| 摘要 |
<p>A limit switch for a rolling door assembly includes a disc (60) rotatably mounted for synchronized rotation with a take-up axle (16). The disc (60) has a face having a spiral groove (68) with a length proportional to the length of travel of a rolling door (10) between the open and closed positions. An arm (70) has one end pivotally mounted and has an opposite end frictionally engaging the groove (68) of the disc for pivotal movement between a first position corresponding to the open position of the door and a second position corresponding to the closed position of the door. A first relay (80) is operably connected to the drive and adapted to close when the arm is in the first position stopping the drive. A second relay (82) is operably connected to the drive and adapted to close when the arm is in the second position stopping the drive.</p> |
