Abstract: Method and device for automatically and semi-automatically starting and stopping a sheet-turning operation and for sheet-format adjusting during sheet transport through a recto-and-verso printing press, wherein the sheets are singly transported in succession, by at least one transport drum, between two printing units, wherein, with the aid of remotely operated actuating and position-locking elements, gripper-control elements and sheet-holding segments of a storage drum are disposed so that sheets are transfered from the storage drum to a turning drum by the leading or trailing edge of the sheets, depending upon the mode of operation thereof, the grippers being, with respect to a suction device, adjusted to an appropriate sheet format. Adjustment of the sheet format can be performed both in recto-printing mode as well as in recto-and-verso printing mode.

Abstract: A device for positioning printing material for use in a printing apparatus in which printing is applied to the printing material by passing the same through between an impression cylinder and a blanket cylinder, the device comprising positioning member disposed in an recessed portion formed on an outer surface of the impression cylinder, the positioning member including, a stopper with which a leading end of the printing material comes to contact, drive means for moving the stopper forward and backward in a direction of transport of the printing material, control unit for controllably driving the drive means while the impression cylinder is being rotated, and operation means for operating the control means. Accordingly, displacement of superimposed printed images in a direction of transport of the printing material resulting from the fact that the positioning member improperly positions printing material can be corrected rapidly and accurately.

Abstract: In a plate exchange apparatus for a rotary press, a plate winding rod is pivotally fitted in a winding rod hole in an outer circumferential portion of a plate cylinder and has a spring groove extending almost an entire length thereof. A plurality of leaf springs are provided in the spring groove. Each leaf spring is constituted by a leaf spring member to have a U-shaped section, and has an end formed with a press portion to urge a leading end of a plate against a surface of a gap of the plate cylinder and the other end formed with a bent portion to catch a bent end wound on a circumferential surface of the plate cylinder. A biasing member biases the plate winding rod in a predetermined rotational direction. A plate winding rod pivoting unit is coupled to an end portion of the plate winding rod by a cam mechanism.

Abstract: An arrangement on transfer drums for in-registry sheet transfer in sheet rotary printing machines, has gripper units mounted on cylinders, toothed segments which during a sheet transfer are in engagement, each of the gripper units having a gripper shaft, a gripper and a turnable gripper traverse which receives the gripper shaft and said gripper and fixedly connected with one of the turnable toothed segments, and an elastic element associated with the toothed segment.

Abstract: Device for correcting the register of a sheet-overprint and for compensating for a distorted sheet in a sheet-fed rotary printing machine by deforming the leading edge of the sheet on a travel path thereof before the leading edge enters a printing unit, including an adjustable bending device for bending, in rhythm with a printing cycle of the machine, a support beam extending transversely to the travel path of the sheet and carrying a plurality of mutually adjacent sheet grippers, includes a pregripper device for executing swinging movements about a stationary axis and an axis adjustable into a given position, respectively, the pregripper device including a gripper fly forming the support beam for the sheet grippers, and respective rigid levers supporting the gripper fly at least at both ends thereof on a gripper-fly shaft, the bending device being cooperatively engageable with the pergripper device and being formed of a single adjustable deforming stop disposed substantially midway between the respective end

Abstract: A structure of an intermediate cylinder of a sheet-feed press is disclosed.The present invention comprises a main shaft 10, a front edge gripper holder 12 formed integrally with the main shaft 10, having a group of front edge grippers 20 aligned in an axial direction, and having an arcuate outer surface section, holding discs 24 disposed at both side portions of the main shaft 10 in such a fashion that the rotation thereof relative to the main shaft 10 can be adjusted, and a rear edge gripper holder 22 having a group of rear edge grippers 28 aligned in the axial direction between the holding discs 24, and having a sheet member 38 disposed similarly on the outer peripheral surfaces between the holding discs 24, having an arcuate section, and partially overlapping the outer surface of the front edge gripper holder 12.

