| 摘要 |
PURPOSE:¦To make a detecting means simple by measuring the change in the angle of the propelling direction of an excavator with respect to a reference line for excavation on the basis of the position change of one target. CONSTITUTION:When the propelling direction of an excavator changes its angle, for example, upward, that is, when the propulsion line B of the excavator deviates from a reference propulsion line A, the angle of a telescope 17 placed along the line A is changed to the positin where the virtual image C' of a spot light source C on the line B is visiable, and the displacement amount (h) of the measurement scale (a) is read from the changed angle theta2 of that time and the center P of a target 16, and on the basis of the changed angle theta2, the changed angle of the line B with repsect to the line A is calculated. |
