Abstract: A locking device for a roller blind gimbal includes a drive worm gear meshed with a crown gear to which a roller blind is coupled, and a pair of pinion gears meshed to the crown gear for co-rotation therewith, the pinion gears having locking openings in their hubs engageable by a locking element that is spring biased towards the locking openings when they are aligned in a locking position. The locking position of the openings is periodically reached by rotation of the crown gear and pinion gears in a blind raising direction. Release of the locking element is obtained by rotating a driving worm gear in a blind lowering direction to release the engagement between the locking element and the hub openings in the pinion gears.