Arrangement for selectively connecting coaxial gear wheels of a gear train of a dual mode printing machine

摘要

A printing machine which has a plurality of printing units each including several rollers is equipped with a gear train which drives at least one roller of each of the printing units. At least associated two of the gear wheels of the gear train are coaxially mounted on a common shaft, one of them being movable toward and out of contact with the other gear wheel for establishing entraining connection therewith and for permitting angular displacement of the associated gear wheels relative to one another, respectively. The angular position of the associates gear wheels is to be changed when the mode of operation of the printing machine is to be changed from first page printing mode to first and second page printing mode. The arrangement which connects and disconnects the associated wheels includes a plurality of moving units which simultaneously act on the other gear wheel and which are mounted on an annular clamping element mounted on the other side of the one gear wheel from the one gear wheel. The moving unit may include a cylinder-and-piston unit having a toothed piston rod meshing with a pinion mounted on a threaded element meshingly received in a threaded bore of the other gear wheel, or an angular displacement motor having a threaded output shaft meshingly received in such threaded bore, or a cylinder-and-piston unit having a piston rod articulated to an eccentric disk rotatably mounted on a bearing block rigid with the other gear wheel.