Operating mechanism for a venetian blind

摘要

An operating mechanism is provided which can raise, lower and tilt slats of a venetian blind, particularly an outside blind mounted externally of a building, and which comprises: a support body for rotatably receiving a rotatable drive shaft; a releasable clutch mechanism having at least a first element mounted for rotation by the drive shaft and a second element releasably engaged with the first element for moving the slats between opposite first and second angular positions; means defining the first and second angular positions; arresting means on the support body adapted to cooperate with the second element for establishing the opposite first and second angular positions; a retractable stop engageable with the second element to arrest the second element in an intermediate position between the opposite first and second positions and a lost motion mechanism interposed between the drive shaft and the retractable stop for engaging the retractable stop with the second element only after a predetermined number of revolutions of the drive shaft. <IMAGE>