Patent US3817150A successfully refreshed from Google Patents.
US3817150A
Expired / Lapsed
US
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Hydraulic actuator with mechanical feedback
Assignee: MEGAVAULT
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Filing: 1972-12-29
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Granted: 1974-06-18
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Expires: 1992-12-29
Abstract
Abstract A hydraulic actuator having a selectively positioned, rotary output shaft. The actuator includes a control assembly in which a spool valve controls the admission and return of working fluid through a valve port. The spool valve position is controlled by a pilot assembly which communicates with valve chambers exerting pressure on opposite ends of the spool valve. The pilot assembly includes opposed nozzles connected with the valve chambers and a flapper between the nozzles which may be moved back and forth between them to variably restrict their output and hence the pressure in the valve chambers. The flow of fluid from the control assembly is directed to an output assembly which has first and second movable pistons mounted in piston chambers. The first piston chamber is continuously connected to a source of working fluid at supply pressure, while admission of fluid to the second piston chamber is controlled by the spool valve via the valve port. The pistons are connected by a link secured to an output shaft and exert opposing torques on the link. When fluid is directed into the second piston chamber, the second piston exerts the greater torque rotating the shaft in one direction. When fluid is vented from the second piston chamber, the first piston rotates the output shaft in the opposite direction. A finger feeds back a portion of the motion of the link to the flapper via a spring to center the flapper when the output shaft is in a selected position.
Inventors
- 👤 R Cox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:46
CPC Classifications
F; F15; F15B; F15B9/00; F15B9/02; F15B9/08; F15B9/12; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86582; Y10T137/8659; Y10T137/86598
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
452 words
A hydraulic actuator comprising, a control assembly having, a first housing, an enclosed bore within said first housing, a valve port communicating with said bore, inlet means adapted for connection to a source of fluid under pressure for admitting fluid under pressure to said bore, outlet means for outflow of fluid from said bore, two valve chambers at opposite ends of said bore in communication with said inlet means, valve means subjected to the pressures within said valve chambers movably mounted within said bore for controlling communication between said valve port and said inlet and outlet means, said valve means occupying a neutral position within said bore in which said valve port is closed when the pressures in said valve chambers are equal, unequal pressures in said valve chambers moving said valve means in opposite directions from said neutral position to positions in which said valve port communicates with one at a time of said inlet means and said outlet means; and two flow passages, each communicating with one of said chambers, a pilot assembly having a second housing, a cavity in said second housing, opposed nozzles opening into said cavity and communicating with said flow passages to direct fluid therefrom into said cavity as opposed jets, a flapper disposed between said nozzles in spaced relation therewith and movable back and forth between them to variably restrict said nozzles and thereby vary the pressures in said valve chambers, and actuating means for urging said flapper towards either said nozzle with a selected variable force, an output assembly having a third housing, first and second piston chambers in said third housing, said first piston chamber communicating with said inlet means, said second piston chamber communicating with said valve port, first and second pistons slidably mounted in said piston chambers, each said piston having a piston rod extending outwardly from the associated said piston chamber, an output shaft rotatably mounted in said third housing, a link fixedly secured to said output shaft, the ends of said link acted upon by said piston rods to transmit opposing torques to said output shaft, the torque exerted by said second piston exceeding the torque exerted by said first piston when both piston chambers communicate with said inlet means thereby causing rotation of said output shaft in one direction, the torque exerted by said first piston eXceeding the torque exerted by said second piston when said second chamber communicates with said outlet means thereby causing rotation of said shaft in an opposite direction; and feedback means connected with said flapper and with said link responsive to movement thereof for urging the flapper to a centered position between said nozzles when said output shaft is in a selected position.
Claim 2
Dependent Claim
452 words
A hydraulic actuator comprising, a control assembly having, a first housing, an enclosed bore within said first housing, a valve port communicating with said bore, inlet means adapted for connection to a source of fluid under pressure for admitting fluid under pressure to said bore, outlet means for outflow of fluid from said bore, two valve chambers at opposite ends of said bore in communication with said inlet means, valve means subjected to the pressures within said valve chambers movably mounted within said bore for controlling communication between said valve port and said inlet and outlet means, said valve means occupying a neutral position within said bore in which said valve port is closed when the pressures in said valve chambers are equal, unequal pressures in said valve chambers moving said valve means in opposite directions from said neutral position to positions in which said valve port communicates with one at a time of said inlet means and said outlet means; and two flow passages, each communicating with one of said chambers, a pilot assembly having a second housing, a cavity in said second housing, opposed nozzles opening into said cavity and communicating with said flow passages to direct fluid therefrom into said cavity as opposed jets, a flapper disposed between said nozzles in spaced relation therewith and movable back and forth between them to variably restrict said nozzles and thereby vary the pressures in said valve chambers, and actuating means for urging said flapper towards either said nozzle with a selected variable force, an output assembly having a third housing, first and second piston chambers in said third housing, said first piston chamber communicating with said inlet means, said second piston chamber communicating with said valve port, first and second pistons slidably mounted in said piston chambers, each said piston having a piston rod extending outwardly from the associated said piston chamber, an output shaft rotatably mounted in said third housing, a link fixedly secured to said output shaft, the ends of said link acted upon by said piston rods to transmit opposing torques to said output shaft, the torque exerted by said second piston exceeding the torque exerted by said first piston when both piston chambers communicate with said inlet means thereby causing rotation of said output shaft in one direction, the torque exerted by said first piston eXceeding the torque exerted by said second piston when said second chamber communicates with said outlet means thereby causing rotation of said shaft in an opposite direction; and feedback means connected with said flapper and with said link responsive to movement thereof for urging the flapper to a centered position between said nozzles when said output shaft is in a selected position.
Claim 3
Dependent Claim
114 words
A hydraulic actuator as defined in claim 1 wherein said feedback means includes, a finger slidably mounted in the adjacent portions of said housing, one end of said finger contacting said link and moved thereby in a linear direction toward and away from said flapper by pivoting motion of said link, a first spring disposed between one side of said flapper and the opposite end of said finger, said first spring holding said finger against said link, and a second spring acting against the other side of said flapper and opposing said first spring to urge said flapper to a centered position between said nozzles when said output shaft is in said selected position.
Claim 4
Dependent Claim
77 words
A hydraulic actuator as defined in claim 1 wherein said first and second pistons are of equal cross-sectional area and wherein the axis of rotation of said output shaft is closer to said first piston rod than to said second piston rod to provide sufficient leverage to said second piston to enable it to exert a greater torque on said output shaft than said first piston when both said piston chambers are connected to said inlet means.
Claim 5
Dependent Claim
127 words
A hydraulic actuator as defined in claim 1 wherein said bore is of generally cylindrical configuration and said valve means is a spool valve mounted for reciprocation within said bore, said spool valve including a generally cylindrical body concentric with and spaced from said bore, axially spaced, peripherally extending first and second lands fixedly connected with said spool body in sliding sealing contact with said bore; said lands, when said spool is in the neutral position, closely overlapping the opposite edges of said valve port on opposite sides thereof and preventing flow of fluid through said valve port; displacement of said spool from the neutral position in either direction opening said valve port for flow of fluid between the valve port and the interior of said bore.
Claim 6
Dependent Claim
71 words
A hydraulic actuator as defined in claim 4 further including, third and fourth lands spaced on opposite sides of said first and second lands, respectively, said third and fourth lands secured to said spool body extending into sliding sealing contact with said bore, said third and fourth lands being acted upon by the fluid pressures in said chambers to cause axial motion of said spool valve when the pressures are unequal.
Claim 7
Dependent Claim
30 words
A hydraulic actuator as defined in claim 1 wherein said valve means further includes, means for preventing fluid communication between said outlet means and said first and second valve chambers.
Claim 8
Dependent Claim
58 words
A hydraulic actuator as defined in claim 2 further including, a fluid filled sump in said third housing enclosing said link, an annular opening extending between said finger and the adjacent portions of said housings through which fluid may pass from said sump, and a passage connecting an outlet end of said annular opening with said outlet means.
Claim 9
Dependent Claim
149 words
A hydraulic actuator as defined in claim 3 wherein said feedback means includes. a finger slidably mounted in the adjacent portions of said housings, one end of said finger contacting said link and moved thereby in a linear direction toward and away from said flapper by pivoting motion of said link, a first spring disposed between one side of said flapper and the opposite end of said finger and holding said finger against said link, and a second spring acting against the other side of said flapper and opposing said first spring to urge said flapper to a centered position between said nozzles when said output shaft is in a selected position, the point of contact of said finger with said link being intermediate saiD output shaft and said second piston rod whereby the linear stroke of said finger is less than the linear displacement of said second piston.
Claim 10
Dependent Claim
81 words
A hydraulic actuator as defined in claim 5 wherein said inlet means communicates with said bore in a region thereof between said second and forth lands on said spool valve and wherein said outlet means communicates with said bore in a region thereof between said first and third lands on said spool valve, said spool body further including passage means through said spool body and internally thereof for conducting fluid from said inlet means to said first and second valve chambers.
Claim 11
Dependent Claim
303 words
In a hydraulic actuator having a pilot valve assembly including a flapper, two orifices for directing jets of hydraulic fluid toward opposite sides of said flapper, actuating means for selectively urging the flapper toward each of the orifices to variably restrict the jet flow therefrom, and feedback means for acting on said flapper in opposition to said actuating means in accordance with the response of a controlled device, and including a movable feedback element; and a control assembly having an inlet for actuating fluid, on outlet for said actuating fluid, and a valve port, valve means movable back and forth along a predetermined path within the control assembly for selectively connecting and disconnecting said valve port with one at a time, or neither, of said inlet and said outlet in different positions along said path, and two pressure chambers for applying actuating pressure to said valve means to variably position the latter along said path, the improvement comprising: an output assembly having a rotary output member, first and second crank arms on said output member for turning the latter, first and second hydraulic cylinders having actuating elements engaging said first and second crank arms, respectively, to apply opposed actuating torques to said output member and also having first and second actuating chambers for said actuating elements, said second chamber communicating with said valve port, means for delivering fluid under a preselected pressure to said first chamber to apply torque to said output member through said crank arm that is less than the torque applied through said second crank arm when said inlet is connected to said valve port; and a feedback connector acting between said feedback element and one of said crank arms at a point spaced from said output member to transmit rotary motion of said output member to said feedback element.
Claim 12
Dependent Claim
303 words
In a hydraulic actuator having a pilot valve assembly including a flapper, two orifices for directing jets of hydraulic fluid toward opposite sides of said flapper, actuating means for selectively urging the flapper toward each of the orifices to variably restrict the jet flow therefrom, and feedback means for acting on said flapper in opposition to said actuating means in accordance with the response of a controlled device, and including a movable feedback element; and a control assembly having an inlet for actuating fluid, on outlet for said actuating fluid, and a valve port, valve means movable back and forth along a predetermined path within the control assembly for selectively connecting and disconnecting said valve port with one at a time, or neither, of said inlet and said outlet in different positions along said path, and two pressure chambers for applying actuating pressure to said valve means to variably position the latter along said path, the improvement comprising: an output assembly having a rotary output member, first and second crank arms on said output member for turning the latter, first and second hydraulic cylinders having actuating elements engaging said first and second crank arms, respectively, to apply opposed actuating torques to said output member and also having first and second actuating chambers for said actuating elements, said second chamber communicating with said valve port, means for delivering fluid under a preselected pressure to said first chamber to apply torque to said output member through said crank arm that is less than the torque applied through said second crank arm when said inlet is connected to said valve port; and a feedback connector acting between said feedback element and one of said crank arms at a point spaced from said output member to transmit rotary motion of said output member to said feedback element.
Claim 13
Dependent Claim
370 words
A hydraulic actuator comprising, an output assembly having a first housing, first and second piston chambers in said first housing, said first piston chamber adapted for continuous connection to a source of fluid at a supply pressure, first and second pistons slidably mounted in said piston chambers, an output shaft rotatably mounted in said first housing, crank arms connected with said output shaft and said pistons to transmit opposing torques to said output shaft, the torque exerted by said second piston exceeding the torque exerted by said first piston when both piston chambers are at the same pressure thereby causing rotation of said output shaft in one direction, the torque exerted by said first piston exceeding the torque exerted by said second piston when said second chamber is at a return pressure lower than the supply pressure thereby causing rotation of said shaft in an opposite direction; a control assembly having a second housing provided with an inlet for incoming flow fluid at the supply pressure, an outlet for exit of fluid at the return pressure and a port communicating with said second piston chamber; and valve means movable relative to said second housing for closing said port and for selectively placing said port in communication with either of said inlet and said outlet, a pilot assembly having a third housing and a movable member resiliently biased in two opposite directions toward a neutral position, signal controlled means for eXerting a force of predetermined magnitude on said movable member to displace it in either of said two directions on application of a signal to said signal controlled means, means responsive to the position of said movable member connected with said valve means for causing movement thereof, said responsive means causing said valve means to close said port when said movable member is in the neutral position and causing said valve means to place said second piston chamber in communication with either of said inlet and outlet when said movable member is displaced in the opposite directions; and feedback means connected with at least one of said crank arms and with said movable member for urging the latter to said neutral position when said output shaft is in a selected position.
Claim 14
Dependent Claim
370 words
A hydraulic actuator comprising, an output assembly having a first housing, first and second piston chambers in said first housing, said first piston chamber adapted for continuous connection to a source of fluid at a supply pressure, first and second pistons slidably mounted in said piston chambers, an output shaft rotatably mounted in said first housing, crank arms connected with said output shaft and said pistons to transmit opposing torques to said output shaft, the torque exerted by said second piston exceeding the torque exerted by said first piston when both piston chambers are at the same pressure thereby causing rotation of said output shaft in one direction, the torque exerted by said first piston exceeding the torque exerted by said second piston when said second chamber is at a return pressure lower than the supply pressure thereby causing rotation of said shaft in an opposite direction; a control assembly having a second housing provided with an inlet for incoming flow fluid at the supply pressure, an outlet for exit of fluid at the return pressure and a port communicating with said second piston chamber; and valve means movable relative to said second housing for closing said port and for selectively placing said port in communication with either of said inlet and said outlet, a pilot assembly having a third housing and a movable member resiliently biased in two opposite directions toward a neutral position, signal controlled means for eXerting a force of predetermined magnitude on said movable member to displace it in either of said two directions on application of a signal to said signal controlled means, means responsive to the position of said movable member connected with said valve means for causing movement thereof, said responsive means causing said valve means to close said port when said movable member is in the neutral position and causing said valve means to place said second piston chamber in communication with either of said inlet and outlet when said movable member is displaced in the opposite directions; and feedback means connected with at least one of said crank arms and with said movable member for urging the latter to said neutral position when said output shaft is in a selected position.
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |