Motorized window blind electrical actuator

Claim 1

A motorized window blind actuator for a window blind having a motor operatively attached to the window blind to control opening and closing of the window blind by an output shaft means of the motor, comprising: input means for receiving regulated electrical power and a first variable reference voltage signal, the first variable reference voltage signal being proportional to a desired position of the window blind between and including open and closed positions defined by end stop means; feedback voltage means for producing a second variable reference voltage signal from the regulated electrical power; connection means for connecting the output shaft means of the motor to the feedback voltage means, rotation of the output shaft means causing proportional change in the second variable reference voltage signal which is in turn proportional to the actual position of the window blind between and including the open and closed positions; comparator means for comparing the first and second variable reference voltage signals and for producing a drive signal based on the comparison of the first and second variable reference voltage signals; drive means connected to the motor, the drive means instructing the motor to rotate the output shaft means according to the drive signal to bring the first and second variable reference voltage signals within a predetermined range to cause the window blind to move to the desired position; and over-current sensing means for sensing circuit current above a pre-set level for over a predetermined time, including current monitoring means and timing means, the over-current sensing means disabling the driver means upon the window blind reaching an end stop open or closed position, or jamming or sticking between an open and a closed position.