EP0461258A1 - Control unit for upper swivel body of hydraulic excavator - Google Patents
Control unit for upper swivel body of hydraulic excavator Download PDFInfo
- Publication number
- EP0461258A1 EP0461258A1 EP90903220A EP90903220A EP0461258A1 EP 0461258 A1 EP0461258 A1 EP 0461258A1 EP 90903220 A EP90903220 A EP 90903220A EP 90903220 A EP90903220 A EP 90903220A EP 0461258 A1 EP0461258 A1 EP 0461258A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- driving motor
- pressure
- swivel body
- upper swivel
- controller
- 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.)
- Withdrawn
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/08—Superstructures; Supports for superstructures
- E02F9/10—Supports for movable superstructures mounted on travelling or walking gears or on other superstructures
- E02F9/12—Slewing or traversing gears
- E02F9/121—Turntables, i.e. structure rotatable about 360°
- E02F9/123—Drives or control devices specially adapted therefor
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/08—Superstructures; Supports for superstructures
- E02F9/10—Supports for movable superstructures mounted on travelling or walking gears or on other superstructures
- E02F9/12—Slewing or traversing gears
- E02F9/121—Turntables, i.e. structure rotatable about 360°
- E02F9/128—Braking systems
Definitions
- This invention relates to a hydraulic drive unit for an upper swivel body equipped with a driver's cabin and working machine of a hydraulic excavator, and more specifically, to a control unit for an upper swivel body of a hydraulic excavator by which an abrupt pressure rise in a hydraulic line is prevented when the upper swivel body having a large inertia is accelerated or decelerated.
- a control unit for an upper swivel body of this kind of a hydraulic excavator is arranged such that a port of an upper swivel body driving motor 3 is connected to the discharge line of a hydraulic pump 1 through a meter-in-poppet valve 2 and the other port of the driving motor 3 is connected to the return line to a tank 5 through a meter-out-poppet valve 4. Further, the other port of the driving motor 3 is connected to the discharge line of the hydraulic pump 1 through a meter-in-poppet valve 12 and the one port of the driving motor 3 is connected to the return line to the tank 5 through a meter-out-poppet valve 15.
- the pilot line of the meter-in-poppet valve 2 is formed from the upstream side to the downstream side thereof through an orifice 6 and a proportional solenoid valve 8 controlled by a controller 7, and the pilot line of the meter-out-poppet valve 4 is formed from the upstream side to the downstream side thereof through an orifice 9 and a proportional solenoid valve 8a controlled by the controller 7.
- the pilot line of the meter-in-poppet valve 12 is formed from the upstream to the downstream thereof through an orifice 13 and a proportional solenoid valve 14 controlled by the controller 7
- the pilot line of the meter-out-poppet valve 15 is formed from the upstream side to the downstream side thereof through an orifice 16 and a proportional solenoid valve 14a controlled by the controller 7.
- a swinging speed signal is output to the solenoid A of the proportional solenoid valves 8, 8a from the controller 7 in accordance with an actuated amount of an electric lever 17, so that a pilot flow of fluid having an amount corresponding to the signal is produced from the upstream side to the downstream side of the meter-in-poppet valve 2. Accordingly, a pressure difference corresponding to the above pilot flow is produced between the upstream and the downstream of the meter-in-poppet valve 2 by the orifice 6, whereby a degree of opening of the meter-in-poppet valve 2 is determined.
- An amount of fluid passing through the meter-in-poppet valve 2 is determined in accordance with the degree of opening. Further, a pilot flow of fluid having an amount corresponding to the above signal is produced between the upstream and the downstream of the meter-out-poppet valve 4. Accordingly, a pressure difference corresponding to the above pilot flow is produced between the upstream and the downstream of the meter-out-poppet valve 4 by the orifice 9, whereby a degree of opening of the meter-out-poppet valve 4 is determined. An amount of fluid passing through the meter-out-poppet valve 4 is determined in accordance with the degree of opening. A swinging speed of the driving motor 3 to the right is determined by the amount of fluid passing through the meter-in-poppet valve 2 and the amount of fluid passing through the meter-out-poppet valve 4.
