| 摘要 |
<p>PURPOSE:To improve the working efficiency by connecting a front boom rotational angle detecting sensor to a changeover valve for connecting a pilot pressure oil pressure source to a pilot port for pump regulator maximum flow cut control. CONSTITUTION:When an offset oil pressure remote control valve 14 is operated, an offset cylinder 10 is extended/contracting and a front boom makes rotational movement, and when it is detected by means of an angle sensor 43 that the boom is located within a front center portion angle range, a signal is inputted into a controller 50. When an engine 52 is rotated at a high speed, first and second pumps 22, 23 discharge their maximum flows and quicken the speed of side face digging. Also, when it is detected that the boom is in a right oblique or left oblique front angle range, a solenoid changeover valve 48 is changed over to an open oil passage position (B) from a tank linkage oil passage position (A) by the controller 50, and pilot pressure from a pump 26 acts on a maximum flow cut control pilot port 47, and the flows of the pumps 22, 23 are cut by operating regulators 44, 45, and the speed of side face digging is slowed.</p> |
