Abstract: A method and a device for converting a mode of operation from straight printing to perfecting in a sheet-processing machine, includes a cam/follower control for operating a gripper system, in which cam followers are maintained in a position in which they are disengaged from control cams before a conversion of the mode of operation is performed. The method and the device convert a gripper system of a reversing drum between a straight or one-sided printing mode and a perfecting or recto-verso printing mode, by controlling pivoting and opening movements of grippers of the gripper system with a control cam. Initially, a cam follower is locked in a position in which it is disengaged from the control cam. Subsequently, a further cam follower is locked in a position in which it is disengaged from a further control cam. Then the gripper system is converted.

Abstract: A device for transporting sheets in recto or verso printing operation has tongs grippers each with upper and lower grippers. The upper gripper, or rigid gripper, that forms the gripper pad can be locked directly or indirectly in recto printing operation.

Abstract: In a sheet gripper, a dimensionally stable base material and an elastic clamping surface material are connected to each other in a form-fitting manner. The elastic clamping surface material functions as a clamping surface of the sheet gripper. This forms a sheet gripper having a long service life and is easy manufacture.

Abstract: In an apparatus for clamping and releasing a gearwheel rim with respect to a main gearwheel that bears the gearwheel rim, a clamping apparatus includes an axially guided, displaceable clamping plate clamping the gearwheel rim between the plate and the main gearwheel. Antifatigue bolts are used for such a purpose. The bolts are expanded by an actuator for releasing the clamped gearwheel rim to an extent that cancels the clamping action.

Abstract: A method for cyclically conveying sheets through a printing-technological machine adjusts a sheet position with high accuracy. The sheets following one another are in each case held at the front edge in grippers of a gripper system during the conveyance, and wherein the sheet position is adjusted in that a pneumatic apparatus is actuated by a control device which processes signals from at least one fixed-location sensor for the sheet position, as at least one sheet runs past, a large number of measured position values of the sheet are determined successively by using at least one sensor, from the measured position values a characteristic value for the sheet position being determined in the control device, the characteristic value as actual value being compared with a setpoint, and the pneumatic apparatus being set for a following sheet as a function of the comparison in each case between the actual and intended value of the preceding sheet.

Abstract: A process provides for the safe operation of a printing machine. The printing machine has a first cylinder driven by a first motor, and a second cylinder driven by a second motor. The first cylinder accepts sheets of paper from the second cylinder or delivers them to the second cylinder by a gripper system. In the case of a deviation in the synchronized running between the cylinders, the gripper system is retracted at least in part far enough into the first cylinder that the possibility of a collision of the gripper system with the second cylinder is eliminated.

Abstract: In a device for changing over a gripper control in a turning configuration of a sheet-processing machine, there is provided a slide to be guided axially displaceably by radial stops. The device changes over a gripper control from recto printing to verso printing on a transfer device such as a drum or a cylinder of a turning configuration in a sheet-processing machine.

Abstract: A sheet-fed rotary printing press for selective recto printing and recto and verso printing includes a three-drum reversing device having three cylinders cooperatively disposed behind one another between respective impression cylinders of two adjacent printing units. The three cylinders include one at least double-size transfer cylinder, one at least double-size storage drum, and one at least single-size reversing drum. Grippers prescribe a circular periphery of the transfer cylinder. The transfer cylinder has an outer contour smaller than the circular periphery prescribed by the grippers of the transfer cylinder. Other grippers prescribe a circular periphery of the reversing drum. The reversing drum has an outer contour smaller than the circular periphery prescribed by the grippers of the reversing drum. A method of operating the three-drum reversing device is also provided.

Abstract: A method of varying a drum profile of a vario drum for transporting printing material sheets, in which shell segments of the vario drum are pivoted inward and outward. Sheet supporting elements assigned to the shell segments are reversibly deformed by pivoting the shell segments. A vario drum suitable for implementing the method and a machine containing the vario drum for processing printing material sheets contain the shell segments and the associated sheet supporting elements.

Abstract: A machine for processing printing material sheets, in particular a sheet-fed printing press, has a sheet transport drum for transporting the printing material sheets and at least one sheet supporting element. The sheet supporting element, which is formed with a sheet supporting surface, is compatible with the sheet transport drum, for supporting the printing material sheets in a first operating mode. When the machine is operated in the first operating mode the sheet supporting element is held attached to the sheet transport drum, and when the machine is operated in a second operating mode the sheet supporting element is stored in the machine detached from the sheet transport drum. A corresponding printing material processing machine is suitable for carrying out the novel method.

Abstract: A sheet-processing machine, particularly a rotary printing press, includes a blast-air supply system and a pneumatic sheet-guiding device connected thereto. The sheet-guiding device has a sheet-guiding surface formed with air passage openings and serves for having the sheets dragged thereover in a sheet travel direction. The air passage openings serve for expelling sheet-carrying air flows during operation. The sheet-guiding device further includes flow ducts for aligning sheet-carrying air flows. The air passage openings in the sheet guiding surface form opening cross-sections of the flow ducts in the form of slots having a length which is many times greater than the width thereof.

Abstract: Devices for turning sheets in a rotary printing machine are described. The devices have a storage drum for handling sheets, which are each held by a holding device, and a turning drum is disposed downstream of the storage drum and has a holding device for engaging a rear edge of the sheet to be turned. An operation of detaching the sheet to be turned from the storage drum and carrying it along by the turning drum leads to the formation of a pressure reduction in an area formed between the sheet to be turned, the storage drum and the turning drum. The pressure reduction is compensated for by supplying ambient air, blast air and/or compressed air. The turning device has a channel and/or a passage orifice connected to an inner chamber of the turning drum. Via the channel and/or passage orifice air can be sucked and/or blown into the reduced-pressure area.

Abstract: A machine processing printing-material sheets contains a first sheet transport drum and a second sheet transport drum disposed immediately after the first sheet transport drum in a sheet transport direction. The first sheet transport drum has gripper systems which describe a gripper flight circle during its rotation and a drum profile deviating substantially from a circular shape with outer contour regions running between the gripper systems and set back from the gripper flight circle. The second sheet transport drum has a sheet support surface with pneumatic grooves formed therein. The sheet support surface is composed of a first and second comb segments each with segment prongs. The pneumatic grooves are introduced into the segment prongs of at least one of the comb segments. The pneumatic grooves are preferably introduced both into the segment prongs of the first comb segment and into the segment prongs of the second comb segment.

Abstract: A sheet-processing machine includes a revolving sheet holding device for aiding in transporting sheets to be processed. A device for producing suction air or air blast has a movable air delivery element accommodated on the revolving sheet holding device. An actuating element cooperatively engages with the air delivery element for driving the air delivery element. The actuating element is either fixed to a frame of the machine or is movable relative to the sheet holding device.

Abstract: In a method of operating a machine processing printing material sheets and having a sheet transport drum in various operating modes, drum circumferential shells are kept fixed on the sheet transport drum in an outer position in a first of the operating modes and in an inner position in a second of the operating modes. During a drum conversion to be carried out before the start of a third of the operating modes, the drum circumferential shells are removed from the sheet transport drum and, in this third operating mode, the sheet transport drum is rotated without the drum circumferential shells.

Abstract: A sheet-guiding device in a sheet-processing machine, in particular a sheet-fed rotary printing press, includes gripper devices disposed on revolving components of the sheet-processing machine for guiding the sheets to be printed on an air cushion formed by blast air. A multiplicity of free jet nozzles, disposed radially outside a path of movement of the gripper devices, form the air cushion. The free jet nozzles serve for producing free air jets tangentially delimiting an optimized path of movement of the sheets. The optimized path of movement extends in the vicinity of the path of movement of the gripper devices.

Abstract: A gripper device in a sheet-processing machine includes a gripper, a gripper pad associated with the gripper and a first drive for moving the gripper out of an opened position thereof into a closed position thereof. The gripper is cooperatively engageable with the gripper pad for producing a clamping force for holding sheets being processed. A second drive is separately operable from the first drive during a production printing operation of the sheet-processing machine. The first and second drives are operable for positioning the gripper and/or the gripper pad so that clamping faces of one of the gripper and/or the gripper pad are movable by the second drive perpendicularly to clamping faces of the other of the gripper and/or the gripper pad.

Abstract: A device for locking, with respect to a first power transmission element, a further power transmission element that is lockable in a rotational position thereof, provides for the first and the further power transmission element to have a common working chamber with a variable volume to which a pressure medium can be applied, it being possible for the pressure medium in the working chamber to be solidified by applying an electric voltage or a magnetic force field thereto.

Abstract: A reversing or turning assembly of a sheet-processing machine includes an impression cylinder having a circumferential surface for transporting sheets thereon for printing the sheets in a printing nip associated with the impression cylinder. Gripper devices are provided for gripping the printed sheets at a respective trailing edge thereof and for lifting the gripped sheets off the impression cylinder for reversing the gripped sheets. The circumferential surface of the impression cylinder is formed with recesses in a region thereof occupied by the trailing edge of the sheets, for permitting the gripper devices to penetrate or dip into the recesses to grip the sheet trailing edge. The recesses have a position being variable in circumferential direction of the circumferential surface of the impression cylinder for adapting to different sheet formats.

Abstract: A method and an apparatus for reversing sheet material in a sheet-processing machine having at least two printing units, a reversing drum with a gripper system, and an impression cylinder that can be operated as a storage drum in perfecting mode and to which a further gripper system for one edge of the sheet material is assigned. In perfecting mode, one of the edges of the sheet material is gripped at an angular offset before the transfer centerline between the reversing drum and the storage drum, before the edge of the sheet material fixed to the storage drum is released.