US3987702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and device for electrohydraulic control of a hydraulic actuator
Assignee: Airbus Defence and Space GmbH
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Filing: 1974-07-19
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Granted: 1976-10-26
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Expires: 1994-07-19
Abstract
Abstract Method and apparatus for the electric hydraulic control of a hydraulic actuator, said control comprising a redundant servovalve circuit with switching and monitoring logic. The apparatus has a plurality of electrohydraulic servovalves each controlled by separate electrical input channels and connected to a central pressure medium source. The control further has a control spool triggered by the servovalve to control the actuator and a hydraulic logic system for monitoring errors in the servo output signal. The positioning land of the control spool is acted upon on the one side by one group of signals consisting of the combined output signals of the same sign from one selected group of servovalves and is acted upon on the other side by the central pressure medium supply while the remaining sevovalve signals are applied separately to a hydraulic logic system including a comparator and alarm means.
Inventors
- 👤 Holm Diethard Boss
- 👤 Hans Albert Butschek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:03
CPC Classifications
F; F15; F15B; F15B21/00; B; B64; B64C; B64C13/00; F15B18/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
197 words
A method for effecting an electrohydraulic control of a hydraulic actuator by means of a system employing a pair of servovalves, a control spool and a pressure comparator, comprising the steps of: producing a first pressure signal when said pair of servovalves are in a first condition and supplying said first pressure signal directly to one end of an elongated housing slideably supporting said control spool therein; producing a second pressure signal from a central pressure medium supply and supplying same to the opposite end of said elongated housing and effecting an application of force to one side of said control spool equal to the force applied to the opposite side of said control spool by said first pressure signal, a rendering of said forces unequal causing said control spool to move in said housing to effect a control of said hydraulic actuator; producing a pair of third pressure signals when at least one of said servovalves is moved to a second condition; and supplying each of said third pressure signals to spaced locations on a pressure comparator, issuing fourth pressure signal from the comparator, and operating an alarm means in response to said fourth pressure signal.
Claim 2
Independent Claim
197 words
A method for effecting an electrohydraulic control of a hydraulic actuator by means of a system employing a pair of servovalves, a control spool and a pressure comparator, comprising the steps of: producing a first pressure signal when said pair of servovalves are in a first condition and supplying said first pressure signal directly to one end of an elongated housing slideably supporting said control spool therein; producing a second pressure signal from a central pressure medium supply and supplying same to the opposite end of said elongated housing and effecting an application of force to one side of said control spool equal to the force applied to the opposite side of said control spool by said first pressure signal, a rendering of said forces unequal causing said control spool to move in said housing to effect a control of said hydraulic actuator; producing a pair of third pressure signals when at least one of said servovalves is moved to a second condition; and supplying each of said third pressure signals to spaced locations on a pressure comparator, issuing fourth pressure signal from the comparator, and operating an alarm means in response to said fourth pressure signal.
Claim 3
Dependent Claim
353 words
In combination with a hydraulic actuator, a device for effecting an electrohydraulic control of said hydraulic actuator, comprising: servovalve circuit means including at least a pair of identical electrohydraulic servovalves each having an energized and an unenergized condition and each servovalve including at least a pair of output terminals thereon, each servovalve producing a first pressure signal at one of said pair of output terminals and a second pressure signal at the other one of said pair of output terminals dependent upon the condition thereof; means defining an elongated housing and a control spool slideably disposed therein for operating said actuator, and passageway means for connecting one end of said housing means to said one output terminal of each of said pair of servovalves so that said first pressure signals are applied to one face of said control spool; means defining a pressure source connected to the opposite end of said housing means, said pressure source means generating a third pressure signal to exert an equal and opposite force on an opposite face of said control spool relative to said first pressure signals, said control spool being movable in either direction if one of said first and third pressure signals is changed so that the force applied to opposite faces of said control spool are no longer equal to thereby effect a control of said hydraulic actuator; means defining a hydraulic logic system having a first pressure comparator means, said first pressure comparator means having a first outlet port means said first and second inlet ports which are each connected in fluid circuit with one end of said other of said output terminals of said pair of servovalves and said second pressure signal, said first pressure comparator means being responsive to a change in one of said second pressure signals from one of said pair of servovalves to produce a fourth pressure signal at said first outlet port means thereof; means defining an alarm responsive to a signal; and means in said hydraulic logic system responsive to said fourth pressure signal to generate said signal to effect an activation of said alarm means.
Claim 4
Dependent Claim
353 words
In combination with a hydraulic actuator, a device for effecting an electrohydraulic control of said hydraulic actuator, comprising: servovalve circuit means including at least a pair of identical electrohydraulic servovalves each having an energized and an unenergized condition and each servovalve including at least a pair of output terminals thereon, each servovalve producing a first pressure signal at one of said pair of output terminals and a second pressure signal at the other one of said pair of output terminals dependent upon the condition thereof; means defining an elongated housing and a control spool slideably disposed therein for operating said actuator, and passageway means for connecting one end of said housing means to said one output terminal of each of said pair of servovalves so that said first pressure signals are applied to one face of said control spool; means defining a pressure source connected to the opposite end of said housing means, said pressure source means generating a third pressure signal to exert an equal and opposite force on an opposite face of said control spool relative to said first pressure signals, said control spool being movable in either direction if one of said first and third pressure signals is changed so that the force applied to opposite faces of said control spool are no longer equal to thereby effect a control of said hydraulic actuator; means defining a hydraulic logic system having a first pressure comparator means, said first pressure comparator means having a first outlet port means said first and second inlet ports which are each connected in fluid circuit with one end of said other of said output terminals of said pair of servovalves and said second pressure signal, said first pressure comparator means being responsive to a change in one of said second pressure signals from one of said pair of servovalves to produce a fourth pressure signal at said first outlet port means thereof; means defining an alarm responsive to a signal; and means in said hydraulic logic system responsive to said fourth pressure signal to generate said signal to effect an activation of said alarm means.
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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) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |