WO2002029166A1 - Soupape bidirectionnelle et autoreglable - Google Patents

Soupape bidirectionnelle et autoreglable Download PDF

Info

Publication number
WO2002029166A1
WO2002029166A1 PCT/US2001/030550 US0130550W WO0229166A1 WO 2002029166 A1 WO2002029166 A1 WO 2002029166A1 US 0130550 W US0130550 W US 0130550W WO 0229166 A1 WO0229166 A1 WO 0229166A1
Authority
WO
WIPO (PCT)
Prior art keywords
boom
bucket
valve
spool
self
Prior art date
Application number
PCT/US2001/030550
Other languages
English (en)
Inventor
Jason P. Fance
Harish Narotham
Original Assignee
Husco International, Inc.
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 Husco International, Inc. filed Critical Husco International, Inc.
Priority to AU2001294901A priority Critical patent/AU2001294901A1/en
Publication of WO2002029166A1 publication Critical patent/WO2002029166A1/fr

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/431—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like
    • E02F3/432—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like for keeping the bucket in a predetermined position or attitude
    • E02F3/433—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like for keeping the bucket in a predetermined position or attitude horizontal, e.g. self-levelling

Definitions

  • This invention relates broadly to controls for hydraulic loaders, and more particularly, pertains to valves which efficiently maintain the rotational attitude of a boom-mounted bucket during raising and lowering of the boom.
  • the hydraulic power system of the loader also typically includes a self-leveling valve which enables the operator of the loader to operate both valves simultaneously in a centralized control in an effort to maintain the bucket in a level position during up and down movement of the boom.
  • boom pump flow is directed to the head side of the boom cylinder.
  • a flow divider proportions the flow exhausting from the rod side of the boom cylinder into two paths. One path is directed to the head side of the bucket cylinder and is used to tip the bucket cylinder. The other path is dumped via a separate line to tank through the main control valve.
  • An unloader spool prevents the bucket from excessive tipping and ensures that the bucket cylinder cannot cavitate.
  • This valve allows self-level only during the "Raise" cycle.
  • this design is limited for use in loader systems where the main control valve is of a series-type configuration. Also, this system is limited to use where the boom valve is located upstream of the bucket control valve.
  • U.S. Patent No. 5,579,675 issued to Wilke describes a hydraulic fluid control valve for preventing uncontrolled load movement in the event of a fluid loss, such as from the bursting of a hose and further for allowing an operator to move the load in a controlled way despite fluid loss.
  • the control valve is situated between a conventional main spool valve and a piston/cylinder hydraulic actuator, which powers the load. Fluid can flow to the actuator only when the control valve spool is in a position that provides a fluid path.
  • the amount of spool movement, and therefore the amount of spool metering opening is controlled proportionally by the rate of flow from the main spool valve, which is directly in the control of the operator.
  • a further self-level valve is set forth in U.S. Patent No. 5,797,310, issued to Casey et al.
  • This self-level valve is used for loader applications which require self-level valves when raising and lowering the boom of a loader.
  • Oil flow during "Raise” and “Lower” cycles are similar, in that pump flow is directed to the boom cylinder.
  • a flow divider splits the flow from the return line of the boom cylinder by a preset ratio. Some of this return flow is used to operate the bucket cylinder, while the excess oil is dumped to tank through the main control valve.
  • Unloader spools prevent the bucket from tipping out of control, and a relief valve and unloader spool are used to allow the boom to continue operating when the bucket has become fully tipped or crowded.
  • This valve requires using an unloader spool when lifting the boom which also has the function of a relief valve to allow the operator to continue lifting the boom when the bucket cylinder is fully tipped.
  • the use of a relief valve will result in the reduction of the lift capacity when the bucket cylinder is fully tipped.
  • the two-way self-level valve is designed predominantly for use on loader systems, which have one or more hydraulic cylinders for positioning the loader boom and one or more hydraulic cylinders for positioning the loader bucket.
  • the two-way self-level valve will maintain the rotational level of the bucket relative to the start angle whilst the boom is being lowered or raised without the loader operator requiring to operate two services simultaneously.
  • the spool and compensator control the ratio between the rate of oil being delivered to the head side of the boom cylinder and the rate of oil leaving the rod side of the bucket cylinder. This ratio will be maintained regardless of the machine loading conditions and the rate of flow to the boom cylinder.
  • the spool and the compensator control the ratio between the rate of oil being delivered to the rod side of the boom cylinder and the rate of oil leaving the head side of the bucket cylinder. This ratio will be maintained regardless of the machine loading conditions and the rate of flow to the boom cylinder.
  • the counterbalance valve prevents cavitation of the boom cylinder rod side when lowering the boom.
  • a self-leveling hydraulic system controls at least two functions including a boom and a bucket .
  • Double acting cylinders are provided for both the boom and bucket, the cylinders being controlled by separate boom and bucket directional control valves, and a source of pressure supplying the control valves.
  • a self-leveling valve is in fluid communication with the rod end of the boom cylinder whereby flow from the rod end of the boom cylinder is divided into first and second flows.
  • a first passage communicates the first of the flows to the head end of the bucket cylinder to supply a sufficient flow to maintain the bucket at a level position as the boom is raised, and a second passage communicates the second of the flows back through one of the control valves to a tank.
  • the improvement resides in the self-leveling valve including a spool structure for controlling the rate of flow being delivered to and returned from the boom and bucket cylinders, and a pressure-compensated valve structure connected to the spool structure for maintaining the ratio of hydraulic flow between the rate being delivered into the head of the boom cylinder and the rate being exhausted from the rod side of the boom cylinder during raising and lowering cycles of the boom.
  • the spool structure is constructed and arranged to constantly maintain hydraulic pressure on the head side of the bucket so as to prevent cavitation therein.
  • the self-leveling valve permits continuous lifting of the boom regardless of the position of the bucket cylinder.
  • the self-leveling valve is comprised of a first spool having one end in communication with the boom cylinder and the other end in communication with the first pressure compensated valve which, in turn, is in communication with one end of a second spool having another end in communication with a second pressure-compensated valve in communication with the other end of the first spool.
  • the one end of the second spool is also in communication with a counterbalance valve.
  • the first and second pressure-compensated valves are in communication with the bucket cylinder.
  • a bleed orifice is connected between the self-leveling valve and the tank.
  • the bucket cylinder directional control valve is in communication with the second pressure-compensated valve and the second spool.
  • the hydraulic flow from the rod side of the bucket cylinder is directed to the second pressure-compensated valve through the first spool and the boom directional control valve and to the tank.
  • the pressure-compensated valve maintains a predetermined pressure drop across the spool regardless of the load imposed by the bucket.
  • a self-leveling valve is interposed between boom and bucket cylinder directional control valves and boom and bucket cylinders used to raise and lower a boom of a loader and maintain a level position of a boom-mounted bucket.
  • the valve includes a first spool valve interconnected with a first pressure-compensated valve used for raising of the boom.
  • a second spool valve is interconnected with a second pressure-compensated valve and counterbalance valve used for lowering of the boom.
  • the self-level spools and pressure-compensated valves maintain a predetermined ratio of hydraulic flow across selective ports of the spool valves so as to regulate balanced hydraulic flow into and out of the boom and bucket cylinders.
  • Fig. 1 is a hydraulic schematic of self-leveling hydraulic system constructed in accordance with the present invention showing the system in neutral;
  • Fig. 2 is a schematic of the present invention illustrating a raise cycle
  • Fig. 3 is a schematic of the present invention illustrating a lower cycle.
  • Fig. 1 illustrates the neutral condition of the overall hydraulic system which is generally identified by the reference numeral 10.
  • the system includes a vehicle frame 12 of a loader to which is pivotally mounted a boom 14. At the forward end of the boom 14 is attached to a bucket 16 with movement of the boom 14 being controlled by a boom cylinder 18 and movement of the bucket 16 controlled by a bucket cylinder 20.
  • the overall system 10 receives pressurized fluid from a pump 22, the output of which is communicated to a main control valve 24 comprised of a first three-position, directional control valve 26 which controls the boom cylinder 18, and a second, three-position, directional control valve 28 which controls the bucket cylinder 20.
  • the main control valve 24 includes a conventional relief valve 30 used to dump fluid into a reservoir or tank 32 when the working system pressure is exceeded.
