| 摘要 |
An operator (10, 210) for moving in upward and downward directions a sectional door (D) having a counterbalancing system (30) including a drive tube (31) interconnected with the door comprising, a reversible motor (41), selectively driven in two directions by the motor, a driven gear (54) freely rotatably mounted on the drive tube and engaging the drive gear, a slide guide (56) non-rotatably mounted on the drive tube, a disconnect (70) mounted on the slide guide and selectively movable between a first position rotatably connecting the driven gear and the slide guide and a second position disconnecting the drive gear and the slide guide, and an actuator (80) for selectively moving the disconnect between the first position and the second position.
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