| 摘要 |
A bailer mounted to the derrick of a top head drive well drilling rig. The bailer includes a winch line drum mounted by a bracket to the derrick. A positive displacement hydraulic motor mounts one end of the drum and receives fluid under pressure from the existing hydraulic pressure supply. Valving is provided to allow reverse operation of the motor so equipment can either be raised or lowered relative to the derrick. The hydraulic delivery line to the motor includes a one way restrictor that will allow relatively free passage of fluid to the motor in a driving or lifting mode but will reverse flow of fluid from the motor, thereby affording a braking effect for lowering a load at a selected rate.
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