  • a two-way, self-level valve 34 Positioned between the control valves 26,28 and the boom and bucket cylinders 18,20 respectively, is a two-way, self-level valve 34 having a spring-biased, "Raise” spool 36 and a spring-biased “Lower” spool 38. It is the purpose of the self-level valve 34 to maintain the rotational angle of the bucket 16 during lifting and lowering of the boom 14 without the operator having to operate two sets of controls simultaneously.
  • Spool 36 has a spring chamber and is provided with a plurality of ports A2 to X2, B2 to Y2, C2 to Z2, and D2 to W2.
  • Spool 38 has a spring chamber and is provided with a plurality of ports Al to XI, Bl to Yl, CI to Zl, and Dl to WI. Also included in the self-level valve 34 is a "Raise” spring-biased, pressure-compensated valve 40 and a “Lower” spring-biased, pressure-compensated valve 42. Interconnected with the boom cylinder 18, and the spools 36,38 is a lower counterbalance valve 44 having a damping orifice 46. The counterbalance valve 44 improves system operation when the boom 14 is fully loaded. A bleed orifice 48 is included between the spool 36 and the relief valve 30 to prevent opening of the spools 36,38 when not necessary such as during operation of the bucket 16 alone.
  • Self-Level Raise Cycle (See Fig. 2
  • the loader operator raises the loader boom 14 by operating the main control valve boom spool 26.
  • the open center in the valve 24 starts to close and raises the pressure in the main control valve bridge, and subsequently the main control valve workport 1A.
  • This pressure build-up is proportional to the amount of movement of the boom spool 26 in the main control valve 24.
  • Workport 1 A is directly connected to port A of the self-level valve assembly 34 which, in turn, is connected to the pilot chamber of the raise self-level spool 36.
  • the boom cylinder head side is directly connected to port C on the self-level valve 34 which, in turn, is connected to the spring chamber of the raise self-level spool 36.
  • the spool areas at both ends of the self- level spools 36,38 are equal.
  • the raise self-level spool 36 will remain closed if the force in the spring chamber of the spool (generated by the oil pressure in the boom cylinder head side), plus the force from the raise spring, is greater than the force in pilot chamber of the raise self-level spool 36.
  • the raise self-level spool 36 will open when the pressure in port A in the self-level spool increases, to such an extent that the force in the pilot chamber of the spool 36 is greater than the combined force of the spring and the pressure in the spring chamber of the spool.
  • flow will take place across the raise self-level spool ports of A2 to X2. This flow is known as "raise meter-in” flow.
  • the rate of "raise meter-in" fluid flow is determined by the force balancing on the spool 36 induced by the pressures in the pilot chamber and the spring force and pressure in the spring chamber of the raise self-level spool 36.
  • Part of the return oil from the rod side of the loader boom cylinder(s) 18 is used to tip the bucket 16 forward by way of the open spool 36 between ports C2 and Z2, which opens a direct flow path to the head side of the bucket cylinder 20.
  • This boom return oil is directed to the raise self-level spool via port D of the self-level valve 34, which is directly connected to port C2 of the raise self-level spool 36.
  • Ports C2 and Z2 are timed to open before the "raise meter-in" ports open. This ensures that before the boom cylinder 18 raises, there is a connection open between these two ports.
  • Port Z2 is connected directly to the head side of the bucket cylinder 20 and maintains fluid in the bucket cylinder, therefore preventing cylinder cavitation.
  • the excess return oil from the boom cylinder 18 is directed to workport IB of the main control valve 24 by way of the open spool 36 between ports W2 and D2.
  • the excess oil is returned into port D of the self-level valve 34 which communicates to port W2 of the raise self-level spool 36.
  • Ports W2 and D2 are timed to open before the "raise meter-in" ports open. This ensures a free passage for the excess oil to flow into port B of self-level valve 34. Because of the main control valve boom spool configuration, the excess oil returning to the main control valve 24 via port B of the self-level valve 34 and workport IB of the main control valve 24 will be directed to tank 32 (parallel circuit).
  • Modifying the boom spool 36 to a series circuit will allow this return oil to be directed back to the open center of the main control valve 24 for use of this oil in the second spool (series circuit).
  • the raise self-level spool 36 will also open ports Y2 and B2. This flow between ports Y2 and B2 is now identified as the "raise meter-out” flow.
  • the raise pressure compensator 40 controls the pressure compensation across the raise self-level spool ports of Y2 and B2, this works as follows. Pressurized oil from the rod side of the bucket cylinder 20 communicates directly with the inlet port of the raise pressure compensator 40 via port F of the self-level valve 34.
  • This control pressure is sensed across the normally open pressure compensator 40 and into the compensator pilot chamber.
  • the pressure in the pilot chamber of the raise pressure compensator 40 will begin to close the opening across the pressure compensator 40 until the pressure drop across it stabilizes and controls the pressure drop across ports Y2 and B2 of the raise self- level spool 36.
  • the "raise meter-out" oil from the bucket cylinder 20 will enter port B of the self-level valve 34 and add to the excess oil from the boom cylinder rod side. Therefore, the oil will be directed to tank 32 through the main control valve 24 via workport 1 B .
  • the "raise meter-in” flow will also have a controlled pressure drop.
  • By controlling the pressure drops in the "raise meter-in” and “raise meter-out” flows it is possible to control the rate of flow across the spool 36 for the meter-in and meter-out.
  • Self-Level Lower Cycle (See Fig. 3)
  • the loader operator lowers the loader boom 14 by operating the main control valve boom spool.
  • the open center in the valve 24 starts to close and raises the pressure in the main control valve bridge, and subsequently the main control valve workport IB.
  • This pressure build-up is proportional to the amount of movement of the boom spool 26 in the main control valve 24.
  • Workport ⁇ IB is directly connected to port B of the self-level valve assembly 34 which, in turn, is connected to the pilot chamber of the lower self-level spool 38.
  • the boom cylinder rod side is directly connected to port D on the self-level valve 34 which, in turn, is connected to the spring chamber of the lower self-level spool 38.
  • the spool areas at both ends of the self-level spools 36,38 are equal.
  • the lower self-level spool 38 will remain closed if the force in the spring chamber chamber of the spool (generated by the oil pressure in the boom cylinder rod side), plus the force from the lower spring, is greater than the force in pilot chamber of the lower self-level spool 38.
  • the lower self-level spool 38 will open when the pressure in port B of the self-level valve 34 increases, to such an extent that the force in the pilot chamber of the spool 38 is greater than the combined force of the spring and the pressure in the spring chamber of the spool.
  • flow will take place across the lower self-level spool ports of Al to XI. This flow is known as "lower meter-in” flow.
  • the rate of "lower meter-in” fluid is determined by the force balancing on the spool 38 induced by the pressures in the pilot chamber and the spring force and pressure in the spring chamber of the lower self-level spool 38.
  • the resulting "lower meter-in” oil flow across the lower self-level spool 38 will be directed to the rod side of the boom cylinder 18 to lower the boom 14.
  • Part of the return oil from the head side of the loader boom cylinder(s) 18 is used to crowd the bucket 16 back by way of the open spool 38 between ports CI and Zl, which opens a direct flow path to the rod side of the bucket cylinder 20.
  • This boom return oil is directed to the lower self-level spool 38 view port C of the self-level valve 34, which is directly connected to port CI of the lower self-level spool 38.
  • Ports CI to Zl are timed to open before the "lower meter-in" ports open. This ensures that before the boom cylinder 18 lowers, there is a connection open between these two ports.
  • Port Zl is connected directly to the rod side of the bucket cylinder 20 and this fluid, which is directed to the rod side of the bucket cylinder 20 is used to crowd the bucket 16 back during the lower cycle.
  • the excess return oil from the boom cylinder 18 is directed to workport 1A of the main control valve 24 by way of the open spool 38 between ports WI and Dl and the lower counterbalance valve 44.
  • the excess oil is returned into port C of the self-level valve 34 which communicates with the inlet port of the lower counterbalance valve 44.
  • the counterbalance valve 44 remains closed until there is sufficient force in the pilot side of the counterbalance valve to shift the spool over. Both of the ends of the counterbalance valve 44 have the same area, so the spool 38 is balanced between the oil pressure in the pilot chamber on one side of the counterbalance valve 44 and the oil pressure in the spring chamber plus the spring force in the opposing side.
  • a damping orifice 46 is included in the pilot chamber of the counterbalance valve 44 to damp its movement. This increases the stability of the counterbalance valve 44.
  • This counterbalance valve 44 ensures that the boom 14, when loaded with a high load, cannot cavitate down and maintains fluid in the rod side of the boom cylinder.
  • the excess return oil, after passing through the lower counterbalance valve 44, is then directed to port WI of the lower self-level spool 38. Ports WI and Dl are timed to open before the "lower meter-in" ports open This ensures a free passage for the excess oil to flow into port A of self- level valve 34.
