US3472125A - Hydraulic servo cylinder override - Google Patents

Hydraulic servo cylinder override Download PDF

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Publication number
US3472125A
US3472125A US679044A US3472125DA US3472125A US 3472125 A US3472125 A US 3472125A US 679044 A US679044 A US 679044A US 3472125D A US3472125D A US 3472125DA US 3472125 A US3472125 A US 3472125A
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United States
Prior art keywords
piston
cylinder
valve
pressure
hydraulic
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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 - Lifetime
Application number
US679044A
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English (en)
Inventor
Paul H Noble
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.)
Fellows Gear Shaper Co
Original Assignee
Fellows Gear Shaper Co
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Filing date
Publication date
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Publication of US3472125A publication Critical patent/US3472125A/en
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Expired - Lifetime 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
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • 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
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31505—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and a return line
    • F15B2211/31511—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and a return line having a single pressure source
    • 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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31523—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member
    • F15B2211/31529—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member having a single pressure source and a single 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41509—Flow control characterised by the connections of the flow 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
    • F15B2211/70—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
    • F15B2211/7055—Linear output members having more than two chambers
    • 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
    • F15B2211/765—Control of position or angle 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/895—Manual override

Definitions

  • a novel electro-hydraulic servo override mechanism is disclosed to mechanically override position signals for driving a piston to enable piston motion to be terminated in a predetermined position within its cylinder without shutting down the electrical command system by diverting the flow of fluid pressure.
  • the invention pertains to that art in which motive fluid is applied to opposite working member faces with the motive fluid being applied to or evacuated from one of said faces to cause the working member to move in one direction and being applied simultaneously to or evacuated simultaneously from bot-h of said faces to cause the working member to move in the opposite direction, wherein an hydraulic override system causes the motive fluid to be directed away from the working member causing its motion to cease.
  • the invention is a unique hydraulic override for an electro-hydraulic servo system. It provides for an outlet port and conduit means therefrom, positioned through the wall of the electro-hydraulically controlled piston cylinder wall. Said port may be opened by fluid pressure from within the cylinder when mechanical means in the conduit are open to allow the hydraulic uid which is driving the piston to pass through said port and conduit thus halting the pressured movement of the piston without affecting the normal operating characteristics of the servo System.
  • FIGURE l is a diagrammatic view, partly in section, of an electro-hydraulic servo mechanism with an override system according to the invention, schematically illustrated;
  • FIGURE 2 is a fragmentary diagrammatic view, partly in section, of a variation of the system shown in FIG- URE l.
  • FIGURE l 10 designates a piston assembly, generally comprising a piston 12 and a cylinder barrel 14.
  • a rod 16 connects the piston to any driving, stamping or like members (not shown) which are to be reoiprocated.
  • a member might be a platen in an injection molding machine, a milling machine table or any other mechanical element.
  • FIGURE 1 An illustration of such a control system is shown in FIGURE 1 to be comprised of a pump 20, hydraulic lines 22, 24, 26, 28 and 30, and a reservoir 31 which may connect with a recirculating system, or the like.
  • variable restrictor means 34 varies the pressure ratio between the end of piston 12 by alternately opening and closing a valve in line 30.
  • valve means 34 When valve means 34 is closed to prevent fluid passage through line 30, fluid ows through pipe 24 and 28 into an 'annular groove 36 in cylinder 14, to build pressure between piston 38 and the front cylinder wall 18.
  • An annular opening is helpful to even distribution of uid pressure across the entire surface of the piston head or rod end. Because the area on the piston head 38 is greater than that on the rod end 40 of the piston due to the space taken by the rod, the piston is d-riven toward the rod end of the cylinder. The uid behind the cylinder flows out through the rear annular groove 42 and pipe 26 and mixes with fluid in pipes 22 and 24.
  • valve means 34 opens, and because the restriction means 32 in pipe 24 hinders passage of fluid into pipes 28 or 30 and uid may flow freely from pipe 30 into reservoir 31 or the like. Fluid pressure in pipe 26 is therefore greater than that in pipe 28, and the piston is driven toward the front wall 18 of the cyilnder. The fluid between the head of the piston 38 and the front wall of the cylinder 18 escapes from the cylinder through pipe 28, mixing with the restricted fluid flow from pipe 24, and
  • FIGURE 1 these means are seen to be comprised of a port means 50 located in a predetermined position in the wall of the cylinder, said port means as illustrated is annular.
  • Means 52 connects the port means to a check valve assembly 54; an outlet port conduit 56 connects with a mechanical valve 58; two pipes 60 and 64 are shown leading from valve 58.
  • the pipe 60 leads to a reservoir 62, but could lead to a recirculating system, or the like. It will be well understood that alternate circuitry and mechanisms could be fashioned to accomplish the purposes of the invention.
  • Pipe 64 connects valve 58 with pump 20 so that liuid pressure from pump is exerted through pipe 64 equal to the pressure being exerted through pipe 22.
  • the pump 20 When the mechanical valve 58 is in its normal closed position, the pump 20 causes uid pressure to be directed through pipe 64, valve 58, pipe 56 and exerts said pressure on the downstream side of closed check value 54 with a force equal to or greater than the pressure of the ud being exerted from the inside of the cylinder 38 through the annulus 50 and connecting means 52.
