Device for feeding printing plates onto the plate cylinder of printing machines, especially sheet-fed offset printing machines

A device for feeding a printing plate onto the plate cylinder of a printing machine and especially a sheet-fed offset printing machine, the plate cylinder having a channel and a print start region, a tension rail located in said channel adjacent said print start region and having an openable and closable gripping region for receiving a front edge of the printing plate, the gripping region being in the form of a gap extending over the format width of the plate cylinder and opening substantially tangentially with respect to the outer circumference of the cylinder, a sheet metal section extending over the format width of the print cylinder, said device being characterized by an introduction rail on said sheet metal section and extending across the format width of the plate cylinder, means supporting said introduction rail for movement between retracted and active positions, said introduction rail engaging the outer circumference of the plate cylinder in the vicinity of the print start region when said introduction rail is in said active position, said introduction rail having an introduction face which, when said introduction rail is in said active position, coacts with the plate cylinder to define a second gap aligned with the gap of the opened gripping region of said tension rail and guiding the front edge of the printing plate into the opened gripping region.