Door operator unit

摘要

A door operator unit includes a drive motor connected to a speed reduction differential planetary gear drive mechanism having a drive unit output shaft. An electromagnetic brake is interposed the motor output shaft and the planetary gear drive mechanism and is releasable when energized to allow rotation of the motor output shaft and the drive unit output shaft. A first ring gear is normally held stationary by mechanism including a release block and is operable in response to disengagement of the release block to permit rotation of the drive unit output shaft when the brake is engaged to allow manual opening and closing of the door by way of an auxiliary drive shaft drivingly connected to the ring gear. A torque limiting clutch may be interposed the operator unit output shaft and a second ring gear of the differential planetary gear drive mechanism.