EP1351879B1 - Chariot elevateur a fourche avec dispositif de commande - Google Patents

Chariot elevateur a fourche avec dispositif de commande Download PDF

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Publication number
EP1351879B1
EP1351879B1 EP02708269A EP02708269A EP1351879B1 EP 1351879 B1 EP1351879 B1 EP 1351879B1 EP 02708269 A EP02708269 A EP 02708269A EP 02708269 A EP02708269 A EP 02708269A EP 1351879 B1 EP1351879 B1 EP 1351879B1
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EP
European Patent Office
Prior art keywords
control
pressure
valve
throttle
forklift truck
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.)
Expired - Lifetime
Application number
EP02708269A
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German (de)
English (en)
Other versions
EP1351879A2 (fr
Inventor
Peter Bruck
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Hydac Fluidtechnik GmbH
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Hydac Fluidtechnik GmbH
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Publication date
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Publication of EP1351879A2 publication Critical patent/EP1351879A2/fr
Application granted granted Critical
Publication of EP1351879B1 publication Critical patent/EP1351879B1/fr
Anticipated expiration legal-status Critical
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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
    • B66F17/00—Safety devices, e.g. for limiting or indicating lifting force
    • B66F17/003—Safety devices, e.g. for limiting or indicating lifting force for fork-lift trucks
    • 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
    • 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
    • F15B11/003—Systems with load-holding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/413—Flow control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow 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
    • F15B2211/40—Flow control
    • F15B2211/455—Control of flow in the feed line, i.e. meter-in 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
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out 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
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot pressure control
    • F15B2211/5756—Pilot pressure control for opening a valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7052—Single-acting output members
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S91/00—Motors: expansible chamber type
    • Y10S91/02—Exhaust throttled motor control

