Printing machine transfer drum adjustable to variable sheet lengths

Printing machine sheet transfer drum adjustable to variable sheet lengths, the transfer drum being formed with transverse drum channels and having sheet carriers forming respective meshing comb-like structures adjustable relative to one another, and devices for gripping the leading and trailing edges of a sheet, the gripping devices being disposed in the drum channels and secured to the sheet carriers, the gripping devices having at least one continuous sheet-supporting rail extending from side to side of the sheet transfer drum, comprising a rigid main drum body formed of one piece with one of the comb-like structures and having at most two separable parts including the device for gripping the leading edge of the sheet, and a hollow, substantially cylindrical body partly surrounding said main drum body in circumferential direction thereof and being supported at most at two bearing locations on said main drum body, said hollow, substantially cylindrical body having a one-piece member formed with a surface for supporting a sheet over substantially the entire width thereof, the device for gripping the trailing edge of the sheet being disposed on said hollow body and forming therewith a rotatable sheet carrier unit.