| 摘要 |
A power option is provided for a manually-operated material lift that employs a telescoping mast system which is extended or retracted by a winch. A reversible electric motor is connected to the winch via two-way reduction gearing that remains in the drive train during manual operation and requires no clutches or disconnect means. The power option is initiated by selecting the position of a reversing switch that controls the motor, and closing an on/off switch which energizes the motor for rotation in the selected direction. When the on/off switch is open, the lift may be manually operated in the conventional manner.
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