EP1052215A2 - Hydraulic lifting device - Google Patents

Hydraulic lifting device Download PDF

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Publication number
EP1052215A2
EP1052215A2 EP00108142A EP00108142A EP1052215A2 EP 1052215 A2 EP1052215 A2 EP 1052215A2 EP 00108142 A EP00108142 A EP 00108142A EP 00108142 A EP00108142 A EP 00108142A EP 1052215 A2 EP1052215 A2 EP 1052215A2
Authority
EP
European Patent Office
Prior art keywords
lifting
speed
hydraulic
lowering
hydraulic oil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP00108142A
Other languages
German (de)
French (fr)
Other versions
EP1052215A3 (en
EP1052215B1 (en
Inventor
Octavian Mare
Hans-Peter Schrad
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dambach Lagersysteme GmbH
Original Assignee
Dambach Lagersysteme GmbH
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
Priority to DE1999121629 priority Critical patent/DE19921629B4/en
Priority to DE19921629 priority
Application filed by Dambach Lagersysteme GmbH filed Critical Dambach Lagersysteme GmbH
Publication of EP1052215A2 publication Critical patent/EP1052215A2/en
Publication of EP1052215A3 publication Critical patent/EP1052215A3/en
Application granted granted Critical
Publication of EP1052215B1 publication Critical patent/EP1052215B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66FHOISTING, 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
    • B66F9/00Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06Devices 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
    • B66F9/075Constructional features or details
    • B66F9/20Means for actuating or controlling masts, platforms, or forks
    • B66F9/22Hydraulic devices or systems

Abstract

A hydraulic lifting device, in particular for battery-powered industrial trucks, comprises a pump (P) which can be driven by an electric motor (M) and by means of which, in load lifting operation, at least one hydraulic lifting cylinder (13) hydraulic oil from a reservoir (11) via a supply line (L1, L4.1, L4 .2) can be supplied, the hydraulic oil in load-lowering operation from the lifting cylinder (13) via a return line (L4.1, L4.2, L1.3, L2, L1.1, L1.2, L6, L7, L5) below Flow through a hydraulic motor (P) driving the electric motor (M) can be conveyed back into the reservoir (11), and a control device for changing the lifting or lowering speed of the lifting cylinder (13). It is provided that the control device has a dimension sensor device (20) for detecting the lifting or lowering speed of the lifting cylinder (13), the speed of the lifting cylinder (13) being adjustable by means of the speed of the motor (M) when the detected stroke speed exceeds a first limit value (vHG) or the detected lowering speed exceeds a second limit value (vSG), and the speed of the lifting cylinder (13) can be regulated by falling below the limit values by means of the hydraulic oil volume flow in the feed or return line. <IMAGE>

Description

The invention relates to a hydraulic lifting device especially for battery powered industrial trucks, with a pump that can be driven by an electric motor, by means of at least one hydraulic one in load lifting operation Lift cylinder hydraulic oil from a reservoir Can be supplied via a supply line, the hydraulic oil in load-lowering operation from the lifting cylinder via a Return line flowing through the as a generator working electric motor driving hydraulic motor in the reservoir is returnable, and with a Control device for changing the lifting or lowering speed of the lifting cylinder.

In vehicles with such a hydraulic Lifting device are equipped, it is in the Rule around electrically powered industrial trucks or Forklift trucks, their operability or duration of the Capacity of the battery is determined. At the operating time the battery until the next necessary charge extend, it is known that when the load is raised in the Potential energy system over one too electric motor working as a generator in the battery feed again. A hydraulic lifting device with a corresponding energy recovery is for example shown in DE 43 17 782 C2, an electric motor has, which drives a pump, which is in load lifting operation Hydraulic oil from a reservoir to the hydraulic one Promotes lifting cylinder, the adjustment or Lifting speed of the hydraulic lifting cylinder above control of the speed of the electric motor is achieved becomes. In the load lowering mode, the hydraulic oil from the hydraulic lifting cylinder guided by a hydraulic motor, which is also in this state as Hydromotor acting pump can act. The hydraulic motor drives a generator or as in this state Generator working electric motor, from which means a suitable, known electrical circuit the associated battery for energy recovery is charged. It occurs both in the load lifting as well in load lowering the problem is that with only a small Changes in position of the lifting cylinder or its deliberately slow adjustment (creep speed) of the electric motor and thus the pump with a very small one Speed are operated, which on the one hand is an unfavorable Efficiency and high wear the pump is connected so that its life is reduced is.

The invention has for its object a hydraulic To create lifting device of the type mentioned even with only slight and / or slow changes in position of the hydraulic lifting cylinder is excessive Wear of the pump is reliably avoided.

This object is achieved with a hydraulic Lifting device of the type mentioned solved that the control device is a sensor device for Detection of the lifting or lowering speed of the lifting cylinder has, the speed of the lifting cylinder is controllable by means of the speed of the motor when the detected stroke speed a first limit or the detected lowering speed a second limit exceeds, and being the speed of the lifting cylinder if the limit values are undershot using the Hydraulic oil volume flow in the supply or return line is adjustable.

According to the invention, the speed of the electric motor for controlling the lifting or lowering speed of the hydraulic lifting cylinder is only used if the lifting cylinder is adjusted sufficiently quickly or the lifting speed detected by the sensor device has a predetermined first limit value v HG or the lowering speed a predetermined second limit value v exceed SH . The two limit values can be the same or different and are preferably of the order of 0.1 m / sec. The limit values should be chosen so that the pump at these limits has a minimum speed on the order of 500 for the speed of the lifting cylinder min -1. At this or a higher speed, on the one hand, a sufficiently high degree of efficiency is ensured and, in particular, excessive wear of the pump is avoided. If the lifting cylinder is adjusted at a relatively low speed below the specified limit values, as is the case, for example, when starting from the rest position due to inertia and also at a selected crawl speed, the speed of the lifting cylinder will not exceed the speed of the electric motor and thus Pump, but changed over the volume or mass flow of the hydraulic oil flowing in the feed or return line.

In a preferred embodiment of the invention it is provided that the supply line has a branch line, via which hydraulic oil can be branched off from the supply line in load lifting operation, and that a flow control valve is arranged in the branch line, by means of which the hydraulic oil volume flow supplied to the hydraulic cylinder can be changed. When lifting a load from the rest position, the electric motor and thus the pump are suddenly brought to a preselected minimum speed of, for example, 500 min −1 and at the same time the current regulator valve in the branch line is opened completely. The pump conveys the hydraulic oil from the reservoir in the supply line, a not inconsiderable part of the hydraulic oils flowing out again through the branch line with the open flow control valve. If the flow control valve is now gradually closed, the volume flow of the hydraulic oil supplied to the hydraulic cylinder in the supply line increases, as a result of which the lifting cylinder is adjusted at an increasing speed. If the adjustment of the lifting cylinder is slower again, the flow control valve is opened accordingly and thus more hydraulic oil is discharged from the supply line via the branch line, so that the hydraulic oil volume flow supplied to the lifting cylinder decreases. In this way it is ensured that even with very small and / or very slow lifting movements of the lifting cylinder at speeds below the predetermined limit values, the electric motor or the pump are operated with a sufficient minimum speed. If after a complete closing of the flow control valve and thus the branch line a further increase in the lifting speed of the lifting cylinder is desired, this is achieved by increasing the speed of the pump.

The detection of the lifting or lowering speed of the Lift cylinder takes place directly by means of the sensor device on the lifting cylinder, either using a Displacement sensor system the current actual position of the load or of the lifting cylinder and taken into account the speed over time or also the speed tapped directly can be.

In a further development of the invention it is provided that a flow control valve is arranged in the return line, by means of which the volume flow of the hydraulic oil returned from the hydraulic cylinder to the storage container can be changed. When lowering the lifting cylinder or the load with low lowering speeds, the speed change is achieved solely by changing the flow cross section of the flow control valve and thus the volume or mass flow of the hydraulic oil derived from the lifting cylinder. The hydraulic oil flowing in the return line also flows through a hydraulic motor or the pump which acts as a hydraulic motor in this state, the electric motor rotating in idle. If the lowering speed reaches a value above the predetermined limit value, the change in the lowering speed can be achieved by regulating the electric motor to a certain speed, whereby a counter torque is generated, with such a lowering speed ensuring that the speed of the pump and thus of the electric motor is above the device-specific minimum speed, for example, 500 min -1. In this state, the potential energy of the overall system caused by the raised load is converted into electrical energy by the electric motor acting as a generator and supplied to the battery.

