| 摘要 |
A drive mechanism for use with an overhead shaft of a sectional door for raising and lowering the door via a rotation of the overhead shaft. The drive mechanism has a support structure, a first gear, a drive shaft, a second gear, a pocket wheel and an actuator. The second gear is interconnected to the first gear so that a rotation of the second gear is transmitted to the first gear and vice versa. The pocket wheel is operable between first and second positions. The second gear is rotatable along a first direction corresponding to a raising of the sectional door and along an opposite second direction corresponding to a lowering of the sectional door. The actuator is used for rotating the pocket wheel about the drive shaft, operating the pocket wheel between the first and second positions, and driving the second gear along the first and second directions when the pocket wheel is in the second and first positions respectively. The drive mechanism includes a first ratchet assembly for blocking rotation of the second gear along the second direction when the pocket wheel is in the second position. The drive mechanism may also include a second ratchet assembly for blocking rotation of the second gear along the first direction when the pocket wheel is in the first position.
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