| 摘要 |
PURPOSE:To enable a bucket to be selectively switched to horizontal movement or circular movement by providing a switching valve between the level cylinder of an oil-pressure circuit having a function to automatically and horizontally push out the bucket and a boom cylinder. CONSTITUTION:A switching valve 22 is provided in pipelines 10 and 11 leading a level cylinder 9 with a boom cylinder 6 and held at a switching position (m) and a returning position (n) through a shuttle valve 23 to be controlled by two signal circuits (b) and (g). In such a system, when a bucket 5 is moved circularly, the switching valve 25 is switched at a switching position (y), and thereby the switching valve 22 is switched to a switching position (m) to interrupt the pipelines 10 and 11. Thus, even during the rod extension movement of the arm cylinder 7, the boom cylinder 6 does not move and the bucket 5 moves circularly from downward to upward as the arm 4 turns. |
