Patent ID: 6603644
Filing Date: 2003-08-05
Classification: A47H,H02H

Abstract:
A motor-driven curtain assembly, comprising:a longitudinally extending hollow top rail; a longitudinally extending drive shaft mounted rotatably in said top rail; a motor for driving rotatably said drive shaft; a curtain unit coupled to said drive shaft such that rotation of said drive shaft in a positive direction results in movement of said curtain unit to a closed position, and such that rotation of said drive shaft in a negative direction results in movement of said curtain unit to an open position; and a motor-control device including a driving circuit coupled to said motor for enabling rotation of said motor in the positive and negative directions, a control unit coupled to said driving circuit and operable so as to control said driving circuit to enable rotation of said motor in a selected one of the positive and negative directions, a current limiting circuit adapted to couple said driving circuit to an external power source, and adapted to limit current flow from the external power source to said driving circuit when said motor is subjected to an increase in load resistance, and an overload detector, coupled to said control unit and said current limiting circuit, for generating a control signal that is indicative of the amount of current flowing from said current limiting circuit to said driving circuit and that is provided to said control unit, thereby enabling said control unit to deactivate said driving circuit for stopping operation of said motor when overloading of said motor occurs.