| 摘要 |
<p>PURPOSE:To make the detecting of a rotary bucket abutting against a buried pipe during its forward excavation possible by protrusively attaching a rotatable lever to the lower side of a rotary bucket body, and providing a motion detecting means for the rotation of the lever. CONSTITUTION:A lever 22 rotatable in any direction is protrusively attached lower than an excavating tooth 20 provided on the lower side of a rotary bucket body 11. In addition to that, an energizing means for giving force to check the rotation of the lever 22 and a motion detecting means for the rotation of the lever 22 are provided. In the case where the lower periphery of a rotary bucket 4 abuts a buried pipe during the forward excavation of the rotary bucket 4, and the lever 22 rotates against the force generated by the energizing means, the motion detecting means detects the rotation of the lever 22. The rotary bucket 4 is stopped by an automatic control or an operator's manipulation. The force given to the lever 22 by the energizing means is established weaker than the force by which the lever 22 can damage the buried pipe.</p> |
