Patent US4750862A successfully refreshed from Google Patents.
US4750862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modular propeller blade pitch actuation system
Assignee: RTX Corp
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Filing: 1986-11-28
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Granted: 1988-06-14
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Expires: 2006-11-28
Abstract
Abstract A modular, easily replaceable, pitch actuation system is removably secured within the hub of an aircraft. The modular system houses a driving system which provides a rotational output to set the pitch of propeller blades mounted to the hub, and a pitch changing system that controls the driving system. The driving system includes a high-speed, low-torque hydraulic motor that drives an harmonic drive to amplify the torque of the motor. The pitch changing system includes an actuator which positions a valve that controls the hydraulic motor, and a nulling gear which repositions the valve and acts as a pitch lock.
Inventors
- 👤 Philip E. Barnes
- 👤 Edward H. Kusiak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:05
CPC Classifications
B; B64; B64C; B64C11/00; B64C11/30; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
188 words
Apparatus for changing the pitch of a propeller blade mounted to a hub, said apparatus comprising: a housing removably disposed within said hub, driving means disposed with said housing for providing a high-torque rotational output to set the pitch of said propeller blade, said driving means comprising; means for providing a rotational input, an hydraulic pump for impelling fluid, said pump attaching to and driven by said means for providing a rotational input, a high-speed hydraulic motor driven by said fluid impelled by said hydraulic pump, said motor providing a low-torque rotational output, and harmonic drive means attaching to and driven by said hydraulic motor for amplifying said low-torque rotational output to provide said high-torque rotational output, and a valve disposed within said housing communicating with said fluid impelled by said pump for controlling a flow of said fluid to said hydraulic motor thereby controlling said high-torque rotational output, and actuator means disposed within said housing and attaching to said valve for controlling the position of the valve to control said high-torque rotational output, and attaching to said high-torque rotational output for nulling the position of said valve.
Claim 2
Dependent Claim
188 words
Apparatus for changing the pitch of a propeller blade mounted to a hub, said apparatus comprising: a housing removably disposed within said hub, driving means disposed with said housing for providing a high-torque rotational output to set the pitch of said propeller blade, said driving means comprising; means for providing a rotational input, an hydraulic pump for impelling fluid, said pump attaching to and driven by said means for providing a rotational input, a high-speed hydraulic motor driven by said fluid impelled by said hydraulic pump, said motor providing a low-torque rotational output, and harmonic drive means attaching to and driven by said hydraulic motor for amplifying said low-torque rotational output to provide said high-torque rotational output, and a valve disposed within said housing communicating with said fluid impelled by said pump for controlling a flow of said fluid to said hydraulic motor thereby controlling said high-torque rotational output, and actuator means disposed within said housing and attaching to said valve for controlling the position of the valve to control said high-torque rotational output, and attaching to said high-torque rotational output for nulling the position of said valve.
Claim 3
Dependent Claim
25 words
The apparatus of claim 1 wherein said actuator means further comprises: lock means for stopping the high-torque rotational output from moving undesirably toward low pitch.
Claim 4
Dependent Claim
72 words
The apparatus of claim 1 wherein said actuator means comprises: a linear actuator, a linkage attaching to said actuator and to said valve such that motion of the actuator positions the valve, and a gear means rotatably mounted upon said actuator and attaching to said high-torque rotational output such that motion of said high torque rotational output moves said gear, and said actuator and linkage thereby, such that said valve is nulled.
Claim 5
Dependent Claim
31 words
The apparatus of claim 3 wherein said lock means comprises: a stop upon said actuator which engages said gear means should said high-torque rotational output be moving undesirably towards low pitch.
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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) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |