| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a hydraulic circuit for a back hoe shovel, which facilitates connection of circuits, and also facilitates switching operation of the circuits. SOLUTION: According to the back hoe shovel which can mount thereon a long attachment and a standard attachment in an exchangeable manner, a controllable pressure reducing valve is arranged across a pilot line. When the long attachment is mounted on the shovel, the speed of an actuator is regulated, while the regulation of the actuator speed is canceled to increase the speed when the standard attachment is mounted on the shovel.</p> |