Definitions

  • the invention relates to a forklift with a control device, according to the features of the preamble of claim 1.
  • a forklift truck is known from DE 42 39 321 A.
  • the proportional load lowering of forks on forklifts is often caused by seat valves with a constant opening behavior.
  • the poppet valves can be directly operated or pilot operated.
  • the use of poppet valves is particularly necessary because of the forklift manufacturers a so-called "stacker-proof" load maintenance is required, which allows only very small leaks. By avoiding leaks in the hydraulic circuit, it is ensured that the fork, with or without loading, can not lower itself on its own, which would be a safety problem.
  • a load-independent maximum volume flow limitation is in the known solutions of a in Series with the other components of the hydraulic circuit switched constant volume flow controller adopted.
  • the well-known control devices are disadvantageous in that when lowering the load fork without load only the weight of the moving parts, especially in the form of the fork, is available on the mast to the hydraulic oil from the working cylinder (plunger cylinder) back to the tank as part of the hydraulic circuit to promote.
  • the pressure at the cylinder may drop to values ⁇ 8 bar.
  • the known constant-volume flow controller is a particularly large hurdle, because its aperture must be chosen so small that a control pressure difference of at least 7 bar can be set. Smaller control pressures would lead to unstable behavior in the hydraulic circuit of the work facility and can not be tolerated for safety reasons.
  • Another problem is the decreasing characteristic required by the customer for the volumetric flow controller. For reasons of safety and practicability, it should be ensured that as the load increases, the lowering speed should be lower. If this is carried out in the known control devices via the constant volume flow regulator, this also leads in principle to an increased instability within the hydraulic circuit.
  • a safety circuit for the control circuit of a power lift is known in which by means of a control valve in response to the pressure difference between two adjacent control lines the Position of the lifting cylinder is set to a desired value, wherein the pressure in a control line from a Heilaufrich and the pressure level in the control lines is influenced by a setpoint generator.
  • an electro-hydraulic lifting module in particular for forklift known, with a provided between a pressure source and a consumer line magnetic switching valve for the stroke control of a load line on the load side loadable hydraulic consumer, and with a branched off in a line from the consumer discharge line provided, electrically operable Zweiwegestromregler for the lowering control, which has an adjustable orifice plate and a pressure compensator in the discharge line, wherein the pressure compensator is arranged either upstream of the orifice or downstream of the orifice.
  • the pressure compensator should be stacker-tight and is designed such that it maintains a pressure difference across the orifice at zero flow rate in the two-way flow controller, the corresponds approximately to the force of the control spring of the pressure compensator, being regulated even when going to zero flow rate of the total leakage flow by means of the pressure compensator.
  • the present invention seeks to optimize the known solutions to the effect that an improved lowering behavior for the working device of a work machine, in the form of the fork of a forklift is achieved and yet the desired stability criteria for the hydraulic circuit are met ,
  • This object is achieved by a forklift with control device having the features of claim 1 in its entirety.
  • the pressure compensator in a pilot circuit of the hydraulic circuit monitors the pressure difference of the orifice such that upon reaching a predetermined control pressure difference in the hydraulic circuit, the pressure balance the pilot pressure for the control valve limited such that this is a control position takes to maintain the maximum flow rate, the previously known flow control valves in the main stream replaced by the pressure compensator in the pilot circuit, which only needs to be designed for low volume flows.
  • the control system with simple and inexpensive components can be realized, which are otherwise functionally reliable in operation and allow stable control behavior.
  • the volume flow when lowering the working device in the form of a fork even without loading can be significantly increased, so that it can not come to obstacles in operation during lowering.
  • the degressive activation behavior by the operator is required for safety reasons and is easily achieved with the control device according to the invention.
  • the device according to the invention utilizes a poppet valve controlled by a proportional pressure reducer as a control diaphragm for a maximum volumetric flow limitation integrated in the system.
  • a proportional pressure reducer as a control diaphragm for a maximum volumetric flow limitation integrated in the system.
  • Preferably can be used as a metering orifice screwed into the control block of the working device measuring nozzle, which is to be interpreted to a control pressure difference of only 3 to 4 bar at nominal flow rate.
  • the pressure difference of the measuring nozzle is monitored by the pressure compensator in the pilot circuit of said poppet valve, wherein upon reaching the control differential pressure, the pressure compensator opens and thus limits the maximum pilot pressure of the poppet valve.
  • the respective stroke of the seat valve then takes a control position to maintain the maximum flow rate.
  • the inventive device has a self-contained hydraulic circuit 10 with a hydraulic pump P for the fluid and pressure supply and a tank T for the fluid storage.
  • a hydraulic pump P for the fluid and pressure supply
  • a tank T for the fluid storage.
  • To the hydraulic circuit 10 as a whole with 12 designated working device is connected, which has a conventional working cylinder 14 for lifting and lowering a fork 16 of a conventional forklift not shown.
  • the fork 16 may be provided on its upper side with a load 18.
  • the lifting and lowering of the fork 16 is shown in Fig.1 with arrows 20. Will the lift valve 22 actuated, this switches through and over the hydraulic pump P and when the check valve 24 is open, the hydraulic medium is fed under pressure into the working cylinder 14 and thus the load fork 16 is raised with its load 18.
  • the control device is provided with a valve control unit which occupies a control position when lowering the load fork 16 under the load 18, in which a prescribable maximatotumum flow in the hydraulic circuit 10 is maintained.
  • the valve control unit is provided with a pressure compensator 26, which limits the pilot pressure for a control valve 28 such that this assumes a control position to maintain the maximum volume flow with reaching a predetermined control pressure difference in the hydraulic circuit 10.
  • the pressure balance 26 with its two control terminals 30 and 32 is connected in front of and behind a metering orifice 34 to the hydraulic circuit 10, wherein the metering orifice 34 provides said control pressure difference for driving the pressure compensator 26.
  • the metering orifice 34 itself is connected in the hydraulic circuit 10 between the working device 12 and the control valve 28.
  • the control valve 28 is controlled by a proportional pressure reducer 36, which is connected with its output 38 to the pilot circuit 40 of the control valve 28.
  • Task of the pressure compensator 26 is to limit the pilot pressure upon reaching the control pressure difference at the metering orifice 34.
  • the input 42 of the proportional pressure reducer 36 is connected to a connection point 44 in the hydraulic circuit 10, wherein the connection point 44 between the orifice 34 and the working device 12 opens into the hydraulic circuit 10.
  • the hydraulic pump P with the actuating valve 22 may also open to this connection point 44 in the hydraulic circuit 10 or as shown in the 1 at an upstream point between the connection point 44 and the working device 12.
  • In the output 38 of the proportional pressure reducer 36 is shown in FIG.
  • the characteristic of the proportional pressure reducer 36 is adjustable in 1 shows a fluid-conducting connection between the output 38 and a tank connection 48 and, moreover, establishes a fluid-conducting connection between the input 42 and the output 38 in its other switching position.
  • the pressure compensator 26 assumes a blocking position in its switching position shown in FIG. 1, in which the pilot control circuit 40 is shut off by a further tank connection 50. In the other switching position concerning the pressure compensator 26, a fluid-conducting connection between the pilot control circuit 40 and the further tank connection 50 is produced.
  • a Notablingfunktion the fork is realized via a conventional shut-off 52.
  • the control valve 28 is a pilot-operated seat valve 54 with a continuously variable opening cross-section depending on the pilot pressure, which in the illustration according to FIG. 1 is once reproduced as a switching symbol and once with its actual internal structure.
  • the pilot control takes place via a force translator 56 with a transmission piston 58.
  • This force translator 56 is necessary in order to achieve a full opening of the control valve 28 and thus the lowest possible flow resistance during load lowering without loading (load pressures under circumstances ⁇ 8 bar).
  • load pressures under circumstances ⁇ 8 bar load pressures under circumstances ⁇ 8 bar.
  • the requirement is taken into account that the load lowering function must work without a running pump, ie the primary pressure supply of the proportional pressure reducer 36 can only by means of Tap the load pressure done. Therefore, when lowering without loading, the pilot pressure can never become greater than the actual load pressure.
  • the piston side of the power booster 58 is fluidly connected to the pilot circuit 40 and the rod side is fluidly connected to the tank. Furthermore, the power transmission piston 58 via its control rod in operative connection with the other switching parts of the seat valve.
  • pilot-seat valve 54 closes the working device 12 leak-tight from the tank port T, in the manner of a poppet valve, while in the other switching position depending on the pilot pressure in size continuously variable control aperture 64 the pertinent connection is produced with proportionally variable throttle characteristic.
  • the mentioned pressure compensator 26 in the pilot circuit 40 is designed only for small volume flows, for example, in the order of about 1 1 / min. Further, the pressure drop across the orifice plate 34, in particular formed by a measuring nozzle, monitored by the pressure compensator 26, which establishes a connection of the pilot line of the seat valve 54 to the tank connection upon reaching the control pressure difference and thus prevents further increase of the sinking volume flow. By changing the orifice diameter, the maximum sinking volume flow is variable. Furthermore, the maximum opening cross section of the control orifice 64 of the control valve 28 is chosen to be very large in view of the pilot control pressure limitation of the pressure compensator 26.
  • the opening cross section for the control orifice 64 of the control valve 28 designed such that at the same pilot pressure in the pilot circuit 40 of the self-adjusting sinking volume decreases with increase in load or load 18 on the working device 12. Furthermore, open into the pilot circuit 40 of the control valve 28, both the output 66 of the pressure compensator 26 and the already mentioned output 38 of the proportional pressure reducer 36. Similarly, the inputs 42 of the proportional pressure reducer 36 and the control terminal 30 are connected as a driving input for the pressure compensator 26 fluidly, and via a branch point 68 in the hydraulic circuit 10th
  • the device according to the invention utilizes the poppet valve 54, which is precontrolled by the proportional pressure reducer 36, with the control orifice 64 for the maximum volumetric flow limitation required in the hydraulic circuit 10. Trained as a measuring nozzle measuring orifice 34 is designed for a control differential pressure of only 3 to 4 bar at nominal flow rate.
  • the pertinent control differential pressure at the metering orifice 34 is monitored by the pressure compensator 26 in the pilot circuit 40 of the seat valve 54.
  • the pressure compensator 26 Upon reaching the predetermined control differential pressure, the pressure compensator 26 opens into its fluid-permeable switching position and thus limits the maximum pilot pressure of the poppet valve 54.
  • the stroke of the poppet valve assumes a control position to maintain the maximum flow rate.
  • the maximum opening cross-section of the poppet valve with its control orifice 64 can be selected to be very large, because a regulation of the piston position takes place by the pilot control pressure limitation of the pressure compensator 26. This also leads to a further increase in the lowering speed.
  • the geometry of the poppet valve 54 is designed so that with increased load pressure, the flow forces require a significant increase in the pilot pressure to achieve the same stroke. This leads to the result that decreases at the same pilot pressure of adjusting sinking volume flow with increasing load. As a result, a system characteristic can be achieved in which the operator of the forklift with increasing load requires more adjustment to achieve the same lowering speed.
  • the pertinent degressive behavior is favorable for a meaningful operation and also serves safety aspects.
  • the self-adjusting sinking flows V s at a constant pilot pressure p s (isobars) can be seen in FIG. 2, wherein the topmost line, as shown in FIG. 2, indicated by an arrow 70, represents the maximum limit by the pressure compensator 26.
  • the control orifice 64 of the control valve 28 thus receives in addition to its original function as a steadily opening poppet valve the additional function as a control orifice of a metering orifice 34, pressure compensator 26 and just this control orifice 64 formed constant flow control valve for limiting the maximum lowering speed. This has a reduction in the main volume flow of the lowering function functional surfaces and thus an increase in the lowering speed without loading result.
  • the constant-current regulator formed by metering orifice 34, pressure compensator 26 and control orifice 64 can ensure a stable lowering movement with a control pressure difference of only 3 to 4 bar. This leads to a larger orifice diameter, which also results in an increase in the lowering speed without loading.
  • the control of the control valve 28 is effected by means of the force translator, which is formed from valve body 56 and piston 58 substantially.
  • the force translator which is formed from valve body 56 and piston 58 substantially.
  • the primary connection of the proportional pressure reducer is supplied from the load pressure of the lifting function.
  • the power converter 56 eliminates the problem that when lowering without loading only an extremely low pilot pressure (depending on the mast version ⁇ 7 bar) is available to open the control valve 28. Only with the force translator 56 is a complete opening of the control valve guaranteed under all circumstances and thus an extremely low flow resistance during lowering without load.
  • the metering orifice 34 is connected in a tank connection line, between the connecting line T on the control valve 28 and the tank T. Furthermore, the first control terminal 30 between the pressure compensator 26 and tank port T of the control valve 28 is arranged to extend.
  • the second control terminal 32 is connected to the pressure compensator 26 as in the embodiment according to Figure 1 and flows with its other free end in the fluid direction behind the orifice 34 in the tank connection line to the tank T.
  • the pertinent arrangement has the advantage that all connections the pressure compensator 26 are decoupled by the valve seat 64 leakage-free from the consumer 12 so that only the proportional pressure reducing valve 36 remains as the only possible leakage point, but which can be dimensioned such that the outgoing of this valve 36 leakage is far below the required forklift leaks ,
  • the arrangement shown in Figure 3 thus allows a nearly leak-free operation with still very good control behavior for the overall device.
  • Hydraulics can also be understood as the use of pneumatic media.
  • a corresponding orifice or a throttle can be set with an adjustable cross section, which provides the required control pressure difference for the pressure compensator 26.

