Hydraulic circuit of working machine

摘要

A hydraulic circuit for a working machine is provided which prevents a decrease in the working speed of a clamshell bucket upon expansion of an expansion arm, so that improvement of the operability can be achieved. A hydraulic circuit for a working machine is configured such that a clamshell bucket is attached to a tip end of an expansion arm and the expansion arm and the clamshell bucket are operated by pressure oil supplied from a common pressure source. The operating pressure is reduced for driving the expansion arm to the expansion side based on the operating pressure for opening the clamshell bucket. By the configuration, the clamshell bucket can be opened rapidly, and improvement of the operability is achieved.