  • the check valve '54 is shut tight and there is no loss of liuid pressure from within the cylinder to interfere with the uid drive of the piston.
  • the mechanical valve 58 is opened. This may be done manually or by remote control. The opening of this valve closes oi the pressure ow of the liquid from pipe ⁇ 64 through valve 58 into pipe S6 described above. At the same time, the opening of the valve 58 opens a conduit to enable uid to iiow from pipe 56 into reservoir 62 or the like. This ow of iluid from pipe 56 reduces the pressure upon the downstream side of closed check valve 54, and the uid pressure from within the cylinder forces the check valve open.
  • valve 58 With the valve in an open position, fluid from the cylinder ows out of the outlet port 50 thus causing a loss of pressure within the cylinder on one side of the piston and a large pressure differential is created between the rod end and the head end of the piston, depending on the position of the piston relative to the port 50 when the valve 58 is opened.
  • This outow of uid through the outlet port 50 may be referred to as dumping So that the whole process might be better understood, the steps will now be explained beginning with the piston at the rod end 44 of the cylinder barrel when valve 34 fails to open. In this position the rod 16 is fully extended. If the rod were connected to a stamping machine, it would be locked shut. To alleviate this condition, the mechanical valve 58 is opened.
  • the piston will begin to move toward wall 18 of the cylinder by fluid pressure from pump 20 being exerted through pipes 22 and 26, with pressure to pipe 28 being effectively diminished by the dumping of fluid out of port 50.
  • valve 58 This is accomplished by opening valve 58. Pressure from pump 20 through pipe 64 is cut oi, as previously explained, and the fluid ows from pipe 56 through valve 58 and as pressure downstream to the check valve is released, the valve will-open. As the piston moves forward, the fluid in front of the cylinder head 38 passes out of the port 50, pipe 56 and into reservoir 62 or a recirculating system, or the like.
  • valve means 34 were locked open and the valve 58 were not opened the piston would be forcefully driven to wall 18 and would sit there because the fluid pressure coming through pipe 26 would be greater than the Huid pressure passing through pipe 28.
  • the piston would be forcefully driven to wall 18 and would sit there because the fluid pressure coming through pipe 26 would be greater than the Huid pressure passing through pipe 28.
  • the invention as illustrated utilizes both a mechanical valve 58 and a check valve 54.
  • the purpose of the check valve is to allow the mechanical valve 58 to be positioned at a distance from the piston assembly 10 and port 50. Either the mechanical valve or the check valve should be positioned close to the port 50 so that when the mechanical valve is closed and no dumping is taking place, the pipe line connected to the outlet port conduit 50 is isolated near the outlet port. This reduces the total volume of oil under compression from the servo valve to a minimum. By keeping the total volume under compression at a minimum the natural resonant frequency of the servo system is kept as high as possible.
  • An electro-hydraulic servo system having a hydraulic override system comprising:
  • solenoid valve means for normally controlling the position of a piston within a cylinder by dictating flow of hydraulic uid to opposed sides of said piston in accordance with a programmed sequence
  • hydraulic override means for interrupting the programmed sequence of movements for said piston by dumping hydraulic fluid from one side of the piston through a port means which is positioned through a wall of said cylinder at an intermediate point which stops travel of said piston in a lirst direction of movement and which limits travel of said piston in a second direction of movement after it has been stopped from moving in said rst direction
  • said hydraulic override means including a valve means which can be actuated to release a ow of hydraulic uid through said port means when it is desired to override a programmed sequence of movements for said piston, whereby said piston can be stopped from its programmed sequence of travel at a point which is intermediate its programmed limits of travel
  • said port means comprising an annular groove formed within said cylinder wall with an outlet conduit in communication with the annular groove, and including a check valve in said outlet conduit intermediate the cylinder and said valve means, said check valve functioning to permit a one-way flow of hydraulic fluid out of said cylinder when said valve means is actuated to open
  • valve means is manually operated.
  • said means for maintaining said check valve closed comprises means for applying to the downstream side of the check valve a total pressure which is equal to or greater than iluid pressure in said cylinder on the port means side of said piston.
  • check valve is positioned in close proximity to the communication of said outlet conduit with said cylinder so as to effectively isolate said outlet conduit from the cylinder whereby iluid is maintained at a minimum and the natural resonant frequency of the system is kept as high as possible.
  • a hydraulic system for controlling the position of a reciprocating piston within a cylinder comprising:
  • a first hydraulic circuit for dictating reciprocating movements of said piston within said cylinder said rst hydraulic circuit having means for directing a flow of hydraulic iiuid to opposite sides of said piston in accordance with a programmed sequence of operation
  • a second hydraulic circuit for overriding the programmed operation of said rst hydraulic circuit by dumping hydraulic fluid from said cylinder, said second hydraulic circuit comprising:
  • valve means in said outlet conduit for opening and closing the outlet conduit to a reservoir
  • said valve means in said outlet conduit having two positions, a iirst position for opening said outlet conduit to a reservoir, and a second position for opening said outlet conduit to line pressure from said rst hydraulic circuit, whereby said second circuit can be used to override the operation of said iirst circuit by moving said valve means to its iirst position for dumping hydraulic Huid into said reservoir, and
  • a check valve means intermediate said valve means and the communication point of said outlet conduit with said cylinder for preventing a ow of hydraulic Huid hack into said cylinder through said outlet conduit.
  • said first hydraulic circuit includes solenoid valve means for dictating a program of reciprocating movements to said piston.

