Abstract: An auxiliary drive for the ductor roller of a sheet-fed offset press continues to advance the ductor roller in small angular steps during press stoppages. The damping unit drive which continues to run during press stoppages drives the ductor roller stepwise by way of an eccentric drive linkage and a ratchet wheel disposed on the ductor roller journal. When the press is running, a rocker lever in the drive linkage can be pivoted away from the throw zone of the eccentric for example, by a piston actuated by oil pressure of the press's oil supply system. In alternative embodiments, the lever arm can be pivoted away by a compressed air cylinder or a suction cylinder which become operative when the press is running.

Abstract: A gripper device for manually adjusting the position of a pair of gripper rows disposed on opposite sides of the periphery of double-size sheet-guiding cylinders, to a work and turn angle of exactly 180.degree.. Each of the gripper rows includes a cam follower roller and at least one cam follower roller is adapted to have its center-line displaced relative to the axis of the gripper shaft so that the distance between the axes can be varied.

Abstract: An offset inking unit includes a distributor roll having a first roll train that communicates via a first branch roll with an ink transport roll engaged, as viewed in the direction of rotation of the plate cylinder, by two front inking rolls and having a second roll train connected in parallel to the first roll train that communicates via a second branch roll with a spreader roll which, as viewed in the direction of rotation of the plate cylinder, is engaged at least by the first inking roll of the two front inking rolls. Also as viewed in the direction of rotation of the plate cylinder, the second inking roll of the two front inking rolls communicates at least with another rear inking roll via another ink transport roll. Damping is optionally effected directly on the printing plate or on a front inking roll.

Abstract: A sheet-turning drum in a sheet-fed rotary printing press for optionally first printing or perfecting printing is provided that is simple to assemble and adapted to be changed over for differing printing requirements. To this end, the sheet-turning drum is subdivided into a unitary main member and a cylindrical drum envelope. The latter having a sheet support surface and flanges disposed on its end faces for securing the envelope between mounting flanges on the main member. The sheet support surfaces of the drum envelope can be in the form of a smooth metal surface, an ink-repellent fabric or support rollers retained on carrying rods.

Abstract: A shifting gear for the inkbox roller of a printing press having a freewheeling journal arranged on the roller axis including a drive pin connected to a slide block carried by the journal and a swingably borne slide block frame having a swinging axis connected with an oscillating drive to the press roller, the swinging axis of the slide block frame being shiftably arranged by a setting gear with respect to the drive pin of the freewheeling journal, and the setting gear having a setting sindle and drive nut connected with a bearing lever swingable on the machine frame and carrying the swinging axis of the slide block frame, the spindle having a setting groove whose pitch corresponds to the maximal setting range of the setting gear and the drive nut carrying a guide pin positioned in the setting groove. In the preferred embodiment, the setting spindle is connected with a turning grip and, with interposition of an indexing arrangement, the setting spindle is adjustable in small annular steps.

Abstract: A shift-over device for controlling the turning drum grippers of a rotary sheet printing press optionally changeable for one-side printing or two-side printing and having a relatively rotatable gripper opening cam and an axially movable gripper turning cam includes a rotatable switching shaft carrying a stop arm with adjustable stops mounted on the press frame for engaging the stop arm and limiting the rotation of the switching shaft in opposite directions. A first crank arm is secured to the switching shaft and carries a lash lever coupled to the gripper opening cam for relatively rotating it incident to oscillations of the switching shaft. A second crank arm is secured to the switching shaft and coupled to a push arm having face cams engageable with push rods connected to the gripper turning cam for axially shifting it incident to oscillations of the switching shaft.

Abstract: The amount of travel and the phase of axial reciprocation for sets of distributing rollers provided on each of at least two inking units of a rotary printing unit are independently adjustable from a central location. For each of the inking units, one eccentric drive adjustable in reciprocating phase and in the stroke or amount of travel is connected to the end portion of an impression cylinder twice the size of associated plate cylinders so that the axial reciprocating movements of the distributing rollers are derived in synchronism with the rotation of the impression cylinder and in a ratio of 1:2 to the rotation of the associated plate cylinders. In one embodiment, a single bolt clamps the two eccentric drives one on top of the other to the end portion of the impression cylinder. In another embodiment, the two eccentrics drives are concentrically arranged in ring-fashion to permit separate clamping and unclamping of each of the four independent adjustments of the amount of travel and phase of reciprocation.

Abstract: A clamping device for thin flexible printing plates has a tensioning rail at the trailing wall of a wide longitudinal groove in the plate cylinder. The tensioning unit is mounted for axial and peripheral adjustment on a support of "L" cross-section having a first leg seated with respect to the bottom of the groove and a second leg presenting an upstanding reference surface interposed between the tensioning rail and the trailing wall of the groove. A set of tensioning springs recessed in the tensioning rail bear against the reference surface and apply peripheral tension to the plate. A spring detent latches the tensioning rail temporarily against the reference surface, overcoming the tensioning springs while the trailing edge of the plate is being gripped. The spring detent is mounted upon and movable with the support. Screws having a plurality of selectable holes anchor the support in a series of peripheral positions for accommodation of plates of different length.

Abstract: A fluid supply system for a lithographic printing press in which a fountain roller journalled in the frame of the press and driven at a slow speed is partially submerged so that a film of fluid is formed on its surface. A distributor roller is journalled in the frame parallel to the fountain roller and spaced therefrom to form a gap. A ductor roller movable broadwise in the gap is supported by a pair of arms which are, in turn, rigidly supported by a shaft journalled in the frame. A driving arm having a thrust rod connected thereto is rigidly secured to the shaft. The driving arm is coupled to a cam follower which engages a rotary cam so that upon rotation of the cam the shaft oscillates to swing the ductor roller back and forth for successive engagement of the fountain roller and the distributor roller to convey fluid therebetween. Opposed way surfaces are provided at the ends of the arms oriented generally perpendicular to the plane of the arms.