GB2235729A - Control valve apparatus - Google Patents

Control valve apparatus Download PDF

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Publication number
GB2235729A
GB2235729A GB9013576A GB9013576A GB2235729A GB 2235729 A GB2235729 A GB 2235729A GB 9013576 A GB9013576 A GB 9013576A GB 9013576 A GB9013576 A GB 9013576A GB 2235729 A GB2235729 A GB 2235729A
Authority
GB
United Kingdom
Prior art keywords
control
pump
valve
block
pumps
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.)
Granted
Application number
GB9013576A
Other versions
GB2235729B (en
GB9013576D0 (en
Inventor
Joerg Gruenert
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.)
Bosch Rexroth AG
Original Assignee
Mannesmann Rexroth AG
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 Mannesmann Rexroth AG filed Critical Mannesmann Rexroth AG
Publication of GB9013576D0 publication Critical patent/GB9013576D0/en
Publication of GB2235729A publication Critical patent/GB2235729A/en
Application granted granted Critical
Publication of GB2235729B publication Critical patent/GB2235729B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2253—Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/002—Hydraulic systems to change the pump delivery
    • 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
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/44—Control of exclusively fluid gearing hydrostatic with more than one pump or motor in operation
    • F16H61/448—Control circuits for tandem pumps or motors
    • 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
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • 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
    • F15B2211/20576—Systems with pumps with multiple pumps
    • 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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/355—Pilot pressure control
    • 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/65—Methods of control of the load sensing pressure
    • 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
    • F15B2211/67—Methods for controlling pilot pressure
    • 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
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

In a control valve apparatus consisting of two control blocks (1, 2), with pump control for a plurality of hydraulic drives, particularly for mobile equipment, hydraulically actuable control slide valves (10-12) are activated proportionally by means of respective control devices (6) which control the supply of the hydraulic actuating fluid. The adjustable output pumps (P1, P2) are activated proportionally at the same time by the highest control pressure at the time, via two way valve series (3). By means of the proportionally actuable control slide valves (10-12) it is possible to operate the drives of the control block (1) simultaneously, according to their load, even in a proportional pump control arrangement. <IMAGE>

