US3960348A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aerodynamic surface control feel augmentation system
Assignee: RTX Corp
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Filing: 1975-08-04
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Granted: 1976-06-01
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Expires: 1995-08-04
Abstract
Abstract In a helicopter, a pilot-actuated lever controls, through linkage mechanisms, a servo valve to drive a hydraulic piston; the piston moves a swash plate which in turn controls movement of rotor blade pitch positioning mechanisms against the force of blade loading, caused by aerodynamic forces. Blade loading, heretofore monitored visually by the pilot on a cruise guide indicator instrument, is used herein to control a secondary input to the servo valve, thereby to alter the position linkage mechanism which causes the force of a spring attached thereto to impose a force on the collective pitch control for blade loadings in excess of one-third of maximum allowable blade loads, in a direction tending to drive the control to lower collective pitch (lower blade loading). This provides "feel" to the pilot in proportion to blade loading when at critical magnitudes. A trim system is selectively actuatable to provide an input to the auxiliary valve which tends to maintain the collective pitch control in a selected position.
Inventors
- 👤 Donald W. Fowler
- 👤 Sean J. O'Connor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:51
CPC Classifications
B; B64; B64C; B64C13/00; B64C13/24; B64C13/38; B64C13/40; B64C13/46; G; G05; G05D; G05D1/00; G05D1/0055; G05D1/0066
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
204 words
A system for positioning a control surface of an aircraft comprising: means for sensing the aerodynamic loading of at least one control surface and providing a load signal in response thereto; a hydraulic actuator, including a piston for positioning the control surface, and having a servo valve for positioning said piston in response to fluid pressure; a control lever; mechanical linkage interconnected between said control lever, said servo valve and said piston in a fashion such that the motion of said control lever to a given position causes said mechanical linkage to actuate said servo valve which drives said piston to reposition the control surface, and to return said mechanical linkage to a null position to deactivate said servo; auxiliary valve means responsive to said load signal for actuating said servo valve independently of said mechanical linkage; and means connected to said mechanical linkage to induce a force into said mechanical linkage in response to motion of said piston actuated by said auxiliary valve, said force being imparted to said control lever in such a manner as to move said control lever in a direction to reduce the aerodynamic loading of the control surface and thereby to reduce the magnitude of said load signal.
Claim 2
Independent Claim
204 words
A system for positioning a control surface of an aircraft comprising: means for sensing the aerodynamic loading of at least one control surface and providing a load signal in response thereto; a hydraulic actuator, including a piston for positioning the control surface, and having a servo valve for positioning said piston in response to fluid pressure; a control lever; mechanical linkage interconnected between said control lever, said servo valve and said piston in a fashion such that the motion of said control lever to a given position causes said mechanical linkage to actuate said servo valve which drives said piston to reposition the control surface, and to return said mechanical linkage to a null position to deactivate said servo; auxiliary valve means responsive to said load signal for actuating said servo valve independently of said mechanical linkage; and means connected to said mechanical linkage to induce a force into said mechanical linkage in response to motion of said piston actuated by said auxiliary valve, said force being imparted to said control lever in such a manner as to move said control lever in a direction to reduce the aerodynamic loading of the control surface and thereby to reduce the magnitude of said load signal.
Claim 3
Dependent Claim
42 words
A system according to claim 1 wherein said auxiliary valve means actuates said servo valve in response to said load signal in such a manner as to drive said piston in a direction to reduce the aerodynamic loading of the control surface.
Claim 4
Dependent Claim
98 words
A system according to claim 2 further comprising: means responsive to said control lever for providing a continuous signal indication of the position thereof, said means being selectably actuated to also provide a reference signal indication in response to a selected position of said control lever; means for comparing the continuous signal indication of said control lever position to the reference signal indication to provide a trim error signal in proportion to the difference therebetween; and summing means responsive to said trim error signal and said load signal for providing the sum thereof to said auxiliary valve means.
References Cited (Backward Citations)
US2051837A
Cited
US2831643A
Cited
US3021097A
Cited
US3050276A
Cited
US3220317A
Cited
US3034483A
Cited
US3463423A
Cited
US3580139A
Cited
US3764095A
Cited
US3744928A
Cited
US3862730A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |