| 摘要 |
<p>Overhead doors operating apparatus uses a single motor power unit to operate a selected one of a plurality of overhead doors through a selectively energized coupling, such as an electromagnetic clutch, or if desired, all of the doors in unison by energizing all the couplings. Thus only one motor power unit, instead of a power unit for each door, is needed to operate selectively one or more of the doors.</p> |
