Two principles for adjusting the circumferential register in rotary printing machines are known from the prior art: first, a rotary shift of the forme cylinders via a planetary gear, or second, an axial shift of helical gears in the drive trains. However, it is known per se that planetary gears necessitate an expensive gear mechanism. On the other hand, in apparatus with helical gears, usually only a relatively coarse adjustment is usually possible. Furthermore, the problem generally arises in these geared mechanisms either that there is a great amount of play, or if they are designed for play-free operation then that they are extremely expensive to manufacture.