US3561322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stability augmentation system
Assignee: Boeing Co
•
Filing: 1968-06-04
•
Granted: 1971-02-09
•
Expires: 1988-06-04
Abstract
Abstract A stability augmentation system is provided which has triple redundancy and is fail-functional. For each axis desired to be controlled, a hydraulic servocontrol mechanism is provided having three signal sources, and three actuator units. The actuator''s pistons are connected together in tandem with a relief valve connected across each piston to prevent the piston of a failed unit from hampering the operation of the control. Means are provided to furnish a feedback signal to the servovalves controlling the pistons when pressure is being relieved across the piston to attempt to balance the output of the servovalve. The hydraulic servocontrol mechanism may be combined with a hydraulic boost actuator comprising two tandem pistons having their pressure differential limited by boost relief valves and being controlled by a spool valve to provide an integrated hydraulic control actuator having a single output member. The relief valve has a slider with a conduit therein positioned between a pair of fluid channels. The conduit is closed when the slider is centered in the valve and is open when the slider is not centered. Centering plungers, held in place by hydraulic pressure, normally hold the slider in its centered position. When the pressure differential across the slider exceeds the pressure of one of the plungers, the slider moves from its centered position.
Inventors
- 👤 Milton I Gerstine
- 👤 Hans G Krauss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:29
CPC Classifications
F; F15; F15B; F15B18/00
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
188 words
A hydraulic servocontrol mechanism comprising: a. a plurality of signal sources; b. a hydraulic servoactuator having an output member responsive to signals from said signal sources, said servo actuator having a plurality of individual units with each unit including: 1. a cylinder; 2. a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod; 3. a servovalve in communication with said cylinder by means of channels for suppLying hydraulic fluid to said cylinder; 4. a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder said relief valve having passage means therein for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and 5. means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston.
Claim 2
Dependent Claim
188 words
A hydraulic servocontrol mechanism comprising: a. a plurality of signal sources; b. a hydraulic servoactuator having an output member responsive to signals from said signal sources, said servo actuator having a plurality of individual units with each unit including: 1. a cylinder; 2. a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod; 3. a servovalve in communication with said cylinder by means of channels for suppLying hydraulic fluid to said cylinder; 4. a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder said relief valve having passage means therein for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and 5. means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston.
Claim 3
Dependent Claim
20 words
a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod;
Claim 4
Dependent Claim
20 words
a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod;
Claim 5
Dependent Claim
186 words
a hydraulic servoactuator having an output member responsive to signals from said signal sources, said servoactuator having a plurality of individual units with each unit including: a. a cylinder; b. a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod; c. a servovalve in communication with said cylinder by means of channels for supplying hydraulic fluid to said cylinder; d. a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder and for releasing the pressure differentiaL said relief valve having passage means for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and e. means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston; B. a hydraulic boost actuator including:
Claim 6
Dependent Claim
186 words
a hydraulic servoactuator having an output member responsive to signals from said signal sources, said servoactuator having a plurality of individual units with each unit including: a. a cylinder; b. a piston and a piston rod positioned in said cylinder, said piston connected to said output member by said rod; c. a servovalve in communication with said cylinder by means of channels for supplying hydraulic fluid to said cylinder; d. a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder and for releasing the pressure differentiaL said relief valve having passage means for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and e. means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston; B. a hydraulic boost actuator including:
Claim 7
Dependent Claim
34 words
The servocontrol of claim 1 including means responsive to said sensing means for providing a warning signal to indicate a failure when said pressure differential across said piston is greater than a preselected maximum.
Claim 8
Dependent Claim
156 words
The servocontrol of claim 1 wherein said relief valve comprises a valve body, a slider mounted in said valve body, a pair of fluid channels, each providing communication between one end of said slider and one end of said piston, said slider having at least one conduit therein which is closed when the slider is centered and is open to flow of fluid between said channels when said slider is moved from its centered position, a pair of centering plungers, one mounted at each end of said slider for normally holding said slider in its centered position, said plungers being held in position by a constant hydraulic pressure acting on one end of each of said plungers whereby when the pressure differential across said piston exceeds a preselected maximum, the force acting on said slider overcomes the centering pressure of said plungers and moves said slider in the direction of the channel having the lesser pressure.