Although for the supply line and the return line individual flow control valves may be provided can, is in a preferred embodiment of the invention provided that the current control valve Line section of the return line at the same time part the branch line is, so that the flow control valve both when lifting and lowering the hydraulic Lift cylinder is effective in the manner mentioned.

In load-lowering mode, that which flows back to the storage container drives Hydraulic oil a hydraulic motor. This can be independent of the pump, is alternative however, it is also possible that the pump is in load-lowering mode works as a hydraulic motor.

The line arrangement is preferably provided such that the pump both in load lifting operation and in load lowering operation in the same direction from the hydraulic oil is flowed through and thus always in the same direction of rotation rotates, it is preferably provided that also the electric motor in both operating states in the turns in the same direction. In this way, the keep design effort low. Beyond that due to the same direction of rotation of the motor both in Load lifting operation as well as the load lowering the reaction times essential when changing the direction of movement shortened, which enables more precise positioning.

To maintain an approached lifting position to ensure and in case of system failure or a power failure a drop in the hydraulic Avoid lifting cylinder or the load is in the Return line a check valve may be arranged, which in the locked position is biased. In the event of a power failure close the shut-off valve and the flow control valve automatically and thus prevent the hydraulic oil from flows back into the reservoir in the hydraulic cylinder. It is particularly provided that the check valve is located near the flow control valve. Here if the engine control fails during the lowering process Holding function by the shut-off valve and the flow control valve ensured in a two-channel manner.

Further details and features of the invention are from the following description of an embodiment with reference to the drawing, the only figure is a circuit diagram of an inventive hydraulic lifting device shows.

A hydraulic lifting device shown in the figure 10 comprises a reservoir 11 for hydraulic oil, of one of several sections L1.1, L1.2 and L1.3 existing supply line L1 with two hydraulic lifting cylinders 13 is connected. The used below Information "upstream" and "downstream" refer to a Oil flow from the reservoir 11 to the lifting cylinders 13, i.e. in the feed direction for load lifting operation.

In the first section L1.1 of the feed line is L1 a first check valve 12 is arranged, the one Oil flow in the feed direction, i.e. to the lifting cylinders 13 allows and prevents backflow.

Downstream of the first check valve 12 is a hydraulic pump P arranged by means of an electric motor M is driven, the energy via a power connection 21 from a battery, not shown. Of the Pump P leads a leakage line L3 back into the reservoir 11.

A second section closes downstream of the pump P. L1.2 of the feed line L1, which leads to a check valve 15 leads between an open position in which one Flow in both directions is possible, and one Locking position is adjustable, in which only one oil flow in the feed direction, i.e. to the lifting cylinders 13, possible and backflow is prevented. The lock valve 15 is in a mechanical manner, for example by means of a Spring biased into a locked position, which is at one takes any power failure automatically.

Between the pump P and the check valve 15 is a second check valve 14 arranged, which also only an oil flow in the feed direction, i.e. to the lifting cylinders 13 allows and prevents backflow.

A third section closes the check valve 15 L1.3 of the supply line L1, which is located at its downstream located end in two connecting lines L4.1 and L4.2 branches, each to one of the hydraulic Guide lift cylinder 13.

In the third section L1.3 of the feed line L1 branches a drain line L5, which is a normally closed Has valve 17 and in the reservoir 11th leads back.

Between the second check valve 14 and the check valve 15 branches from the second section L1.2 of the Feed line L1 from a branch line L2, in which a Flow control valve 16 is arranged and between the first check valve 12 and the pump P in the first Section L1.1 of the feed line L1 opens.

