US3752039A - Master-slave hydraulic control system - Google Patents

Master-slave hydraulic control system Download PDF

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Publication number
US3752039A
US3752039A US3752039DA US3752039A US 3752039 A US3752039 A US 3752039A US 3752039D A US3752039D A US 3752039DA US 3752039 A US3752039 A US 3752039A
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United States
Prior art keywords
piston
captive
sensing means
sensing
oil
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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
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English (en)
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T Hewins
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International Business Machines Corp
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International Business Machines Corp
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    • 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
    • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
    • F15B7/06—Details
    • F15B7/10—Compensation of the liquid content in a system
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8821—With simple rectilinear reciprocating motion only
    • Y10T83/8837—With application of force to opposite ends of tool supporting crosshead

Definitions

  • ABSTRACT A master-slave hydraulic control system is disclosed which provides an improved synchronization control together with the ability to rapidly change the stroking characteristics of the cylinders by removing and inserting a second control member into a mounting apparatus moved with themaster control piston. Further, the two pistons are continuously maintained in close synchronization and are not allowed to get out of synchronization by the accumulation of more than a slight quantity ofcaptive hydraulic fluid or oil.
  • the portion of the system on the opposite side of the driven piston from the captive oil is generally vented or valved into a reservoir or other low pressure holding means.
  • the pressure differential across the driven piston is generally considerably less than the pressure differential across the driving piston.
  • the captive oil supply will continue to increase, and when the captive oil supply increases sufficiently, this causes the two pistons to becme unsynchronized and additionally creates a situation after a sufficient length of time where the pistons stroke, in addition to being unsynchronized, also is relatively uncontrollable because the travel of the driven piston has been translated with respect to the travel of the driving piston and eventually will result in the driven piston reaching its physical end of travel and being unable to further respond to the pressure transmitted to it through the captive oil supply.
  • This can result in several problems, the most obvious one is that the tool or working mechanism attached to the driven piston is prevented from travelling through its normal required movement.
  • a second more destructive result will be either a rupture at a weak point in the system between the two pistons or the forcing of the captive oil past the pistons in such a way that it may damage either the cylinder walls or the pistons or seals associated therewith.
  • the system is capable of rapid change in the length of the strokes of the pistons by the removal and reinsertion of selective control members which act to control the stroke of the master and slave pistons.
  • An additional advantage of this system is accomplished by the use of magnetic sensing proximity switches to detect positions of travel, and thus avoid exposed electrical switches which can be exceedingly hazardous in explosive and unstable environments.
  • FIG. 1 is a line schematic diagram of the hydraulic equipment controls and hydraulic connections of the invention.
  • FIG. 2 is a schematic electrical diagram of the related control elements and circuitry.
  • FIG. 3 is a schematic of the electrically controlled directional valve.
  • FIG. 4 is a perspective view of the interchangeable control member together with the midpoint detector and related limit controls.
  • FIG. 5 is a perspective view of an electrical control element embodied in the interchangeable control member of FIG. 4, together with an illustration of the attaching of one limit dog to the interchangeable control member.
  • master cylinder and slave cylinder and piston as used in this application and claims are used to mean a cylinder or piston which controls another cylinder or piston and a controlled working cylinder or piston, regardless of which cylinder or piston is actually powered by pressurized hydraulic fluid from an external source.
  • magnetic as applied to the limit dogs or limits and describing material includes all materials ferrous and nonferrous which are attractable to a magnet.
  • the primary control of the system is influenced through the movement of the piston in master cylinder 10.
  • Master cylinder is fixed and provided with the necessary motive power to move its piston ill by pressure source 16.
  • Pressure source 16 is illustrated as a hydraulic pressure pump, however, it may be any convenient pressure source and could even be hydrostatic or pneumatic pressure. 7
  • Captive oil line 22 Connected to the captive oil side of piston 11 and cylinder 10 is captive oil line 22.
  • Captive oil line 22 provides a pressure route to the captive oil side of slave cylinder 12 and piston 13.
  • Piston 13 is connected by way of a piston rod to the working tool 14.
  • working tool 14 will be characterized as a drive motor and electrostatic painting disc, but may be any suitable tool for the job being performed.
  • cylinder 12 Opposite the captive oil side of piston 13 is a portion of cylinder 12 which may be either valved to the reservoir 20 or may be pressurized by the selective positioning of directional control valve 18.
  • the slave pressure line 17 is provided.
  • the slave pressure line 17 does not always have a positive pressure exerted upon it but may be periodically vented or valved.
  • Directional control valve 18 is either a unitary valve or a system of individual valves electrically controlled to accomplish the same purpose. The unitary valve could be such as one illustrated in FIG. 3 where the solenoids 74, 76 rotate the core 72 of valve 18.
  • Two paths 73 formed in core 72 provide continuity between the pressure line 19 and one of the cylinders, either the master 10 or slave l2, and at the same time provide continuity between the other of the cylinders and the drain line.
  • the other cylinder is relieved and allowed to drain back through directional valve 18 into the reservoir 20.
  • the oil trapped between piston 13 and piston 11 is, in theory, constant in volume.
  • high pressure hydraulic fluid from pressure source 16 forced into either cylinder 10 or cylinder 12 may be forced past the the seals on pistons 11 and 13.
  • the volume of the captive oil in line 22 and the two cylinders 10 and 12 will increase.
  • Other causes of increase in the captive oil supply can be an increase in temperature as the system is operated.
  • a relief line 25 or bleed return line 25 is connected to the captive oil line 22, and includes bleed valve 24.
  • the bleed return line 25 terminates with the reservoir 20.
  • the volume of the' captive oil in the cylinders 10, 12 and captive oil line 22 may be reduced at anytime by the opening of a bleed valve 24 inserted into bleed return line 25.
  • the reduction of the captive oil supply may be very finely controlled.
  • the relative positions of pistons 11 and 13 are finely controlled, and thus the operation of piston 11 within hydraulic cylinder 10 may be precisely translated into the appropriate positioning of piston 13 within cylinder 12.
  • Such a shroud 34 is mounted around the slave piston shaft connected to slave piston 13 and extending generally downward from the working tool M and enclosing at least a portion of the slave cylinder 12. This shroud will reciprocate together with the movement of piston 13.
  • a connecting rod or piston shaft is extended through the end portion of cylinder lit) and mounted thereon are extensions for holding control members.
  • a control member 42 which is interchangeable, is removably attached to the mounting bracket 63 and shaft extending from piston ll.
  • This control member 42 may be in many forms but is preferably in the form of a light weight, rigid, nonmagnetic material in the form of either a generally U-shaped channel or other convenient structural shape. This control member is suitable for removal and replacement with ease by releasing holding means or clip 45.
  • a member of a magnetic or ferrous material 28 which is hereafter referred to as the master dog 28.
  • a magnetic proximity sensing switch 26 Positioned rigidly at a point which is the midpoint of travel of one end of the master dog 28 is a magnetic proximity sensing switch 26. This switch 26 reacts when the magnetic material in master dog 28 comes into close proximity thereto.
  • Interchangeable control member 42 has positioned, at preselected locations thereon, two relatively small clampable pieces of magnetic material 38, 66. These two pieces may either be adjustably mounted or rigidly and fixedly mounted as desired. In FIG. l, these two magnetic pieces are designated as 38 for the up limit dog and 40 for the down limit dog. Mounted in a preselected fixed position in proximity to the paths of dogs 38, 40 is a magnetic activated sensing switch 36 of the double pole, double throw type. As one dog comes in proximity to the magnetic activated sensing switch 36, the switch is tripped in response to that dog and changes its state from a connection in one circuit to a connection in a second circuit and the process is reversed when the second dog approaches the sensing switch 36 from the opposite direction.
  • the schematic control diagram for the appropriate switches and controls, power is provided by power source 44.
  • power source 44 Connected in series with power source 44 is a double pole, double throw magnetic actuated proximity switch 36 which responds to one of two actuators 33, 60.
  • the ferrous actuated switches in the preferred embodiment have internal magnets which cause a change in switch positions in response to the proximity of the ferrous or magnetic material of the up and down limit dogs 33 and 60.
  • Branching from the terminals of the switch 36 and connected one side in parallel with each other is an up solenoid 74 and a down solenoid 76.
  • the up and down solenoids 76 and 76 are in turn connected back to the power source Branching from the down solenoid loop prior to down solenoid 76 and after double pole, double throw switch 36 is a parallel circuit extending to the power source M. In this parallel circuit and connected in series is proximity sensing switch 36 in turn connected to proximity sensing switch 26, which in turn is connected to solenoid bleed valve 26.
  • Proximity sensing switch 36 associated with the slave piston 13, is normally maintained in its open position when the magnetic dog 32 is not in proximity to sensing switch 30.
