FR2792871A1 - Rotary printer impression cylinder has multiple cylinders mounted on eccentric bushes adjusted by gear drive - Google Patents

Abstract

The rotary printer impression cylinder has multiple cylinders (2, 3) mounted by eccentric nearing bushes (7, 8) in the printer frame sidewalls. The bearings are mounted in a door at one side (35). The bushes are gear-driven by gears mounted on the door. One bush (7) is coupled with a drive mounted on the sidewall (34).

Description

1i 2792871 The invention relates to a printing unit of a machine for

  rotary printer comprising a plurality of printing group cylinders, a first printing group cylinder being respectively mounted by a first eccentric sleeve and a second printing group cylinder respectively by a second eccentric sleeve in a first and a second wall lateral, the first and the second eccentric sleeve of the second side wall carrying teeth with which can be brought into engagement a respective pinion, the pinions being mounted on a door of the second side wall, in which are mounted, in the state closed, the first and / or the second eccentric sleeve of the second side wall, and the pinions can be brought out of engagement with the teeth, in the open state of the door for which is released an opening of the second side wall, the pinions being furthermore connected in terms of the drive via a transmission, and the first

  eccentric sleeve of the second sidewall being driven.

  US-PS 4,458,590 shows a dual printing unit, the two printing groups of which each comprise a printing forme cylinder and a transfer cylinder. In order to achieve the tight print position and the off print stop position, the print form cylinder and the transfer cylinder of a printing unit and at least the print form cylinder of the printing Another printing unit is mounted in eccentric sleeves, which can be actuated by a common drive. A disadvantage of this lies in the fact that during a modification of the printing clamping of one printing unit, the cylinder or cylinders of the other printing unit are also displaced, which requires

  new adjustments of these, taking a lot of time.

  DE 44 14 084 A1 shows a rotary printing machine having printing group cylinders which are mounted in side walls by means of eccentric sleeves. A wall

  lateral contains an opening that can be closed with a door.

  In the open state of the door, the printing group cylinders are accessible on one side, so that a sheath can be slid or slid into it. Print group cylinders are mounted with their

  eccentric sleeve, in the door when it is in the closed state.

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  An eccentric sleeve carries a toothing in which, in the closed state, a pinion is mounted on the door and can be pivoted by means of a power jack disposed on the door. The pivoting movement can be transmitted by a coupling rod, from a pinion to another pinion which, when the door is in the closed state, is also engaged with the toothing of an eccentric sleeve. In the case of this drive of an eccentric sleeve, the synchronization with the drive of the other eccentric sleeve of the group cylinder

  printing, mounted in the other side wall, is complicated.

  The object of the invention is to provide a drive for an eccentric sleeve mounted in a printing group door, which allows using simple technical means, a synchronization of the movement of the two eccentric sleeves of a drive cylinder

printing group.

  According to the invention, this object is achieved for a printing unit of the type mentioned in the introduction, thanks to the fact that the first eccentric sleeve is connected in terms of the drive with a drive arranged on the second wall lateral. The drive arranged on the second side wall can be inexpensively connected, without the need for synchronizing hydraulic metering means, to the eccentric sleeve mounted in the first side wall, for synchronized driving, with the aid of mechanical elements, for example a synchronization shaft mounted in the two side walls. It is of no importance here that the drive motor, for example a pneumatic power cylinder, is disposed in the region of the first or second side wall. The drive may, when opening the door, advantageously be uncoupled from a printing unit cylinder to be made accessible, the opening movement of the door being for example a pivoting movement or a movement of

sliding.

  The invention also relates to the features hereafter considered in isolation or in all their technically possible combinations.

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  - The first eccentric sleeves of the first and second side walls are driven synchronously by the drive. - The first and second eccentric sleeves of the first side wall are connected in the plane of the drive via a coupling rod, and the eccentric sleeves of the second side wall are connected by a transmission driving the second. eccentric sleeve of the second side wall in a manner synchronized with the

  second eccentric sleeve of the first side wall.

  - The pivot axes of the first and second sleeve

  the first lateral wall as well as the hinge points of the coupling rod which is articulated thereon, form a parallelogram (FIG. 1), the toothed transmission ratios of the first eccentric sleeve-first pinion and toothing of the second eccentric second pinion sleeve are identical , and the pivot axes of the first and second pinion and the points of articulation of the coupling rod on the first and the second

  pinion form a parallelogram (Figure 2).

  - On the first eccentric sleeve of the second side wall is articulated a coupling rod which is hingedly connected to a pivoting lever which is fixed to a shaft mounted in the two side walls, being drivable by a power jack, and on which is fixed another pivotally connected lever, via a coupling rod, to the first eccentric sleeve of the first

side wall.

  Other features and advantages of the invention will emerge from

  the following description of some exemplary embodiments of

  schematically in the accompanying drawings, which show: FIG. 1 a double-sided printing unit in side view, having a mechanism for making the tight printing position and the offset printing stop position, FIG. 2 a variant of Figure 1, FIG. 3 section 11-II according to Figure 2, FIG. 4 section IV-IV according to Figure 2, FIG. 5 detail V according to Figure 1 or 2,

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  Fig. 6 the cylinders according to FIGS. 1 or 2, in the discarded position

stop printing.

  The double printing unit shown in Fig. 1 comprises a first printing unit 1 with a first printing forme cylinder 2 and a first transfer cylinder 3, and a second printing unit 4 with a second printing unit 1. impression cylinder 5 and a second transfer cylinder 6. The first impression-form cylinder 2 is mounted by means of a first eccentric sleeve 7, the first transfer cylinder 3 by means of a second eccentric sleeve 8, the second impression-form cylinder 5 by means of a third eccentric sleeve 9 and the second transfer cylinder 6 by means of a fourth eccentric sleeve 10, in a first side wall 11. The journals of the shape cylinders 2, 5, 3, 6, also referred to as printing group cylinders in the following, are only shown by their centers in the offset position A and in the closed position of printing B. The pr and the second eccentric sleeve 7, 8 are connected in the plane of the drive, via a transmission. According to the present exemplary embodiment, the transmission is of a configuration such that on the first eccentric sleeve 7 is fixed a double lever 12, and on the second eccentric sleeve 8 a lever 13, which are connected to each other in an articulated manner, by means of a coupling rod 14. The double lever 12 is further hingedly connected, by means of a coupling rod 15, to a drive member in the form of a pivoting lever 16. The pivoting lever is pivotally mounted on the first side wall 11. This is achieved by means of a shaft 17 mounted in the first side wall 11, on which is fixed the pivoting lever 16, and which the case It is furthermore mounted in a second, not shown, side wall. Other explanations on this subject will be given later on the occasion about another embodiment. On the pivoting lever 16 acts a motor, for example a power cylinder 18 based on the

  first side wall 11 or an electric displacement magnet.

  In a similar manner to the first printing unit 1, in the second printing unit 4, on the third eccentric sleeve 9 is fixed a double lever 19 and on the fourth eccentric sleeve 10 a

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  lever 20, which are both connected to each other in terms of the drive, via a coupling rod 21. The double lever 19 is further hingedly connected to the pivoting lever 16, via the rod 22. The mechanisms 12 to 22 cited, for the actuation of the eccentric sleeves 7 to 10, may advantageously be arranged in the region of the inner side of the first side wall 11 (S2i). Depending on the space available, the power cylinder 18 may advantageously also be disposed on the outer side of the first side wall 11 (S2a). For this purpose, the first side wall 11 is passed through the shaft 17, which is provided on the outside of the wall

  side, of a separate lever on which the power cylinder 18 acts.