Description

55-466.517 CONTROL VALVE APPARATUS The invention relates to a control
valve apparatus, consisting of two control blocks with pump control for a plurality of hydraulic drives, particularly, but not exclusively, for mobile equipment.
In known control valve apparatus the control slide valves are switched through the pump adjustment means. The pump only begins to operate when the control slide valves have reached their switching positions. The control of the quantity, i.e. the fine control, is taken over by the pump. The pump regulation is carried out proportionally, in accordance with the rated value prescribed by the control devices. In this way, the speed is controlled independently of the load in the drive of a control block. The control slide valves are 6-way control valves which determine only the direction of movement of the drives. Unlike a known throttle control construction, the sliding pistons are switched to their end positions without any fine control phase (directional control). The control pressure of the control devices acts on the pistons of the control slide valves and at the same time on the pump regulator. In this known control valve apparatus, however, only one drive can be effectively controlled in a control block. If a plurality of drives are controlled simultaneously, only the one with the smallest load will move, whilst the others with the higher load will remain in their starting positions.
The aim of the invention is to improve the known control valve apparatus so that a plurality of drives of at least one control block can be effectively driven simultaneously. According to a first aspect of the invention there is provided control valve apparatus comprising two control blocks, with pump control for a plurality of hydraulic drives, each control block having an associated quantity- controlled pump, at least one drive associated with a control block being adapted to be acted upon by pressure medium from both pumps.and each control block having a parallel channel connected to the pump and serving solely for parallel operation of the pumps, a connecting line of the control block associated with the pump which is to be operated being connected to the pressure line of the other pump via a non-return valve, each drive having an associated control slide valve in the control valve apparatus, said slide valve being hydraulically actuable by a control is device and having, in addition to two switching positions which act on the associated drive in opposite directions, a third switching position for parallel operation of the pumps for one or more drives of a control block, wherein two or more of the control slide valves of at least one control block are proportionally actuable and, upon being actuated, the parallel channel of the control block in question is connected to the tank after the proportionally actuable control slide valves and the maximum control pressure for proportional adjustment of the control slide valves also forms the control pressure for the regulation of the pump.
According to a second aspect of the invention there is provided control valve apparatus comprising two control blocks for operating a plurality of hydraulic drives, each block having an associated pump, with at least one drive associated with one of the control blocks capable of being operated by both pumps, said control blocks having drive associated with one of the control blocks having respective connections to their associated pumps for parallel operation of the pumps, each of the drives having an associated valve in the control apparatus which can be moved to a position for parallel operation of the pumps for one or more drives of a control block, and wherein two or more valves of at least one control block are actuable proportionally and upon such actuation, the connection of the associated control block to its pump is connected to the hydraulic reservoir of the apparatus. and the control pressure for proportional control of the valves also regulates the associated pump.
By using proportionally actuable control slide valves and connecting the parallel channel, which is connected in known manner to the pump input of the other controlled block, to the tank, it is possible to achieve affective proportional throttle control of a plurality of drives simultaneously under different loads.
An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing.
In the drawing, reference 1 denotes a control block which is connected to the input of a control block 2 via a "parallel" channel 20, a directional valve 4, a connecting line 25 and a non-return valve 24. The control block 2 is connected to the input of the control block 1 via a "paralleV' channel 21, a connecting line 22 and a non-return valve 23. The pump P1 normally supplies the control block 1 with working fluid whilst the pump P2 supplies the control block 2 with working fluid. The hydraulic control pressure is directly connected to the associated control chambers of the control slide valves 10, 11, 12, 13 by the transmitter devices 6 via directional valves 7 in order to limit the load and via control lines 30-37. The maximum control pressure of each control block, set on the control devices 6, is connected to the pump adjusting means 27 and 26 via a two-way valve series 3.
The two control lines "rotary mechanism right" 38 and "rotary mechanism left" 39 on the control device 6 lead to a control block (not shown) for a rotary mechanism of a mobile apparatus.
When the drives are selected on the control devices 6, control pressure is transmitted through the switch directional valves 7 and through the control lines 30-37 to the control slide valves 10, 11, 12 in the control block and at the same time through the two-way valve series 3 at the connection X2 to the directional valve 4. The directional valves 7 are connected into the control lines between the transmission equipment 6 and control slide valves 10-12 in order to limit the load. If the maximum load set on the drive equipment is exceeded, the electrical overload safety device causes the directional valves 7 to drop back into the resting position shown and remove the load from the control line leading to the tank. As a result, in cases of overload, the drive in question cannot be operated. When a drive is selected in the control block 1 the directional valve 4 switches the existing connection between the parallel channel 20 and the control block 2 to the tank. The connecting line 25 is now free from pressure, so that it is no longer possible to operate the two pumps P1 and P2 for control block 2 in parallel. The working fluid of pump P1 is thus available only to the drives which are actuated by the control block 1. The same control pressure, which actuates the directional valve 4 by means of the two-way valve series 3, also actuates the pump adjustment means or regulator 27 for pump Pl. As a result of the unloading of the parallel channel 20 to the tank, specific conditions are created at the control sides of the control slide valves 10, 11, 12, so as to prevent the pumping pressure from 5W k 1. 5 feeding back through the non-return valve 24, the parallel channel 21 in the control block 2, the connecting line 22 and the non-return valve 23. This enables satisfactory proportional operation of the control slide valves without any opposing pressure in the pump P1 and also enables parallel operation of all the drives of the control block 1.
The control slide valves 10, 11, 12 are operated by the control devices 6 proportionally and in advance of the proportional pumping regulation. If only one drive is actuated, the speed is regulated, independently of load, directly by the pump regulation. For parallel operation of the drives in the control block 1, the drive with the highest control pressure, which is selected by means of the two-way valve series 3 takes over the control of the pumping. The drives selected share the pumped flow in accordance with their prescribed rated performances as in the case of a throttle control. Fine control is taken over as a whole by the pump control, whilst the proportionally actuated control slide valves distribute the working fluid in accordance with the conditions of load. The drives are then operated in accordance with load. In this case the operator has to convert from a mode of operation independent of load (1 drive) to a mode of operation dependent on load.
The spring force in the direction valve 4 which counteracts the control pressure is less than the control force of the control slide valves 10, 11, 12 and this is in turn less than the control force of the pump adjustment means 25. Since all the equipment is operated with the same control pressure, the time sequence which first of all switches on the directional valve 4 and then causes the control slide valves 10, 11, 12 to open proportionally and then operates the pump P1 accordingly is established. The switching and control forces are adjusted by means of mechanical springs.
The pressure limiting valves 9 are provided at the entrance to each control block and serve to break down any excess pressure in the pumps P1 or P2 leading to the tank.
1 1

Claims (9)

