| 摘要 |
<p>PURPOSE:To stand the rotation of a front rod of a boring machine or the vibration of an excavating machine by making a lower part and an upper part of a holder of a magnetic field detector a weight part and a fixing part where the detector is fixed, respectively, and supporting both ends of the holder by a bearing. CONSTITUTION:A magnetic field detector is constituted of horizontal eccentricity detecting sensors 611, 612 and vertical eccentricity detecting sensors 621, 622, which is fixed to an upper part of a holder 20 thereof. A lower part of the holder 20 is made a large weight part 22. A void is formed within a front rod 10 of a boring machine. Bearings 21A, 21B are housed at both ends of the void, into which both ends of the holder 20 are inserted. Accordingly, even if the underground excavator vibrates or rolls, the magnetic field detector is kept vertical by the weight part 22. The sensors 611, 612 can be held within the horizontal plane and the sensors 621, 622 can be within the vertical plane at all times.</p> |