  • the lower self- level spool 38 When the "lower meter-in" flow starts to take place, the lower self- level spool 38 will also open ports Yl to Bl. This flow between ports Yl and Bl is now identified as the "lower meter-out” flow.
  • the lower pressure compensator 42 controls the pressure compensation across the lower self-level spool ports of Yl to Bl, this works as follows. Pressurized oil from the head side of the bucket cylinder 20 communicates directly with the inlet port of the lower pressure compensator 42 via port E of the self-level valve 34. This control pressure is sensed across the normally open pressure compensator and into the compensator pilot chamber.
  • the pressure in the pilot chamber of the lower pressure compensator 42 will begin to close the opening across the pressure compensator 42 until the pressure drop across it stabilizes and control the pressure drop across ports Yl to Bl of the lower self- level spool 38.
  • the "lower meter-out" oil from the bucket cylinder 20 will enter port A of the self-level valve and add to the excess oil from the boom cylinder head side. Therefore, the oil will be directed to tank 32 through the main control valve 24 via workport 1A.
  • the "lower meter-in” flow will also have a controlled pressure drop.
  • By controlling the pressure drops of the "lower meter-in” and “lower meter-out” flows it is possible to control the rate of flow across the spool for the meter-in and meter-out.
  • the two-way self-level valve 34 provides a direct connection from the bucket service ports of the main control valve 24 and the bucket cylinder 20.
  • both the self-level spools 36,38 remain in the neutral position (closed) and operation of the bucket cylinder 20 is unaffected by the presence of the two- way self-level valve 34 in the system.
  • the bleed orifice 48 connected between port B of the self-level valve 34 and system tank 32 prevents the raise or lower self- level spools 36 or 38 from opening during independent operation of the bucket service. This is accomplished by preventing any pressure build-up due to internal leakage across the self-level spools 36,38.
  • Boom Raise and Bucket Crowd Dual Operation Crowding the bucket 16 whilst raising the boom 14 will result in additional pump flow (or boom return flow if the boom main control valve spool is series spool) coming from the main control valve port 2A and into the self-level valve 34.
  • This flow is directed to the rod side of the bucket cylinder 20.
  • the boom return flow which normally goes to head side of the bucket cylinder 20 from port Z2, will instead be directed to tank 32 through port 2B of the main control valve 24.
  • the flow from the head side of the bucket cylinder 20 will add to the boom return flow from port Z2 and be diverted directly to tank 32 through port 2A of the main control valve 24.
  • Boom Lower and Bucket Crowd Dual Operation Crowding the bucket 16 while lowering the boom 14 will result in additional pump flow (or boom return flow if the boom main control valve spool 26 is series spool) coming from the main control valve port 2A and into the self-level valve 24.
  • This oil flow will add to the boom return oil flow from port Zl which normally crowds the bucket 16 to keep the loader bucket level.
  • the flow from the head side of the bucket cylinder 20 will be diverted directly to tank 32 through the port 2B of the main control valve 24.
  • Boom Lower and Bucket Tip Dual Operation Tipping the bucket 16 whilst lowering the boom 14 will result in additional pump flow (or boom return flow if the boom main control valve spool 26 is series spool) coming from the main control valve port 2B and into the self-level valve 34.
  • This flow is directed to the head side of the bucket cylinder 20.
  • the boom return flow which normally goes to rod side of the bucket cylinder 20 from port Zl, will instead be directed to tank 32 through port 2 A of the main control valve 24.
  • the flow from the rod side of the bucket cylinder 20 will add to the boom return flow from port Zl and be diverted directly to tank 32 through port 2A of the main control valve 24.
  • the present invention provides an improved self-leveling system which makes use of a unique spool, counterbalance valve and pressure compensator arrangement that maintains the level of the bucket throughout raising and lowering of the boom, and simultaneously tipping and crowding of the bucket.
  • a unique spool, counterbalance valve and pressure compensator arrangement that maintains the level of the bucket throughout raising and lowering of the boom, and simultaneously tipping and crowding of the bucket.
  • such system functions to prevent cavitation of the bucket without an unloader valve because the self-level spools, counterbalance valve and pressure compensator valves always maintain pressure on the head side of the bucket cylinder.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Operation Control Of Excavators (AREA)