- a swinging speed signal is output to the solenoid B of the proportional solenoid valves 14, 14a from the controller 7 in accordance with an actuated amount of the electric lever 17, so that a pilot flow of fluid having an amount corresponding to the signal is produced from the upstream side to the downstream side of the meter-in-poppet valve 12 and between the upstream and the downstream of the meter-out-poppet valve 15. Accordingly, a swinging speed of the upper swivel body driving motor 3 to the left is determined in the same manner as that of the above swinging to the right.
- an object of this invention is to provide a control unit for an upper swivel body of a hydraulic excavator by which the upper swivel body driving motor 3 can be smoothly controlled in acceleration and deceleration, an operator is not required to have considerable practice, and swinging can be easily controlled.
- a control unit for an upper swivel body of a hydraulic excavator comprises an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump to the inlet of an upper swivel body driving motor through a meter-in-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by a controller and connecting the outlet of the driving motor to the return line to a tank through a meter-out-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by the controller, wherein a pair of pressure control valves controlled together with the proportional solenoid valves by the controller are connected to the discharge line and the return line, respectively so as to control an input pressure and an output pressure of the driving motor when the driving motor rotates to the right.
- one of the pressure control valves controls and increases the driving pressure of the upper swivel body driving motor in accordance with a speed increase signal of the driving motor output from the controller, and the other pressure control valve controls and decreases the braking pressure of the driving motor in accordance with a speed decrease signal of the driving motor output from the controller.
- a control unit for an upper swivel body of a hydraulic excavator comprising an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump to the outlet of an upper swivel body driving motor through a meter-in-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by a controller and connecting the inlet of the driving motor to the return line to a tank through a meter-out-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by the controller
- a pair of pressure control valves controlled together with the proportional solenoid valves by the controller are connected to the discharge line and the return line, respectively so as to control an input pressure and an output pressure of the driving motor when the driving motor rotates to the left (reversely).
- the driving pressure or the braking pressure in the driving line of the driving motor is risen, but since the value thereof is controlled by the pressure control valves, an abrupt rise of the pressure can be prevented, whereby the upper swivel body driving motor can be smoothly controlled. Further, since the driving pressure or the braking pressure of the upper swivel body is controlled in accordance with the amount of acceleration or deceleration thereof, the amount of operation carried out to the upper swivel body by an operator is made uniform and thus the operator need not to have considerable practice.
- Figure 1 is an electro-hydraulic circuit diagram showing the embodiment of this invention, wherein the same numerals as used in Figure 3 showing the conventional electro-hydraulic circuit are used to designate components similar to those used in Figure 3 and they are not described further.
- the high pressure port of a pressure control valve 11 is connected between an orifice 9 equipped with the pilot line of a meter-out-poppet valve 4 and the proportional solenoid valve 8a of a meter-in-poppet valve 2, and the low pressure port of the pressure control valve 11 is connected to the return line to a tank 5.
- the high pressure port of a pressure control valve 10 is connected between an orifice 16 equipped with the pilot line of a meter-out-poppet valve 15 and the proportional solenoid valve 14a of a meter-in-poppet valve 12, and the low pressure port of the pressure control valve 10 is connected to the return line to the tank 5.
- an acceleration signal corresponding to a desired swinging speed of the driving motor 3 is output from a controller 7 to the solenoid A for the proportional solenoid valve 8 of the meter-in-poppet valve 2 and a signal is output to the solenoid C of the pressure control valve 10 to provide a set pressure corresponding to a degree of opening signal of the poppet valve shown in Figure 2.
- the hydraulic pressure thereof is set to be gradually increased in accordance with the degree of opening of the meter-in-poppet valve 2 as shown in Figure 2, and thus an abrupt rise of the driving pressure of the driving motor 3 can be prevented.
- a deceleration signal corresponding to a desired swinging speed in the driving motor 3 is output from the controller 7 to the solenoid A for the proportional solenoid valve 8a of the meter-out-poppet valve 9 and a signal is output to the solenoid D of the pressure control valve 11 to provide a set pressure corresponding to a degree of opening signal of the poppet valve shown in Figure 2.
