发明授权
US4221996A Hoisting apparatus 失效
起重设备

Hoisting apparatus
摘要:
A hoisting apparatus and a control circuit therefor comprising a reversible electric motor drivingly connected to a hoisting drum for hauling an object up and down. The control circuit includes first and second photosensitive elements each responsive to a light beam for initiating rotation of the electric motor in either direction and means for terminating rotation of the electric motor.
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