Abstract:
The contact pressure between an adjustably mounted first cylinder and a second cylinder in a printing machine, and particularly in a web-fed printing machine can be adjusted. An actuator is usable to force the first cylinder toward the second cylinder with an adjustable force. A fixing device is usable to fix the first cylinder in a desired position relative to the second cylinder.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This patent application is a division of U.S. application Ser. No. 10/471,291, filed Dec. 19, 2003 now U.S. Pat. No. 7,021,209, which application is the U.S. National Phase, under 35 U.S.C. 371, of PCT/DE2002/00167, filed Jan. 19, 2002; published as WO 2002/074542 A2 and A3 on Sep. 26, 2002 and claiming priority to DE 101 13 313.8, filed Mar. 20, 2001, the disclosures of which are expressly incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention is directed to devices for adjusting the contact pressure of a displaceably seated roller. The contact pressure is adjusted using at least one actuator. A fixation device can hold the roller in an adjusted position. 
   BACKGROUND OF THE INVENTION 
   A plurality of rollers are provided in conventional printing presses, for example in web-fed rotary printing presses. Inking rollers, in particular, are provided, which are used for transferring the ink from an ink reservoir to the plate cylinders. The ink transferred to the plate cylinders can be metered by the inking rollers, so that the ink is transferred as a uniform film of defined thickness. It is thus possible to even out interferences, such as speed fluctuations and rotary oscillations, for example. 
   Moreover, dampening unit rollers, which transfer a dampening agent, for example water, to the printing group, can also be provided in the printing press. 
   Pairs of rollers are often formed by rollers which are in engagement with each other, wherein at least one of the rollers has a cylinder surface made of an elastic material, so that this cylinder surface can be at least slightly deformed as a function of the contact pressure of the oppositely located roller. The result of the elastic deformation of the roller surface is a contact area extending in a straight line between the rollers, which contact area is called a contact strip. The width of the contact strip can be varied by adjusting the contact pressure between the rollers, wherein the width of the contact strip has a considerable effect on the printing result. If, for example, the contact strip in an inking unit is too narrow, not enough ink is transferred, while in the situation in which the contact strip is too broad, the elastic roller can be damaged by the roller&#39;s flexing. 
   In order to be able to adjust the strip width, in particular as a function of the respective operating conditions, for example the temperature of the printing presses, or the degree of their wear, it is necessary to adjustably seat one of the rollers so that it can be pushed in the direction of the opposite roller, by the use of an actuator, with an adjustable force. Once the correct contact pressure between the two rollers has been established, a fixation device, which is usable for fixing the first roller in place relative to the second roller, is actuated in order to maintain the contact pressure permanently. 
   A device for adjusting the contact pressure between two rollers is known from DE 197 19 305 A1. In the bearing arrangement described there, the adjustably seated roller is pushed against the opposite roller by a spring which is supported on the frame of the printing press. By use of this spring, a defined contact pressure always exists between the two rollers as a function of the respectively selected spring characteristic. A clamping mechanism, with a clamping lever and a clamping plate, is described for fixing the roller in place in the contact position, by the use of which, the roller shaft can be fixed in place against the frame of the printing press by frictional contact. 
   A device for the semi-automatic adjustment of rollers is known from DE 199 19 733 A1. An adjustably seated roller is maintained in a roller holder, which itself is seated in a frame holder which is arranged fixed in place on the frame. In this case, the roller holder and the frame holder can be displaced with respect to each other and are connected with each other by a spring-elastic assembly. Here the spring-elastic assembly has have a defined pre-tension, so that the roller, which is adjustably seated on the roller holder, can be pressed with a defined contact pressure against the opposite roller. Arresting bolts are provided for arresting the roller holder on the frame holder, because of whose advancement, the roller holder can be clamped with frictional contact to the frame holder. 
   DE 42 31 873 A1 describes a device for roller adjustment. A roller is initially displaced in the radial direction by the use of a pressure chamber and is subsequently fixed in place. 
   DD 64 064 describes a device for the fixed clamping of bearing bushes of printing cylinders. No suggestion regarding the adjustment of rollers is provided. 
   DE 100 01 582 A1 discloses a roller which is displaced by two hydraulic cylinders. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is directed to providing devices for adjusting the contact pressure of an adjustably seated roller. 
   In accordance with the present invention, this object is attained by the provision of at least one actuator which has at least one pressure chamber that can be charged with a pressure medium. Typically, several such pressure chambers are arranged in the circumferential direction of the roller. The actuator may be a pressure proof diaphragm situated in a gap. The actuator may also be a pressure hose. A fixation device, which has multi-disk elements, can fix the positioned roller in place in the radial direction. The actuator is used to push a first roller against a second roller in a web-fed rotary printing press. The roller is held in a roller holder which is displaceably seated on a frame holder. 
   A particular advantage of the fixation device of the present invention lies in that such a fixation device can be produced in an extremely compact, and therefore space-saving manner. This is achieved in that several multi-disk elements are frictionally clamped for fixing the adjustable components in place relative to each other. By the arrangement of several, and in particular a plurality, of such multi-disk elements one behind the other, the required frictional force is distributed over a plurality of frictional faces between the multi-disk elements. Because of the clamping of the multi-disk elements arranged one behind the other, the clamping force acts oppositely on all frictional faces. 
   Suitable multi-disk elements are known, for example, from multi-disk clutches employed for the frictional connection of rotatably seated shafts. In contrast to the previously known multi-disk clutches, the disks of the fixation device of the present invention can be displaced in respect to each other in at least one direction and, as a function of the play between the components of the fixation device, can be displaced against each other within a defined adjustment range and subsequently can be fixed in place. Thus, the adjustment movement does not take place in the manner of a pivoting or rotational movement, as in the case of the prior art multi-disk clutches, but takes place in the manner of a translatory movement in the plane defined by the orientation of the frictional faces of the multi-disk elements. 
   Basically all elements, or structures, wherein the disks can be clamped together with the application of a sufficient contact pressure, can be employed as clamping devices. It is particularly advantageous if the clamping device is embodied in the manner of a pre-tensed spring element. A spring force of sufficient strength is exerted by the pre-tensed spring element on the multi-disk elements in the fixed position of the fixation device that they are dependably fixed against each other by frictional contact. Because of this, an unintentional release of the fixation device, for example in case of the loss of power, such as must be feared in connection with other clamping device, is not possible. In order to be able to release the clamping device, for adjusting the components of the fixation device, it is necessary in connection with the present invention to provide an actuating element on the fixation device, by the use of which, the spring element can be pressed together sufficiently far, so that the multi-disk elements can be relaxed and therefore can be displaced in respect to each other. 
   In principle, any arbitrary drive mechanisms, for example electrically, hydraulically or pneumatically acting systems, can be employed for actuating the spring element. It is particularly advantageous if the actuating element is embodied in the manner of a plunger which is displaceably arranged in a pressure chamber. By charging the pressure chamber with a pressure medium, such as, for example, compressed air or hydraulic fluid, the plunger can be displaced against the spring force of the spring element, so that the multi-disk elements are relaxed. 
   The advantages to be gained by use of the present invention consist, in particular, in the very compact structure made possible by the disclosed construction. As is known from the prior art, the roller is fastened on a roller holder, which itself is displaceably seated on a frame holder. The frame holder, in turn, can either be fastened fixed in place on the frame of the printing press, or alternatively, it can be arranged on appropriate actuating devices, which are used, for example, for placing the roller seated in the roller holder against or away from the oppositely located roller. 
   A recess is provided on the roller holder, or on the frame holder, which recess is engaged by a section of the frame holder, or of the roller holder. The dimensions of the section, or of the recess, are selected in such a way that a gap is formed between the recess and the section, by use of which gap the actuating range between the roller holder and the frame holder is defined. The roller holder can be displaced within this gap in respect to the frame holder. To be able to obtain the actuating forces required for the actuating movement, or to be able to press the first roller with a defined contact pressure against the oppositely located roller, at least one actuator is arranged in the gap, which at least one actuator exerts a pulling and/or a pushing force on the roller holder and, in the process, is supported on the frame. Because of the arrangement of the actuator in the gap between the frame holder and the roller holder, it is possible to provide extraordinarily compact structures. In this connection, it is, of course, immaterial whether the recess is provided on the frame holder or on the roller holder, so that, in principle, both constructions are alternatively conceivable. 
   Basically the configuration of the recess and of the section to be received therein can be arbitrary and can be matched to the respective individual case. Thus, it is conceivable for the recess to be embodied right-angled and only having play, with respect to the section engaging it, in one direction, so that the roller holder can only be displaced in one actuating direction. However, if a displacement of the roller holder in various directions is desired, for example because the roller seated in the roller holder must be placed against several rollers, it is particularly advantageous for the recess and the section to be each embodied as being rotationally symmetrical, so that a circumferential gap is formed between them. Because of this, it is possible for the roller holder to be displaced in an actuating plane in different actuating directions in relation to the frame holder. The actuating range of the actuating movement is thus limited by the width of the circumferential groove. 
   If the roller holder can be displaced relative to the frame holder in different actuating directions, for example in a total actuating plane, several actuators are required to provide the actuating movement required for this. Therefore, in accordance with a preferred embodiment of the present invention, at least three actuators are arranged in the gap between the roller holder and the frame holder, by use of which at least three actuators the first roller can be pushed in respectively differing directions. By the appropriate selection of the forces exerted by the respective actuators, a force resulting from the combined triggering of the different actuators can be provided in any arbitrary direction on the roller holder, and therefore on the roller seated in the roller holder. In this case, the actuators are preferably arranged, distributed in a star shape, in the gap between the roller holder and the frame holder. If four actuators are arranged opposite each other in the gap, it is possible, because of this, to dependably prevent the tilting of the actuators, since by use of the drive mechanism of one actuator, the respectively oppositely arranged actuator is compressed. 
   The shape in which the actuators are embodied is, in principle, arbitrary. Electrically, or also piezo-electrically acting systems are therefore also conceivable. It is particularly advantageous for the actuator to be configured in the manner of a pressure-exerting body which can be charged with a pressure medium. If hydraulic fluid is used as the pressure medium, it is possible to provide very high pressures with correspondingly large actuating forces. 
   In accordance with a preferred embodiment of the present invention, a pretensed gas, and in particular compressed air, is employed as the pressure medium. Since gases are inherently compressible, an elastic spring effect, acting between the frame holder and the roller holder, is the result of the use of a pretensed gas as the pressure medium. It is possible, because of this spring effect, to compensate for mechanical interferences caused, for example, by imbalances or out-of-roundness. Moreover, compressed air is typically available as an energy transfer source in most printing presses. 
   The device for setting the contact pressure between the displaceably seated roller and an oppositely located roller can also be used for placing the displaceably seated roller into contact with, or out of contact from the other roller. However, for this purpose, it is necessary to select the actuating range between the frame holder and the roller holder to be sufficiently large to be able to perform the actuating movement required for the out-of contact movement. Moreover, it is necessary to select the actuator between the frame holder and the roller holder to be suitable for performing such an actuating movement. To be able to perform the into-contact or out-of-contact movement independently of the actuation of the device, it is advantageous if the device is fastened on an additional out-of-contact device. For example, this out-of-contact device can be embodied in the manner of a pivot arm, by the use of which, the frame holder can be displaced, in relation to the frame of the printing press, between an in-contact position and out-of-contact position. 
   The compactness of the device in accordance with the present invention can, as a whole, be further increased by situating a fixation device in a device for adjusting the contact pressure between two rollers. 
   It is particularly advantageous for this purpose if the fixation device extends along the center axis of the device coaxially in respect to the longitudinal axis of the roller which is maintained on the roller holder. 

   
     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 schematic side-elevation view of a fixation device in accordance with the present invention, in cross section, in 
       FIG. 2 , a schematic side-elevation view of a device for adjusting the contact pressure between two rollers, together with a fixation device, in accordance with the present invention in cross section, in 
       FIG. 3 , a schematic end view of the device in accordance with  FIG. 2  in a base position, in 
       FIG. 4 , a schematic end view of the device in accordance with  FIG. 2  in a deflected position, in 
       FIG. 5 , a front perspective view of the device in accordance with  FIG. 2 , and in 
       FIG. 6 , a second preferred embodiment of an actuator in accordance with the present invention, in cross section. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring initially to  FIG. 1 , there may be seen a fixation device, generally at  01 , in accordance with the present invention. The fixation device  01  represented in  FIG. 1  has an element, for example a base body  02  which is formed by a cover  03  and a sleeve  04 , and an element which is displaceably seated in the sleeve  04 , for example a bolt  06 , on whose exterior a fastening plate  07  has been provided. The base body  02  can be fastened to a frame, for example, while a roller lock for seating a roller, for example, can be screwed to the fastening plate  07 . 
   The bolt  06  has a defined radial play with respect to the sleeve  04 , so that the bolt  06  can be displaced in relation to the base body  02  in any arbitrary actuating directions  08  in an actuating plane extending perpendicularly with respect to the drawing plane of  FIG. 1 . Because of this, it is possible to displace the fastening plate  07 , for example upward or downward, in the direction of the movement arrow  08 . Because of the circularly symmetrical embodiment of the fixation device  01 , however, it is also possible to perform actuating movements in other arbitrary directions with respect to the actuating plane. Multi-disk elements  09  are fastened at equidistant spacings on the inside of the sleeve  04  on the base body  02  and mesh with bolt multi-disk elements  11  fastened on the bolt  06 . The contact faces between the sleeve multi-disk elements  09 , and the bolt multi-disk elements  11  extend in planes which extend parallel with the actuating planes of the possible actuating movements. In the course of displacing the bolt  06  in relation to the base body  02 , the sleeve multi-disk elements  09  slide along the bolt multi-disk elements  11 , wherein the actuating movement is limited by the play between the bolt  06  and the base body  02 . 
   A clamping device  12 , which is provided with a pressure piston  15 , which is displaceably seated in a pressure cylinder  16 , is provided for fixing the fixation device  01  in a defined position. A pressure chamber  14  can be charged via a connection  13  with a pressure medium, for example hydraulic fluid or compressed air, so that the pressure piston  15  is pushed inside the pressure cylinder  16  in the direction of the sleeve multi-disk elements  09 , or the bolt multi-disk elements  11 . As a result of this, the multi-disk elements  09 ,  11  are clamped between the clamping device  12  and an end stop  17  formed on the sleeve  04 . As soon as the surface pressure between the pressure piston  15  and the front bolt multi-disk element  11  exceeds a defined pressure, the individual multi-disk elements  09 ,  11  come into frictional contact with each other, producing a static friction state, so that the bolt  06  is fixed in place relative to the base body  02 . 
   A device  20  for adjusting the contact pressure between a first or movable roller  21  and a second or fixed roller  22  is represented in  FIG. 2 . The movable roller  21  can be releasably fastened at the ends of its shaft  23  in a quick-release closure  24  provided on the device  20 . Such quick-release closures  24  are generally known and have a semicircular-shaped bearing shell into which the ends of the roller shaft  23  can be placed. By fastening an upper bearing shell, which is not specifically represented in  FIG. 2 , the roller shaft  23  can then be fixed in place in the quick-release closure  24 . 
   The device  20  is essentially constructed utilizing a frame holder  26  and a roller holder  27 , which holders can be displaced, in respect to each other, in an actuating plane extending perpendicularly to the drawing plane. The frame holder  26  is constructed from a base plate  28  which, for example, can be pivotably fastened on a frame of a printing press by a pivot arm, and a sleeve body  29 . On its side facing the roller  21 , the sleeve body  29  has a recess  31 , which is engaged by a cylinder-shaped section  32  of the roller holder  27 . The inner diameter of the recess  31 , or the outer diameter of the section  32 , have been selected here in such a way, that a gap  33 , which is circularly cylindrical in the base position, of a gap width of approximately 1 mm to 10 mm, and in particular of 2 mm, is formed. The maximum actuating range for displacing the roller holder  27  relative to the frame holder  26  is defined by the gap  33 . 
   To perform the actuating movements required for adjusting the movable roller  21 , or to be able to provide the desired contact pressure between the movable roller  21  and the fixed roller  22 , a total of four actuators  34 , each of which is embodied in the manner of a pressure hose, are arranged distributed over the circumference of the gap  33 , only two of which actuators  34  are represented in section in  FIG. 2 . The pressure chambers  36  constituted by the walls of the actuators  34  can be charged with pressure by feed lines, which are not specifically represented in  FIG. 2 , but which may be seen at  48  in  FIG. 5 . A force acts on the roller holder  27  as a function of the respective pressure conditions in the four actuators  34 , so that the movable roller  21  can be pressed against the fixed roller  22  with the desired contact pressure by an appropriate control of the pressure in the several actuators  34 . Since the air cushion under pressure in the actuators  34  is compressible, it is possible to absorb mechanical interferences by the resultant spring effect. 
   In the contact pressure adjusting device  20 , a height h 36  of the pressure chamber  36  in the radial direction of the movable roller  21  is less than a width b 36  of the pressure chamber  36  in the axial direction of the roller  21 , as seen in  FIG. 2 , and/or of a length l 36  of the pressure chamber  36  in the circumferential direction of the roller  21 , as seen in  FIG. 5 . 
   The ratio of the width b 36  and/or the length l 36  of the pressure chamber  36  to the height h 36  of the pressure chamber  36  is greater than 3, and is preferably greater than 5. 
   For fixing the roller holder  27  in place relative to the frame holder  26 , roller multi-disk elements  37  are fastened on the roller holder  27  and are arranged so they mesh with sleeve multi-disk elements  38  fastened on the sleeve body  29 , and cooperate with each other for forming a multi-disk packet. A piston  39 , which is T-shaped in cross section, is provided for the frictionally connected clamping of the multi-disk packet formed by the multi-disk elements  37  and  38 , and whose circular piston head  40  comes to rest with a circular ring-shaped flange  41  against the outermost sleeve multi-disk element  38  of the multi-disk packet. A pressure plate  42  is fastened to the opposite end of the piston  39 , on which pressure plate a spring force, which is a function of a spring element  43 , and which is embodied in the manner of a plate spring packet, acts. The spring element  41  is pre-stressed and is mounted between the pressure plate  42  and the sleeve body  29 , so that the multi-disk packet, constituted by the multi-disk elements  37 ,  38 , is clamped by the spring force which is transmitted by the piston  39  to the multi-disk elements  37 ,  38 . 
   For displacing the roller holder  27  relative to the frame holder  26 , in particular when adjusting the contact pressure between the rollers  21 ,  22 , it is necessary to release the fixation device that is constituted by the multi-disk elements  37 ,  38 , or by the piston  39  and the pressure plate  42 . A pressure connector  44  is provided in the base plate  28  for this purpose, and through which a pressure chamber  46  between the pressure plate  42  and the base plate  28  can be charged with a pressure medium, for example compressed air. As soon as the air pressure acting on the pressure plate  42  exceeds the spring force of the spring element  43 , the piston  39  is lifted off the outermost sleeve multi-disk element  38  so that the latter are no longer frictionally clamped and can be displaced relative to each other. 
   Adjusting the contact pressure between the rollers  21 ,  22  takes place in the following manner, for example. First, the pressure chamber  46  is charged with sufficient pressure so that the multi-disk elements  37 ,  38  are no longer frictionally clamped. Subsequently, each of the actuators  34  is charged with an amount of pressure just sufficient so that the desired contact pressure between the rollers  21 ,  22 , or between the roller  21  and further rollers, which are not represented in  FIG. 2 , is achieved and results in a contact strip of the desired width. As soon as the correct setting at the desired contact pressure between the rollers  21 ,  21  has been achieved, the pressure in the pressure chamber  46  is released, so that the piston  39  clamps the multi-disk elements  37 ,  38  against each other, so that the roller holder  27  is fixed in place in the desired position relative to the frame holder  26 . At the end of the adjustment procedure, the pressure in the actuators  34  is released. 
   The functional principle of operation the contact pressure adjusting device  20 , during the required actuating movement, is schematically represented in  FIGS. 3 and 4 .  FIG. 3  shows the frame holder  26  with the recess  31 , and the section  32  of the roller holder  27  engaging it. By properly selecting the dimensions, a gap  33  is formed between the frame holder  26  and the section  32  of the roller holder  27 , in which gap  23  the actuators  34  are arranged, which actuators  34  are schematically indicated in  FIGS. 3 and 4  by force arrows. The possible actuating movements between the frame holder  26  and the roller holder  27  are defined by the actuating plane, which extends in the drawing plane in the representation of  FIG. 3  and  FIG. 4 , wherein the actuating range of the actuating movements is limited by the width of the gap  33 . 
   As represented in  FIG. 4  by way of example, the roller holder  27  and, as a result the roller  21  fastened on it, can be laterally displaced relative to the frame holder  26 , which lateral displacement is caused by an appropriate control of the actuators  34  and the resultant force effect on the section  32 . As soon as the desired position of the roller holder  27 , relative to the frame holder  26 , has been achieved, the fixation device constituted by the multi-disk elements  37 ,  38 , or by the piston  39  and the pressure plate  42 , can be activated, so that the position of the roller holder  27  is permanently fixed and the actuators  34  need no longer be operated. 
     FIG. 5  shows the contact pressure adjusting device  20  having the base plate  28 , the frame holder  26 , the roller holder  27  and the actuators  34 , in a perspective view from the front. The four actuators  34 , which are embodied in the manner of pressure hoses, and which can be charged with compressed air via supply lines  48 , are arranged between the sleeve body  29  of the frame holder  26  and the roller holder  27 , on whose frontward oriented side the quick-release closure  24  in the shape of a half shell can be partially seen. The multi-disk elements  37 ,  38 , not visible here, can be relaxed by means of the pressure plate  42 . The extraordinarily compact construction of the device  20  can be noticed which, because of its wholly rotationally symmetrical embodiment, with the exception of the base plate  28 , has a lesser diameter than the roller  21  itself, as can be seen in  FIG. 2 . 
     FIG. 6  shows a second preferred embodiment, at  50 , of an actuator  50  for a contact pressure adjusting device  20  in cross section. The principal configuration of the device  20  with the frame holder  26 , the roller holder  27  and the fixation device for fixing the roller holder  27  relative to the frame holder  26  corresponds to the configuration described in  FIG. 2  and therefore need not be further described. A cylinder-shaped diaphragm  51 , whose upper and lower edges are connected with the inner diameter of the sleeve body  29  (not represented in  FIG. 6 ), is arranged in the gap  33  for constituting the actuator  50 . The diaphragm is furthermore connected with the inner diameter of the sleeve body  29  in four strip-shaped areas  52 , for example by being glued to it, so that four pressure chambers  53  are formed by the sleeve body  29  and the diaphragm  53  as the result, which four pressure chambers  53  are evenly distributed over the circumference of the gap  33 . Each of the pressure chambers  53  can be charged with compressed air via pressure inlet openings  54  so that, as a function of the respective pressure in the four pressure chambers  53 , a resultant force acts on the section  32  of the roller holder  27 . 
   The height h 53  of the pressure chamber  53  of the contact pressure adjusting device  20  in the radial direction of the roller  21  is less than the width of the pressure chamber  53  in the axial direction of the roller  21  and/or the length l 53  of the pressure chamber  53  in the circumferential direction of the roller  21 . 
   The ratio of the width b 53  and/or the length l 53  of the pressure chamber  53  to the height h 53  of the pressure chamber  53  is greater than 3, and in particular is greater than 5. 
   While preferred embodiments of devices for adjusting the contact pressure of an adjustably mounted cylinder, 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 various changes in, for example the specific source of the fluid under pressure, the type of printing press with which the devices are used 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 appended claims.