- the hydraulic pressure thereof is set to be gradually increased in accordance with the degree of opening of the meter-out-poppet valve 9 as shown in Figure 2, and thus an abrupt rise of the braking pressure of the driving motor 3 can be prevented. Further, since an amount to actuate the upper swivel body is made uniform, an operator can easily perform a swinging operation.
- shock conventionally caused to a hydraulic excavator when it swings can be decreased and an operator is not required to have considerable practice to perform a swinging operation.
- This invention is applied to a hydraulic drive unit for an upper swivel body equipped with a driver's cabin and working machine of a hydraulic excavator, and particularly useful as a control unit to prevent an abrupt pressure rise in a hydraulic line which is caused when the upper swivel body is accelerated or decelerated.
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
This invention relates to a control unit for an upper swivel body of a hydraulic excavator which is used in order to prevent an abrupt pressure rise in a hydraulic line and to make a smooth swivel control when the upper swivel body equipped with a driver's cabin and a working machine and having a large inertia is accelerated or decelerated. To this end, pressure control valves (10), (11) controlled together with proportional solenoid valves (8), (8a) by a controller (7) are connected to a discharge line and return line of a hydraulic pump (1) so as to control an input pressure and an output pressure of an upper swivel body driving motor (3) when the motor rotates. Particularly, one of the pressure control valves (10) controls and increases the driving pressure of the driving motor (3) in accordance with a speed increase signal outputted from the controller (7) and the other pressure control valve (11) controls and decrease the braking pressure of the driving motor (3) in accordance with a speed decrease signal outputted from the controller (7).
Description
- This invention relates to a hydraulic drive unit for an upper swivel body equipped with a driver's cabin and working machine of a hydraulic excavator, and more specifically, to a control unit for an upper swivel body of a hydraulic excavator by which an abrupt pressure rise in a hydraulic line is prevented when the upper swivel body having a large inertia is accelerated or decelerated.
- As shown in Figure 3, a control unit for an upper swivel body of this kind of a hydraulic excavator is arranged such that a port of an upper swivel
body driving motor 3 is connected to the discharge line of a hydraulic pump 1 through a meter-in-poppet valve 2 and the other port of the drivingmotor 3 is connected to the return line to atank 5 through a meter-out-poppet valve 4. Further, the other port of thedriving motor 3 is connected to the discharge line of the hydraulic pump 1 through a meter-in-poppet valve 12 and the one port of thedriving motor 3 is connected to the return line to thetank 5 through a meter-out-poppet valve 15. The pilot line of the meter-in-poppet valve 2 is formed from the upstream side to the downstream side thereof through anorifice 6 and aproportional solenoid valve 8 controlled by acontroller 7, and the pilot line of the meter-out-poppet valve 4 is formed from the upstream side to the downstream side thereof through anorifice 9 and aproportional solenoid valve 8a controlled by thecontroller 7. On the other hand, the pilot line of the meter-in-poppet valve 12 is formed from the upstream to the downstream thereof through anorifice 13 and aproportional solenoid valve 14 controlled by thecontroller 7, and the pilot line of the meter-out-poppet valve 15 is formed from the upstream side to the downstream side thereof through anorifice 16 and aproportional solenoid valve 14a controlled by thecontroller 7. - When the upper swivel body arranged as described above is to be swung to the right, a swinging speed signal is output to the solenoid A of the
proportional solenoid valves controller 7 in accordance with an actuated amount of anelectric lever 17, so that a pilot flow of fluid having an amount corresponding to the signal is produced from the upstream side to the downstream side of the meter-in-poppet valve 2. Accordingly, a pressure difference corresponding to the above pilot flow is produced between the upstream and the downstream of the meter-in-poppet valve 2 by theorifice 6, whereby a degree of opening of the meter-in-poppet valve 2 is determined. An amount of fluid passing through the meter-in-poppet valve 2 is determined in accordance with the degree of opening. Further, a pilot flow of fluid having an amount corresponding to the above signal is produced between the upstream and the downstream of the meter-out-poppet valve 4. Accordingly, a pressure difference corresponding to the above pilot flow is produced between the upstream and the downstream of the meter-out-poppet valve 4 by theorifice 9, whereby a degree of opening of the meter-out-poppet valve 4 is determined. An amount of fluid passing through the meter-out-poppet valve 4 is determined in accordance with the degree of opening. A swinging speed of the drivingmotor 3 to the right is determined by the amount of fluid passing through the meter-in-poppet valve 2 and the amount of fluid passing through the meter-out-poppet valve 4. - When the upper swivel body is to be swung to the left, a swinging speed signal is output to the solenoid B of the
proportional solenoid valves controller 7 in accordance with an actuated amount of theelectric lever 17, so that a pilot flow of fluid having an amount corresponding to the signal is produced from the upstream side to the downstream side of the meter-in-poppet valve 12 and between the upstream and the downstream of the meter-out-poppet valve 15. Accordingly, a swinging speed of the upper swivelbody driving motor 3 to the left is determined in the same manner as that of the above swinging to the right. On the other hand, since signals corresponding to the signals output to the solenoids A and B are also output to the dischargeamount control unit 1a of the hydraulic pump 1 from thecontroller 7, the hydraulic pump 1 is controlled to discharge fluid the amount of which corresponds to the amount of fluid passing thorough the meter-in-poppet valves poppet valves - Since, however, the upper swivel body has a large inertial, a driving hydraulic pressure or braking hydraulic fluid pressure is abruptly risen when the upper swivel
body driving motor 3 is accelerated or decelerated regardless of that the upper swivel body swings to the right or to the left, operating fluid returns to the tank through maximum hydraulicpressure regulating valves motor 3 is decreased by the amount of the returned operating fluid. Therefore, when an operator controls the drivingmotor 3, the operator must actuate the electric lever additionally, taking into consideration the amount of the operating fluid returning to the tank through the maximum hydraulicpressure regulating valves body driving motor 3 can be smoothly controlled in acceleration and deceleration, an operator is not required to have considerable practice, and swinging can be easily controlled. - A control unit for an upper swivel body of a hydraulic excavator according to this invention comprises an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump to the inlet of an upper swivel body driving motor through a meter-in-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by a controller and connecting the outlet of the driving motor to the return line to a tank through a meter-out-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by the controller, wherein a pair of pressure control valves controlled together with the proportional solenoid valves by the controller are connected to the discharge line and the return line, respectively so as to control an input pressure and an output pressure of the driving motor when the driving motor rotates to the right. In particular, one of the pressure control valves controls and increases the driving pressure of the upper swivel body driving motor in accordance with a speed increase signal of the driving motor output from the controller, and the other pressure control valve controls and decreases the braking pressure of the driving motor in accordance with a speed decrease signal of the driving motor output from the controller.
- Further, in a control unit for an upper swivel body of a hydraulic excavator comprising an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump to the outlet of an upper swivel body driving motor through a meter-in-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by a controller and connecting the inlet of the driving motor to the return line to a tank through a meter-out-poppet valve the degree of opening of which is controlled by a proportional solenoid valve controlled by the controller, a pair of pressure control valves controlled together with the proportional solenoid valves by the controller are connected to the discharge line and the return line, respectively so as to control an input pressure and an output pressure of the driving motor when the driving motor rotates to the left (reversely).
- When the upper swivel body driving motor is swung to the right or to the left in response to a signal from the controller and accelerated or decelerated, the driving pressure or the braking pressure in the driving line of the driving motor is risen, but since the value thereof is controlled by the pressure control valves, an abrupt rise of the pressure can be prevented, whereby the upper swivel body driving motor can be smoothly controlled. Further, since the driving pressure or the braking pressure of the upper swivel body is controlled in accordance with the amount of acceleration or deceleration thereof, the amount of operation carried out to the upper swivel body by an operator is made uniform and thus the operator need not to have considerable practice.
-
- Figure 1 is an electro-hydraulic circuit diagram showing an embodiment of this invention;
- Figure 2 is a diagram showing the relationship between a degree of opening of a poppet valve and a driving pressure or braking pressure in Figure 1; and
- Figure 3 is an electro-hydraulic circuit diagram showing a prior art.
