Device for preventing overwinding of a roller blind

摘要

The invention relates to a slip coupling for preventing the overwinding of the motor spring of a roller blind. In one embodiment the slip coupling is incorporated as part of a bracket for supporting one end of the roller. The bracket has a cylindrical bearing which is rotatable within a circular aperture in the face of the bracket and receives a pin of the spindle of the roller so as to be rotatable therewith. The bearing carries a spring the ends of which engage with stops on the face of the bracket so that the bearing is prevented from rotation when the torque exerted by the motor spring is below a predetermined level. When the motor spring is overwound the ends of the springs are caused to flex to override the stops and so reduce the tension in the motor spring. In a second embodiment the slip coupling is located within the roller.