| 摘要 |
The invention is an electronic wire length measuring apparatus for accurately measuring and indicating the height of a traveling block above a fixed reference point in oil well drilling applications where a traveling block is hooked to a cable and pulley arrangement and to a winch drum, said winch drum being used to vary the height of the traveling block. The wire length measuring apparatus produces an output visual indication of the height of the traveling block independent of variations in drum size, wire size, number of layers on the drum, and the weight load on the traveling block, which causes a lower actual traveling block position due to stretching in the wire.
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