| 摘要 |
A lifting mechanism (30) includes a bracket (34) to hold the lifting mechani sm (30). Two rollers (31) are respectively rotatably mounted in the bracket (34 ). A balance wheel set (32) is mounted in the bracket (34) and includes a first wheel (32 1) rotatably mounted between the two rollers (31) and simultaneously rotated with the two rollers (31), and a second wheel (322) rotatably mounted in the bracket (34) near the firs t wheel (321). A constant force motor spring (33) is mounted and wound between the first wheel (321) and the second wheel (322). Due to the constant force motor spring (33), a cord to raise or lower the slats is unnecessary and the cordless venetian blind can be opened or closed easily.
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