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

Claims (11)

  1. Chariot élévateur à fourche équipé d'un dispositif de commande destiné à un dispositif de travail (12), raccordé à un circuit hydraulique (10), sous forme d'une fourche à charges (16) - du chariot élévateur - que peut soulever et abaisser un vérin de travail (14) et comportant une unité de commande des soupapes qui, quand on abaisse la fourche à charges (16) et aussi quand une charge (18) s'y trouve, prend une position de réglage dans laquelle un débit volumétrique maximal prédéfinissable est conservé dans le circuit hydraulique (10), l'unité de commande des soupapes étant équipée d'une balance de pression (26), d'un diaphragme et d'une soupape de commande (28),
    caractérisé en ce que la balance de pression (26) est disposée dans un circuit pilote (40) du circuit hydraulique (10) et surveille la différence de pression du diaphragme de telle manière que, quand une différence de pression de réglage prédéfinissable est atteinte dans le circuit pilote (40), la balance de pression (26) limite la pression pilote pour la soupape de commande (28) de telle manière que celle-ci prend une position de réglage afin de conserver le débit volumétrique maximal.
  2. Chariot élévateur à fourche selon la revendication 1, caractérisé en ce que par ses deux raccords de commande (30, 32) la balance de pression (26) est raccordée au circuit hydraulique (10) par une section transversale prédéfinissable en amont et en aval du diaphragme qui fournit la différence de pression de réglage pour commander la balance de pression (26).
  3. Chariot élévateur à fourche selon la revendication 2, caractérisé en ce que le diaphragme est un diaphragme de mesure (34) ou un étrangleur.
  4. Chariot élévateur à fourche selon la revendication 3, caractérisé en ce que le diaphragme de mesure (34) est monté dans le circuit hydraulique (10) entre le dispositif de travail (12) et la soupape de commande (28) ou que le diaphragme de mesure (34) est monté dans une conduite de raccordement au réservoir entre la soupape de commande (28) et le réservoir (T) .
  5. Chariot élévateur à fourche selon la revendication 4, caractérisé en ce que la soupape de commande (28) peut être commandée par un réducteur de pression proportionnelle (36) dont la sortie (38) est raccordée au circuit pilote (40) de la soupape de commande (28) et dont l'entrée (42) est raccordée à un point de raccordement (44) situé dans le circuit hydraulique (10) entre la soupape de commande (28) et le dispositif de travail (12).
  6. Chariot élévateur à fourche selon l'une des revendications 1 à 5, caractérisé en ce que la soupape de commande (28) est une soupape à siège (54) pilotable qui sépare de manière étanche aux fuites d'un raccord de réservoir (T) le dispositif de travail (12) dans l'une des positions de commutation et établit la liaison par l'intermédiaire d'un diaphragme de réglage (64) dans l'autre position de commutation.
  7. Chariot élévateur à fourche selon l'une des revendications 1 à 6, caractérisé en ce que la balance de pression (26) dans le circuit pilote (40) est uniquement conçue pour de petits débits volumétriques, en particulier de l'ordre de grandeur de 1 l/mn.
  8. Chariot élévateur à fourche selon la revendication 6 ou 7, caractérisé en ce que le diaphragme de mesure (34) est formé par une tuyère de mesure dont la différence de pression est surveillée par la balance de pression (26).
  9. Chariot élévateur à fourche selon l'une des revendications 6 à 8, caractérisé en ce qu'il est possible de choisir que le diaphragme de réglage (64) de la soupape de commande (28) ait une très grande section transversale maximale d'ouverture, ce qui est possible grâce à la limitation de pression pilote permise par le débit volumétrique maximal par l'intermédiaire de la balance de pression (26).
  10. Chariot élévateur à fourche selon la revendication 9, caractérisé en ce que la section transversale d'ouverture pour le diaphragme de réglage (64) de la soupape de commande (28) est conçue de telle manière que, quand la pression pilote est identique, le débit volumétrique d'abaissement qui s'établit diminue à mesure que la charge augmente sur le dispositif de travail (12).
  11. Chariot élévateur à fourche selon l'une des revendications 5 à 10, caractérisé en ce que la sortie (66) de la balance de pression (26) aussi bien que la sortie (38) du réducteur de pression proportionnelle (36) débouchent dans le circuit pilote (40) de la soupape de commande (28) et que les entrées (30, 32) de la balance de pression (26) et du réducteur de pression proportionnelle (36) sont reliées l'une à l'autre de manière à conduire les fluides.
EP02708269A 2001-01-15 2002-01-10 Chariot elevateur a fourche avec dispositif de commande Expired - Lifetime EP1351879B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10102409A DE10102409A1 (de) 2001-01-15 2001-01-15 Steuervorrichtung für eine an einen hydraulischen Kreis angeschlossene Arbeitseinrichtung
DE10102409 2001-01-15
PCT/EP2002/000155 WO2002055426A2 (fr) 2001-01-15 2002-01-10 Dispositif de commande pour un dispositif de travail raccorde a un circuit hydraulique

Publications (2)

Publication Number Publication Date
EP1351879A2 EP1351879A2 (fr) 2003-10-15
EP1351879B1 true EP1351879B1 (fr) 2006-11-29

Family

ID=7671147

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02708269A Expired - Lifetime EP1351879B1 (fr) 2001-01-15 2002-01-10 Chariot elevateur a fourche avec dispositif de commande

Country Status (6)

Country Link
US (1) US7040215B2 (fr)
EP (1) EP1351879B1 (fr)
JP (1) JP4094954B2 (fr)
AT (1) ATE346819T1 (fr)
DE (2) DE10102409A1 (fr)
WO (1) WO2002055426A2 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10235982B3 (de) * 2002-08-06 2004-01-22 Weiler Werkzeugmaschinen Gmbh Antrieb für linear bewegbare Bauteile einer Werkzeugmaschine
DE10253492A1 (de) * 2002-11-16 2004-05-27 Zf Friedrichshafen Ag Einrichtung zur Herstellung der Betriebsbereitschaft einer hydraulischen Betätigungsvorrichtung
FR2902684B1 (fr) * 2006-06-27 2010-02-26 Montabert Roger Procede de commutation de la course de frappe d'un appareil a percussions mu par un fluide incompressible sous pression, et appareil pour la mise en oeuvre de ce procede
DE102012010522A1 (de) * 2012-05-25 2013-11-28 Hydac Fluidtechnik Gmbh Ventil für Ventilanordnung
DE102012015356A1 (de) 2012-08-03 2014-05-15 Hydac Fluidtechnik Gmbh Ventil, insbesondere vorgesteuertes Proportional-Wegesitzventil
DE102012015354A1 (de) 2012-08-03 2014-05-15 Hydac Fluidtechnik Gmbh Ventil, insbesondere vorgesteuertes Proportional-Wegesitzventil
DE102013206977A1 (de) 2013-04-18 2014-11-06 Robert Bosch Gmbh Stromregelventilbaugruppe
KR102593990B1 (ko) * 2017-07-24 2023-10-24 후루까와 로크 드릴 가부시끼가이샤 액압식 타격장치

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126031A (en) * 1964-03-24 hayner
US4250794A (en) * 1978-03-31 1981-02-17 Caterpillar Tractor Co. High pressure hydraulic system
DE3708143C1 (en) * 1987-03-13 1988-09-01 Rexroth Mannesmann Gmbh Safety circuit for the control circuit of a power lift
DE4239321C2 (de) * 1992-11-23 1995-11-09 Heilmeier & Weinlein Elektrohydraulisches Hubmodul
DE29508392U1 (de) * 1995-05-19 1995-08-10 Heilmeier & Weinlein Fabrik für Oel-Hydraulik GmbH & Co KG, 81673 München Elektrohydraulisches Hubmodul

Also Published As

Publication number Publication date
DE50208840D1 (de) 2007-01-11
EP1351879A2 (fr) 2003-10-15
DE10102409A1 (de) 2002-07-25
WO2002055426A3 (fr) 2002-09-19
JP2004517016A (ja) 2004-06-10
US20040065081A1 (en) 2004-04-08
WO2002055426A2 (fr) 2002-07-18
US7040215B2 (en) 2006-05-09
JP4094954B2 (ja) 2008-06-04
ATE346819T1 (de) 2006-12-15

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