- An embodiment of this invention will be described in detail with reference to Figures 1 and 2. Figure 1 is an electro-hydraulic circuit diagram showing the embodiment of this invention, wherein the same numerals as used in Figure 3 showing the conventional electro-hydraulic circuit are used to designate components similar to those used in Figure 3 and they are not described further. In Figure 1, the high pressure port of a
pressure control valve 11 is connected between anorifice 9 equipped with the pilot line of a meter-out-poppet valve 4 and theproportional solenoid valve 8a of a meter-in-poppet valve 2, and the low pressure port of thepressure control valve 11 is connected to the return line to atank 5. On the other hand, the high pressure port of apressure control valve 10 is connected between anorifice 16 equipped with the pilot line of a meter-out-poppet valve 15 and theproportional solenoid valve 14a of a meter-in-poppet valve 12, and the low pressure port of thepressure control valve 10 is connected to the return line to thetank 5. - When an upper swivel
body driving motor 3 is to be swung to the right and accelerated, an acceleration signal corresponding to a desired swinging speed of thedriving motor 3 is output from acontroller 7 to the solenoid A for theproportional solenoid valve 8 of the meter-in-poppet valve 2 and a signal is output to the solenoid C of thepressure control valve 10 to provide a set pressure corresponding to a degree of opening signal of the poppet valve shown in Figure 2. Although the driving pressure of the drivingmotor 3 is risen by the inertia of the upper swivel body at this time, the hydraulic pressure thereof is set to be gradually increased in accordance with the degree of opening of the meter-in-poppet valve 2 as shown in Figure 2, and thus an abrupt rise of the driving pressure of the drivingmotor 3 can be prevented. On the other hand, when thedriving motor 3 is to be decelerated, a deceleration signal corresponding to a desired swinging speed in thedriving motor 3 is output from thecontroller 7 to the solenoid A for theproportional solenoid valve 8a of the meter-out-poppet valve 9 and a signal is output to the solenoid D of thepressure control valve 11 to provide a set pressure corresponding to a degree of opening signal of the poppet valve shown in Figure 2. Although the braking pressure of the drivingmotor 3 is risen by the inertia of the upper swivel body at this time, the hydraulic pressure thereof is set to be gradually increased in accordance with the degree of opening of the meter-out-poppet valve 9 as shown in Figure 2, and thus an abrupt rise of the braking pressure of the drivingmotor 3 can be prevented. Further, since an amount to actuate the upper swivel body is made uniform, an operator can easily perform a swinging operation. - When the driving
motor 3 is be swung to the left (reversely) and accelerated or decelerated, prescribed signals are output to the meter-in-poppet valve 12, the meter-out-poppet valve 15, the solenoid B for theproportional solenoid valves pressure control valves driving motor 3, as in the acceleration or deceleration when the upper swivel body is swung to the right. Further, since an amount to operate the upper swivel body is made uniform, an operator can easily perform an swinging operation. - Because of the above description, shock conventionally caused to a hydraulic excavator when it swings can be decreased and an operator is not required to have considerable practice to perform a swinging operation.
- This invention is applied to a hydraulic drive unit for an upper swivel body equipped with a driver's cabin and working machine of a hydraulic excavator, and particularly useful as a control unit to prevent an abrupt pressure rise in a hydraulic line which is caused when the upper swivel body is accelerated or decelerated.
Claims (4)
- A control unit for an upper swivel body of a hydraulic excavator, comprising an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump (1) to the inlet of an upper swivel body driving motor (3) through a meter-in-poppet valve (2) the degree of opening of which is controlled by a proportional solenoid valve (8) controlled by a controller (7) and connecting the outlet of said driving motor (3) to the return line to a tank (5) through a meter-out-poppet valve (4) the degree of opening of which is controlled by a proportional solenoid valve (8a) controlled by the controller (7), wherein pressure control valves (10), (11) controlled together with said proportional solenoid valves (8), (8a) by said controller (7) are connected to said discharge line and said return line, respectively so as to control an input pressure and an output pressure of said driving motor (3) when said driving motor (3) rotates to the right.
- A control unit for an upper swivel body of a hydraulic excavator according to claim 1, wherein one of said pressure control valves (10) controls and increases the driving pressure of said upper swivel body driving motor (3) in accordance with a speed increase signal of said driving motor (3) output from said controller (7), and the other pressure control valve (11) controls and decreases the braking pressure of said driving motor (3) in accordance with a speed decrease signal of said driving motor (3) output from said controller (7).
- A control unit for an upper swivel body of a hydraulic excavator, comprising an electro-hydraulic circuit formed by connecting the discharge line of a hydraulic pump (1) to the outlet of an upper swivel body driving motor (3) through a meter-in-poppet valve (12) the degree of opening of which is controlled by a proportional solenoid valve (14) controlled by a controller (7) and connecting the inlet of said driving motor (3) to the return line to a tank (5) through a meter-out-poppet valve (15) the degree of opening of which is controlled by a proportional solenoid valve (14a) controlled by the controller (7), wherein pressure control valves (10), (11) controlled together with said proportional solenoid valves (14), (14a) by said controller (7) are connected to said return line and said discharge line, respectively so as to control an input pressure and an output pressure of said driving motor (3) when said driving motor (3) rotates to the left (reversely).
- A control unit for an upper swivel body of a hydraulic excavator according to claim 3, wherein one of said pressure control valves (11) controls and increases the driving pressure of said upper swivel body driving motor (3) in accordance with a speed increase signal of said driving motor (3) output from saidcontroller (7), and the other pressure control valve (10) controls and decreases the braking pressure of said driving motor (3) in accordance with a speed decrease signal of said driving motor (3) output from said controller (7).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4698489A JPH02225730A (en) | 1989-02-28 | 1989-02-28 | Controller of upper part swiveling body in hydraulic excavator |
JP46984/89 | 1989-02-28 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0461258A1 true EP0461258A1 (en) | 1991-12-18 |
EP0461258A4 EP0461258A4 (en) | 1993-03-31 |
Family
ID=12762482
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19900903220 Withdrawn EP0461258A4 (en) | 1989-02-28 | 1990-02-16 | Control unit for upper swivel body of hydraulic excavator |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0461258A4 (en) |
JP (1) | JPH02225730A (en) |
WO (1) | WO1990010117A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0791753A1 (en) * | 1994-12-08 | 1997-08-27 | Komatsu Ltd. | Device for preventing the reversal of a hydraulic actuator |
US6052636A (en) * | 1997-08-04 | 2000-04-18 | Caterpillar Inc. | Apparatus and method for positioning an excavator housing |
EP0942103B1 (en) * | 1998-03-11 | 2003-10-01 | Poclain Hydraulics Industrie | Valve device for an hydraulic motor driving a large inertial mass |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59126829A (en) * | 1983-01-10 | 1984-07-21 | Hitachi Constr Mach Co Ltd | Oil pressure controller for oil-pressure shovel |
JPH0663265B2 (en) * | 1985-11-29 | 1994-08-22 | 株式会社小松製作所 | Hydraulic circuit of construction machinery |
JPH0431326Y2 (en) * | 1986-04-30 | 1992-07-28 |
-
1989
- 1989-02-28 JP JP4698489A patent/JPH02225730A/en active Pending
-
1990
- 1990-02-16 EP EP19900903220 patent/EP0461258A4/en not_active Withdrawn
- 1990-02-16 WO PCT/JP1990/000184 patent/WO1990010117A1/en not_active Application Discontinuation
Non-Patent Citations (2)
Title |
---|
No further relevant documents disclosed * |
See also references of WO9010117A1 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0791753A1 (en) * | 1994-12-08 | 1997-08-27 | Komatsu Ltd. | Device for preventing the reversal of a hydraulic actuator |
EP0791753A4 (en) * | 1994-12-08 | 2000-01-26 | Komatsu Mfg Co Ltd | Device for preventing the reversal of a hydraulic actuator |
US6052636A (en) * | 1997-08-04 | 2000-04-18 | Caterpillar Inc. | Apparatus and method for positioning an excavator housing |
EP0942103B1 (en) * | 1998-03-11 | 2003-10-01 | Poclain Hydraulics Industrie | Valve device for an hydraulic motor driving a large inertial mass |
Also Published As
Publication number | Publication date |
---|---|
EP0461258A4 (en) | 1993-03-31 |
WO1990010117A1 (en) | 1990-09-07 |
JPH02225730A (en) | 1990-09-07 |
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