Branches from the second section L1.2 of the feed line L1 between the pump P and the second check valve 14 a bypass line L6 in which a pressure relief valve 19 is arranged and in the drain line L5 between the valve 17 and the reservoir 11 flows. One branches from the bridging line L6 bypass line also opening into the drain line L5 L7 from, in which a further check valve 18 is arranged. This further check valve 18 is also between one Open position in which there is a flow in both directions is possible, and a locking position adjustable, in the only one flow from drain line L5 to the second Section L1.2 of the supply line L1 possible and a Flow in the opposite direction is prevented.

The two lifting cylinders 13 are each only schematic shown sensor device 20 associated with the current position of the lifting cylinder 13 or the load detected and a corresponding control signal to a processing unit in which the lifting or lowering speed the lifting cylinder is calculated.

The following are different modes of operation Lifting device 10 explains:

In load lifting operation, ie for lifting the lifting cylinders 13, hydraulic oil must be conveyed from the reservoir 11 through the supply line L1 into the corresponding chamber of the lifting cylinders 13. Starting from a standstill of the lifting cylinders 13, the current control valve 16 in the branch line 8 is opened completely and at the same time the electric motor M is brought to a minimum speed of 500 min −1 with the pump P. The hydraulic oil drawn in by the pump P from the reservoir 11 via the first section L1.1 of the supply line L1 and delivered via the continuing second section L1.2 is completely or at least almost completely via the branch line L8 in this state due to the fully open flow control valve 16 returned to a region of the feed line L1 located upstream of the pump P. The flow control valve 16 is then gradually closed, as a result of which an increasing proportion of the volume flow of hydraulic oil conveyed by the pump P passes through the third section L1.3 of the supply line and the supply lines L4.1 and L4.2 to the lifting cylinders 13, as a result of which they initially slow and then be raised with increasing speed. An increase in the lifting speed is achieved by reducing the flow cross-section of the flow control valve 16 and the associated increase in the volume flow of hydraulic oil to the lifting cylinders 13. Accordingly, the lifting speed can be reduced by increasing the flow cross section of the flow control valve and thus reducing the volume flow of hydraulic oil to the lifting cylinders. The maximum lifting speed to be set in this way is achieved when the flow control valve 16 is completely closed. If a further increase in the lifting speed of the lifting cylinder 13 is desired, this can be achieved by increasing the speed of the electric motor M and thus of the pump P.

The change in the lifting speed of the lifting cylinders 13, which takes place either by controlling the flow control valve 16 for the purpose of changing the flow cross section or by controlling the electric motor for the purpose of changing the speed, is carried out as a function of the current lifting speed, which is determined by the sensor devices 20. If the current lifting speed is below a predetermined limit value v HG , the lifting speed is changed solely by actuating the flow control valve. If the current stroke speed is above the limit v HG, changing the lifting speed is carried out solely by driving the electric motor M, it being ensured in this state that the rotational speed of the electric motor M is above a minimum speed, for example, 500 min. 1

During the load lowering operation, ie the lowering of the lifting cylinders 13, the hydraulic oil must be returned from the lifting cylinders into the storage container 11. For this purpose, the check valve 15 and the flow control valve 16 are opened. The hydraulic oil can then flow from the lifting cylinders 13 via the supply lines L4.1 and L4.2, the third section L1.3 of the supply line L1 and through the check valve 15 into the branch line L2, whereby it flows through the flow control valve 16 and into the first Section L1.1 of the feed line L1 flows in. The hydraulic oil is prevented from flowing directly back into the reservoir 11 by the first check valve 12. The hydraulic oil then flows through the pump P, which can work as a hydraulic motor in this state, and enters the bypass line L6 and from there via the bypass line L7 and the opened further shut-off valve 18 into the drain line L5 leading to the reservoir 11. At low lowering speeds of the lifting cylinders 13, which are detected by the sensor devices 20, the backflow of the hydraulic oils is achieved solely by actuating the flow control valve 16 in the branch line L8. The electric motor, which is driven by the pump P, which acts as a hydraulic motor and flows through the hydraulic oil in the same direction as in the load-lifting mode, operates in idle mode, so that the hydraulic oil is introduced into the reservoir 11 without pressure. A change in the lowering speed can be achieved by changing the flow cross-section of the flow control valve 16. Upon complete opening of the flow regulating valve 16, the pump P and the motor M to rotate at a speed corresponding to the minimum speed, for example 500 min. 1 The associated lowering speed of the lifting cylinder 13 corresponds to the limit value v SG .

If a higher lowering speed is desired, their change takes place via the control of the speed the electric motor M to generate a counter torque, the pump P flowing through and driving Hydraulic oil that acts as a generator in this state Electric motor drives, with an excess of energy on the electric motor M removed and via line 21 in the Battery is powered.

Claims (9)

  1. Hydraulic lifting device, in particular for battery-powered industrial trucks, with a pump (P) which can be driven by an electric motor (M), by means of which at least one hydraulic lifting cylinder (13) hydraulic oil from a reservoir (11) via a feed line (L1, L4.1, L4) during load lifting operation .2) can be supplied, the hydraulic oil in load-lowering operation from the lifting cylinder (13) via a return line (L4.1, L4.2, L1.3, L2, L1.1, L1.2, L6, L7, L5) below Flow through a hydraulic motor (P) driving the generator (M) and back into the reservoir (11), and with a control device for changing the lifting or lowering speed of the lifting cylinder (13), characterized in that the control device has a dimension Sensor device (20) for detecting the lifting or lowering speed of the lifting cylinder (13), the speed of the lifting cylinder (13) being controllable by means of the speed of the motor (M) when the detected stroke speed exceeds a first limit value v HG or the detected lowering speed exceeds a second limit value v SG , and the speed of the lifting cylinder (13) can be regulated by falling below the limit values by means of the hydraulic oil volume flow in the feed or return line.
  2. Lifting device according to claim 1, characterized in that the feed line is a branch line (L2) has, via the hydraulic oil in the lifting operation can be branched off from the feed line, and that in the Branch line a flow control valve (16) arranged by means of which the hydraulic cylinder (13) supplied hydraulic oil volume flow is changeable.
  3. Lifting device according to claim 1 or 2, characterized characterized in that in the return line Flow control valve (16) is arranged by means of whose is the volume flow from the hydraulic cylinder (13) returned to the storage container (11) Hydraulic oil is changeable.
  4. Lifting device according to claim 3, characterized in that the current control valve (16) Line section (L2) of the return line at the same time Is part of the branch line.
  5. Lifting device according to one of claims 1 to 4, characterized in that the pump (P) in the load lowering area works as a hydraulic motor.
  6. Lifting device according to one of claims 1 to 5, characterized in that the pump (P) both in Load lifting operation as well as load lowering operation in the flows in the same direction from the hydraulic oil is.
  7. Lifting device according to one of claims 1 to 6, characterized in that the electric motor (M) both in load lifting operation and in load lowering operation spins in the same direction.
  8. Lifting device according to one of claims 1 to 7, characterized in that in the return line a check valve preloaded in the blocking position (15) is arranged.
  9. Lifting device according to claim 8, characterized in that the check valve (15) near the flow control valve (16) is arranged.
EP20000108142 1999-05-10 2000-04-13 Hydraulic lifting device Expired - Lifetime EP1052215B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE1999121629 DE19921629B4 (en) 1999-05-10 1999-05-10 Hydraulic lifting device
DE19921629 1999-05-10

Publications (3)

Publication Number Publication Date
EP1052215A2 true EP1052215A2 (en) 2000-11-15
EP1052215A3 EP1052215A3 (en) 2005-09-21
EP1052215B1 EP1052215B1 (en) 2012-02-15

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Family Applications (1)

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EP20000108142 Expired - Lifetime EP1052215B1 (en) 1999-05-10 2000-04-13 Hydraulic lifting device

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EP (1) EP1052215B1 (en)
DE (1) DE19921629B4 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1188709A2 (en) * 2000-09-18 2002-03-20 Still Gmbh Lifting device
EP1239167A1 (en) * 2001-03-07 2002-09-11 Dambach Lagersysteme GmbH &amp; Co. KG Hydraulic lifting device
DE102004039848A1 (en) * 2004-08-17 2006-03-09 Jungheinrich Ag Fluid circuit and truck with fluid circuit
EP2123594A1 (en) * 2008-05-23 2009-11-25 BT Products AB Industrial lift truck with speed control
CN102116285A (en) * 2010-01-05 2011-07-06 雷蒙德股份有限公司 Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
WO2020011957A1 (en) * 2018-07-11 2020-01-16 Parker Hannifin Emea S.À.R.L. A control valve assembly for a load handling vehicle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10154449A1 (en) * 2001-11-06 2003-05-15 Dambach Lagersysteme Gmbh & Co Hydraulic lifting device, in particular for battery-powered industrial trucks, and method for controlling it
DE102011016542A1 (en) * 2011-04-08 2012-10-11 Jungheinrich Aktiengesellschaft Industrial truck, in particular reach truck with a mast

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548296A (en) * 1980-02-26 1985-10-22 Oil Drive Kogyo, Ltd. Hydraulic elevator
DE4416173A1 (en) * 1994-05-06 1995-11-09 Jungheinrich Ag Hydraulic lifting system for battery operated ground conveyor vehicle
DE4317782C2 (en) * 1993-05-28 1996-01-18 Jungheinrich Ag Hydraulic lifting device for battery-powered industrial trucks or the like
EP0908413A2 (en) * 1997-10-08 1999-04-14 Still Wagner GmbH &amp; Co. KG Lift truck with a load grasping device and method for descending the load grasping device
DE19748782A1 (en) * 1997-11-05 1999-05-06 Clark Material Handling Gmbh Hydraulic lifting arrangement for battery-powered fork-lift truck or similar

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2095861B (en) * 1981-03-31 1985-01-03 Meidensha Electric Mfg Co Ltd Fork lift control system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548296A (en) * 1980-02-26 1985-10-22 Oil Drive Kogyo, Ltd. Hydraulic elevator
DE4317782C2 (en) * 1993-05-28 1996-01-18 Jungheinrich Ag Hydraulic lifting device for battery-powered industrial trucks or the like
DE4416173A1 (en) * 1994-05-06 1995-11-09 Jungheinrich Ag Hydraulic lifting system for battery operated ground conveyor vehicle
EP0908413A2 (en) * 1997-10-08 1999-04-14 Still Wagner GmbH &amp; Co. KG Lift truck with a load grasping device and method for descending the load grasping device
DE19748782A1 (en) * 1997-11-05 1999-05-06 Clark Material Handling Gmbh Hydraulic lifting arrangement for battery-powered fork-lift truck or similar

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1188709A2 (en) * 2000-09-18 2002-03-20 Still Gmbh Lifting device
EP1188709A3 (en) * 2000-09-18 2005-04-13 Still Gmbh Lifting device
EP1239167A1 (en) * 2001-03-07 2002-09-11 Dambach Lagersysteme GmbH &amp; Co. KG Hydraulic lifting device
DE102004039848A1 (en) * 2004-08-17 2006-03-09 Jungheinrich Ag Fluid circuit and truck with fluid circuit
US7441406B2 (en) 2004-08-17 2008-10-28 Jungheinrich Aktiengesellschaft Fluid circuit and industrial truck having a fluid circuit
EP2123594A1 (en) * 2008-05-23 2009-11-25 BT Products AB Industrial lift truck with speed control
WO2009141242A1 (en) * 2008-05-23 2009-11-26 Bt Products Ab Industrial lift truck with speed control
CN102116285A (en) * 2010-01-05 2011-07-06 雷蒙德股份有限公司 Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
US20110162447A1 (en) * 2010-01-05 2011-07-07 John Bryant Kirk Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
US8196464B2 (en) * 2010-01-05 2012-06-12 The Raymond Corporation Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
AU2010257399B2 (en) * 2010-01-05 2014-05-22 The Raymond Corporation Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
CN102116285B (en) * 2010-01-05 2015-03-04 雷蒙德股份有限公司 Apparatus and method for monitoring a hydraulic pump on a material handling vehicle
WO2020011957A1 (en) * 2018-07-11 2020-01-16 Parker Hannifin Emea S.À.R.L. A control valve assembly for a load handling vehicle

Also Published As

Publication number Publication date
DE19921629B4 (en) 2005-05-25
EP1052215B1 (en) 2012-02-15
EP1052215A3 (en) 2005-09-21
DE19921629A1 (en) 2000-11-16

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