Claim 9
Dependent Claim
18 words
a servovalve in communication with said cylinder by means of channels for suppLying hydraulic fluid to said cylinder;
Claim 10
Dependent Claim
18 words
a servovalve in communication with said cylinder by means of channels for suppLying hydraulic fluid to said cylinder;
Claim 11
Dependent Claim
79 words
a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder said relief valve having passage means therein for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and
Claim 12
Dependent Claim
79 words
a differential pressure responsive relief valve in communication with said servovalve and said cylinder for limiting the differential pressure across said piston in said cylinder said relief valve having passage means therein for permitting fluid flow between the two sides of said piston when the differential pressure exceeds a preselected maximum, each of said relief valves including sensing means for sensing the position of said relief valve when the pressure differential across the piston exceeds a preselected maximum; and
Claim 13
Dependent Claim
23 words
The servocontrol of claim 3 wherein said sensing means is comprised of a linear variable differential transformer integrally formed in said relief valve.
Claim 14
Dependent Claim
68 words
The servocontrol of claim 4 wherein said transformer includes a primary winding and two secondary windings positioned adjacent said slider of said relief valve, said slider is made of a magnetic material and said secondary windings are connected so that signals do not issue from said transformer when said slider is centered but a signal issues from said transformer when said slider is moved from its centered position.
Claim 15
Dependent Claim
25 words
means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston.
Claim 16
Dependent Claim
25 words
means responsive to said sensing means for supplying a signal to said servovalve to cause said servovalve to decrease the pressure differential across said piston.
Claim 17
Dependent Claim
65 words
The servocontrol of claim 4 wherein said signal from said transformer is in the form of a negative feedback signal, said means which is responsive to said transformer signal comprises a demodulator, a threshold circuit, an integrating amplifier, and a servoamplifier, connected to said servovalve for supplying said signal thereto to integrate the output of said servovalve to zero and to thereby recenter said slider.
Claim 18
Dependent Claim
24 words
The servocontrol of claim 6 including a warning means and wherein said signal from said transformer energizes said warning means to indicate a failure.
Claim 19
Dependent Claim
19 words
The servocontrol of claim 7 wherein there are at least three signal sources, and at least three actuator units.
Claim 20
Dependent Claim
11 words
An integrated hydraulic actuator comprising: A. a hydraulic servocontrol mechanism including:
Claim 21
Dependent Claim
11 words
An integrated hydraulic actuator comprising: A. a hydraulic servocontrol mechanism including:
Claim 22
Dependent Claim
31 words
The integrated hydraulic actuator of claim 9 including a relief valve operatively connected to each of said cylinders of said boost actuator for preventing excessive pressure buildups across said boost pistons.
Claim 23
Dependent Claim
173 words
The integrated hydraulic actuator of claim 10 wherein said relief valves in said hydraulic servocontrol mechanism and in said hydraulic boost actuator comprise a valve body, a slider mounted in said valve body, a pair of fluid channels, each providing communication between one end of said slider and one end of the piston associated therewith, said slider having at least one conduit therein which is closed when said slider is centered and is open to flow of fluid between said channels when said slider is moved from its centered position, a pair of centering plungers, one mounted at each end of said slider for normally holding said slider in its centered position, said plungers being held in position by a constant hydraulic pressure acting on one end of each of said plungers whereby when the pressure differential across said pistons exceeds a preselected maximum the force acting on said slider overcomes the centering pressure of one of said plungers and moves the slider in the direction of the channel having the lesser pressure.
Claim 24
Dependent Claim
95 words
The integrated hydraulic actuator of claim 11 wherein said sensing means of said servocontrol is comprised of a linear variable differential transformer integrally formed in said relief valves in said servocontrol and wherein said transformer includes primary windings and two sets of secondary windings positioned adjacent said slider of said relief valve, said slider is made of a magnetic material, and said secondary windings are connected so that no signals issue from said transformer when said slider is centered but a signal issues from said transformer when said slider is moved from its centered position.
Claim 25
Dependent Claim
67 words
The integrated hydraulic actuator of claim 12 wherein said signal from said transformer is in the form of a negative feedback signal, said means, which is responsive to said transformer signal comprises a demodulator, a threshold circuit, an integrating amplifier, and a servoamplifier, connected to said servovalve for supplying said signal thereto to integrate the output of said servovalve to zero and to thereby recenter said slider.
Claim 26
Dependent Claim
26 words
The integrated hydraulic actuator of claim 13 including a warning means and wherein said signal from said transformer energizes said warning means to indicate a failure.
References Cited (Backward Citations)
US2219967A
Cited
US3128968A
Cited
US2289463A
Cited
US3220317A
Cited
US3136224A
Cited
US3190185A
Cited
US3295420A
Cited
US3286600A
Cited
US3452645A
Cited
US3426650A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |