Single control tilt drive unit

A method for maintaining horizontal slats of a blind in an open position wherein the slats are suspended by cord ladders and can be raised and lowered by a drive system, comprising the steps of:

• suspending the slats from a head rail for retraction and extension by a common drive system and wherein the slats are adapted to be tilted by the common drive system between a closed position substantially parallel to a plane common to a longitudinal center axis of each slat and an open position in which the slats are generally perpendicular to said plane,
• providing said drive system with a roller having a circumferential track formation on a radially outer surface thereof, the roller being adapted to be rotatably driven, and
• providing a movable tilt member that is engaged in the circumferential track formation on the roller for sliding movement in the track formation and is operatively engaged with means to tilt said slats, and wherein the track formation is non-uniform having a free zone and a tilt zone, and
• engaging said tilt member in said track formation such that when the tilt member is engaged in said free zone, the slats will be retained in the open position and when the tilt member is engaged in the tilt zone, rotation of said roller will cause the slats to be tilted to either of two opposite positions of tilt.

Tilt drive unit for a covering for an architectural opening, such as venetian blinds, the tilt drive unit including:

• a roller having a circumferential track formation on a radially outer surface thereof and the roller being adapted to be rotatably driven;
• and
• a movable tilt member that is engaged by the circumferential track formation on the roller for sliding movement in the track formation and is operatively engaged with means to tilt slats of the covering;
• and
• wherein the track formation has a free zone and a tilt zone and wherein the free zone includes a substantially linear, pair of circumferential grooves and the tilt zone includes a convoluted groove which intersects the pair of linear grooves, whereby when the tilt member is engaged by the free zone, the slats will be retained in the open position and whereby when the tilt member is engaged by the tilt zone, rotation of the roller will cause the slats to be tilted to either of two opposite positions of tilt.