Abstract: A hypocycloid drive device for adjusting slat angles of a venetian blind includes a housing, a roller, a hypocycloid drive reducer, a tilt cord and a tilt rod. The roller is rotatably mounted in the housing and is rotated by pulling the tilt cord. The hypocycloid drive reducer is coupled to the roller and is used to reduce an angular speed of and rotate the tilt rod. The tilt rod is adapted to change slat angles of the venetian blind. Consequently, volume of the hypocycloid drive device is minimized to accommodate convenient installation of the hypocycloid drive device.

Abstract: A lift control device for a roller shade has a side cover, a roller, a chain retaining wheel, a chain and a follower spool. The side cover has an axle and multiple inner teeth. The roller is rotatably mounted around and is eccentric to the axle. The roller has multiple teeth partially engaging with the inner teeth on the side cover and at least one stub. The chain retaining wheel has an eccentric hole to rotatably receive the roller. The follower spool is attached to the chain retaining wheel and engages with the roller to rotate with the roller. Accordingly, a shade blind connected to the follower spool is actuated in instant when the chain is drawn. The follower spool is kept from rotating even when a large force applied to the follower spool, and the safety of using the roller shade is improved.