Abstract: 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.

Abstract: In a workpiece cutoff measuring device, in combination with a miter saw, or the like, a workpiece guide rail extends laterally from the plane of the saw and slidably supports a workpiece length measuring frame longitudinally slidably supported by the guide rail. The frame supports a conventional spring wound measuring tape case for indicating a desired dimension for cutting a workpiece to length and includes a tape clamp for maintaining the tape in a selected extended position.

Abstract: An entrance door having its top and bottom rails pivotally connected with arms supported for rotation by a shaft bearing journalled in the door jamb. The door jamb includes a tension member preventing distortion of the door jamb and displacement of the shaft supporting thrust bearing by the mass of the door thus insuring free swinging door movement.