WO1984003543A1 - Systeme de commande d'instrument actionne par pilote - Google Patents

Systeme de commande d'instrument actionne par pilote Download PDF

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Publication number
WO1984003543A1
WO1984003543A1 PCT/US1983/000700 US8300700W WO8403543A1 WO 1984003543 A1 WO1984003543 A1 WO 1984003543A1 US 8300700 W US8300700 W US 8300700W WO 8403543 A1 WO8403543 A1 WO 8403543A1
Authority
WO
WIPO (PCT)
Prior art keywords
pilot
valve
operated control
pilot operated
valves
Prior art date
Application number
PCT/US1983/000700
Other languages
English (en)
Inventor
Jesse L Field Jr
Original Assignee
Towmotor Corp
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 Towmotor Corp filed Critical Towmotor Corp
Publication of WO1984003543A1 publication Critical patent/WO1984003543A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems
    • 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
    • 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
    • E02F9/2278—Hydraulic circuits
    • E02F9/2285—Pilot-operated systems
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks

Definitions

  • This invention relates to a pilot operated control system and more particularly to a pilot operated control system having first and second pilot valves and a pilot operated control valve actuatable to first and second fluid directing positions in response to either of the first and second pilot valves being at a respective first and a second pilot position.
  • Pilot operated control systems have frequently been ⁇ sed in controlling fluid powered implements, such as used on material handling and earthmoving equipment and the like.
  • these pilot operated control systems require a pilot valve and a pilot operated control valve for each implement function. This, however, is expensive, requires a significant amount of space, requires a control lever for actuating each pilot valve and requires a large number of conduits.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a pilot operated control system is provided which
  • OMPI includes a first pilot valve, a second pilot valve and a pilot operated control valve.
  • the first and second pilot valves are each connected to and in fluid communication with the pilot operated control valve and the first and second pilot valves and the pilot operated control valve are each actuatable between first and second fluid directing positions.
  • the pilot operated control valve is actuatable to the first fluid directing position in response to either of the first and second pilot valves being at the first fluid directing position and actuatable to the second fluid directing position in response to either of the first and second pilot valves being at the second fluid directing position.
  • a pilot operated control system for a lift mast assembly having first and second pumps, a pilot operated control valve and an extensible hydraulic jack is provided.
  • the pilot operated control valve is connected to the second pump and the hydraulic jack and actuatable between a first position, at which hydraulic fluid is directed from the second pump to extend the hydraulic jack, and a second position, at which hydraulic flow is directed from said second pump to retract said hydraulic jack.
  • a first pilot valve is connected to the first pump and the pilot operated control valve and actuatable between a first position, at which hydraulic fluid is directed from the first pump to the pilot operated control valve to actuate the pilot operated control valve to the first position thereof, and a second position, at which hydraulic fluid is directed from the first pump to the pilot operated control valve to actuate the pilot operated control valve to the second position thereof.
  • a second pilot valve is connected to the first pump and the pilot operated
  • OMPI control valve and actuatable between a first position, at which hydraulic fluid is directed from the first pump to the pilot operated control valve to actuate the pilot operated control to the first position thereof, and a second position, at which hydraulic fluid is directed from the first pump to the pilot operated control valve to actuate the pilot operated control valve to the second position thereof.
  • a first pressure responsive shuttle valve is connected to and between the first and second pilot valves and the pilot operated control valve. The first shuttle valve is responsive to pressurized hydraulic fluid flow passed by the first and second pilot valves, at the first position thereof, to prevent hydraulic fluid flow from passing between the first and second pilot valves.
  • a second pressure responsive shuttle valve is connected to and between the first and second pilot valves and the pilot operated control valve. The second shuttle valve is responsive to pressurized hydraulic fluid flow passed by the first and second pilot valves, at the second position thereof, to prevent hydraulic fluid flow from passing between the first and second pilot valves.
  • the pilot operated control system eliminates the previously required plurality of pilot operated control valves, maintains good to excellent fluid flow modulation by utilizing pilot valves and a pilot operated control valve, permits actuation of a single pilot operated control valve to at least two fluid directing positions by a plurality of pilot valves, eliminates the need for more than two fluid motor conduits, offers excellent operator control by limiting the number of switches for actuating the solenoid valves to two on each control lever, reduces the space required to mount the pilot operated control valve and reduces the overall cost of the system.
  • pilot operated control system of the subject invention is also useful in applications wherein a single pilot operated control valve is controllably responsive to a pair of pilot valves located at two remote or separate locations to direct fluid flow in at least two directions to actuate a double acting fluid operated motor in two directions.
  • Fig. 1 is a diagrammatic side elevational view of an embodiment of the present invention showing a lift truck having a lift mast assembly mounted thereon and the pilot operated control system for controlling the mast assembly connected thereto;
  • Fig. 2 is a diagrammatic front elevational view of Fig. 1 showing the lift mast and associated fluid operated motors of the pilot operated control system in greater detail;
  • Fig. 3 depicts schematically the pilot operated control system of Fig. 1 in which first and second pilot valves are each connected to actuate a pilot operated control valve between first and second fluid directing positions.
  • a pilot operated control system 10 for controlling the position of an implement 12, such as a lift mast assembly 14 of a vehicle such as a lift truck 16 is shown.
  • the lift mast assembly 14 has at least a pair of spaced apart uprights 18, a carriage assembly 20 and a container handling assembly 22.
  • the carriage assembly assembly 20 has a guide frame 24 mounted on the spaced apart uprights 18 and a lift jack 26 connected thereto for elevationally moving the guide frame 24 along the uprights 18.
  • the carriage assembly 20 also has a support frame 28 movably mounted on the guide frame 24 and a side shift jack 30 connected to the support frame 28 and the guide frame 24 for shifting the support frame 28 along the guide frame 24, transversely of the uprights 18 and sideways relative to the lift truck 16.
  • the support frame 28 includes an upper frame portion 32 to which the container handling assembly 22 is connected.
  • a plurality of telescopic suspension link members 34 connect the container handling assembly 22 to the upper frame portion 32. This permits a limited amount of movement of the container handling assembly 22 relative to the support frame 28 for positioning the container handling assembly 22 on a container (not shown) to be lifted.
  • a pair of extension jacks 36 are connected to an extensible frame 38 of the container handling assembly 22 to extend and retract the extensible frame to accommodate different sized containers.
  • a pair of slewing cylinders 40 are connected to the support frame and the extensible frame 38 of the container handling assembly 22 to slew the container handling assembly 22 relative to the lift truck 16 and the upper frame portion 32 and thereby align the container handling assembly 22 and the extensible frame 38 thereof for engagement with the container to be lifted.
  • a plurality of twist locks 42 are provided, one at each corner of the extensible frame 38, for selectively connecting the container handling assembly to the container to be lifted.
  • Each twist lock 42 is powered by a twist lock jack 44 associated therewith for rotating the twist lock between locking and unlocking positions with respect to the container to be lifted.
  • the lift mast assembly 14 is preferably pivotally mounted at a lower end portion thereof to the lift truck 16.
  • a pair of tilt jacks 46 are provided for tilting the lift mast assembly 14 in directions towards and away from the lift truck 16.
  • the pilot operated control system 10 is suitable for controlling all or predetermined ones of the jacks 26,30,36,40,44 heretofore described.
  • the pilot operated control system 10 has first and second pilot valves 48,50, a pilot operated control valve 52 and a plurality of selector valves 54.
  • the number of selector valves provided is in part determined by the number of jacks and implement functions to be controlled.
  • The- pilot valves 48,50 are preferably mounted on the lift truck 16 at a location thereon convenient for operator control, and the pilot operated control valve 52 is located on the lift truck 16 at another location spaced from the pilot valves 48,52.
  • the selector valves 54 are preferably mounted on the implemen (s) to be controlled or at a location in close proximity thereto. In the embodiment shown in Fig. 1, the selector valves are mounted on the support frame 28 of the carriage assembly 20. The importance of the locations of valves 48, 50 and 52 will become apparent during subsequent discussion.
  • the first and second pilot valves 48,50 are manually actuatable, 3 position, infinitely variable valves each having a spool 70 shiftable between first and second fluid directing positions 56 and 58 from a neutral position 60.
  • Each of the pilot valves 48,50 have first and second ports 62,64, an inlet port 66 and a reservoir port 68.
  • Each pilot valve spool 70 is normally biased to the neutral position 60 via a pair of centering springs 72.
  • first source of pressurized fluid flow 74 such as a hydraulic pump, is connected to the inlet port 66 of the pilot valves 48 and 50 by conduit 76 which supplies pressurized fluid flow to the pilot valves.
  • a reservoir conduit 78 connects the reservoir port 68 of each pilot valve 48 and 50 to a reservoir 80 and passes fluid flow therebetween.
  • pressurized fluid flow from the first source is blocked at the pilot valves 48 and 50 and the first and second ports 62 and 64 thereof are in communication with tank.
  • the pressurized fluid flow delivered from the first source 74 is passed by the spools from the inlet port 66 to the first port 62 and the second port 64 is in communication with the reservoir port 68.
  • pressurized fluid flow delivered from the first source 74 is passed by the spools from the inlet port 66 to the second port 64 and the first port 62 is in communication with the reservoir port 68.
  • pilot operated control valve 52 which is infinitely variable, has a valve spool 84 which is shiftable between a first fluid directing position 86 and a second fluid directing position 88 from a neutral position 90.
  • the control valve 52 has first and second signal ports 92 and 94, an inlet port 96, first and second control ports 98 and 100 and a reservoir port 102.
  • Valve spool 84 is normally biased to the neutral position 90 via a pair of centering springs 104 and shiftable to the first and second fluid directing positions 86 and 88 in response to fluid pressure being applied to the valve spool 84 at ports 92 and 94.
  • a second source 106 of pressurized fluid flow such as a hydraulic pump, is connected by a conduit 108 to the inlet port 96 of the pilot operated control valve 52 and the reservoir port 102 is connected to the reservoir 80 via conduit 110.
  • the inlet port 96 and reservoir port 102 are in fluid communication with one another and the first and second control ports 98 and 100 are blocked.
  • valve spool 84 At the first position 86 of the valve spool 84, fluid is passed by valve spool 84 from the second source 106 to the first control port 98 and the reservoir port 102 is in fluid communication with the second control port 100.
  • the inlet port 96 At the second position 88 of the valve spool 84, the inlet port 96 is in fluid communication with the second control port 100 and the first control port 98 is in fluid communication with the reservoir port 102.
  • a first shuttle valve 112 having a pair of. inlet passages 114 and 116 and an outlet passage 118, is provided to tee the first port 62 of the first and second pilot valves 48 and 50 to the first signal port 92 of the control valve 52.
  • a second shuttle valve 120 having a pair of inlet passages 122 and 124 and an outlet passage 126 is provided to tee the second port 64 of the first and second pilot valves 48 and 50 to the second signal port 94 of the control valve 52.
  • first shuttle valve 112 has a ball check 127 operatively associated with the pair of inlet passages 114 and 116 and a pair of seats 131 associated therewith and the second shuttle valve 120 has a ball check 129 operatively associated with the pair of inlet passages 122 and 124 and a pair of seats 133 associated therewith to prevent fluid flow from passing between the first port 62 of the first and second pilot valves 48,50 and the second port 64 of the first and second pilot valves 48 and 50.
  • the ball checks 127,129 are pressure responsive. In the event that both inlet passages 114, 116, 122, and 124 of either shuttle valve are pressurized the shuttle valve will only pass the fluid at the highest pressure to the respective outlet passage 118,126.
  • the first port 62 of the first pilot valve 48 is connected to one inlet passage 114 of the first shuttle valve 112 via conduit 128, and .the first port 62 of the second pilot valve 50 is connected to the other inlet passage 116 of the first shuttle valve 112 via conduit 130.
  • the outlet passage 118 of the first shuttle valve.112 is connected to the first signal port 92 of the pilot operated control valve 52 via conduit 132.
  • the second port 62 of the first pilot valve 48 is connected to one inlet passage 122 of the second shuttle valve 120 via conduit 134 and the second port 64 of the second pilot valve 50 is connected to the other inlet passage 124 of the second shuttle valve 120 via conduit 136.
  • the outlet passage 126 of the second shuttle valve 120 is connected to he second signal port 94 of control valves 52 via conduit 138.
  • the plurality of selector valves 54 previously mentioned are connected in parallel to the first and second control ports 98 and 100 of the pilot operated control valve 52 via conduits 140 and 142 respectively. Since the selector valves are mounted close to the implement to be controlled and only a single control valve is used to modulate fluid flow only conduits 140 and 142 are required.
  • Each selector valve provided is a two position solenoid operated valve having a fluid flow passing position 144 and a fluid flow blocking position 146 and a shiftable therebetween via a solenoid 148.
  • the plurality of selector valves 54 includes; a side shift selector valve 150, a twist lock selector valve 152, a spread selector valve 154 and a slewing selector valve 156.
  • Each of these selector valves 150, 152, 154, and 156 are connected to their respective hydraulic jacks 30,44,36,40.
  • a pair of electrical switches 158 are connected to each control lever 82.
  • the switches 158 are connected to a source 160 of electric power and a respective one of the solenoids 148. Therefore, each selector valve is independently selected to pass fluid delivered from the control valve 52 to its respective hydraulic jack.
  • selector valves do not modulate fluid flow or determine the direction of fluid flow. This is determined by the condition established at the control valve 52.
  • the operator of the lift truck has control of the implements 12 mounted thereon by actuating a selected one of the first and second pilot valves 48 and 50 and a selected one of the plurality of selector valves 54 by simply actuating the proper one of the switches 158 and the control lever 82 upon which the proper switche is mounted.
  • actuating a selected one of the first and second pilot valves 48 and 50 and a selected one of the plurality of selector valves 54 by simply actuating the proper one of the switches 158 and the control lever 82 upon which the proper switche is mounted.
  • the pilot operated control system 10 is applicable for use in applications wherein the implement 12 is controlled from two or more separate spaced apart locations on the vehicle 16.
  • the operator In operation, to power a selected implement, for example, to side shift the carriage support frame 28 the operator must actuate the side shift selector valve 150 to the fluid flow passing position 144 thereof. This is accomplished by actuating the proper one of the switches 158 on the control lever 82 of the second pilot valve 50 to pass electrical current from the electrical energy source 160 to the solenoid 148 of side shift selector valve 150.
  • the jack 30 now connected is to receive pressurized fluid flow from directed by control valve 52 from the second source 106.
  • the operator In order to pass fluid flow from the second source 106, the operator must determine which direction to shift the second pilot valve 50. To extend jack 30, the operator must shift the pilot valve spool 70 toward the first position 56 and to retract jack 30 the spool 70 should be shifted to the second position 58. Assuming the operator requires extension of side shift jack 30, he will progressively shift the second pilot valve spool 70 toward the second position 58. Due to the fine modulating characteristics of the pilot valves 48 and 50 and the pilot operated control valve 52, the speed of actuation of the jack 30 is proportional to the amount of movement of the second pilot valve 50 spool 70.
  • Pressurized fluid from source 74 at the inlet port 66 of the second pilot valve 50 is directed by the valve spool 70 at a selected modulated pressure and flow level to the first port 62.
  • Conduit 136 will carry this fluid flow to the inlet passage 116 of the first shuttle valve 112.
  • the ball check 127 will respond to this pressurized fluid flow by shifting toward inlet passage 114 thereof and against adjacent seat 131. This check action will block passage 116 from passage 114 and open
  • control valve 52 Since the control valve 52 is of the infinitely variable type, the fluid exiting control port 98 will be passed at a flow rate established by the position of the spool 84. This fluid will be passed by conduit 140 to selector valve 150 and by selector valve to jack 30 resulting in extension thereof. The exhaust fluid from jack 30 will D ⁇ ⁇ returned to the reservoir 80 via selector valve 150, conduit 142 and control valve 52.
  • the pilot operated control system heretofore described provides excellent controllability of the jacks and thus the implement connected thereto, reduces operator fatigue, is simple in operation, low in cost, reduces the number of conduits required and permits a single pilot operated control valve to be actuated to two different fluid directing positions from either one of a first and second pilot valve.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

Système de commande actionné par pilote (10) qui élimine les problèmes de coût excessif, de complexité du système, de réduction de la visibilité de l'opérateur, de fatigue de l'opérateur et de manoeuvrabilité de moteurs actionnés par fluide (30, 36, 40, 44) à partir d'un emplacement unique ou d'une pluralité d'emplacements espacés. Le système de commande actionné par pilote (10) possède une première et une seconde soupapes pilotes (48, 50) reliées à une soupape de commande actionnée par pilote (52). Les soupapes pilotes (48, 50) peuvent être actionnées chacune entre une première (56) et une seconde (58) positions de commande de fluide pour déplacer la soupape de commande actionnée par pilote (52) entre la première (86) et la seconde (88) positions de commande de fluide. Le système de commande actionné par pilote (10) offre ainsi un système de commande moins complexe et moins coûteux avec une visibilité améliorée et manoeuvrabilité précise des moteurs actionnés par fluide à partir d'un emplacement unique ou d'emplacements espacés. Ce système de commande actionné par pilote (10) est particulièrement utile pour commander le mât d'élévation (14) d'un chariot élévateur (16).
PCT/US1983/000700 1983-03-08 1983-05-09 Systeme de commande d'instrument actionne par pilote WO1984003543A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US47328783A 1983-03-08 1983-03-08

