EP0067815B1 - Systeme avec dispositif d'actionnement a force constante - Google Patents

Systeme avec dispositif d'actionnement a force constante Download PDF

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Publication number
EP0067815B1
EP0067815B1 EP19810901579 EP81901579A EP0067815B1 EP 0067815 B1 EP0067815 B1 EP 0067815B1 EP 19810901579 EP19810901579 EP 19810901579 EP 81901579 A EP81901579 A EP 81901579A EP 0067815 B1 EP0067815 B1 EP 0067815B1
Authority
EP
European Patent Office
Prior art keywords
fluid
control valve
pilot
valve
actuator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19810901579
Other languages
German (de)
English (en)
Other versions
EP0067815A4 (fr
EP0067815A1 (fr
Inventor
Lowell R. Hall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Tractor Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
Publication of EP0067815A1 publication Critical patent/EP0067815A1/fr
Publication of EP0067815A4 publication Critical patent/EP0067815A4/fr
Application granted granted Critical
Publication of EP0067815B1 publication Critical patent/EP0067815B1/fr
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3144—Directional control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6058—Load sensing circuits with isolator valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/78—Control of multiple output members
    • F15B2211/781—Control of multiple output members one or more output members having priority

Definitions

  • This invention is directed to pilot operated control valve systems and particularly those having an actuator requiring a continuous force on the actuator at the same time other work is being performed.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a fluid system has a fluid source, an actuator, a tank and a pilot Operated control valve.
  • the pilot operated control valve has first and second ends and is movable between an actuated position and a neutral position. At the actuated position, the source communicates with the actuator and is blocked from a downstream control valve, and at the neutral position the fluid from the source is blocked from communication with the actuator and communicates with the downstream control valve through the pilot operated control valve.
  • a pilot control valve is connected to a source of pressurized pilot fluid and the first and second ends of the pilot -operated control valve.
  • the pilot control valve is movable between a neutral position at which the source of pressurized pilot fluid is blocked from communication with the first and second ends, and an actuated position at which pressurized pilot fluid from the source is communicated with the first end establishing a differential pressure between the first and second ends.
  • a means modulatably reduces the pilot differential pressure between the first and second ends of the pilot operated control valve at the actuated position of the pilot operated control valve in response to the fluid pressure in the actuator reaching a predetermined level, so that the pilot operated control valve is controllably moved between the neutral and actuated positions to maintain the predetermined pressure level in the actuator and to pass fluid to the downstream control valve.
  • a fluid system is generally indicated by reference numeral 10 and includes a fluid source, such as, a pump 12 and a pilot operated control valve 14 connected to the pump 12 by a conduit 16.
  • An actuator 18 is connected to the pilot operated control valve 14 by a pair of conduits 20, 22.
  • a control valve 24 is connected to the pilot operated control valve 14 by a conduit 26 and positioned downstream of the pilot operated control valve 14.
  • a tank 28 is connected to the pilot operated control valve 14 by a conduit 30.
  • the pilot operated control valve 14 is movable between a first or neutral position "A", a second or actuated position “B” and a third position “C".
  • the pilot operated control valve 14 is biased by centering springs 31 to the neutral position in a conventional manner.
  • the fluid source or pump 12 is blocked from communication with the actuator 18 and is in fluid communication with the downstream control valve 24.
  • the fluid source 12 is in communication with the actuator 18 through conduit 20 and the return flow in line 22 communicates with the control valve 24 through conduit 26.
  • the third position "C" the fluid source 12 is blocked from communication with the control valve 24 and is in communication with the actuator 28 through conduit 22.
  • the return flow in conduit 20 from actuator 18 returns to tank 28 through conduit 30.
  • a pilot control valve 32 is connected to a source of pressurized pilot fluid, such as a.pilot pump 34, by a conduit 36.
  • the pilot control valve 32 is connected to first and second ends 38, 40 of the pilot operated control valve 14 by first and second conduits 42, 44 respectively.
  • a conduit 46 connects the pilot control valve 32 to the tank 28.
  • the pilot control valve 32 is movable between a first or neutral position "A"', a second, detented or actuated position "B"' and a third position “C”'.
  • the neutral position "A"' the first and second ends 38, 40 of the pilot operated control valve 14 are blocked from communication with the source of pressurized pilot fluid 32 and are in communication with the tank 28.
  • the actuated position"B"' the first end 38 is in communication with the source 34 of pressurized pilot fluid, and the second end 40 is open to the tank 28.
  • the second end 40 is in cdm- munication with the source 34 of pressurized pilot fluid and the first end 38 is open to the tank 28.
  • a differential pressure is established between the first and second ends 38, 40 of the pilot operated control valve 14 by the difference in the pressures between the first and second ends 38, 40.
  • a means 48 is provided for modulatably reducing the pilot differential pressure between the first and second ends 38, 40 of the pilot operated control valve 14 in response to the fluid pressure in the actuator 18 reaching a predetermined level, so that the pilot operated control valve 14 is controllably moved between the neutral and actuated positions "A, B" to maintain the predetermined pressure level in the actuator 18 and to pass fluid to the downstream control valve 24.
