| 摘要 |
<p>PURPOSE:To raise the efficiency of operations by providing a throttle valve by which to form a throttle path when applying oil pressure signals to the pilot oil chamber of an oil-pressure switch valve for an actuator of high load pressure and also to form an open path when the signals disappear. CONSTITUTION:When an operating lever 38 is fully tilted for raising a boom and high pilot pressure oil from a pilot valve 15 flows into a pilot oil path 30, the spool of foil pressure switch valves 9 and 6 moves to D-position, and pressure oil in first and second pumps 2 and 3 is ready to flow into the boom cylinder 13. When operating the operating lever of a slewing motor 12, at the same time, a throttle valve 16 is switched from F-position to G-position as the pilot pressure for operating the boom rises. Pressure oil passing through an oil path 34 from the branched oil path of the oil path 23 to an oil pressure switch valve 14 is throttled at G-position path of the throttle valve 16, and the pressure oil of the pump 2 is properly distributed to the switch valve 6.</p> |