Publications (1)

Publication Number Publication Date
WO1984003543A1 true WO1984003543A1 (fr) 1984-09-13

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Application Number Title Priority Date Filing Date
PCT/US1983/000700 WO1984003543A1 (fr) 1983-03-08 1983-05-09 Systeme de commande d'instrument actionne par pilote

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EP (1) EP0139644A1 (fr)
WO (1) WO1984003543A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2633987A1 (fr) * 1988-07-08 1990-01-12 Kubota Ltd Circuit hydraulique pour vehicule de travaux
US6125970A (en) * 1997-06-10 2000-10-03 Kabushiki Kaisha Toyoda Jidoshokki Seisakusha Hydraulic device for forklift
WO2012094211A1 (fr) * 2011-01-04 2012-07-12 Crown Equipment Corporation Véhicule de manipulation de matériels possédant une tubulure située sur une unité d'alimentation pour maintenir la pression de fluide au niveau d'un orifice de sortie à une pression commandée correspondant à une pression de fonctionnement de dispositif auxiliaire

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE653600A (fr) * 1963-12-21 1965-01-18
US3354789A (en) * 1965-12-29 1967-11-28 Clark Equipment Co Control system
FR2191679A5 (fr) * 1972-06-26 1974-02-01 Cmi Corp

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE653600A (fr) * 1963-12-21 1965-01-18
US3354789A (en) * 1965-12-29 1967-11-28 Clark Equipment Co Control system
FR2191679A5 (fr) * 1972-06-26 1974-02-01 Cmi Corp

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2633987A1 (fr) * 1988-07-08 1990-01-12 Kubota Ltd Circuit hydraulique pour vehicule de travaux
US6125970A (en) * 1997-06-10 2000-10-03 Kabushiki Kaisha Toyoda Jidoshokki Seisakusha Hydraulic device for forklift
WO2012094211A1 (fr) * 2011-01-04 2012-07-12 Crown Equipment Corporation Véhicule de manipulation de matériels possédant une tubulure située sur une unité d'alimentation pour maintenir la pression de fluide au niveau d'un orifice de sortie à une pression commandée correspondant à une pression de fonctionnement de dispositif auxiliaire
CN103328371A (zh) * 2011-01-04 2013-09-25 克朗设备公司 具有用于将在输出端口处的流体压力维持在与辅助装置操作压力对应的命令压力的、位于动力单元上的歧管的物料搬运车辆
AU2011353519B2 (en) * 2011-01-04 2015-09-10 Crown Equipment Corporation Materials handling vehicle having a manifold located on a power unit for maintaining fluid pressure at an output port at a commanded pressure corresponding to an auxiliary device operating pressure
US9290366B2 (en) 2011-01-04 2016-03-22 Crown Equipment Corporation Materials handling vehicle having a manifold located on a power unit for maintaining fluid pressure at an output port at a commanded pressure corresponding to an auxiliary device operating pressure

Also Published As

Publication number Publication date
EP0139644A1 (fr) 1985-05-08

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