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公开(公告)号：EP0436740A4
公开(公告)日：1991-09-11
申请号：EP90911699
申请日：1990-08-02
CPC分类号： E02F3/437
摘要： This invention relates to linear excavation by a hydraulic excavator, such as a power shovel, having three service machines, a boom, an arm and a bucket. An oil pressure in an oil chamber on the boom-down side of a boom cylinder is introduced into a tank while kept at a predetermined set pressure at the time of linear excavation and the oil pressure on the boom-up side is led to the tank through a check valve for inhibiting the outflow of the oil so as to keep the boom under a so-called "float state" and to execute linear excavation by the operation of only the arm and the bucket. The present invention disposes also an automatic bucket driving system for driving and controlling automatically the bucket to a set bucket angle and operation this automatic bucket driving system at the time of linear excavation so as to further reduce the load on the operator.
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公开(公告)号：EP0402474A4
公开(公告)日：1992-06-24
申请号：EP89913242
申请日：1989-11-29
CPC分类号： E02F9/2296 , E02F9/2242 , E02F9/2282 , E02F9/2292
摘要： A service valve circuit in a hydraulic excavator having a predetermined actuator operation valve and which is connected for operating a special attachment. A confluence valve (17) which effects electromagnetic proportional flow-rate control is provided in a confluence circuit (16) that makes communication betwen the inflow circuits (3F, 3R) of two variable pumps (2F, 2R). There are further provided an electric switch (21) which turns on or off the confluence valve (17) depending upon a required flow rate, and a volume (22) which adjusts the flow rate after passing the confluence valve (17) over a range of a maximum of 1 to 2 pumps depending upon the required flow rate. The necessity of confluence for the flow rate required by the special attachment (e) or the confluent flow rate is set in advance to eliminate excess or lack of confluent flow rate. Therefore, there is no need of adjusting the flow rate depending on the number of revolutions of the engine, and no delay develops in the operation even when the operation of special attachment is switched into the turning operation or the running operation.
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公开(公告)号：EP0448716A4
公开(公告)日：1992-08-26
申请号：EP90900989
申请日：1989-12-18
CPC分类号： E02F3/438 , E02F9/2296
摘要： The teaching/playback method of a working machine in accordance with the present invention is the method which is used for automating the operations of a hydraulic excavator and other construction equipment. The operations of a working machine actuator by an operator are stored and are played back in order to carry out automatically the same operation. Particularly, the present method makes it possible to carry out the same operation as the operation at the time of teaching even when a load condition to the working machine actuator at the time of teaching changes at the time of playback. To this end, a pump delivery quantity at the time of teaching and a feed flow rate to each working machine actuator are stored. When the pump delivery quantity changes due to the change of the load at the time of playback, an output control of an engine is conducted so that the pump delivery quantity is in conformity with the delivery quantity at the time of teaching. When the feed flow rate to the working machine actuator changes, a flow rate regulating valve disposed in its inflow circuit is controlled so that the pump delivery quantity is also in conformity with the flow rate at the time of teaching.
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