  In the tight printing position B of the eccentric sleeves 7 to 10, shown in FIG. 1, the printing group cylinders 2, 3, 5, 6 are brought together and clamped together, and a strip 23 is made passing between the transfer cylinders 3, 6 is printed in an indirect printing process, for example offset printing or gravure printing. Inking mechanisms for inking plates or printing forms on impression-form cylinders 2, and, where appropriate, humidification groups in the case of offset printing, are not shown . The tight printing position B is carried out for a power jack 18 in the extraction position, traction forces being applied to the coupling rod 15 and to the coupling rod 14 via the double lever 12, and the lever 13 coming into abutment, in an extreme position, against an adjustable stop 24. Simultaneously, the pivoting lever 16 applies compressive forces to the rod 22 and, via the double lever 19, to the coupling rod 21, the lever 20 abuts against an adjustable stop

  when the tight printing position B is reached.

  To make a modification or adjustment of the print clamp, ie a slight change in the distance between the first and the second transfer cylinder 3, 6, the stop 24 is displaced. of the stop 24 towards the lever 13, the latter and thus also the second eccentric sleeve 8 are rotated in the clockwise direction, and on this occasion, the first transfer cylinder 3 is pushed back from the second transfer cylinder 6, in

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  thus producing a decrease in printing clamping. Simultaneously, during this pivoting movement of the lever 13, the double lever 12 and with it the first eccentric sleeve 7 are also rotated clockwise through the coupling rod 14. The eccentricities e1 and e2 are dimensioned (preferably el <e2) and positioned so that the first impression-form cylinder 2 moves away from the first transfer cylinder 3 by about the same value as the latter is approaching the first impression-form cylinder 2. This spacing distance approximately constant between the first impression-form cylinder 2 and the first transfer cylinder 3 is also retained, when in the opposite case, the stop 24 is removed with respect to the lever 13 and that is therefore a tightening

higher print.

  By continuing the rotation of the first and the second eccentric sleeve 7, 8 towards the stopping position A, the movement conditions of the first impression-form cylinder 2 and the first transfer cylinder 3 change on the other hand, in that the first impression-form cylinder 2 moves away from the first transfer cylinder 3 more than the latter follows the previous one, so that it is established between the two printing-group cylinders 2 , 3, an interstice a2 (see Figure 6). This stopping of the printing is performed by inverting the control of the power jack 18, the latter applying during its retraction, a compressive force to the coupling rod 15 via the pivoting lever 16, and to the coupling rod 14 via the double lever 12; it will be mentioned here only to be complete, that at the beginning of the operation of setting apart position, it is firstly the spacing distance b described later, on the coupling rod 15 (Figure 5), which is resorbed. By observing the magnitude and the position of the eccentricities e 1 and e 2, it is visible that during the relative rotation of the eccentric sleeves 7, 8 in the direction of the realization of the stopping position A, it occurs a significant radial displacement movement of the first impression-form cylinder 2 of the first transfer cylinder 3, while the latter approaches mainly in the tangential direction of the first

  first impression form cylinder 2.

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  The spacing conditions described are also established for the second printing forme cylinder 5 and the second transfer cylinder 6 of the second printing unit 4. It is thus possible to vary the printing clamping between the first and the second transfer cylinder 3, 6, without a significant distance variation occurring between the second impression-form cylinder 5 and the second transfer cylinder 6. Furthermore, it also occurs during the movement of moving to the offset print stopping position (retracting movement) of the power cylinder 18, moving the printing group cylinders 5, 6 to the stopping position A, an interstice a2 s establishing between these and a global gap al being established between the first and the second transfer cylinder 3, 6 (see Figure 6). To avoid repetition, more detailed explanations will be dispensed with. The coupling rod 15 is of a configuration adjustable in length against the force of a spring, in the opposite direction of the actuating direction towards the tight printing position. In detail (Figure 5), the coupling rod 15 comprises a sleeve 26 in which is screwed, by means of a threaded connection 29, a pin 27 on which have been arranged an alignment of spring washers 28 prestressed. The spindle 27 can be screwed into a spindle head 30 articulated to the double lever 12, the spindle 27 being pulled, when the depth of screwing increases, against the force of the spring washers 28, out of the hinged sleeve on the Pivoting lever 16. On this occasion, a measurement value b is adjusted from which the spindle 27 has been pulled out of the sleeve 26 by being lifted from an abutment position. In this position, the spindle 27 is locked in rotation in the spindle head 30, by means of the counter nut 31. With this adjustment, the coupling rod 15 applies, via the lever 12 and the connecting rod. coupling 14, a pulling force with which it pulls the lever 13 against the stop 24. To reduce the print clamping, the stop 24 is rotated to move towards the lever 13. On this occasion, the lever 13 and the dual lever 12 rotates clockwise and pin 27 is drawn from a certain value out of the sleeve 26, against the force of the spring washers 28, producing an increase in the distance b . Conversely, to increase the strength

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  printing, the stop 24 is remote from the lever 13, which produces the rotation of the lever 13 and the double lever 12 in the opposite direction of the clockwise, the pin 27 being drawn inside the sleeve 26 under the action of the spring washers 28, producing the decrease of the distance b. In both cases, the position of the second impression-form cylinder 5 and the second transfer roll 6 is not changed. For this purpose, the force exerted by the pivoting lever 16 on the coupling rod 15 is greater than the force of the spring washers 28. Thanks to the possibility of adjusting the length of the coupling rod 15, the mechanisms for producing the position the print-out position and the print-out position, as well as to vary the printing clamp, can be actuated by a common drive 16, 18 for both printing units 1, 4, without being obliged to when changing the print clamp on one of the printing units, take into account variations in the setting of cylinders in the other printing unit. The coupling rod 15 can also be articulated on the second eccentric sleeve 8, the abutment 24 then preferably to cooperate with the double lever 12, in order to avoid alternating flanks due to play. Instead of the rod of coupling 15, the rod 22 may also be of an adjustable configuration in length, the rod 22 in this case to be pre-stressed by applying a

compression force.

  It is also possible to mount fixedly in the side walls 11, the second transfer cylinder 6, by removing the fourth eccentric sleeve 10, the coupling rod 21, the lever 20 and the abutment 25. The pivoting movement of the lever double 19 to the tight printing position is then advantageously limited by means of a stop 59 (shown in fine lines in Figure 1). By moving the stopper 59, the tightening or adjustment of the clamping of the second impression-form cylinder 5 is produced with respect to the second transfer roll 6, the clamping pressure being reduced for a movement of the stop 59 in the direction of the lever double 19, and increased for the opposite direction. On this occasion, the setting of the printing unit 1 is not modified following the variation of the

  distance b on the coupling rod 15.

  The coupling rod 15 can also be of a rigid configuration, that is to say be of an invariable length, when the first group

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  1 cooperates only with a pressure cylinder, that is to say that only one pressure cylinder is used in place of the second printing forme cylinder 5 and the second transfer cylinder 6. On the plan of the distribution of the place, it is advantageous to articulate the coupling rod 15 and respectively the rod 22 on the first eccentric sleeve of the printing forme cylinder 2, 5, and to dispose on the opposite side of this eccentric sleeve 7, 9 the connecting rod 14, 21 connecting the latter to the second and fourth sleeve respectively

  eccentric 8, 10 of the transfer cylinder 3, 6.

  As already mentioned, the printing group cylinders 2;

  3, 5, 6 can be cantilevered into a single side wall 11.

  These printing group cylinders 2, 3, 5, 6 can also be mounted and supported on both sides in side walls. Without this being represented in the drawings, it will be noted that in a similar manner to FIG. 1, the second lateral wall receives eccentric sleeves 7 to 10 of the same type, in which the other journals of the printing group cylinders are mounted. 2, 3, 5, 6. There will also be provided a mechanism 12 to 16, 19 to 22 of the same type as in FIG. 1, for the realization of the tight printing position and the stopping position of the printing stop and for adjusting the printing, preferably on the inner side of the second side wall (Sli). FIG. 2 shows such a mechanism for the variant according to which the second wall has an opening that can be closed by a door, through which it is possible to replace the

  sleeves blanket transfer cylinders. For the description of this

  alternatively, for the sake of simplicity, the same reference numerals for identical or similar parts will be kept to a large extent. A first printing forme cylinder and a first transfer cylinder 2, 3 of a first printing unit 1, and a second printing forme cylinder and a second transfer cylinder 5, 6 of a second printing unit 4, are on the one hand, as shown in Figure 1, mounted in a first side wall 11. These printing group cylinders 2, 3, 5, 6 are further mounted in a second side wall 34 with their journals 32, 33 remote from the first side wall 11 (Figures 2 to 4). In this case, the first and third eccentric sleeve 7, 9 receiving the pins 32 of the first and second cylinder

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  of printing form 2, 5, are mounted directly in the second side wall 34, while the second and the fourth eccentric sleeve 8, 10 housing the journals 33 of the first and second transfer cylinder 3, 6 are mounted indirectly in the second side wall 34. They are received by doors 35, 36, as they are in their closed state, the doors being slidably mounted on the outer side of the second side wall 34. It is also possible that all the sleeves eccentric 7 to 10, or for example only the first and the third eccentric sleeve 7, 9, are mounted in the doors 35, 36, this depending on those of the cylinders

  printing group 2, 3, 5, 6 which carry a sheath.

  On the first eccentric sleeve 7 are fixed a drive lever 37 and a sector 38 which carries a toothing 39. While the drive lever 37 is advantageously arranged on the inner side (Sli) of the second side wall 34 sector 38 is placed on the outer side (Sla). With the toothing 39 of the sector 38 engages a pinion 40, which is advantageously formed as a toothed sector. The pinion 40 is fixed on a shaft 41, which is mounted in the door 35. The pinion 40 is disposed in a recess of the door 35, on the inner side thereof. The shaft 41 leads on the outside of the door 35, where a coupling lever 42 is fixed on the shaft 41 (Figure 3). The second eccentric sleeve 8 also carries a toothing 43, which is machined in a sector 44 fixed on the second eccentric sleeve 8. With the toothing 43 of the sector 44 engages a second pinion 45, which is mounted on the door 35 by means of an axis 46. The coupling lever 42 and the second gear 45 are connected to each other in an articulated manner, by means of a coupling rod 14.1. The driving lever 37 is connected to a pivoting lever 16.1, via a coupling rod 15. The pivoting lever 16.1 is pivotally mounted on the second side wall 34 and is hingedly connected to a power jack 18 resting on the second side wall 34. As already mentioned with reference to FIG. 1, it is also possible, by eliminating the power jack 18, that the pivoting lever 16.1 is fixed on a shaft 17 from the first side wall 11 and driven by a power jack 18 fixed on the first

side wall 11.

  In a similar manner to the first printing unit 1, on the third eccentric sleeve 9 of the second impression-form cylinder are attached a drive lever 47 and a sector 48, the latter bearing a toothing 49. With the toothing 49 engages a first gear 50 which, like a coupling lever 51, is fixed on a shaft 52 mounted in the door 35. The arrangement on one side and the other of the door is similar to the arrangement of the first pinion 40 and the coupling lever 42, shown in FIG. 3. Furthermore, in a manner similar to that shown in FIG. 4, on the fourth eccentric sleeve 10 is fixed a sector 53 bearing a toothing 54 with which a second gear 55 is engaged. The latter is in the form of a toothed segment and is pivotally attached to the door 35 by means of an axle 56. The pinions 50 and 55 are connected to one another. the other in an articulated manner by means of a coupling rod

  21.1, the first of them through the coupling lever 51.

  In addition, the pivoting lever 16.1 and the driving lever 47 are connected

  in terms of training, via a rod 22.

