US3895884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Torque sensitive pitch lock
Assignee: RTX Corp
•
Filing: 1974-07-05
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Granted: 1975-07-22
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Expires: 1994-07-05
Abstract
Abstract This invention is concerned with pitch lock of the variable pitch fan blades of a propulsor whose pitch is varied by a rotary type actuator and where the pitch lock input signal is manifested by a negative torque reaction imparted by the blades.
Inventors
- 👤 Merritt B Andrews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:56
CPC Classifications
F; F01; F01D; F01D7/00; F05; F05D; F05D2260/00; F05D2260/70; F05D2260/74; F05D2260/76
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
For a fan propulsor having a hub rotatably supporting a plurality of circumferential blades mounted therein for pitch change movement, means including a rotary actuator having connection means connected to said blades for imparting pitch change movement, a pitch lock element on said connection means and movable therewith, a retractable pitch lock element normally urged out of engagement with said pitch lock element and means responsive to the blades when they are extracting energy out of the airstream for engaging said pitch lock elements to prevent the pitch from going to a lower blade angle.
Claim 2
Dependent Claim
95 words
For a fan propulsor having a hub rotatably supporting a plurality of circumferential blades mounted therein for pitch change movement, means including a rotary actuator having connection means connected to said blades for imparting pitch change movement, a pitch lock element on said connection means and movable therewith, a retractable pitch lock element normally urged out of engagement with said pitch lock element and means responsive to the blades when they are extracting energy out of the airstream for engaging said pitch lock elements to prevent the pitch from going to a lower blade angle.
Claim 3
Dependent Claim
58 words
For a fan propulsor as claimed in claim 1 including a drive shaft, a main gearbox having a ring gear interconnecting said hub and said drive shaft, spline means between said hub and ring gear normally transmitting rotary movement to said hub, and said spline functioning to displace said ring gear axially to engage said pitch lock elements.
Claim 4
Dependent Claim
17 words
For a fan propulsor as claimed in claim 2 wherein said spline is of the helical type.
Claim 5
Dependent Claim
25 words
For a fan propulsor as claimed in claim 3 including an arm projecting from said retractable pitch lock element to abut against said ring gear.
References Cited (Backward Citations)
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Cited
US2988153A
Cited
US2974730A
Cited
US3187819A
Cited
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Cited
US3672788A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |