Excavator with hydraulic drive system

摘要

The excavator has hydraulic driving (5) and excavator circuits (8). It has a pilot pressure source and a feeder path valve (10), charged with pilot pressure by the source to move it between a feed position, in which oil is fed from the first into the second circuit, and a closing position, in which the circuits are separated. A first path valve (16) is charged with oil from the driving circuit, and switched from closing into connection position, when the oil pressure in that circuit rises above a set level. A second path valve (17) in series with the first one, is switched from closing into connection position by a switch (14) via a solenoid (17a), when the oil pressure in the driving circuit rises above the set level.