  In the tight printing position represented by B in FIG. 2, eccentric sleeves 7 to 10, the pivoting lever 16.1 imparts to the coupling lever 15 (in a similar manner to the embodiment according to FIG. traction, the distance b shown in Figure 5 being established in this case. (The method of construction of the coupling rod 15 also corresponds to that shown in FIG. 5). The pivoting movement of the driving lever 37 and the first eccentric sleeve 7 generated on this occasion, is transmitted to the second eccentric sleeve 8, via the toothing 39 of the sector 38, the first pinion 40, of the coupling lever. 42, the coupling rod 14.1, the second pinion 45 and the segment 44. The second pinion 45 comes into abutment, in the tight printing position, against an adjustable stop 24.1 disposed on the door 35. At the reversing the control (retraction) of the power jack 18, the first printing unit 1 is moved to the offset position of the printing stop A. By applying a compressive force on the coupling rod 15, it is rotated the eccentric sleeves 7 and 8 in the position A, via the transmission chain which has just been described. On this occasion, the first printing forme cylinder 2 and the first transfer cylinder 3

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  take the positions shown in FIG. 6. The adjustment of the printing is carried out by adjusting the stop 24.1, a rotation thereof towards the second pinion 45 reducing the impression clamping, and a rotation in FIG.

the opposite sense increases it.

  When the first printing unit 1 is brought into the tight printing position, the second printing unit 4 is also brought into the tight printing position B, the printing position of the second printing cylinder being printing form 5 and the second transfer cylinder 6 is effected by compressive biasing of the rod 22 and further transmission of the press printing movement through the drive lever 47, the sector 48, the first pinion 50, the coupling lever 51, the coupling rod 21.1, the second pinion 55 and the sector 53, the second pinion 55 abutting the adjustable stopper 25 1 disposed on the door 35. The setting apart print stop position, that is to say the spacing of the second printing cylinder and the second transfer cylinder 5, 6 in the position A, is performed in the opposite way to the setting movement. in tight printing position, after inversio n of the control of the power jack 18. The modification of the print clamping is effected by moving the stopper 25.1, the print clamping being reduced for a displacement towards the second gear 55, and increased for a displacement s' away from the second pinion 55. Due to the automatic length adjustment of the coupling rod 15, modifications of the printing clamps on one of the printing units 1, 4 have no feedback on the positions of the cylinders printing group of the other printing group. Therefore, these cylinders do not move and they do not require new adjustments resulting in downtime of the machine. The continual availability of their correct setting can provide a condition for good quality

printing.

  Thanks to the drive links of the eccentric sleeves 7 through the teeth 39, 43, 49, 54 with the pinions 40, 45, 55 mounted on the door 35, these driving links can be easily interrupted. Thus, the door 35 can simply be moved to the right in an open position, the pinions 40, 45,

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  , 55 accompanying the displacement of the door 35 during the displacement thereof and being extracted from the teeth 39, 43, 49, 54. Conversely, during the displacement of the door 35 in the closed state shown in FIG. 2, the pinions 40, 45, 50, 55 engage again in the teeth 39, 43, 49, 54, thus restoring the connection on the plane of the drive of the press-in position mechanism and in position offset print stop. In the open state of the doors 35, 36, these release an opening 57 in the second side wall 34, through which it is possible to slide a blanket sleeve on or from the first cylinder

  3 or on or second transfer cylinder 6.

  The driving connection described, eccentric sleeves 7, 8 and 9, 10 respectively, through the teeth 39, 43, 49, 54 with the pinions 40, 45, 50, 55 mounted on the door 35, can also be used for eccentric displacements of another configuration (for example without elastic coupling rod, other configurations of eccentricities el, e2, ...). This drive connection represents an advantageous and economical mechanical drive synchronization of a drive, which can be disconnected by means of the door 35, with a drive on the other side wall 11 (S2), such as As shown in FIG. 1, it is thus possible to dispense with an individual drive for the second eccentric sleeve 8, which must be placed on the door 35 and which is difficult to synchronize. In each position, the transmission ratio of the first and second eccentric sleeve 7, 8 in the second side wall 34 (SI1) must coincide with the transmission ratio of the first and second eccentric sleeve 7, 8 in the first side wall 11 (S2). The actual synchronization can advantageously be carried out on the constructional plane, when the pivot axes C, D of the first and second eccentric sleeve 7, 8 as well as the articulation points E, F of the coupling rod 14 form a parallelogram (FIG. 1), that the transmission ratios of sector 38-first pinion 40 and sector 44-second pinion 45 are identical, and that the pivot axes G, H of the first and second pinions 40, 45 and the points d articulation I, J of the coupling rod 14.1 form a parallelogram (FIG. 2). These indications are valid in the same way for the design of the drive link of the third

