Device for changing from one sided printing to perfecting for a rotary sheet printing machine

The invention relates to a device for changing over to single-side printing or perfecting on sheet-fed rotary printing machines. Two respective pairs of intermediate spur wheels are disposed between the printing cylinder spur wheel and the turning drum spur wheel, a first pair of the intermediate spur wheels being in the form of a double wheel. The second pair of intermediate spur wheels are secured to a solid shaft or hollow shaft, preferably received in a control means for selectively driving the solid and hollow shaft in unison or differentially to one another. In another embodiment a set of intermediate wheels includes spur wheels associated with first and second printing cylinders. Intermediate spur wheels are disposed between the printing cylinder spur wheels and an annular wheel coupled to the turning drum. The intermediate spur wheels are likewise secured to a solid shaft or hollow shaft received in the control means for selectively driving the solid and hollow shaft in unison or differentially to one another.