Abstract: A sheet-fed rotary offset printing press having a plurality of in-line conventionally mass-produced printing units with plate and blanket cylinders of given unitary diameter and sheet-guiding cylinders having respective diameters which are a multiple of the given unitary diameter, mechanically acting gripper systems carried by the sheet-guiding cylinders for in-line transfer of sheets at a given angular position of the sheet-guiding cylinders and for transporting the sheets in a given travel direction, the printing units having side walls with respective rear and forward edges having supporting and bolt-on surfaces for mutually connecting the side walls of the respective printing units, includes a conventionally mass-produced sheet-transfer cylinder having the given unitary diameter operatively connecting and maintaining an angular position of a point of tangency for sheet transfer both of a sheet-releasing cylinder of one of the printing units and a sheet-guiding cylinder of a succeeding printing unit, the s

Abstract: A suction transfer actuation system for a transfer drum of a multi-color sheet-fed rotary printing press for turning successive sheets, by rear-edge turning, during the sheet transfer from one printing unit to another to facilitate printing on the back side of the sheets. A plurality of suction arms are rigidly connected to a hollow suction rocker shaft connected to actuating levers carrying a pair of guide rollers engaging a curved outer guide cam surface on a guide bar mounted on the transfer drum. The suction actuation system is driven by way of a cam rigidly mounted on the press frame engaged by a cam follower roller to oscillate a drive lever coupled by a link to a drive arm on the rocker shaft to rock the suction arms toward and away from the one printing unit under the guiding influence of the guide cam and guide rollers.

Abstract: In a sheet-fed rotary printing machine having a sheet-turning device including a gripper cylinder and an adjusting member extending in axial direction of and axially displaceable on the gripper cylinder for changing-over a gripper on the gripping cylinder, a clamping device for the adjusting member, includes a preloaded spring, clamping members disposed on both sides of and in vicinity of axial ends of the adjusting member and being displaceable radially to the gripper cylinder, and a pressure bar axially movably guided in the gripper cylinder and biased by a reaction force of the spring in a clamping direction for firmly clamping the clamping members via respective intermediate elements radially towards the gripper cylinder.

Abstract: The device has a transfer cylinder (2) with a drum (4) which is adjustable in the circumferential direction relative to its shaft (3) and which carries sheet grippers (8) with a front stop (8a) for the sheets (B). The diameter of the transfer drum (2) is equal to 1/N of the diameter of the plate cylinder which carries N printing plates. The shaft (3) of the transfer cylinder (2) rotates at a constant speed and executes N revolutions when the plate cylinder is executing one revolution. By means of a controllable setting device, the drum (4) is so displaced relative to the shaft (3) during each revolution that the front stop (8a), when its transfer position in which a sheet is transferred to the impression cylinder (D) is passed, assumes a position by which the exact register of this sheet in relation to the position of the printing plate printing it on the plate cylinder is set.

Abstract: A device for adjusting elements which are adjustable in dependence upon sheet size for gripping and guiding sheets in a sheet-fed rotary printing machine, wherein the adjustable elements are connected to drivable actuating members, comprising a common actuating-drive unit to which the actuating members of a plurality of the adjustable elements are connectible.

Abstract: A sheet transfer device for a printing machine with a transfer drum having a rotational axis, a sheet transfer cylinder located downstream from the transfer drum in a travel direction of a sheet through the printing machine, and cooperating with the transfer drum, and a gripper device on the sheet transfer cylinder for gripping at a take-over location a leading edge of the sheet guided by the transfer drum whereby the sheet is transferred to the sheet transfer cylinder includes a sucker arrangement including suction elements disposed on the transfer drum in vicinity of a trailing edge of the sheet guided by the transfer drum, the suction elements, in a starting position thereof, being flush with the periphery of the transfer drum, a suction-air control device actuable for supplying suction air to the suction elements so that suction contact may be made between the suction elements and the sheet, a device for articulatingly linking the suction elements to the transfer drum so that the suction elements are chan

Abstract: An axially shiftable sheet gripper assembly includes cooperating gripper fingers and gripper abutment surfaces mounted on an axially slidable carriage. The carriage is located in a groove in a sheet transfer drum and carries a control roller at one end. The control roller rides on a control surface of a pivotable control disk. This control disk is movable toward and away from a side face of the sheet transfer drum to regulate the axial movement of the sheet transfer mechanism carriage.