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  and the fourth eccentric sleeve 9, 10 of the second printing unit 4. The transmissions described can also be used for other printing group cylinders, for example on the sleeves

  eccentric 8, 10 of the first and the second transfer cylinder 3, 6.

  In the second printing unit 4 according to FIG. 2, the second transfer cylinder 6 can (in a manner analogous to FIG. 1) be mounted in a fixed manner, the fourth eccentric sleeve 10 and its actuating elements as well as the abutment. 25.1 being deleted. Instead of the latter, an adjustable stop 59.1 is then used which, by cooperating with a drive lever 47.1 of a suitable configuration (shown in line fmin in FIG. 2), serves to adjust the spacing distance of the second impression cylinder 5 with respect to the second transfer cylinder 6. The first printing unit 1 can also only cooperate with a pressure cylinder, the coupling rod 15 then being of a rigid configuration, it is to say of invariable length.

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Claims (5)

  A printing unit of a rotary printing machine comprising a plurality of printing group cylinders (2, 3, 5, 6), a first printing group cylinder (2) being respectively mounted by a first eccentric sleeve (7) and a second printing group cylinder (3) respectively by a second eccentric sleeve (8) in a first and a second side wall (11, 34), the first and second eccentric sleeve (7, 8) of the second side wall (34) carrying teeth (39, 43) with which a respective pinion (40, 45) can be engaged, the pinions (40, 45) being mounted on a door (35) of the second side wall (34), in which the first and / or second eccentric sleeve (7, 8) of the second side wall (34) is mounted in the closed state, and the pinions (40, 45) being brought out of engagement with the teeth (39, 43), in the open state of the door for which is released an opening (57) of the second side wall (34), the pinions (40, 45) being further connected in the transmission plane via a transmission, and the first eccentric sleeve (7) of the second side wall (34). being driven, characterized in that the first eccentric sleeve (7) is connected in the drive plane with a   drive disposed on the second side wall (34).   2. Printing unit according to claim 1, characterized in that the first eccentric sleeves (7) of the first and second side walls (I 1, 34) are driven synchronously by the drive. Printing unit according to claim 2, characterized in that the first and the second eccentric sleeve (7, 8) of the first side wall (11) are connected in the drive plane via a coupling rod (14), and the eccentric sleeves (7, 8) of the second side wall (34) are connected by a transmission driving the second eccentric sleeve (8) of the second side wall (34) synchronously with the second eccentric sleeve (8) of the first side wall (11). 16 2792871   Printing unit according to Claim 3, characterized in that the pivot axes (C, D) of the first and second sleeves (7, 8) of the first lateral wall (11) and the pivot points (E, F) of the coupling rod (14) articulated therewith, form a parallelogram (FIG. 1), in that the toothed transmission ratios (39) of the first eccentric sleeve (7) -the first gear (40). and toothing (43) of the second eccentric sleeve (8) -second pinion (45) are identical, and in that the pivot axes (G, H) of the first and second pinion (40, 45) and the dots articulation (I, J) of the coupling rod (14.1) on the first and second pinions (40, 45) form a parallelogram (Figure 2).   Printing unit according to one of the claims   previous, characterized in that on the first eccentric sleeve (7) of the second side wall (34) is articulated a coupling rod (15) which is hingedly connected to a pivoting lever (16.1) which is attached to a shaft (17) mounted in the two side walls (11, 34), drivable by a power cylinder (18), and to which is attached another pivotally connected lever (16), via a coupling rod (15) to the first eccentric sleeve (7) of the first wall lateral (11).