Abstract

L'invention concerne un système hydraulique autoréglable (10) qui commande au moins deux fonctions, notamment un bras articulé (14) et un godet (16). Des cylindre à double effet (18, 20) sont prévus à la fois pour le bras articulé et pour le godet, ces cylindres étant commandés par des soupapes de commande directionnelle (26, 28) de bras articulé et de godet séparées, et une source de pression (22) alimentant les soupapes de commande. Une soupape autoréglable (34) se trouve en communication fluidique avec l'embout du cylindre, le flux à partir de l'embout du cylindre (18) étant séparé en un premier et un second flux. Un premier passage amène le premier des flux vers la tête du cylindre de godet (20) afin de fournir un flux suffisant pour maintenir le godet à une position de niveau lorsque le bras articulé est élevé, et un second passage amenant le second des flux de retour à travers une des soupapes de commande vers une cuve. La soupape autoréglable (34) comprend une structure tiroir (36, 38) permettant de commander le débit de flux qui est distribué et renvoyé des cylindres de bras articulé (18) et de godet (20), et une structure soupape à compensation par pression (40, 42) reliée à la structure tiroir pour maintenir le rapport du flux hydraulique entre le débit distribué du côté tête du cylindre de bras articulé et le débit émis d'un côté embout du cylindre de bras articulé (18) durant les cycles d'élévation et d'abaissement du bras articulé (14).
PCT/US2001/030550 2000-10-03 2001-09-28 Soupape bidirectionnelle et autoreglable WO2002029166A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001294901A AU2001294901A1 (en) 2000-10-03 2001-09-28 Two-way, self-level valve

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US67851800A 2000-10-03 2000-10-03
US09/678,518 2000-10-03

Publications (1)

Publication Number Publication Date
WO2002029166A1 true WO2002029166A1 (fr) 2002-04-11

Family

ID=24723125

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/030550 WO2002029166A1 (fr) 2000-10-03 2001-09-28 Soupape bidirectionnelle et autoreglable

Country Status (2)

Country Link
AU (1) AU2001294901A1 (fr)
WO (1) WO2002029166A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2868062A1 (fr) * 2004-03-26 2005-09-30 Husco Int Inc Procede de commande du mouvement d'un support de charge

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3563137A (en) * 1969-06-30 1971-02-16 Cessna Aircraft Co Hydraulic self-leveling control for boom and bucket
FR2600317A1 (fr) * 1986-06-23 1987-12-24 Agram Chargeur a correction hydraulique adaptable sur porteur automoteur
DE3643960A1 (de) * 1986-12-22 1988-06-30 Stoll Maschf Gmbh Wilhelm Front- oder hecklader mit werkzeug-parallelfuehrung
JPS63206534A (ja) * 1987-02-18 1988-08-25 Sanyo Kiki Kk 農用ロ−ダのアタツチメント平行移動操作用油圧装置
US4923362A (en) * 1988-06-06 1990-05-08 Deere & Company Bucket leveling system with dual fluid supply
JPH0551940A (ja) * 1991-02-27 1993-03-02 Toyo Umpanki Co Ltd 荷役具姿勢制御装置
US5447094A (en) * 1994-02-07 1995-09-05 Delta Power Hydraulic Co. Hydraulic system for bucket self-leveling during raising and lowering of boom
JPH0960032A (ja) * 1995-08-18 1997-03-04 Toyota Autom Loom Works Ltd ショベルローダのセルフレベリング装置
US5797310A (en) * 1997-01-29 1998-08-25 Eaton Corporation Dual self level valve
US20010015129A1 (en) * 1998-09-24 2001-08-23 Eugene Altman Hydraulic leveling control system for a loader type vehicle

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3563137A (en) * 1969-06-30 1971-02-16 Cessna Aircraft Co Hydraulic self-leveling control for boom and bucket
FR2600317A1 (fr) * 1986-06-23 1987-12-24 Agram Chargeur a correction hydraulique adaptable sur porteur automoteur
DE3643960A1 (de) * 1986-12-22 1988-06-30 Stoll Maschf Gmbh Wilhelm Front- oder hecklader mit werkzeug-parallelfuehrung
JPS63206534A (ja) * 1987-02-18 1988-08-25 Sanyo Kiki Kk 農用ロ−ダのアタツチメント平行移動操作用油圧装置
US4923362A (en) * 1988-06-06 1990-05-08 Deere & Company Bucket leveling system with dual fluid supply
JPH0551940A (ja) * 1991-02-27 1993-03-02 Toyo Umpanki Co Ltd 荷役具姿勢制御装置
US5447094A (en) * 1994-02-07 1995-09-05 Delta Power Hydraulic Co. Hydraulic system for bucket self-leveling during raising and lowering of boom
JPH0960032A (ja) * 1995-08-18 1997-03-04 Toyota Autom Loom Works Ltd ショベルローダのセルフレベリング装置
US5797310A (en) * 1997-01-29 1998-08-25 Eaton Corporation Dual self level valve
US20010015129A1 (en) * 1998-09-24 2001-08-23 Eugene Altman Hydraulic leveling control system for a loader type vehicle

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 012, no. 485 (M - 777) 19 December 1988 (1988-12-19) *
PATENT ABSTRACTS OF JAPAN vol. 017, no. 358 (M - 1440) 7 July 1993 (1993-07-07) *
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 07 31 July 1997 (1997-07-31) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2868062A1 (fr) * 2004-03-26 2005-09-30 Husco Int Inc Procede de commande du mouvement d'un support de charge

Also Published As

Publication number Publication date
AU2001294901A1 (en) 2002-04-15

Similar Documents

Publication Publication Date Title
US4945723A (en) Flow control valves for hydraulic motor system
JP4856131B2 (ja) 作業機械の油圧システム
US9206821B2 (en) Hydraulic switching mechanism for mobile hydraulics, mobile hydraulic machine and valve unit
US7752842B2 (en) Circuit for controlling a double-action hydraulic drive cylinder
KR100228810B1 (ko) 건축기기용 유압장치
US6430922B2 (en) Construction machine
JP3923242B2 (ja) 油圧駆動機械のアクチュエータ制御装置
US5797310A (en) Dual self level valve
JP5427370B2 (ja) バケット平行移動機能を有する多連方向切換弁
US3768372A (en) Control arrangement for hydraulic systems
EP0952358B1 (fr) Unité de soupape à commande pour la rupture de tuyaux
US5186000A (en) Hydraulic drive system for construction machines
US7059237B2 (en) Multiple-directional switching valve
JP2004301214A (ja) 作業用車両の油圧駆動装置
KR102482814B1 (ko) 건설기계용 유압 시스템
EP1450049B1 (fr) Ensemble de vannes à tiroir intégrées dans un boitier fait d'une seule pièce
US4799851A (en) Level lift hydraulic valve
KR102482817B1 (ko) 건설기계용 유압 시스템
JP2004301215A (ja) 作業用車両の油圧駆動装置
US11378989B2 (en) Hydraulic valve with switching regeneration circuit
EP0416130A1 (fr) Soupape hydraulique assurant une compensation de pression
WO2002029166A1 (fr) Soupape bidirectionnelle et autoreglable
KR20230142617A (ko) 작업 기계
KR20220127328A (ko) 건설 기계
US10125797B2 (en) Vent for load sense valves

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP