| 摘要 |
An automatic door opener ( 10 ) for opening or closing a door ( 28 ) includes a motor ( 14 ) driving a drive shaft ( 50 ) and an opener arm ( 18 ) connected to the door ( 28 ) and being responsive to rotation of the drive shaft ( 50 ) for moving the door ( 28 ) to an open or closed position. A clutch ( 46 ) operable to disengage the drive shaft ( 50 ) from the opener arm ( 18 ) is provided in the event of the door ( 28 ) engaging an obstacle, electric power being unavailable, or the door being fully open or fully closed. The door opener ( 10 ) may also include a brake ( 48 ) for selectively preventing movement of the door ( 28 ). Various embodiments of the invention are provided, including an electromagnet ( 80 ) and an electromagnetic brake ( 114 ).
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