A rotary drive system for a roller blind. The drive system comprises a handle a worm gear, a bull gear, and a planetary gear drive system. The handle causes rotation of the worm gear, that engages the bull gear, that engages the planetary gear carrier of the planetary gear drive system. The sun gear of the planetary gear drive system is configured to engage the roller tube of the roller blind. Rotation of the worm gear causes a rotation of the bull gear which rotates the planetary gear carrier, causing the planetary gears to impart rotational motion to the sun gear and rotation of the roller tube at a rate faster than the rotation of the worm gear, said planetary gear carrier causing said planetary gears to impart rotational motion to said sun gear and rotation of the roller tube at a rate faster than the rotation of said worm gear.