| 摘要 |
<p>A borehole surveying instrument of the type having a lengthy pipe-like housing which includes an inclinometer, a directionof-inclination measuring unit and a camera. Instead of the usual film camera, a T.V. camera connected to a monitor outside the borehole is provided, so that measuring operations can be viewed immediately without withdrawal of the instrument from the borehole. The instrument is suspended from a self-bearing electrical cable which supplies power to internal electrical equipment and transmits signals to and from the surveying instrument. The housing is provided with two spaced sets of centering pins extendable and retractable via respective electric motors. Intermediate the sets of centering pins, is a set of six equiangularly spaced telescoping measuring pins, each provided with a respective displacement transducer for immediately furnishing borehole-caliber information referenced to a circle. Each centering pin is exposed to ambient water which may be present at both its ends, so that the associated electric motors for the centering pins need not operate against the opposition of large pressure differentials.</p> |