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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)
  • Fluid-Driven Valves (AREA)
  • Actuator (AREA)
US679044A 1967-10-30 1967-10-30 Hydraulic servo cylinder override Expired - Lifetime US3472125A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US67904467A 1967-10-30 1967-10-30

Publications (1)

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US3472125A true US3472125A (en) 1969-10-14

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US679044A Expired - Lifetime US3472125A (en) 1967-10-30 1967-10-30 Hydraulic servo cylinder override

Country Status (5)

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US (1) US3472125A (de)
AT (1) AT301080B (de)
DE (1) DE1804523B2 (de)
FR (1) FR1566949A (de)
GB (1) GB1203365A (de)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3789736A (en) * 1970-12-11 1974-02-05 Dowty Boulton Paul Ltd Multiple hydraulic actuator
US4119228A (en) * 1976-10-04 1978-10-10 J. I. Case Company Hydraulic circuit for hoisting fluid ram
DE3031779A1 (de) * 1980-08-21 1982-03-25 Joachim Ing.(grad.) 1000 Berlin Hammer Vorrichtung zum ausloesen einer funktion bei einer vorgegebenen position eines durch ein druckmittel getriebenen kolbens
US4765227A (en) * 1982-05-28 1988-08-23 Teledyne Hyson Die cylinder assembly
US4785712A (en) * 1986-05-27 1988-11-22 Mitsubishi Denki Kabushiki Kaisha Hydraulic operating apparatus for electric circuit breaker
US4976186A (en) * 1988-12-20 1990-12-11 Reliance Electric Company Control system for mechanically adjustable speed motor drives
US6138789A (en) * 1997-06-19 2000-10-31 Trw Fahrwerksysteme Gmbh & Co. Kg Hydraulic rack and pinion steering
US6408735B1 (en) * 1999-05-19 2002-06-25 Lucas Industries Limited Actuator
US20050050900A1 (en) * 2003-07-29 2005-03-10 Pratt & Whitney Canada Corp. Multi-position BOV actuator
US9545078B1 (en) * 2012-06-07 2017-01-17 Lely Patent N.V. Electro-hydraulical actuator for a robot arm
US20200003238A1 (en) * 2018-06-29 2020-01-02 Kti Hydraulics Inc. Power Units with Manual Override Controls for Hydraulic Systems

