| 摘要 |
<p>WELL SERVICING APPARATUS Apparatus for a well servicing rig having a rotatable driven drum,an upwardly extending tower adjacent to said drum, a sheave rotatably mounted on an upper part of said tower, and a length of cable partially wound around said drum and extending upwardly over said sheave and downwardly therefrom; said apparatus including at least two sensing elements disposed adjacent to the periphery of said sheave, said sensing elements being adjacent to each other in an arcuate pattern, a plurality of equally spaced, circumferentially arranged triggering elements mounted on said sheave adjacent to the periphery thereof, pulse sorting means connected to said sensing elements, direction indicating means connected to said sensing elements, pulse counting means connected to said pulse sorting means and to said direction indicating means, constant tabulating means connected to said pulse counting means and to constant receiving and retaining means, and read-out means connected to said constant tabulating means.</p> |