  • Magnetic actuated sensing switch 26 is normally maintained in a closed position during the time when the magnetic bar or dog 23 is not in proximity to switch 26.
  • Solenoid valve 26 is selected from the type which normally operates to open the valve only when there is a current flowing through the solenoid portion of the control mechanism.
  • control member 42 is provided in an interchangeable characteristic.
  • the interchangeable control member 62 is supported on one end and is shaped in a generally U-shaped channel. This provides a member which moves in synchronization with the piston ill of master cylinder lltl.
  • Mounted within the U of this interchangeable member are two adjustable blocks or pieces of magnetic material 36, ilt). The amount of movement of the piston M and thus the other related portions of the system is determined by the positioning of these blocks on control member 42, thru their action on switch 36 which controls directional control valve 113, as described earlier.
  • the control member may be titted with an electrical element 46 which, when properly positioned, alters a related electrical circuit. Examples would be a resistive or capacitive element for controlling the speed of the working motor lid it speed changes are necessitated by the change of stroke length. Other changes could be a reduction or increase in the pump speed to control paint flow. Other variables controllable by the above techniques would depend upon the system usage.
  • Hydraulic pump 16 or pressure source 16 is powered to continuously operate and thus provides pressure through the hydraulic fluid through lines 19 to control valve 18.
  • the hydraulic pressure is diverted from line 19 through pressure line 17 to the pressure face of piston 13 of slave cylinder 12.
  • control valve 18 is diverting the pressurized hydraulic flow from pump 16 to line 17, it is also providing a relief passage from line 23 through valve 18 to return line 21.
  • Return line 21 then terminates and dumps its return oil into reservoir 20.
  • piston 13 is forced up by the pressurized fluid in line 17, the capacity of cylinder 12 on the captive oil side of piston 13 is reduced and the hydraulic fluid or oil trapped in that portion of the cylinder is expressed through line 22 into the captive oil side of master piston 11 in cylinder 10.
  • piston 11 and piston 13 desirably move in synchronization, the point at which piston 13 reaches its midpoint should be the same point in time as when piston 11 reaches its midpoint of travel.
  • magnetic member 28 will no longer be in proximity to sensing switch 26 after piston 11 passes its midpoint in a downward stroke in response to the upward movement of piston 13.
  • the conditions described above with piston 13 moving up and piston 11 moving down will continue until such time as magnetic dog 38 comes in proximity to double-pole, double-throw proximity switch 36. At this point, the magnetic dog 38, approaching from the top of switch 36 will shift the state of switch 36 so that the down solenoid 76 activates directional valve 18.
  • long magnetic dog 32 has progressed downward to the point where it has caused proximity sensing switch 30 to sense its presence and close switch 30.
  • the long magnetic dog 32 has continued to progress until it has begun to overlap proximity switch 30, and at the point in time illustrated in FIG. 1, long magnetic dog 28 has just approached into activating proximity to sensing switch 26.
  • the solenoid valve 24 was initially energized when switch 30 closed and will remain open until magnetic dog 28 opens switch 26. Since line 25, connected between captive oil line 22 and the reservoir 20, is fairly small diameter line and only bleeds off a small quantity of oil as piston 11 continues to move upward, piston 13 will continue its downward movement not withstanding the fact that valve 24 has been opened.
  • Valve 24 thus bleeds off a portion of the captive oil supply. This condition is necessitated by the fact that high pressure oil is being forced past pistons 11 and 13 during their respective pressure strokes, and thus the captive oil supply in the captive oil portions of cylinders 10 and 12, together with captive oil line 22, continually increases. in this accumulative arrangement, the slave piston 13 will always tend to lead the master piston 11, and thus the bleeding can be controlled by valve 24 only on the downstroke of piston 13.
  • control member with the capacitive or resistive elements embodied therein may control the paint pump speed or any other electrically controllable variable which is necessary to accomplish the desired work result. Additional magnetic dogs can be added (fixed) to the side of control member 42 to act on other switches, thereby controlling still other functions.
  • a master-slave hydraulic, reversible system comprising:
  • a slave cylinder having a piston
  • a master cylinder having a piston
  • a first position sensing means for sensing the position of said slave cylinder piston and providing an output
  • a second position sensing means for sensing the position of said master cylinder piston and providing an output
  • a captive volume pressure medium relief means responsively controlled by the outputs of said sensing means to automatically synchronize the movemets of said pistons during the operation of said system.
  • said stroke length control means further comprising a sensing means
  • said sensing means operatively connected to a means for reversing the stroke of said pistons within said cylinders.
  • limit defining means further comprises a preselected electrical component for altering the operating characteristics of related and associated electrical circuits.

