock the adjusting racks in position. Compressed air supply from the engine to the annular and auxiliary pistons is controlled to prevent actuation of the annular piston while the adjusting racks are locked by the locking mechanism.
Inventors
- 👤 Wolfgang Pollert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:14
CPC Classifications
F; F02; F02K; F02K3/00; F02K3/02; F02K3/04; 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: 17
Claim 1
Independent Claim
155 words
Apparatus for adjusting fan blades in a turbojet engine of ducted-fan construction of the type which has primary and secondary ducts; said apparatus comprising: drive system and actuating mechanism means positioned substantially inside of an annulus arranged between said primary and secondary ducts and including a piston connected to toothed rack means mounted for movement within said annulus, said fan blades including blade teeth which matingly engage corresponding rack teeth of said toothed rack means, selectively engageable arresting means engageable with said toothed rack means to prevent movement of said toothed rack means, and supporting blade means extending across said primary duct for supporting said annulus, wherein said arresting means includes resiliently biased plunger means extending through cavity means in said supporting blade means, said plunger means being engageable with respective spaced slots in said toothed rack means for arresting said toothed rack means in positions corresponding to predetermined adjusted positions of said fan blades.
Claim 2
Dependent Claim
155 words
Apparatus for adjusting fan blades in a turbojet engine of ducted-fan construction of the type which has primary and secondary ducts; said apparatus comprising: drive system and actuating mechanism means positioned substantially inside of an annulus arranged between said primary and secondary ducts and including a piston connected to toothed rack means mounted for movement within said annulus, said fan blades including blade teeth which matingly engage corresponding rack teeth of said toothed rack means, selectively engageable arresting means engageable with said toothed rack means to prevent movement of said toothed rack means, and supporting blade means extending across said primary duct for supporting said annulus, wherein said arresting means includes resiliently biased plunger means extending through cavity means in said supporting blade means, said plunger means being engageable with respective spaced slots in said toothed rack means for arresting said toothed rack means in positions corresponding to predetermined adjusted positions of said fan blades.
Claim 3
Dependent Claim
45 words
Apparatus according to claim 1, wherein said primary duct is a duct for supplying air to a compressor rotor of said engine, and wherein said secondary duct is a bypass duct with said fan blades forming part of an axial flow fan of said engine.
Claim 4
Dependent Claim
42 words
Apparatus according to claim 2, wherein said engine has a longitudinal engine centerline extending in the direction of air flow through said engine, and wherein said secondary duct is arranged radially outwardly of said primary duct with respect to said engine centerline.
Claim 5
Dependent Claim
29 words
Apparatus according to claim 3, wherein said piston is an annular piston which is movable coaxially with respect to said engine centerline in response to pressurized air supplied thereto.
Claim 6
Dependent Claim
21 words
Apparatus according to claim 4, wherein said annular piston is mounted within said annulus for movement parallel to said engine centerline.
Claim 7
Dependent Claim
29 words
Apparatus according to claim 5, wherein means are provided for directing compressed air from a comprEssor rotor of said engine as said pressurized air to move said annular piston.
Claim 8
Dependent Claim
28 words
Apparatus according to claim 5, wherein said toothed rack means are connected to the annular piston through a ring-shaped rack carrier which extends coaxially to the engine centerline.
Claim 9
Dependent Claim
50 words
Apparatus according to claim 7, wherein control means are provided for controlling the supply of compressed air to said annular piston such that supply of compressed air to said annular piston is prevented until an auxiliary piston disposed adjacent central shafting of said engine has first released said arresting means.
Claim 10
Dependent Claim
25 words
Apparatus according to claim 8, wherein said auxiliary piston is operated by compressed air and is movable in a direction parallel to said engine centerline.
Claim 11
Dependent Claim
55 words
Apparatus according to claim 2, wherein said piston is an annular piston which is supplied with said compressed air by way of an air manifolding system adjacent to central shafting means of the engine, through ducts in supporting blades extending across said primary duct, and through line means within said annulus to said annular piston.
Claim 12
Dependent Claim
46 words
Apparatus according to claim 9, wherein said annular piston is supplied with said compressed air by way of an air manifolding system adjacent to said central shafting means, through ducts in said supporting blade means, and through line means within said annulus to said annular piston.
Claim 13
Dependent Claim
37 words
Apparatus according to claim 11, further comprising valve means interposed downstream of a compressor rotor of said engine for selectively controlling the supply of compressed air from said compressor rotor to actuate said annular and auxiliary pistons.
Claim 14
Dependent Claim
37 words
Apparatus according to claim 9, further comprising valve means interposed downstream of a compressor rotor of said engine for selectively controlling the supply of compressed air from said compressor rotor to actuate said annular and auxiliary pistons.
Claim 15
Dependent Claim
23 words
Apparatus according to claim 12, further comprising valve control means responsive to the position of said annular piston for controlling said valve means.
Claim 16
Dependent Claim
62 words
Apparatus according to claim 14, wherein said valve control means includes iron core means connected to said annular piston and electrical coil means adjacent said iron core means, said iron core means and coil means being operatively arranged to generate electrical signals for controlling the valve means as a result of inductive voltage changes upon changes in position of said annular piston.
Claim 17
Dependent Claim
13 words
Apparatus according to claim 15, wherein said valve means is a threeway valve.
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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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |