Abstract:
A driving mechanism for a cylinder of a rotary printing machine utilizes a drive pinion that engages a drive gear of a cylinder which is supported in an eccentric bushing. The cylinder can be moved between print and non-print positions. The rotational axis of the drive pinion lies on a straight line defined by the axis of rotation of the cylinder and the axis of rotation of the eccentric bushing.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a driving mechanism for a cylinder of a rotary printing press. This cylinder is seated in a eccentric bushing and carries a drive gear on a journal of the cylinder. The drive gear is engaged by a drive pinion. 
     DESCRIPTION OF THE PRIOR ART 
     EP 0 644 048 A2 describes a drive mechanism for a group of cylinders of an offset rotary printing press by means of a toothed belt. 
     DE 3704314 C1 describes an arrangement for adjusting the backlash between the drive wheels of sheet-transporting cylinders of a rotary printing press. In this device, each cylinder is pivotably seated in eccentric bushings. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a drive mechanism for a cylinder of a rotary printing press. 
     The object is attained in accordance with the invention by the arrangement of the axes of rotation of a shiftable transfer cylinder, a fixed drive and a fixed printing cylinder in a manner that will minimize gear backlash when the transfer cylinder is shifted. 
     The advantages which can be obtained by the present invention rest, in particular, in that in connection with cylinders, whose axis of rotation can be changed in location, or respectively in position, a change in the backlash between a toothed gear of the cylinder and an assigned drive pinion is minimized when the position is changed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the present invention is represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
     FIG. 1, a schematic side view of a drive mechanism of a cylinder; 
     FIG. 2, a schematic top plan view on a drive mechanism of a cylinder; and in 
     FIG. 3, an enlarged view of a portion of a drive mechanism, taken from FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A journal  01  of a rotating component  02 , for example of a roller of an inking, or of a dampening system, or a journal of a cylinder  02  of a print unit, or respectively a folding apparatus, of a rotary printing press is seated in a side frame  03  in a manner wherein its location can be changed by means of an eccentric bushing  04 , all as seen most clearly in FIG.  2 . As may be seen, the journal  01  of the cylinder  02  is seated by means of a bearing  06  in a bore  07  of the eccentric bushing  04 . A longitudinal axis  08  of this bore  07  of the eccentric bushing  04 , i.e. the axis of rotation  08  of the cylinder  02 , is offset by an eccentricity e 4  in relation to a longitudinal axis  09  of an outer surface  11 , i.e. a pivot axis  09  of the eccentric bushing  04 . This eccentric bushing  04  is arranged in the side frame  03 , and in rotable by means of a drive mechanism, not specifically represented. A first, for example a straight-fluted gear wheel  12 , and a second, for example a helical gear wheel  13 , for example a drive wheel  13 , are arranged on the journal  01  of the cylinder  02 . 
     In the present preferred embodiment, this cylinder  02  is designed as a transfer cylinder  02  of a print unit of an offset rotary printing press. A printing cylinder  14  is assigned to this transfer cylinder  02 . On its journal  16 , this printing cylinder  14  is provided with a gear wheel, for example a straight-fluted gear wheel  17 . The first gear wheel  12  of the transfer cylinder  02  and the gear wheel  17  of the printing cylinder  14  are in engagement with each other, so that the transfer cylinder  02  and the printing cylinder  14  are interlockingly coupled for being driven by means of the gear wheels  12 ,  17  and constitute a first pair  28  of cylinders. 
     Preferably, this first pair  28  of cylinders is not interlockingly coupled with further cylinders for driving. 
     A drive pinion  18  is assigned to the second gear wheel  13  of the transfer cylinder  02 . This drive pinion  18  may be arranged directly on a rotor  19  of a motor  21 , whose position and/or rpm are controlled. The motor  21  is arranged, fixed in place, on the side frame  03 . However, the drive pinion  18  can have its own support, independent of the rotor  19  of the motor  21 , and can be connected via a coupling with the rotor  19  of the motor  21 . Additional gear wheels can be interposed between the drive pinion  18  connected with the rotor  19  of the motor  21  and the second gear wheel  13  of the transfer cylinder  02 . Preferably, the drive pinion  18  assigned to the rotor  19  of the motor  21  directly engages the gear wheel  13  of the transfer cylinder  02 . 
     A first straight line  22  is defined by an axis of rotation  23  of the drive pinion  18  and the pivot axis  09  of the eccentric bushing  04  as may be seen in both FIGS. 1 and 3. 
     A second straight line  24  extends through the axis of rotation  08  of the transfer cylinder  02  and the pivot axis  09  of the eccentric bushing  04  in a printing-on position. 
     In a printing-off position, the axis of rotation  08  of the transfer cylinder  02  is displaced into a position  08 ′, and a straight line  24 ′ extends through the axis of rotation  08 ′ and the pivot axis  09  of the eccentric busing  04 . 
     The first straight line  22  and the second straight line  24 , or respectively  24 ′, form an opening angle α, or respectively α′, in the printing-on position, or respectively in the printing-off position. 
     A value of this opening angle α, for example 15° in the printing-on position, is approximately equal, with a maximum difference of α-α′&lt;10°, and for example 5°, to a value of the opening angle α′, for example −15°, in the printing-off position. 
     In the “printing-off” position, the axis of rotation  23  of a drive pinion  18 , a pivot axis  09  of the eccentric bushing  04  and an axis of rotation of the cylinder  02  are approximately located on the same straight line. 
     A third straight line  26  is defined by an axis of rotation  27  of a second cylinder  14 , for the axis of rotation of the printing cylinder  14 , and the axis of rotation  23  of the drive pinion  18 . 
     This third straight line  26  and the first straight line  22  form an opening angle β of from 160° to 200°. 
     If the transfer cylinder  02  is placed against, or is moved away from the printing cylinder  14  by pivoting the eccentric bushing  04 , a change in the backlash between the drive pinion  18  and the gear wheel  13  of the transfer cylinder  02  is minimal. 
     In the present preferred embodiment, the print unit is designed as a so-called bridge print unit. In this bridge print unit, a transfer cylinder  02  of a first pair  28  of cylinders,  02  and  04  works together with a transfer cylinder  02  of a second pair  29  of cylinders, as seen in FIG.  2 . These two pairs  28 ,  29  of cylinders are preferably not interlockingly coupled with each other for being driven. 
     This first pair  28  of cylinders can also be used in so-called H-print units or in satellite print units. 
     It is also possible to drive only a single cylinder  02 , or also a plurality of cylinders which, for the purpose of being a driven, are interlockingly coupled with each other, by means of a drive pinion  18  arranged in accordance with the present invention. 
     Pulleys can also be arranged in place of the drive pinion  18  and the drive wheel  13  of the cylinder  02 , whose axes of rotation are arranged corresponding to the axes of rotation of the drive pinions  18  and the drive gear wheels  13  of the cylinders  02 . 
     While a preferred embodiment of a driving mechanism for a cylinder of a rotary printing press in accordance with the present invention has been set forth filly and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example the type of printing being done, the material being printed on and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.