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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)
  • Servomotors (AREA)
  • Actuator (AREA)
US3752039D 1971-12-22 1971-12-22 Master-slave hydraulic control system Expired - Lifetime US3752039A (en)

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US21087371A 1971-12-22 1971-12-22

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US3752039A true US3752039A (en) 1973-08-14

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US3752039D Expired - Lifetime US3752039A (en) 1971-12-22 1971-12-22 Master-slave hydraulic control system

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US (1) US3752039A (de)
JP (1) JPS5411875B2 (de)
DE (1) DE2257625A1 (de)
FR (1) FR2164637B1 (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4310172A (en) * 1979-04-23 1982-01-12 General Motors Corporation Position control system
US4398704A (en) * 1979-07-16 1983-08-16 General Motors Corporation Vehicle pneumatic suspension system with dead band adjustment
US4478129A (en) * 1980-04-15 1984-10-23 Zimmermann & Jansen Gmbh Apparatus for the exact position feedback of a double-acting power piston in a hydraulic power cylinder
US4765509A (en) * 1986-10-02 1988-08-23 Adhesive Engineering Company Pumping system
US6029450A (en) * 1997-12-10 2000-02-29 Hyco Pacoma Gmbh Hydraulic synchronizing circuit
US20040164611A1 (en) * 2003-02-21 2004-08-26 Olivier Masson Motor vehicle master cylinder with device for detecting actuation of a braking system
US20050275366A1 (en) * 2004-06-10 2005-12-15 Moteurs Leroy-Somer Devices and methods for updating the programming of a system for controlling an electric rotary machine
US20190226465A1 (en) * 2018-01-20 2019-07-25 William E. Howseman, Jr. Hydraulically synchronized pumps where the hydraulic motor of the master pump hydraulically drives the hydraulic motor of the slave pump
US20200095785A1 (en) * 2016-12-23 2020-03-26 Peri Gmbh Climbing device having a climbing rail

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR998681A (fr) * 1949-10-03 1952-01-22 Dispositif permettant de commander en synchronisme plusieurs cylindres dans lesquelsagit un fluide moteur
GB724273A (en) * 1951-06-19 1955-02-16 Power Jacks Ltd Improvements in or relating to hydraulic jacking systems
FR1090376A (fr) * 1953-12-31 1955-03-30 Const Savoisiennes De Machines Dispositif d'équilibrage pour plusieurs vérins hydrauliques
FR1137783A (fr) * 1955-09-08 1957-06-04 Boutillon Freres Ets Machine-outil à commande hydraulique pour le travail des métaux en feuille
US3181407A (en) * 1963-08-05 1965-05-04 Pacific Ind Mfg Co Shear machine with adjustable ram having means to immobilize said machine during adjustment
US3476016A (en) * 1967-10-20 1969-11-04 Cascade Corp Apparatus for producing coordinated,simultaneous actuation of multiple rams

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4310172A (en) * 1979-04-23 1982-01-12 General Motors Corporation Position control system
US4398704A (en) * 1979-07-16 1983-08-16 General Motors Corporation Vehicle pneumatic suspension system with dead band adjustment
US4478129A (en) * 1980-04-15 1984-10-23 Zimmermann & Jansen Gmbh Apparatus for the exact position feedback of a double-acting power piston in a hydraulic power cylinder
US4572054A (en) * 1980-04-15 1986-02-25 Zimmermann & Jansen Gmbh Exact position feedback of double-acting power piston in hydraulic cylinders
US4765509A (en) * 1986-10-02 1988-08-23 Adhesive Engineering Company Pumping system
US6029450A (en) * 1997-12-10 2000-02-29 Hyco Pacoma Gmbh Hydraulic synchronizing circuit
US20040164611A1 (en) * 2003-02-21 2004-08-26 Olivier Masson Motor vehicle master cylinder with device for detecting actuation of a braking system
US7018002B2 (en) * 2003-02-21 2006-03-28 Robert Bosch Gmbh Motor vehicle master cylinder with device for detecting actuation of a braking system
US20050275366A1 (en) * 2004-06-10 2005-12-15 Moteurs Leroy-Somer Devices and methods for updating the programming of a system for controlling an electric rotary machine
US7460918B2 (en) * 2004-06-10 2008-12-02 Moteurs Leroy-Somer Devices and methods for updating the programming of a system for controlling an electric rotary machine
US20200095785A1 (en) * 2016-12-23 2020-03-26 Peri Gmbh Climbing device having a climbing rail
US11987998B2 (en) * 2016-12-23 2024-05-21 Peri Se Climbing device having a climbing rail
US20190226465A1 (en) * 2018-01-20 2019-07-25 William E. Howseman, Jr. Hydraulically synchronized pumps where the hydraulic motor of the master pump hydraulically drives the hydraulic motor of the slave pump
US11143173B2 (en) * 2018-01-20 2021-10-12 William E. Howseman, Jr. Hydraulically synchronized pumps where the hydraulic motor of the master pump hydraulically drives the hydraulic motor of the slave pump

Also Published As

Publication number Publication date
DE2257625A1 (de) 1973-06-28
FR2164637A1 (de) 1973-08-03
JPS5411875B2 (de) 1979-05-18
FR2164637B1 (de) 1974-11-08
JPS4868976A (de) 1973-09-19

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