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1841629A (en) * 1928-03-27 1932-01-19 Cie Int Freins Automatiques Servo-motor
US2117595A (en) * 1936-07-11 1938-05-17 Gerhard H J Baule Control for fluid motors
US2675785A (en) * 1954-04-20 Power hydraulic remote-control
US2773484A (en) * 1952-12-27 1956-12-11 Allis Chalmers Mfg Co Pneumatically operated circuit breaker with closing valve cutoff switch
US2954755A (en) * 1957-10-23 1960-10-04 Ibm Hydraulic positioning device
US3002497A (en) * 1960-04-18 1961-10-03 Gen Electric Velocity limited fluid actuator with pressure reset

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2675785A (en) * 1954-04-20 Power hydraulic remote-control
US1841629A (en) * 1928-03-27 1932-01-19 Cie Int Freins Automatiques Servo-motor
US2117595A (en) * 1936-07-11 1938-05-17 Gerhard H J Baule Control for fluid motors
US2773484A (en) * 1952-12-27 1956-12-11 Allis Chalmers Mfg Co Pneumatically operated circuit breaker with closing valve cutoff switch
US2954755A (en) * 1957-10-23 1960-10-04 Ibm Hydraulic positioning device
US3002497A (en) * 1960-04-18 1961-10-03 Gen Electric Velocity limited fluid actuator with pressure reset

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3789736A (en) * 1970-12-11 1974-02-05 Dowty Boulton Paul Ltd Multiple hydraulic actuator
US4119228A (en) * 1976-10-04 1978-10-10 J. I. Case Company Hydraulic circuit for hoisting fluid ram
DE3031779A1 (de) * 1980-08-21 1982-03-25 Joachim Ing.(grad.) 1000 Berlin Hammer Vorrichtung zum ausloesen einer funktion bei einer vorgegebenen position eines durch ein druckmittel getriebenen kolbens
US4765227A (en) * 1982-05-28 1988-08-23 Teledyne Hyson Die cylinder assembly
US4785712A (en) * 1986-05-27 1988-11-22 Mitsubishi Denki Kabushiki Kaisha Hydraulic operating apparatus for electric circuit breaker
US4976186A (en) * 1988-12-20 1990-12-11 Reliance Electric Company Control system for mechanically adjustable speed motor drives
US6138789A (en) * 1997-06-19 2000-10-31 Trw Fahrwerksysteme Gmbh & Co. Kg Hydraulic rack and pinion steering
US6408735B1 (en) * 1999-05-19 2002-06-25 Lucas Industries Limited Actuator
US20050050900A1 (en) * 2003-07-29 2005-03-10 Pratt & Whitney Canada Corp. Multi-position BOV actuator
US7069728B2 (en) * 2003-07-29 2006-07-04 Pratt & Whitney Canada Corp. Multi-position BOV actuator
US9545078B1 (en) * 2012-06-07 2017-01-17 Lely Patent N.V. Electro-hydraulical actuator for a robot arm
US20200003238A1 (en) * 2018-06-29 2020-01-02 Kti Hydraulics Inc. Power Units with Manual Override Controls for Hydraulic Systems
US10760599B2 (en) * 2018-06-29 2020-09-01 Kti Hydraulics Inc. Power units with manual override controls for hydraulic systems

Also Published As

Publication number Publication date
AT301080B (de) 1972-08-25
FR1566949A (de) 1969-05-09
DE1804523B2 (de) 1972-01-13
DE1804523A1 (de) 1969-05-29
GB1203365A (en) 1970-08-26

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