| 摘要 |
<p>A fluid-operated tool for tightening and loosening of screw-threaded connectors has a turnable engaging unit (1) engageable with a screw-threaded connector for tightening and loosening the latter, and a driving unit (6) connected with the engaging unit (1) and acting on the engaging unit so as to turn the latter. The driving unit (6) includes two fluid-operated driving elements (7,8) connected to the engaging unit (1) and operated so that during an initial stage of tightening or a final stage of loosening of a screw-threaded connector, one of the fluid-operated driving elements is actuated and drives the engaging unit, and during a final stage of tightening or an initial stage of loosening of a screw-threaded connector, the other of the fluid-operated driving elements is operated.</p> |
