US3878765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic actuator controls
Assignee: Vickers Inc
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Filing: 1973-03-01
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Granted: 1975-04-22
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Expires: 1993-03-01
Abstract
Abstract A device for controlling the flow of fluid to or the pressure of fluid applied to a hydraulic actuator comprises a pilot valve for controlling a pressure operated main valve. A transducer converts an electrical input signal into a force which is applied to the pilot valve spool. A feedback pressure is applied to piston means on or associated with the spool to apply a force thereto in opposition to the first-mentioned force. For flow control a flow sensor produces a feedback pressure differential dependent on the flow of fluid to the actuator. For pressure control a pressure sensing means produces a pressure equal to the higher of the operating pressures of the actuator. Flow and pressure control can be optionally obtained by providing two pilot valves in series, one responsive to the flow sensor and the other responsive to the pressure sensing means. One of the pilot valves is set to override the feedback signal thereto, whereby the other pilot valve becomes effective as desired.
Inventors
- 👤 Ronald Bernard Walters
- 👤 Donald Alexander Larner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:43
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/02; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/20546; F15B2211/20553; F15B2211/30; F15B2211/305; F15B2211/3052; F15B2211/30525; F15B2211/32; F15B2211/329; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/6054; F15B2211/635; F15B2211/6355; F15B2211/67; F15B2211/70; F15B2211/705; F15B2211/7051; F15B2211/7053; F15B2211/76
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
344 words
In combination, a hydraulic actuator and device for optionally controlling the flow of fluid to or the pressure of fluid applied to said hydraulic actuator, said device comprising fluid pressure operated main control valve means for regulating the fluid flow to the actuator; said main control valve means having control pressure chamber means; first and second pilot valve means for controlling the main control valve, each said pilot valve means including inlet and outlet port means and spool means for regulating the fluid between the respective inlet and outlet port means; means connecting the outlet port means of one of said first and second pilot valve means to the inlet port means of the other of said pilot valve means and connecting the outlet port means of said other pilot valve means to said control pressure chamber means of said main control valve means to enable said main control valve means to be operated by said pilot valve means; first and second transducer means for producing a respective input force dependent on a respective electrical input signal and for applying such force to the respective spool means; first opposed piston means associated wIth said first pilot valve spool means; second piston means associated with said second pilot valve spool means; flow sensing means for producing a pressure difference dependent on the rate of fluid flow to the actuator; pressure sensing means for producing a feedback pressure dependent on the operating pressure of the actuator; first feedback means for applying said pressure difference to said first opposed piston means to apply to said first pilot valve spool means a first feedback force opposed to the respective input force; and second feedback means for applying said feedback pressure to said second piston means to apply to said second pilot valve spool means a second feedback force opposed to the respective input force when the first transducer means is set to normally override the first feedback force, the first feedback force being effective when the second transducer means, is set to normally override the second feedback force.
Claim 2
Dependent Claim
344 words
In combination, a hydraulic actuator and device for optionally controlling the flow of fluid to or the pressure of fluid applied to said hydraulic actuator, said device comprising fluid pressure operated main control valve means for regulating the fluid flow to the actuator; said main control valve means having control pressure chamber means; first and second pilot valve means for controlling the main control valve, each said pilot valve means including inlet and outlet port means and spool means for regulating the fluid between the respective inlet and outlet port means; means connecting the outlet port means of one of said first and second pilot valve means to the inlet port means of the other of said pilot valve means and connecting the outlet port means of said other pilot valve means to said control pressure chamber means of said main control valve means to enable said main control valve means to be operated by said pilot valve means; first and second transducer means for producing a respective input force dependent on a respective electrical input signal and for applying such force to the respective spool means; first opposed piston means associated wIth said first pilot valve spool means; second piston means associated with said second pilot valve spool means; flow sensing means for producing a pressure difference dependent on the rate of fluid flow to the actuator; pressure sensing means for producing a feedback pressure dependent on the operating pressure of the actuator; first feedback means for applying said pressure difference to said first opposed piston means to apply to said first pilot valve spool means a first feedback force opposed to the respective input force; and second feedback means for applying said feedback pressure to said second piston means to apply to said second pilot valve spool means a second feedback force opposed to the respective input force when the first transducer means is set to normally override the first feedback force, the first feedback force being effective when the second transducer means, is set to normally override the second feedback force.
Claim 3
Dependent Claim
344 words
In combination, a hydraulic actuator and device for optionally controlling the flow of fluid to or the pressure of fluid applied to said hydraulic actuator, said device comprising fluid pressure operated main control valve means for regulating the fluid flow to the actuator; said main control valve means having control pressure chamber means; first and second pilot valve means for controlling the main control valve, each said pilot valve means including inlet and outlet port means and spool means for regulating the fluid between the respective inlet and outlet port means; means connecting the outlet port means of one of said first and second pilot valve means to the inlet port means of the other of said pilot valve means and connecting the outlet port means of said other pilot valve means to said control pressure chamber means of said main control valve means to enable said main control valve means to be operated by said pilot valve means; first and second transducer means for producing a respective input force dependent on a respective electrical input signal and for applying such force to the respective spool means; first opposed piston means associated wIth said first pilot valve spool means; second piston means associated with said second pilot valve spool means; flow sensing means for producing a pressure difference dependent on the rate of fluid flow to the actuator; pressure sensing means for producing a feedback pressure dependent on the operating pressure of the actuator; first feedback means for applying said pressure difference to said first opposed piston means to apply to said first pilot valve spool means a first feedback force opposed to the respective input force; and second feedback means for applying said feedback pressure to said second piston means to apply to said second pilot valve spool means a second feedback force opposed to the respective input force when the first transducer means is set to normally override the first feedback force, the first feedback force being effective when the second transducer means, is set to normally override the second feedback force.
Claim 4
Dependent Claim
344 words
In combination, a hydraulic actuator and device for optionally controlling the flow of fluid to or the pressure of fluid applied to said hydraulic actuator, said device comprising fluid pressure operated main control valve means for regulating the fluid flow to the actuator; said main control valve means having control pressure chamber means; first and second pilot valve means for controlling the main control valve, each said pilot valve means including inlet and outlet port means and spool means for regulating the fluid between the respective inlet and outlet port means; means connecting the outlet port means of one of said first and second pilot valve means to the inlet port means of the other of said pilot valve means and connecting the outlet port means of said other pilot valve means to said control pressure chamber means of said main control valve means to enable said main control valve means to be operated by said pilot valve means; first and second transducer means for producing a respective input force dependent on a respective electrical input signal and for applying such force to the respective spool means; first opposed piston means associated wIth said first pilot valve spool means; second piston means associated with said second pilot valve spool means; flow sensing means for producing a pressure difference dependent on the rate of fluid flow to the actuator; pressure sensing means for producing a feedback pressure dependent on the operating pressure of the actuator; first feedback means for applying said pressure difference to said first opposed piston means to apply to said first pilot valve spool means a first feedback force opposed to the respective input force; and second feedback means for applying said feedback pressure to said second piston means to apply to said second pilot valve spool means a second feedback force opposed to the respective input force when the first transducer means is set to normally override the first feedback force, the first feedback force being effective when the second transducer means, is set to normally override the second feedback force.
Claim 5
Dependent Claim
149 words
A device according to claim 1 in which said flow sensing means comprises a housing having at opposite ends thereof fluid connections connected in the flow path of the hydraulic fluid regulated by said main valve means and operating said actuator, a movable member in said housing and dividing said housing into two chambers communicating respectively with said fluid connections, cooperating surface means in said housing and on said movable member to define a fluid path interconnecting said chambers and having a restricted flow cross section, said flow cross section being variable dependently upon the position of said movable member in said housing, and spring means biasing said movable member to a position in which said flow cross section is at a minimum, said movable member being movable against said spring means responsively to fluid pressure difference between said chambers in a direction to increase said flow cross section.
Claim 6
Dependent Claim
37 words
A device according to claim 2 in which said cooperating surface means are so shaped that the pressure difference between said chambers is substantially directly proportional to the rate of fluid flow through said variable cross section.
Claim 7
Dependent Claim
66 words
A device according to claim 2 in which said housing defines a throat between said chambers and said spring means biasses said movable member into registry with said throat to define said position of minimum flow cross section, said movable member being movable axially of said throat in either direction according to the direction of fluid flow between said chambers, said hydraulic actuator being double acting.
Claim 8
Dependent Claim
57 words
A device according to claim 4 in which said throat and said movable member have sharp edges of substantially equal diameter, said housing having a wall diverging in opposite directions from said sharp edge of said throat and said sharp edge of said movable member cooperating with said diverging wall to define said variable flow cross section.
References Cited (Backward Citations)
US2188834A
Cited
US3038498A
Cited
US2909195A
Cited
US3092137A
Cited
US3487750A
Cited
US3555969A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |