Rotary duplicators, such as the MULTILITH lithographic duplicator, manufactured by Addressograph-Multigraph Corporation, are normally provided with exposed handwheels which are used by the operator for various purposes. When the machine is turned off it is frequently desirable to rotate the cylinder slowly for various purposes such as to insert or remove masters, to clean the blanket between runs, to inspect the full surface of a master or of a blanket image, to remove infrequent paper jams, and the like.
Such handwheels are smoothly contoured so as to provide no openings or projections which would endanger the operator by catching his hands or clothing when the machine is operating. There is, however, in spite of the contouring of the wheel, a small residuum of exposure by reason of the fact that the handwheel is rotating rather rapidly when the machine is running.