Abstract: A counterbalancing and sheet clamp retention system for high speed sheet handling drums of the type in which leading and trailing edge clamping bars extend along the length of the drum periphery and are capable of movement between retracted and sheet clamping positions for automatic loading and unloading successive sheets to and from the drum. The clamping bars, supported at opposite ends for movement between their respective retracted and clamping positions, are engaged centrally along their length by a retaining device which moves to a clamping bar engaging position under centrifugal force as the rotational velocity of the drum reaches a predetermined value.

Abstract: A sheet gripper for a rotary press is provided having a hooked gripper finger pivotably connected at its lower end to a clamping element, and a roller disposed upon the gripper finger is biased against the guiding surfaces of a finger support element to ensure smooth changes from open and closed gripper finger positions, substantially without any vibrational motion or displacement resulting in the plane of sheet motion. Preferably, a compression spring is mounted in the clamping element to bias the roller against the gripper support element, the element having a rectilinear guide surface disposed substantially perpendicularly to a retaining surface, and a cam surface which extends upwardly and inclined outwardly from the rectilinear guide surface. Upon oscillation of the gripper shaft, the roller is guided along the rectilinear guide surface and cam surface, thereby defining accurate gripper finger motion.

Abstract: A suction system is arranged in a sheet guiding cylinder of a printing machine which is switchable from the first form mode to the printing on both sides of the sheet which is turned over by the suction system around its rear edge. The suction system includes an arrangement for automatically controlling suction air for operating a suction head which is movable in a sucker body of the suction system.

Abstract: A device for safeguarding a rotary printing machine for printing sheets in a first form and perfector printing operation having a storage and a turning drum, first adjusting elements for adjusting a trailing drum body of the storage drum to different format sizes, second adjusting elements for adjusting the turning drum, and grippers and mechanical and electrical means for safeguarding the printing machine during a system-determined function setting includes a first coupling wheel assigned to the trailing drum body of the storage drum, a second coupling wheel mounted on a shaft journal of the turning drum, both of the coupling wheels being linked free of slippage via drive means in such a way that the second coupling wheel and the turning drum run in synchronism, the second coupling wheel being braced axially via trip cams on a disk secured to the shaft journal so that, in a case of rotation between the second coupling wheel and the turning drum due to a fault, a switching pulse is issued which releases a sig

Abstract: Sheet transfer drum located between two printing units of a multicolor sheet-fed rotary printing press and having a cylindrical surface formed of a plurality of sheet-carrying elements arranged in succession around the circumference of the drum, including a suction means applicable to the trailing edge of a sheet of paper to be printed, mountings located at ends of the sheet transfer drum for carrying the sheet to be printed, each of the end mountings being formed by a respective guide channel oriented in circumferential direction of the sheet transfer drum, the guide channel having a radially outer portion and a radially farther inward portion, at least the outer of the radial portions being substantially equal in length to a maximum format of the sheet.

Abstract: An improved sheet gripper system disposed on the impression cylinder of a printing press having regular sheet grippers mounted on a gripper shaft on the impression cylinder with additional grippers provided in the spaces between the regular grippers, which spaces are intended for cooperating transfer grippers, the additional grippers being adapted to retract into a gripper channel and extend out into the gripper plane only in one zone of the movement of the impression cylinder in which the between-gripper spaces are freed of the cooperating transfer grippers so that the front edge of a sheet is held by both the regular grippers, as it passes through the printing zone, and the additional grippers and the tension to which the printing material is subjected is greatly reduced, and the registry and print quality are improved.

Abstract: Sheet-guiding drum for sheet-fed rotary printing machines, having a drum body carrying at least two gripper bridges adjustable to different paper thicknesses, includes gripper supports carried by the drum, the gripper supports being adjustable in at least substantially radial direction of the drum; play-free adjusting elements carried by the drum body and adjustable independently of one another for adjusting the gripper supports; and a central adjusting device mounted readily accessibly on the drum body for actuating the adjusting elements in common.

Abstract: Apparatus is provided for simple and reliable adjusting of the smoothing means on a storage cylinder of a sheet of set press to adjust the smoothing means relative to the sheet end when the press is selectively changed from first printing to perfecting printing operation. The storage cylinder is mounted on a hollow main shaft in which a hollow intermediate shaft and an adjusting shaft are concentrically mounted. Clamping cams are disposed on the intermediate shaft and act by way of cam followers and expanding finger sleeves to clamp or release the elements which carry the smoothing means on the main shaft. The position of the smoothing means relative to the main shaft is adjusted by way of epicyclic gearing interposed between one end of the adjusting shaft and the hollow main shaft.

Abstract: The turning cylinder and storage cylinder in a perfecting printing press is provided with changeover mechanisms having spring-loaded electromagnetically releasable latches and sensors for detecting latched adjustments. Moreover, a contactless sensor is provided for detecting clamping of the calendering suckers in the storage cylinder even when the cylinder is rotating. Contactless proximity switches determine the correct phase adjustments between the storage cylinder and the turning cylinder for both perfecting and first form printing. An access door and interlock guarantees that the cylinders are turned to a normal position and braked before the access door is opened, and the access door cannot be closed for subsequent printing until changeover has been completed. An indicator array indicates the sequence of adjustments to follow and abnormal conditions.

Abstract: An impression cylinder for a rotogravure press having a recessed sheet stock gripper mechanism with a swivelling mechanism that swivels the grippers within the cylinder contour by revolving the grippers around a theoretical axis on the cylinder contour. The swivelling is rigidly and precisely constrained along an arcuate path by a plurality of arcuate guides disposed along the axial length of the cylinder. The opening and closing of the grippers and the swivelling of the grippers into the cylinder contour are caused to occur in sequence synchronized to the cylinder rotation by cam followers on gripper shaft pivot arms cooperating with cam followers journaled to the gripper shaft that are spring pressed onto cam surfaces fixed to the machine frame at the ends of the cylinder.

Abstract: Sheet transfer cylinder assembly of a sheet-fed rotary printing machine including a sheet transfer cylinder and a device for correcting register of overprints on a sheet by deforming the leading edge of the sheet which includes a gripper fly supported on a shaft and swingably mounted on the sheet transfer cylinder, and a bending device carried by the sheet transfer cylinder in a middle region thereof, the bending device being cooperatively associated with the gripper fly and being actuatable by swinging movement of the gripper fly for flexing the shaft of the gripper fly and deforming the leading edge of the sheet in a direction tangential to the circumference of the cylinder.

Abstract: Sheet transfer cylinder for a sheet-fed rotary printing machine convertible between first form and perfector printing having a gripper device for gripping the leading edge of a sheet and a suction device for gripping the trailing edge of the sheet and tightening and smoothing the sheet in travel direction thereof through the machine and transversely to the travel direction including first control means including at least one circumferential cam for controlling circumferential sheet-tightening movement, second control means including lateral cams for controlling lateral sheet-tightening movement, the suction device having parts thereof disposed side-by-side in axial direction of the cylinder and formed with suction holes, and transmission means operatively connecting the first and the second control means with the parts of the suction device so as to superimpose actions thereon for applying a diagonal tightening force to the sheet, the first and the second control means being independent of one another.

Abstract: The sheet fed rotary press includes a feed cylinder cooperating with a feed table extending in a plane situated below and in spaced relationship from the periphery of the feed cylinder. An auxiliary gripper system located under the feed cylinder provides for the transfer of respective sheets from the feed table to the feed cylinder.

Abstract: A packing sheet overlaying device for offset printing in which a packing sheet can readily be attached to and released from a cylinder of an offset printing machine or the like. The packing sheet is held in position at one end by a gripper which is attached to a bracket which is rotatably mounted on a cam lever shaft. A slot is formed in the bracket and a screw passes through the slot to secure the bracket to the cylinder to lock the packing sheet in place. When it is desired to change the packing sheet, the screw is loosened and the bracket rotated through an angle defined by the length of the slot to thereby form a gap between the gripper and the corresponding edge of the cylinder. The other end of the packing sheet is held in position by a tensioning mechanism including a tensioning knob provided to adjust the tension on the packing sheet.

Abstract: A sheet drawing device for a sheet-fed rotary press comprises a pair of adjusting gears adjustably mounted on a main shaft, a plurality of segment arms rotatably mounted on the main shaft, a bearing block adjustably mounted on each of the segment arms, which is pivotably mounted for adjustment about an axis perpendicular to the bearing axis of the bearing block, a sheet-drawing roll journaled in each bearing block, a plurality of fixtures secured to a gripper shaft which is pivotably mounted in the adjusting gears, each fixture being resiliently connected to a guide which is rotatably mounted on the gripper shaft and which carries a freely rotatable trailing-end gripping roller that is engageable with one of the sheet-drawing rolls, means for controlling pivoting of the gripper shaft to bring the trailing-end gripping rollers into and out of sheet gripping engagement with the sheet-drawing rolls, a second gripper shaft pivotably mounted in the adjusting gears, on which are secured a plurality of driving arms

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: In a transfer cylinder for perfector printing machines having two diametrically opposed sheet-supporting surfaces formed from two groups, respectively, of sheet supports engaging comb-like one within the other, one of the two sheet-supporting groups of one sheet-supporting surface having a device for gripping the leading edge of a sheet, and both of the sheet-supporting groups forming one sheet-supporting surface being adjustable relative to one another about the rotary shaft of the transfer cylinder, each of the sheet supports of a respective sheet-supporting surface being firmly connected to a diametrically opposing sheet support of the other sheet-supporting surface and being disposed on the shaft of the transfer cylinder, the improvement therein includes means for mounting together at least a plurality of the diametrically opposing, mutually firmly connected sheet supports so as to be radially adjustable.

Abstract: A clamp for holding a flexible sheet on a rotary carrier tightens the grip on, and pulls, the sheet upon rotation of the carrier, as a result of centrifugal forces generated on two weights attached to two cooperating arms within the clamp. The magnitude of the grip-tightening force is dependent upon the mass of a grip-tightening weight attached to the clamp. The magnitude of the sheet-pulling force is dependent upon the mass of a sheet-pulling weight attached to the clamp. The clamp faces are mounted for concurrent movement along the periphery of the carrier to prevent tearing or other damage to the sheet when it is pulled as the carrier is rotated.

Abstract: A system for duplicating images on copy sheets utilizing an impression cylinder. The system provides for transfer of an image to one side of each sheet, and the sheet may then be reversed to locate the sheet on the impression cylinder, trailing edge first. The reversing is in synchronism with a second image whereby this second image may be transferred to the opposite side of each sheet. The impression cylinder is provided with a first gripper for engaging the leading edge of each sheet when the sheet is first fed to the impression cylinder. A second gripper is provided on the impression cylinder for engaging the trailing edge of each sheet, and this second gripper turns around to achieve the reversing action after application of the first image. The first gripper is externally mounted and is movable relative to the impression cylinder whereby the relative positions of the grippers can be changed so that different size sheets can be duplexed.

Abstract: A sheet advancing cylinder in an offset printing machine, has a sheet gripping system arranged in its interior. The system includes a rocking member rigidly connected to a first gripper for moving the latter between two terminal positions in a slot formed in the jacket of the cylinder. The movement of the rocking member is such that in the first terminal position the first gripper is flush with the jacket periphery, in an intermediate position it is above the periphery and in the second terminal position it is below the periphery.

Abstract: A printing machine sheet transfer drum adjustable to variable sheet lengths has 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 are disposed in channels of the transfer drum 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. The transfer drum has a rigid main drum body integral with one of the comb-like structures and formed of at most two separable parts including the device for gripping the leading edge of the sheet, and a hollow, substantially cylindrical body partly surrounding the main drum body in circumferential direction thereof. The device for gripping the trailing edge of the sheet being disposed on the hollow body and forming therewith a rotatable sheet carrier unit.

Abstract: An assembly of a sheet-transfer drum, a sheet-turning drum and a storage drum located therebetween for transporting a sheet between individual printing units of a rotary printing press includes a change-over mechanism for converting the printing press from single-side sheet printing to double-side perfector printing and conversely as well as to different format sizes. The change-over mechanism has a control shaft axially displaceable to at least first and second control positions, first and second control pinions mounted on the control shaft, and a plurality of drive wheels couplable with the first control pinion in the first control position of the control shaft, for converting the printing press from single-side sheet printing to double-side perfector printing. A device for guiding and holding a sheet is disposed on the storage drum. A gripper release device for adjusting the format size for perfector printing, and a control member coupled with the gripper-release device are also provided.

Abstract: Sheet turn-over device for a one-side printing and perfecting press with clamping grippers pivotable about a rotary axis and mounted in a sheet turn-over cylinder so as to be adjustable from single-side printing to one-side printing and perfecting includes a gripper shaft coextensive with the rotary axis about which the clamping grippers are pivotable, a gripper tube coaxially disposed on the gripper shaft and separate control means for respectively driving the gripper shaft and the gripper tube. The rotary axis of the gripper shaft as well as of the gripper tube have a location radially inward from a point on a tangent to the periphery of the sheet turn-over cylinder at the point of clamping contact of the grippers.

Abstract: In a printing machine operable for printing selectively on one or on both sides of a sheet, the printing machine having a sheet-turning drum provided with grippers actuatable by control cams and follower rollers cooperating therewith, the control cams and follower rollers being shiftable relative to one another, a device for reversing the operation of the grippers includes control elements carrying the follower rollers, and a tool insertable into the sheet-turning drum so as to project well beyond the periphery thereof, the tool cooperating with the control elements so as to lift the follower rollers from the control cams during shifting of the control cams and the follower rollers relative to one another.

Abstract: Sheet-fed rotary printing press for printing on both sides of a sheet includes an assembly of a transfer drum, a storage drum and a sheet turn-over drum, mounted in succession, and located between two printing units, the storage drum having clamping grippers for gripping the leading edge of a sheet being fed from the transfer drum to the storage drum, the turn-over drum having tong grippers for gripping the trailing edge of the sheet at an imaginary straight line connecting the rotary centers of the storage drum and the turn-over drum as the sheet is being transferred from the storage drum to the turn-over drum and as the clamping grippers of the storage drum release the leading edge of the sheet, the tong grippers exerting a weaker clamping force on the sheet than the clamping force exerted by the clamping grippers thereon and, before the tong grippers have gripped the sheet and before the clamping grippers have released the sheet, the distance between the clamping grippers, on the one hand, and the tong gri

Abstract: A sheet-fed rotary printing press includes a transfer drum assembly includes a rotatable transfer drum having a sheet-supporting peripheral surface, a gripper device carried by the transfer drum for gripping the leading edge portion of a sheet being transferred, and a suction device secured to the transfer drum at the end of the peripheral sheet-supporting surface, as viewed in rotary direction of the transfer drum, for gripping the trailing edge portion of the sheet. The suction device includes a plurality of suckers having suction surfaces disposed in the peripheral surface of the transfer drum and formed with respective suction orifices.

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.

Abstract: An assembly of a sheet transfer drum, a sheet-turning drum and a storage drum mounted on a shaft and located therebetween for transporting a sheet between individual printing units of a rotary printing press, includes a change-over mechanism for converting the printing press from single-side sheet printing to double-side perfector printing and conversely, as well as to different format sizes, the change-over mechanism having a control shaft axially displaceable from a non-controlling position to a single control position, a first control pinion mounted on the control shaft, first adjusting means for adjusting format size for double-side perfector printing, the first control pinion being forcibly coupled to the first adjusting means, a second control pinion mounted on the control shaft, second adjusting means mounted for rotation about the shaft of the storage drum, drive gear means for converting the rotary printing press from single-side sheet printing to double-side perfector printing, first cam means for a

Abstract: Sheet transfer drum for a printing press includes a shaft, a drum body fixed to the shaft, the drum body including a tube segment having two longitudinal edges, and respective guide rings fixed to both ends of the tube segment, the longitudinal edges of the tube segment defining a gap therebetween a gripper assembly is received in the gap and includes a gripper shaft, a row of grippers fixed to the gripper shaft and a vertically adjustable gripper bearing bar cooperating with the row of grippers for gripping a sheet to be transferred by the sheet transfer drum. A bearing is received in the gap for securing the gripper assembly to the shaft. The guide rings are formed with respective slots extending in peripheral direction of the drum body, and threaded fasteners respectively extend through the slots and releasably secure the guide rings to the shaft within the range of the slots.

Abstract: A rotary printing machine including an impression cylinder which has at least two grippers for gripping the forward edge of a sheet of paper for drawing the paper onto the same at each appropriate instant in each cycle of operation of the machine, the grippers being movable circumferentially of the impression cylinder and retainable in a different position which is stationary relative to the impression cylinder, to vary the relative position of the sheet of paper on the cylinder while the cylinder is rotating.