Patent US3811328A successfully refreshed from Google Patents.
US3811328A
Expired / Lapsed
US
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Pulse duration modulation pickoff
Assignee: United States Department of the Army
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Filing: 1973-01-03
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Granted: 1974-05-21
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Expires: 1993-01-03
Abstract
Abstract A pulse duration modulation pickoff is capable of sensing variations in the boundary layer of gas adjacent the rotor surface of a gyro. A gas collector probe senses the variation in boundary layer thickness and couples the signals to the sensor load circuit for responding to gyro changes in attitude. This pickoff method of sensing rotor displacement allows displacement signals to be obtained with no external excitation of the pickoff.
Inventors
- 👤 A Rodgers
- 👤 R Widner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:00
CPC Classifications
F; F15; F15C; F15C1/00; F15C1/005; G; G01; G01C; G01C19/00; G01C19/02; G01C19/04; G01C19/28; Y; Y10; Y10T; Y10T74/00; Y10T74/12; Y10T74/1261; Y10T74/1268
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
148 words
A pulse duration modulation gyro pickoff system for displacement control comprising a gyro motor having a rotor disposed for rotation about a spin axis for providing two degrees of freedom; first and second raised areas on the exterior surface of the rotor forming respective annular rings of width varying around the circumference of said rotor adjacent respective ends thereof, said raised areas of varying width being determined by a gradually increasing line slope from zero width at the edge of respective rotor ends to a predetermined width greater than zero at approximately 360* from said zero width around the rotor periphery; and first and second gas collector probe pickoffs disposed respectively adjacent said first and second raised areas for responding to boundary layer gasee moving adjacent the rotor surface, said first and second collector probes being spaced 90* apart around the periphery of the rotor in parallel planes.
Claim 2
Dependent Claim
148 words
A pulse duration modulation gyro pickoff system for displacement control comprising a gyro motor having a rotor disposed for rotation about a spin axis for providing two degrees of freedom; first and second raised areas on the exterior surface of the rotor forming respective annular rings of width varying around the circumference of said rotor adjacent respective ends thereof, said raised areas of varying width being determined by a gradually increasing line slope from zero width at the edge of respective rotor ends to a predetermined width greater than zero at approximately 360* from said zero width around the rotor periphery; and first and second gas collector probe pickoffs disposed respectively adjacent said first and second raised areas for responding to boundary layer gasee moving adjacent the rotor surface, said first and second collector probes being spaced 90* apart around the periphery of the rotor in parallel planes.
Claim 3
Dependent Claim
53 words
A gyro pickoff system as set forth in claim 1 wherein respective collector probes are positioned to lie over respective raised areas during substantially 50 percent of each rotor revolUtion when the rotor spin axis is normal to the respective pickoff planes for providing a balanced or null pulse duration modulation signal output.
Claim 4
Dependent Claim
79 words
A gyro pickoff system as set forth in claim 2 and further comprising first and second bi-stable fluid amplifiers each having first and second outputs, first and second control ports, and a gas source; said first control ports being coupled to respective probe pickoffs for responding to gyro boundary layer currents sensed thereby, and said second control ports being resistively coupled to respective gas sources for providing a controlled bias pressure thereto and thereby controlling the amplifier switching level.
Claim 5
Dependent Claim
29 words
A gyro pickoff system as set forth in claim 1 wherein said first and second raised areas are rough for enhancing boundary layer gas currents therearound during rotor rotation.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |