Abstract: A magnetic brake has an outer stator surrounding an inner stator with a circumferential slot between the outer stator and the inner stator. A coil is provided in the inner stator adjacent to the circumferential slot. A drag plate is attached to a rotatable shaft extending centrally through the inner stator. A drag ring joined to the drag plate extend into the circumferential slot. The drag ring may be an annular cylindrical ring section separate from the drag plate. Vent holes pass through the inner stator adjacent and parallel to the shaft. The magnetic brake uses both hysteresis and eddy current braking.

Abstract: A dual sprocket contact motion picture film printer maintains film steadiness when running a film negative in contact with an unexposed raw stock film by tensioning perforations along one film side against sprocket teeth of a full fitting sprocket and a shrinkage sprocket on the other side. The films pass through a fluid chamber before passing through a printer aperture and a vacuum pressure applied from one side of the chamber tensions the negative against the sprocket teeth while a positive fluid pressure applied from an opposite side tensions the raw stock against the sprocket. The films are self-aligned by the fluid forces maintaining equal tension on both sides of each film strip as the films pass the aperture of the film printer.