| 摘要 |
A fluid operated wrench has a fluid-operated drive including a cylinder (4) , a piston (5) reciprocatingly movable in the cylinder and having a piston rod (6) with a piston rod end (7), a ratchet mechanism having a ratchet (11) provided with a plurality of teeth, and at least two pawls (9, 10) operatively connectable with the piston rod end (7) and engageable with teeth of the ratchet so that during an advance stroke of the piston (5) one of the at least two pawls engages with at least one ratchet tooth while the other of the at least two ratchets over at least one ratchet tooth, while during a return stroke of the piston the other of the at least two pawls engages with at least one ratchet tooth while the one of the at least two pawls ratchets over at least one ratchet tooth. At least one (9) of the at least two pawls (9, 10) is disengageable from and liftable above the teeth of the ratchet (11) so as to permit the ratchet to turn backwards to release a built up torsion and material flex, so that the fluid operated wrench can be taken off a job.
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