Automatic door opener and closer

摘要

In a door opening and closing apparatus a reversible drive motor and door actuator are mounted in the framing above a door header. The vertically disposed drive shaft of the motor is connected with the door actuator through a friction clutch equipped drive train including a series of speed reducing torque increasing cog belts and pulleys. The drive train operates pivoting linkage secured at one end to the door for biasing the door open or closed in response to the direction of rotation of the drive motor. A circuit connects a source of electrical energy with the drive motor through a plurality of current switching relays also inducing magnetic flux in the field windings of a braking slave motor driven by the driving motor. Door opening action is initiated by a foot pressure switch.