Abstract: In an apparatus for controlling a D.C. motor used in the lifting and lowering operation of a window blind or an awning, pulses induced as a result of rotation of the motor rotor are used for delivering signals to a signal receiving means. The signal receiving means includes a counter for counting the induced pulses, a memory that stores the number of pulses required for the blind or awning to move between its end positions, and a comparator circuit for generating a control signal when the operating current to the motor exceeds a predetermined value, and delivers signals to stop the motor at the end positions of the blind or awning.

Abstract: In a group of blinds each blind consists of a number of thin slats suspended from a horizontal shaft. The slats are attached to cords fixed to the shaft and the slats are turnably adjustable by rotating the shaft, which is connected to both a hand-operated mechanism and automatic drive unit. Said automatic drive unit is provided with a torque limiting device. Moreover, a timing device is connected to said drive unit for all blinds in the group for automatic actuation of all said drive units at determined points of time and setting of the slats in all blinds to closed or open position irrespective of their existing position set by said hand-operated mechanism.