US3753350A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reversible hydraulic actuator with selectable fail-safe operation
Assignee: Rotork PLC
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Filing: 1971-08-30
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Granted: 1973-08-21
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Expires: 1991-08-30
Abstract
Abstract The invention is concerned with a modulating actuator in which a linearly movable output shaft is movable in one direction by a single acting hydraulic motor and in the other direction by the stored energy of a spring device. The hydraulic circuit for the motor includes two solenoid operated control valves, the operation of which is reversible by a manual control so as to select a desired mode of fail-safe operation in the event of power failure. The actuator can be selected to fail-safe in an end position of the output shaft or to stay put in its actual position of movement.
Inventors
- 👤 P Nott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:38
CPC Classifications
F; F15; F15B; F15B21/00; F15B21/08; F15B21/087; Y; Y10; Y10S; Y10S425/00; Y10S425/235
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
An actuator comprising a linearly movable output member, power means operable to move said output member in a first direction of movement, resilient means for moving said output member in a second opposite direction of movement, control means for energising said power means and selector means for selectively adjusting said control means, said selector means being movable to a first position in which failure or deenergisation of said control means results in movement of said output member to an end position of its stroke in response to the stored energy of said resilient means, or to a second position in which the output member stays put and is held in its position of movement upon fialure or de-energisation of said control means.
Claim 2
Dependent Claim
122 words
An actuator comprising a linearly movable output member, power means operable to move said output member in a first direction of movement, resilient means for moving said output member in a second opposite direction of movement, control means for energising said power means and selector means for selectively adjusting said control means, said selector means being movable to a first position in which failure or deenergisation of said control means results in movement of said output member to an end position of its stroke in response to the stored energy of said resilient means, or to a second position in which the output member stays put and is held in its position of movement upon fialure or de-energisation of said control means.
Claim 3
Dependent Claim
49 words
An actuator according to claim 1, wherein the power means comprises a single acting hydraulic motor having a piston connected with said output member, said piston being urged in one direction by a hydraulic pressure fliud and in the opposite direction by the stored energy of said resilient means.
Claim 4
Dependent Claim
62 words
An actuator as claimed in claim 2, wherein the hydraulic motor is connected in a hydraulic circuit which includes a pump driven by a continuously running electric motor, a first control valve operable for controlling the supply of hydraulic pressure to said hydraulic motor, and a second control valve for controlling the return flow of said hydraulic fluid from said hydraulic motor.
Claim 5
Dependent Claim
36 words
An actuator as claimed in claim 3, wherein the valves are both controlled by electrically operable solenoids, said solenoids and said electric motor being operable by said control means which comprises a manually operable electric circuit.
Claim 6
Dependent Claim
60 words
An actuator as claimed in claim 4, wherein the selector means is manually operable to reverse the direction of operation of said second control valve in response to energisation of its solenoid by the electric control circuit whereby said second control valve is selectively held shut or open upon de-energisation of said solenoid upon failure of said electric control circuit.
Claim 7
Dependent Claim
32 words
An actuator as claimed in claim 5, wherein said selector means is operable simultaneously to reverse the electrical supply circuits to both sAid solenoids upon reversal of said second control valve operation.
Claim 8
Dependent Claim
50 words
An actuator as claimed in claim 5, wherein the hydraulic circuit includes a sealed reservoir and hydraulic motor unit so as to permit inversion of said actuator, and said reservoir includes compensating means such as an inflatable bladder to allow for possible expansion and/or contraction of the hydraulic fluid therein.
Claim 9
Dependent Claim
54 words
An actuator as claimed in claim 5, wherein the selector means includes a shaft extending through a flameproof and/or weatherproof barrier into the actuator casing, and said shaft includes a mechanical linkage for selectively connecting said second control valve to the armature of said solenoid at one or other side of its pivotal axis.
Claim 10
Dependent Claim
39 words
An actuator as claimed in claim 8, wherein the mechanical linkage is operable to move the pivotal block connected with said second control valve into engagement with one or other of a pair of spaced pins on said armature.
Claim 11
Dependent Claim
43 words
An actuator as claimed in claim 5, wherein the selector means is operable to connect one or other of a pair of opposed solenoids into the electrical control circuit for controlling the movement of a common armature connected with the second control valve.
Claim 12
Dependent Claim
54 words
An actuator as claimed in claim 5, wherein the piston of said hydraulic motor includes feedback means operating a potentiometer for producing an electric feedback signal proportional to the position of said piston, said feedback signal being compared with an electric input signal for producing a differential operating signal for said electric control circuit.
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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |