Motor driven automatic door opening and closing mechanism - has pulley wheel traversed by screw and rotated to displace screw

摘要

The pulley wheel and screw transmission unit for automatic door opening or closing, has the pulley wheel (1) mounted, free to rotate, within a support frame (8, 9) and transversed by a screw (7), and rotated by a belt from a motor causing axial displacement of the screw (7) relative to the wheel (1) and its support (8, 9). The wheel support (8, 9) may be fixed to the ceiling and one end (12) of the rod (7) fixed to the door. A main switch may be used to energise the motor and 'end of run' circuit-breakers (14, 15, 17, 18) cut the supply to the motor at the termination of opening or closure runs. The circuit-breakers (14, 17) may be mounted on cantilever arms (13, 16) at the ends of the screw (7), and the screw to door connection (12) may be of the knuckle-joint type.