| 摘要 |
<p>The invention relates generally to a pumpjack (or beam pumping unit), and in particular to a sleeve for protecting a polished rod of a pumpjack from damage resulting from normal use. In one form, the pumpjack comprises a polished rod depending from a carrier structure, and the sleeve is slidably disposed over the polished rod and between the polished rod and the carrier structure so as to prevent contact between the polished rod and carrier structure, the sleeve being of such a length as to extend substantially between a bottom clamp for the polished rod, and either of a rod rotator or a top clamp for the polished rod.</p> |
