Mechanism raising and lowering venetian blind - initial movement is made with slats held open by cranks

摘要

When a Venetian blind is raised or lowered, the movement often starts with closing the slats, which are adjusted to their required aperture only at the end. This is sometimes inconvenient, esp. in public rooms, and the present mechanism's movement starts with opening the slats. In an embodiment the cords that tilt the slats are attached to the cranks (24, 25) which always point in opposite directions. When the drive reaches a stop, the slats are fully open, and the blind can be lowered without any further tilting of the slats. When the cord is pulled to raise the blind, the mechanism turns as far as the opposite stop. In the meanwhile, both cranks turn through a complete revolution, during which the slats fully close and fully open again.