Screw transmission mechanism for a blind

摘要

A screw transmission mechanism for a motor-driven blind is constructed to include a driving unit, and at least one cord roll-up unit controlled by the driving unit to lift/lower or tilt the slats of the motor-driven Venetian blind. Each cord roll-up unit includes an amplitude modulation set controlled by the driving unit to lift/lower the slats and bottom rail of the Venetian blind, a frequency modulation set for rotation with the amplitude modulation set to tilt the slats of the Venetian blind, and a linkage adapted to control connection between the frequency modulation set and the amplitude modulation set.