Apparatus for positioning the cylinder in a rotary printing press

Apparatus for positioning a printing cylinder of the type having a larger-diameter central portion and coaxial first and second stubs extending axially beyond the central portion, comprising first and second carriers respectively having coplanar first and second supporting surfaces along which the corresponding stubs can roll relative to said carriers, each of said carriers further having elongated guide means;

• a pair of stops provided on each of said carriers and having end portions extending upwardly beyond the respective surface and defining for the corresponding stub a seat wherein the stub is held against rolling movement along the respective surface, at least one stop of each pair being reciprocable along the guide means of the corresponding carrier and being movable to an inoperative position in which its end portion does not extend upwardly beyond the respective surface so that the corresponding stub is then free to roll along the corresponding carrier, the stops of each pair having mutually inclined faces bounding the respective seat and diverging in a direction upwardly and away from the respective surface when the end portion of the movable stop extends upwardly beyond such surface;
• and means for moving said movable stops relative to the corresponding carriers, said moving means comprising a shaft rotatably journalled in each of said carriers and an eccentric cam mounted on the shaft, said movable stops having followers which abut the respective cams, each of said shafts being rotatable between a first position in which the end portion of the respective movable stop assumes its inoperative position and at least one second position in which the cam maintains the end portion of the respective movable stop at a level above the respective surface.