US3727520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital electrohydraulic servo system
Assignee: Honeywell Inc
•
Filing: 1970-11-06
•
Granted: 1973-04-17
•
Expires: 1990-11-06
Abstract
Abstract The invention comprises a single stage hydraulic control valve system having a plurality of discretely located monitoring pressure and position sensors and controlled by a digital control system through an interfacing stepper motor. The control valve system positions a controlled element in accordance with a command signal. The plurality of pressure and position sensors provide an operation check means for establishing a confidence level of the system operation.
Inventors
- 👤 F Lynch
- 👤 Kown G Mc
- 👤 G Simons
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:11
CPC Classifications
F; F15; F15B; F15B9/00; F15B21/00; F15B21/08; F15B21/087
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
190 words
In an electrohydraulic servo system for positioning a controlled member in accordance with an electric error signal, the combination comprising a hydraulic Pressure actuator for positioning said control member, a source of high pressure hydraulic fluid for said actuator, a rotary control valve means coupled between said source and said actuator for controlling the flow of fluid therebetween, a stepper motor connected with and directly displacing said valve means, electrical error signal providing means including means responsive to predetermined threshold values of said error signal and of a sense corresponding to the sense of said error signal for supplying a first train of digital pulses to said stepper motor for incrementally rotating said valve means and porting corresponding increments of pressure fluid to said actuator, switch means responsive to said pressure fluid increments for supplying a second train of digital pulses corresponding to said pressure pulse train, converter means for converting said second digital pulse train to a feedback signal corresponding to the format of said error signal, and means for supplying said feedback signal to said error signal providing means for reducing said error signal below said threshold value.
Claim 2
Dependent Claim
190 words
In an electrohydraulic servo system for positioning a controlled member in accordance with an electric error signal, the combination comprising a hydraulic Pressure actuator for positioning said control member, a source of high pressure hydraulic fluid for said actuator, a rotary control valve means coupled between said source and said actuator for controlling the flow of fluid therebetween, a stepper motor connected with and directly displacing said valve means, electrical error signal providing means including means responsive to predetermined threshold values of said error signal and of a sense corresponding to the sense of said error signal for supplying a first train of digital pulses to said stepper motor for incrementally rotating said valve means and porting corresponding increments of pressure fluid to said actuator, switch means responsive to said pressure fluid increments for supplying a second train of digital pulses corresponding to said pressure pulse train, converter means for converting said second digital pulse train to a feedback signal corresponding to the format of said error signal, and means for supplying said feedback signal to said error signal providing means for reducing said error signal below said threshold value.
Claim 3
Dependent Claim
47 words
The apparatus as set forth in claim 1 wherein said first train of pulses includes pulses of a sense to drive said stepper motor in one direction and a corresponding number of pulses of an opposite sense to drive said stepper motor back to its original position.
Claim 4
Dependent Claim
52 words
The apparatus as set forth in claim 2 further including monitoring means for monitoring the operation of the system, means responsive to said monitoring means for disabling said stepper motor upon failure of said system, and spring means coupled with said valve means for returning said valve means to its unoperated position.
Claim 5
Dependent Claim
28 words
The apparatus as set forth in claim 1 wherein said electrical error signal is an analog signal and wherein said converter means comprises a pulse to analog converter.
Claim 6
Dependent Claim
31 words
The apparatus as set forth in claim 1 further including means for varying the response of said actuator means including means for varying the pulse repetition frequency of said pulse train.
References Cited (Backward Citations)
US3125856A
Cited
US2188834A
Cited
US3015313A
Cited
US3258025A
Cited
US3452645A
Cited
US3554084A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |