Abstract: A motorized operator for moving a barrier, such as a garage door, between open and closed positions, includes a magnetic sensor for determining position and/or velocity of the barrier. The operator motor is drivingly connected to a speed change transmission which is connected to the barrier. The magnetic sensor includes a housing supporting a speed change mechanism including an output shaft supporting a magnet. The magnet is mounted adjacent a Hall effect sensor circuit which measures the change in the magnetic field generated by the magnet to determine position of the barrier, as well as speed. Control circuitry enables accurate determination of the position of the barrier for setting open and closed limit positions, for example.

Abstract: An electric motor driven barrier operator includes spaced apart frame plates for supporting the motor, an intermediate drive shaft and an operator final output shaft. The motor output shaft, intermediate shaft and final output shaft are mounted on bearings at fixed centers on the frame plates and the motor and intermediate shaft are interconnected by a stretchable flexible drive belt reeved over respective drive pulleys mounted on the motor output shaft and the intermediate shaft. The drive belt may be mounted on the pulleys and replaced without adjusting the position of the motor output shaft, the intermediate shaft or the operator output shaft.

Abstract: An operator for a barrier, such as an upward acting door, includes a control unit having two optical limit switches providing output signals to a controller to effect shut-off of the operator motor when the door reaches open and closed limit positions. The limit switches preferably include LED emitter and phototransistor sensor elements and are preferably mounted on a circuit board in close proximity to a screw member which rotates in timed relation to the position of the door. Linearly movable nut members are mounted on the screw member and include or engage optical shield members which move into positions to provide respective output signals from the optical switches. The door closed optical limit switch may incorporate a pre-limit switch function to override a signal from a door bottom edge obstruction sensor.