Abstract: A sheet feeding unit for a rotary sheet printing machine which is operative for selective face printing or face and back printing with turning of a sheet rear edge and which has a turning cylinder and a printing cylinder located before the turning cylinder, includes elements located underneath the turning drum and the printing drum for conducting and guiding overlong sheets in face and back printing during a turning step on a front edge. The elements include a suction member arranged rotatably over a circular path so as to take over a sheet in a point of intersection of tangent t.sub.s, a stationary segment arch arranged equidistantly relative to the circular path under a point of intersection T.sub.4,5 of the printing cylinder and a sheet guiding cylinder and also provided with guiding rollers, and a guiding plate located above a turning point of the suction member at a distance from the printing cylinder and inside the circular path over a line of a secante.

Abstract: An arrangement for correcting registration during guiding of sheets in a multi-color rotary sheet printing press including a plurality of printing units, each having a printing cylinder, a transfer cylinder connected between printing cylinders of two adjacent printing units for transfer sheets between the printing units, and a plurality of gear drives for driving the printing and transfer cylinders, includes a plurality of adjusting devices arranged within gear drives. Each adjusting device has two conical sleeves fixedly mounted within a gear drive, two conical bushings cooperating with the two conical sleeves, and an adjusting spindle for supporting the two conical bushings for linear displacement toward and away from each other.

Abstract: 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.

Abstract: A driving mechanism for groups of operating elements arranged in a rotary sheet guiding cylinder of a sheet-fed printing machine includes a pair of control shafts arranged in the guiding cylinder parallel to its axis of rotation and being driven by transmission gears arranged in the cylinder, two sets of cams, each supported on an assigned control shaft for activating a group of operating elements in a selected operational mode of the machine, and clutch means provided between the transmission gears and the shafts and operated from one point to actuate one control shaft and deactivate the other control shaft.

Abstract: The control device for a suction gripper on a guiding cylinder of a sheet fed rotary press comprises a tumbler shaft mounted on the sheet guiding cylinder and a suction unit swingable about a pivot point which is supported for movement about the tumbler shaft. The suction unit is either positively driven by a cam drive or self-adjustable by means of a tension spring between the unit and the tumbler shaft.

Abstract: A printing machine has a plurality of printing stations which print images on both major surfaces of each sheet passing through the printing machine. A reversing arrangement turns the respective sheet between two of the printing stations so that the major surface of the respective sheet having a fresh image thereon faces downwardly. A support arrangement is provided which supports this sheet during its advancement to the next following printing station, and includes a blow casing having upwardly oriented passages through which air issues in upward direction to create an air cushion between the respective sheet and the blow casing for supporting the respective sheet during its advancement. An elongated bracket is arranged upwardly of the blow casing and supports a region of the respective sheet which is devoid of the image, during the advancement of the sheet in a path portion located upwardly of the blow casing.

Abstract: A sheet-transfer arrangement is arranged between two printing stations each having a printing roller. The transfer arrangement has a transfer roller provided with a suction gripper system which lifts the trailing edge portion of a sheet travelling on the first printing roller off the surface of the latter. A drive is provided which temporarily advances the suction gripper system relative to the transfer roller circumferentially of the same and in the direction of rotation thereof, in order to cause the trailing edge region of the sheet to bulge away from the first printing roller. A mechanical gripper system is also provided on the transfer roller which receives the trailing edge portion of the sheet from the suction gripper system, pulls the sheet off the first printing roller, turns it and presents it to the second printing roller during the continued rotation of the transfer roller.