  • the means 48 includes a. two position valve 56 connected to the first end 38 and the actuator 18 and is adapted to controllably pass pressurized pilot fluid from the first end 38 in response to the actuator 18 reaching a predetermined level.
  • the fluid from the two position valve 56 is directed to the second end 40 of the pilot operated control valve 14 as hereinafter described.
  • the two position valve 56 is connected to the first end 38 by a conduit 54 and the first conduit 42.
  • a signal conduit 58 connects the two position valve 56 to the actuator 18.
  • the two position valve 56 is movable between a first position, as shown, at which the flow of pressurized pilot' fluid through the conduit 54 is blocked and a second position at which the flow of pressurized pilot fluid is communicated through the conduit 54.
  • the two position valve 56 is biased to its first position by a spring 60 and to its second position in response to fluid pressure in the actuator 18 reaching a predetermined level.
  • the means 48 also includes a second means 50 for controllably communicating the pressurized pilot fluid to the second end 40.
  • the second means 50 includes a resolver valve 52 located in the second conduit 44, a third conduit 55 connected to the two position valve 56 and the resolver valve 52.
  • the resolver valve 52 is adapted to sense the higher of the pressurized pilot fluid in the second and third conduits 44, 55 and deliver the higher pressure to the second end 40.
  • a conduit 62 having an orifice 64 located therein is connected to the third conduit 55 between the two position valve 56 and the resolver 52 and is connected to the tank 28.
  • a second embodiment is shown. It is noted that the same reference numerals of the first embodiment are used to designate similarly constructed counterpart elements of this embodiment.
  • the resolver valve 52, the two position valve 56, conduit 54, third conduit 55, conduit 62 and orifice 64 are deleted.
  • a two position valve 66 is connected to the pilot control valve 32 by conduit 42A and to the first end 38 of the pilot operated control valve 14 by a conduit 42B.
  • the two position valve 66 is also connected to the tank 28 by a conduit 68 and to the actuator 18 by signal conduit 58.
  • the two position valve 66 is movable between a first position, as shown, at which the pressurized pilot fluid from the source 34 is directed to the first end 38, and a second position at which the pressurized pilot fluid is blocked from communication with the first end 38 and the first end 38 is communicated to the tank 28.
  • the two position valve 66 is biased to the first position by a spring 70 and biased to the second position in response to fluid pressure in the actuator 18 reaching a predetermined level.
  • the present invention has particular utility in hydraulic systems that require having one actuator held under a constant force during operation of the system, such as, when lifting and/or transporting several logs in a log fork having clamping arms to hold the logs.
  • an operator moves the pilot control valve 32 to the second, detented position "B"' directing pressurized pilot fluid to the first end 38 of the pilot operated control valve 14 which establishes a differential pressure between the first and second ends 38, 40, thus shifting the pilot operated control valve 14 to the second position "B".
  • Fluid from the source 12 is directed to the actuator 18 by conduit 20 to close the clamping arms, not shown.
  • the return flow by conduit 22 from the actuator 18 is passed to the downstream control valve 24 by line 26. Once the clamping arms, controlled by the actuator 18 clamps the logs, the pressure in the actuator 18 will increase.
  • the two position valve 56 sensing the pressure through conduit 58, will move towards the second position against the bias of spring 60.
  • the pressurized pilot fluid 34 from the first conduit 42 is modulatably directed through the two position valve 56 and the resolver valve 52 to the second end 40 of the pilot operated control valve 14.
  • the centering springs 31 moves the pilot operated control valve 14 towards the neutral position "A" thus allowing fluid from the source 12 to pass to the downstream control valve 24.
  • the two position valve 56 moves towards the first position and reduces the flow.of pressurized pilot fluid 34 to the second end 40.
  • the pressurized fluid in the second end 40 is reduced by the flow of fluid across orifice 64 to tank 28.
  • the higher pressure on the first end 38 moves the pilot operated control valve 14 towards the second position "B" to direct fluid from the source 12 to the actuator 18.
  • the pilot operated control valve 14 will automatically move to a position to maintain the pressure in the actuator 18 at the predetermined pressure level until the pilot control valve 32 is returned to its neutral position"A"'.
  • the second embodiment shown in Fig. 2 operates in a similar manner as the embodiment in Fig. 1 to automatically move the pilot operated control valve 14 to a position to maintain a predetermined pressure level in the actuator 18.
  • the two position valve 66 modulatably controls, in response to the pressure in actuator 18, the pressurized pilot fluid acting on the first end 38.
  • the two position valve sensing the pressure through conduit 58 moves towards the second position against the bias of spring 70.
  • the force of the centering springs 31 acting against the reduced differential pressure moves the pilot operated control valve 14 toward the neutral position "A" as in Fig. 1.
  • an actuator can be maintained at a predetermined pressure while still providing flow to a downstream valve.
  • the pilot operated control valve would automatically shift to its actuated position to supply the flow.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)

Claims (7)

1. Système à fluide (10) comportant une source de fluide (12); un réservoir (28); un dispositif d'actionnement (18); une valve de commande actionnée par un pilote (14) ayant une première et une seconde extrémités (38, 40) et apte à se déplacer entre une position active (B) dans laquelle ladite source (12) est en communication avec ledit dispositif d'actionnement (18) et est bloquée depuis une valve de commande située en aval (24), et une position neutre (A) dans laquelle le fluide provenant de ladite source (12) voit sa mise en communication avec ledit dispositif d'actionnement (18) bloquée, tandis qu'il est mis en communication avec ladite valve de commande située en aval (24) par l'intermédiaire de ladite valve de commande actionnée par un pilote (14); une source (34) de fluide pilote sous pression; et une valvel pilote de commande (32) reliée à ladite source (34) de fluide pilote sous pression et aux- dites première et seconde extrémités (38, 40) et apte à se déplacer entre une position neutre (A') dans laquelle ladite source (34) de fluide pilote sous pression voit sa communication avec lesdites première et seconde extrémités (38, 40) bloquée, et une position active (B') dans laquelle ledit fluide pilote sous pression provenant de ladite source (34) est mis en communication avec ladite première extrémité (38) en établissant ainsi une différence de pression entre les première et seconde extrémités (38, 40); caractérisé en ce qu'il comprend un organe (48) pour réduire de façon modulable la pression pilote différentielle entre les première et seconde extrémités (38, 40) de la valve de commande actionnée par un pilote (14) uniquement dans la position active (B) de la valve de commande actionnée par un pilote (14) en réponse à l'obtention d'une pression de fluide à un niveau prédéterminé dans ledit dispositif d'actionnement (18) tandis que ladite valve pilote de commande (32) est toujours dans ladite position active (B'), de telle sorte que ladite valve de commande actionnée par un pilote (14) est déplacée de manière commandable entre les position neutre et active (A, B) pour maintenir ledit niveau de pression prédéterminé dans ledit dispositif d'actionnement (18) et pour transmettre le volume excédentaire de fluide de travail à la valve de commande située en aval (24).
2. Système à fluide (10) selon la revendication 1, dans lequel ledit organe (48) comprend une valve à deux positions (56, 66) reliée à ladite première extrémité (38) et audit dispositif d'actionnement (18), et conçue pour transmettre de manière commandable le fluide sous pression provenant de ladite première extrémité (38) en réponse à l'obtention dudit niveau de pression prédéterminé par le fluid sous pression dans ledit dispositif d'actionnement (18).
3. Système à fluide (10) selon la revendication 2, dans lequel ledit organe (48) comprend un second organe (50) pour mettre en communication ledit fluide pilote sous pression provenant de ladite valve à deux position (56) avec la seconde extrémité (40).
4. Système à fluide (10) selon la revendication 3, comprenant une première et une seconde conduites (42, 44) reliant respectivement lesdites première et seconde extrémités (38, 40) de la valve-de commande actionnée par un pilote (14) à la valve pilote de commande (32); dans lequel ledit second organe (50) comporte une valve résolutrice (52) disposée dans ladite seconde conduite (44), une troisième conduite (55) reliée à ladite valve à deux positions (56) et à ladite vàlve résolutrice (52), ladite valve résolutrice (52) étant conçue pour détecter la pression la plus élevée du fluide pilote sous pression dans les seconde et troisième conduites (44, 55), et pour transmettre la pression la plus élevée à la seconde extrémité (40).
5. Système à fluide (10) selon la revendication 4, dans lequel ledit organe (48) comprend une quatrième conduite (54) reliant la première extrémité (38) et la valve à deux positions (56), ladite valve à deux positions (56) étant apte à se déplacer entre une première position dans laquelle l'écoulement dudit fluide pilote sous pression provenant de ladite quatrième conduite (54) est bloquée en direction de ladite troisième conduite (55), et une seconde position dans laquelle l'écoulement de fluide sous pression est libre, ladite valve à deux positions (56) étant apte à se déplacer dans sa seconde position en réponse à l'obtention dudit niveau de pression prédéterminé par la pression du fluide dans ledit dispositif d'actionnement (18).
6. Système à fluide (10) selon la revendication 2, dans lequelle ladite valve à deux positions (66) est apte à se déplacer entre une première position dans laquelle ledit fluide pilote sous pression est dirigé vers la première extrémité (38), et une seconde position dans laquelle ledit fluide pilote sous pression voit sa communication avec ladite première extrémité (38) bloquée et ladite première extrémité (38) est mise en communication avec le réservoir (28), ladite valve à deux positions (66) étant apte à se déplacer dans la seconde position en réponse à l'obtention dudit niveau de pression prédéterminé par la pression du fluide dans ledit dispositif d'actionnement (18).
7. Système à fluide (10) selon la revendication 6, dans lequel ladite valve à deux positions (66) est montée entre la valve pilote de commande (32) et la première extrémité (38) de la valve de commande actionnée par un pilote (14).
EP19810901579 1980-12-24 1980-12-24 Systeme avec dispositif d'actionnement a force constante Expired EP0067815B1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1980/001741 WO1982002230A1 (fr) 1980-12-24 1980-12-24 Systeme avec dispositif d'actionnement a force constante

Publications (3)

Publication Number Publication Date
EP0067815A1 EP0067815A1 (fr) 1982-12-29
EP0067815A4 EP0067815A4 (fr) 1984-04-04
EP0067815B1 true EP0067815B1 (fr) 1986-04-02

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810901579 Expired EP0067815B1 (fr) 1980-12-24 1980-12-24 Systeme avec dispositif d'actionnement a force constante

Country Status (5)

Country Link
EP (1) EP0067815B1 (fr)
JP (1) JPH0118285B2 (fr)
BE (1) BE891227A (fr)
DE (1) DE3071525D1 (fr)
WO (1) WO1982002230A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5809862A (en) * 1995-08-04 1998-09-22 Dallman; Jimmie J. Flotation control system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2931389A (en) * 1956-04-18 1960-04-05 Moog Servocontrols Inc Servo valve producing output differential pressure independent of flow rate
DE1952034A1 (de) * 1969-10-15 1971-04-22 Linde Ag Steuereinrichtung fuer eine hydraulische Anlage und Ventil hierzu
US3799200A (en) * 1972-06-12 1974-03-26 Gardner Denver Co Flow and pressure regulating control for hydraulic motors
SE365486B (fr) * 1972-08-14 1974-03-25 Tico Ab
US4041983A (en) * 1975-07-09 1977-08-16 Caterpillar Tractor Co. Pressure controlled swing valve with safety feature

Also Published As

Publication number Publication date
JPS57502013A (fr) 1982-11-11
DE3071525D1 (en) 1986-05-07
EP0067815A4 (fr) 1984-04-04
JPH0118285B2 (fr) 1989-04-05
BE891227A (fr) 1982-03-16
EP0067815A1 (fr) 1982-12-29
WO1982002230A1 (fr) 1982-07-08

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