Abstract:
Flexural vibrations are reduced in rotating components, such as rotating cylinders of a rotary printing press. One or more actuators are placed in a groove or recess in the cylinder. These actuators act in the axial direction of the rotating component. The amount of force exerted by said actuator will vary with the rotational position of the cylinder.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a method, as well as to an arrangement, for reducing bending vibrations in rotating components. An actuator is arranged in the rotating component and exerts an axial force. 
   BACKGROUND OF THE INVENTION 
   A method and device for reducing bending vibrations in rotating systems in known from WO 97/0382. 
   U.S. Pat. No. 5,921,150 A shows an arrangement for reducing bending vibrations in rotating components by the use of an actuator arranged in the rotating component. The actuator has a force component acting in the axial direction of the rotating component. 
   SUMMARY OF THE INVENTION 
   It is the object of the present invention to reduce bending vibrations in rotating components. 
   In accordance with the present invention, this object is attained by the use of at least one actuator. The actuator is arranged in the rotating component and exerts a force in the axial direction of the rotating component. This force may change the axial length of the rotating component. 
   The advantages which can be achieved by the present invention reside, in particular, in that bending vibrations are reduced. The reduction of the so-called “channel beats” of cylinders of rotary printing presses is of particular advantage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
       FIG. 1 , a side elevation view of a cylinder of a rotary printing press in accordance with a first preferred embodiment of the present invention, in the state of rest, 
       FIG. 2 , a side elevation view of the cylinder of  FIG. 1  in the operational state and showing the bending of the cylinder in an exaggerated manner, 
       FIG. 3 , a cross sectional view taken along line III—III through the cylinder of FIG.  1  and in an enlarged view, 
       FIG. 4 , a cross sectional view through a cylinder of a rotary printing press in accordance with a second preferred embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A rotating component, for example, a cylinder, such as a forme cylinder, transfer cylinder, counter-pressure cylinder, damping or guide rollers, called cylinder  01  in what follows, has journals, not represented, on both of its ends. An annular groove  06  is provided on the circumference  04  of the cylinder  01  and approximately in the center of the cylinder&#39;s barrel length  1 . Annular groove  06  receives a plurality of actuators, for example actuators  20  to  31 . The actuators  20  to  31  are arranged inside the circumferential line of the cylinder  01 , as seen most clearly in  FIGS. 1 and 2 . 
   It is also possible to arrange several, for example three or five, annular grooves  06  on cylinder  01 , which annular grooves  06  are spaced apart in the axial direction of cylinder  01  and each have actuators  20  to  31 . In the axial direction means in the direction of the axis of rotation  07  of the cylinder  01 . 
   Each annular groove  06  can be filled, for example with a curable plastic material, in the direction of the surface area of the cylinder  01 . 
   The actuators  20  to  31  can consist, for example, of piezo elements or of double-layer elements. Alternatively, each activator can consist of a cylinder-piston unit, which can be pneumatically or hydraulically actuated. 
   It is furthermore advantageous to employ an actuator which has layered piezo threads with copper foil anodes. The length of this actuator is increased when a voltage is applied. 
   Sensors, for example piezo-ceramic printing pressure sensors, can be arranged on the surface area of the cylinder  01 . These sensors can be located underneath the rubber blanket of the printing forme of the cylinder  01 . The actuators  20  to  31 , as well as the pressure sensors, can be connected with a control device. The control device can be arranged inside or also outside of the cylinder  01 . 
   It is also possible to employ each actuator  20  to  31  simultaneously as a sensor. 
   The transfer of energy and/or transfer of information between a control device, not specifically shown, and the sensors, as well as between the control device and the actuators, is preferably made in a contactless manner. 
   The actuators  20  to  31  can be connected with each other by a control line  08 , as seen in FIG.  3 . 
   The cylinder  01  has a channel  09 , which extends in an axis-parallel direction, and is located in the vicinity of the circumference  04  of cylinder  01 , as seen in FIG.  3 . This channel  09  contains technical assemblies for keeping in place and/or bracing the ends of printing formes or rubber blankets of the cylinder  01  or of the roller. Also, a compensating bore  11  for receiving devices for removing imbalances can be provided in the cylinder  01 . 
   The arrangement for compensating for vibrations, in accordance with the present invention, operates as follows: at a defined location of the circumference  04  of cylinder  01  and at one and/or several defined times, the sensors or actuators determine the actual values of the bending of the cylinder  01  in the operating state. These actual bending values are supplied to the control device, which, in turn, acts with a defined value on the respective actuators  20  to  31 . These actuators  20  to  31  change their size in the axial, or nearly axial, direction of the cylinder. Nearly axial direction means a direction having at least one axial component. In this way, the cylinder  01  is stretched, extended or shortened, at one, or several defined locations at the appropriate respective time, which extending or shortening affects the bending of the cylinder  01 . 
   A force component, or the size of a force applied by each actuator  20  to  31  as a result of the change in size of each actuator  20  to  31 , in the axial or nearly axial direction of the cylinder  01 , is changed as a function of the location of each actuator  20  to  31  in response to rotation of the cylinder  01 . 
   In accordance with another preferred embodiment, as depicted in  FIG. 4 , a rotating component, for example a cylinder  12  or a roller of a rotary printing press can have a channel  13  extending in an axis-parallel direction of the cylinder  12  which channel  13 , for example, has a blind bore  16  for receiving an actuator  17  on its channel bottom area  14 . This actuator  17  can be arranged at the center of the barrel length of the cylinder  12  and can be embodied in the form of so-called “adaptronics”. It is, of course, also possible to arranged several similar actuators, which are spaced apart from each other in the axial direction of the cylinder  12 , with each such actuator being located beneath or under the cylinder surface area. 
   It is also possible to provide each of the actuators  20  to  31  with a bias voltage, regardless of whether they are electrically or pneumatically operable actuators. In this case, each actuator  20  to  31  thus already has an average longitudinal extension “a”, as seen in  FIG. 1  in a position of rest of the cylinder  01 . 
   In the operating state of the cylinder  01  as depicted in an exaggerated manner in  FIG. 2 , an amount “d” of bending of the cylinder  01  is achieved in that the actuator  20  is charged with a voltage that is greater than its bias voltage, up to then, has amounted to, so that actuator  20  increases in size so that it now has a greater longitudinal extension. At the same time, the actuator  26  is charged with a lesser voltage than its previous bias voltage, so that it is reduced in size so that it has a lesser longitudinal extension. Because of this, the actuator  20  now has a greater length “b”, and the actuator  26  now has a lesser length “c”, wherein the lengths are b&gt;a&gt;c. 
   The actuators  21  to  25  and  31  to  27  located on the circumferences  04  of cylinder  01 , and between the actuator  20  and the actuator  26  can each be charged with difference voltages in accordance with their angular position, so that this causes different length changes of the cylinder about its circumference  04  at a defined time. 
   In the course of this, the actuators  20  to  22 , or  31 , 31  located on a first short half of the circumference  04 , increase the previous amounts “a” of their longitudinal extensions, or lengths to the new amounts “b”, or to amounts between “a” and “b”. 
   The actuators  24  to  28 , located on a second short half of the circumference  04 , reduce the previous amounts “a” of their longitudinal extensions or lengths to the new amounts “c”, or to amounts between “a” and “c”. 
   Since the cylinder  01  rotates, the lengths of the actuators  20  to  31  continually change in accordance with the location of each actuator  20  to  31  during rotation of cylinder  01 . 
   Vibration occurring in cylinders  01  or  12  are compensated for by use of the at, least one actuator  17  or the actuators  20  to  31 . A partial change of the length of the cylinder  01  or  12  parallel with its axis of rotation  07  in generated. Bending of the cylinder is affected by this partial change of length. 
   The size of an amplitude of bending vibrations is reduced and/or a frequency of the bending vibrations is changed by use of the actuator  17  or the actuators  20  to  31 . The bending vibrations can also affect other types of vibrations, in particular torsional vibrations. 
   While preferred embodiments of a method and system for compensating for the vibration of rotating components, in accordance with the present invention, have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that changes in, for example supports for the cylinder, a drive assembly for the cylinder and the like, can be made without departing from the true spirit and scope of the present invention which is accordingly to be limited on by the appended claims.