1. Control valve apparatus comprising two control blocks, with pump control for a plurality of hydraulic drives, each control block having an associated quantity-controlled pump, at least one drive associated with a control block being adapted to be acted upon by pressure medium from both pumps, and each control block having a parallel channel connected to the pump and serving solely for parallel operation of the pumps, a connecting line of the control block associated with the pump which is to be operated being connected to the pressure line of the other pump via a non- return valve, each drive having an associated control slide valve in the control valve apparatus, said slide valve being hydraulically actuable by a control device and having, in addition to two switching positions which act on the associated drive in opposite directions, a third switching position for parallel operation of the pumps for one or more drives of a control block, wherein two or more of the control slide valves of at least one control block are proportionally actuable and, upon being actuated, the parallel channel of the control block in question is connected to the tank after the proportionally actuable control slide valves and the maximum control pressure for proportional adjustment of the control slide valves also forms the control pressure for the regulation of the pump.
2. Control valve apparatus as claimed in claim 1, wherein said channel is connected to the tank via a directional valve.
3. Control valve apparatus as claimed in claim 2, wherein the directional valve can be hydraulically actuated by the control pressure of control devices for the control slide valves.
4. Control valve apparatus as claimed in claim 2 or 3, wherein the directional valve is actuated by the same control pressure as is used to control the quantity delivered by the pump in question
5. Control valve apparatus as claimed in any preceeding claim, wherein the control slide valves acting in advance can be actuated proportionally to the regulation of the pump.
6. Control valve apparatus as claimed in any of claims 2 to 5 wherein the switching force of the directional valve counteracting the control pressure, is less than the control force of the control slide valves and the latter is in turn less than the control force of the pump regulator.
7. Control valve apparatus according to claim 6, characterising that the switching and control forces are applied by mechanical springs.
8. Control valve apparatus comprising two control blocks for operating a plurality of hydraulic drives, each block having an associated pump, with at least one drive associated with one of the control blocks capable of being operated by both pumps, said control blocks having respective connections to their associated pumps for parallel operation of the pumps, each of the drives having an associated valve in the control apparatus which can be moved to a position for parallel operation of the pumps for one or more drives of a control block, and wherein two or more valves of at least one control block are actuable proportionally and upon such actuation, the connection of the associated control block to its pump is connected to the hydraulic 1 - 9 reservoir of the apparatus, and the control pressure for proportional control of the valves also regulates the associated pump.
9. Apparatus substantially as hereinbefore described with reference to the accompanying drawing.
Published 1991 atMe Patent Office. State House. 66/71 High Holborn. London WC I R41?. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Pbtnt Cwmlclinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray, Kent.
GB9013576A 1989-06-16 1990-06-18 Control valve apparatus Expired - Fee Related GB2235729B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19893919640 DE3919640C2 (en) 1989-06-16 1989-06-16 Control valve device with two control blocks and pump control for several hydraulic drives

Publications (3)

Publication Number Publication Date
GB9013576D0 GB9013576D0 (en) 1990-08-08
GB2235729A true GB2235729A (en) 1991-03-13
GB2235729B GB2235729B (en) 1993-12-08

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ID=6382837

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9013576A Expired - Fee Related GB2235729B (en) 1989-06-16 1990-06-18 Control valve apparatus

Country Status (2)

Country Link
DE (1) DE3919640C2 (en)
GB (1) GB2235729B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9931648B2 (en) 2006-09-15 2018-04-03 Tyco Fire & Security Gmbh Mist generating apparatus and method
IT202100012032A1 (en) * 2021-05-11 2022-11-11 Cnh Ind Italia Spa IMPROVED MANIFOLD FOR SELECTOR VALVES, HYDRAULIC ARRANGEMENT AND WORK VEHICLE COMPRISING SAME

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19630798A1 (en) * 1996-06-22 1998-01-02 Rexroth Mannesmann Gmbh Pilot control for two hydraulically operated directional valves
DE19652922C2 (en) * 1996-12-19 1999-07-29 O & K Mining Gmbh Hydraulic circuit for a hydraulic excavator
US5940997A (en) * 1997-09-05 1999-08-24 Hitachi Construction Machinery Co., Ltd. Hydraulic circuit system for hydraulic working machine
DE19932326A1 (en) 1999-07-10 2001-01-11 Mannesmann Rexroth Ag Valve arrangement for pilot control of a first and a second hydraulically actuated directional valve

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1952034A1 (en) * 1969-10-15 1971-04-22 Linde Ag Control device for a hydraulic system and valve for this
DE2440251A1 (en) * 1974-08-22 1976-03-04 Linde Ag Control system combining output of two pumps - combined output distributed to all users
US4210061A (en) * 1976-12-02 1980-07-01 Caterpillar Tractor Co. Three-circuit fluid system having controlled fluid combining
DE3007787A1 (en) * 1980-02-29 1981-09-17 Linde Ag, 6200 Wiesbaden Control unit with slide valve - has second flow channel with throttle and sealing valve, with connected actuators
DE3321240A1 (en) * 1983-06-11 1984-12-13 Robert Bosch Gmbh, 7000 Stuttgart Hydraulic unit with at least two pumps
DE3508339A1 (en) * 1985-03-08 1986-09-11 Mannesmann Rexroth GmbH, 8770 Lohr Control valve arrangement, consisting of two control blocks, for several hydraulic drives, in particular of mobile appliances
DE3546336A1 (en) * 1985-12-30 1987-07-02 Rexroth Mannesmann Gmbh CONTROL ARRANGEMENT FOR AT LEAST TWO HYDRAULIC CONSUMERS SUPPLIED BY AT LEAST ONE PUMP
US4788820A (en) * 1987-05-15 1988-12-06 Kabushiki Kaisha Kobe Seiko Sho Hydraulic circuit for large crane

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9931648B2 (en) 2006-09-15 2018-04-03 Tyco Fire & Security Gmbh Mist generating apparatus and method
IT202100012032A1 (en) * 2021-05-11 2022-11-11 Cnh Ind Italia Spa IMPROVED MANIFOLD FOR SELECTOR VALVES, HYDRAULIC ARRANGEMENT AND WORK VEHICLE COMPRISING SAME

Also Published As

Publication number Publication date
DE3919640C2 (en) 1996-10-02
GB2235729B (en) 1993-12-08
GB9013576D0 (en) 1990-08-08
DE3919640A1 (en) 1990-12-20

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Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19960618