Apparatus for applying and withdrawing an impression cylinder acting on the plate cylinder of an intaglio printing press

In an intaglio printing press comprising a frame and co-operating plate and impression cylinders rotatably mounted in said frame, said impression cylinder being provided with two journals each of which is operatively connected to respective screwthreaded spindles, apparatus for applying and withdrawing said impression cylinder respectively to and from said plate cylinder, said apparatus comprising first and second rotatable nuts mounted on each said spindle, means coupling said first nut on each spindle for rotation in unison with said second nut but allowing for movement of said first and second nuts with respect to one another in the axial direction corresponding to the play between the said nuts and the screw thread on the said each spindle, a hand wheel, abutment surfaces fixed with respect to the said frame, transmission means comprising shafts and gearing operatively connecting said hand wheel to said first nuts for allowing selective adjustment of each of said first nuts either in unison or independently of one another with corresponding adjustment of the respective said spindles whereby said first nuts can be displaced to be applied to respective said abutment surfaces by operating said hand wheel, and a piston-cylinder unit operatively connected to each said second nut to lift and lower same, means for supplying said piston-cylinder units with pressure medium through independent fine control valves.