Abstract:
A cylinder which is part of a machine which processes lengths of material includes a rotationally fixed central pin or shaft. A casing or jacket is rotatably supported on the central pin or shaft by a number of bearings. A sleeve can be placed over the outer surface of the jacket or casing. A lubricant space, which extends, in sections, in an axial direction, is located between the pin or shaft and an inner surface of the jacket or casing. A compressed gas space which extends, in sections, in an axial direction, is provided with outlet openings on an outer surface of the jacket or casing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the U.S. national phase, under 35 USC 371, of PCT/EP2005/052557, filed Jun. 3, 2005; published as WO 2006/000516 A1 on Jan. 5, 2006; and claiming priority to DE 10 2004 030 702.4, filed Jun. 25, 2004, the disclosures of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to cylinders for machines that process continuous lengths of material. The cylinder includes a non-rotating shaft or axle and a casing or jacket which is rotatably supported by a plurality of bearings on the shaft. A sleeve can be slid onto the casing or jacket. 
       BACKGROUND OF THE INVENTION 
       [0003]    The basic structure of a cylinder of this general type, which type of cylinder is preferably used in gravure printing presses, can be taken, for example, from EP 0 047 435 B1. In this publication, the principal arrangement of the impression cylinder in a gravure printing press is also described. Options are also presented which allow the impression cylinder to be bent in adjustment to a line of bending of the printing cylinder which is opposite to it. One particular difficulty of known cylinder configurations consists in effectively lubricating and, if necessary, in also effectively cooling the bearings and other movable parts of the impression cylinder, while at the same time providing a suitable structure for facilitating the pulling of various sleeves onto the outer casing or jacket of the impression cylinder. 
         [0004]    A cylinder for use in machines that process continuous lengths of material is known from EP 0 179 363 B1. This cylinder comprises a non-rotatably mounted spindle and a tubular casing, which casing is rotatably mounted on the underlying spindle. The casing of the impression cylinder is made, for example, of steel and bears a sheathing, or covering, which is also called a sleeve, of rubber-like material. At high printing speeds, and thus at high rates of rotation of the cylinder, the flexing work that is performed causes a substantial warming of the sleeve. To efficiently draw off the heat that is produced by this flexation, the cylinder which is described in this prior art document uses a heat exchanger, which is integrated into the cylinder. However, this results in a complicated, and a maintenance-intensive configuration of the cylinder. The particular problems of a simultaneously efficient lubrication of the movable parts of the cylinder cannot be solved by the provision of an integrated heat exchanger. 
         [0005]    In WO 01/85454 A1 a cylinder is shown, in which a lubricant circuit and cooling circuit is constructed. For effective lubrication, and for simultaneous cooling of all of the cylinder movable elements, a fluid flow is generated inside the cylinder, and especially in the space between a stationary support for the cylinder and the tubular casing. However, further difficulties arise with the sealing of the flow area at high rotational speeds and with a desirable optional bending of the cylinder. Furthermore, this prior art configuration provides no solution as to how the exchange of the sleeve to be applied to the casing of the cylinder can be facilitated and/or supported. The conventional use of a running-in layer which is generated on the casing using compressed air is excluded in this prior art cylinder because the lubricant circuit that is provided in the cylinder no longer allows the compressed air to flow out through the cylinder casing. 
       SUMMARY OF THE INVENTION 
       [0006]    The object of the present invention is to provide cylinders for machines that process continuous lengths of material. 
         [0007]    The object is attained in accordance with the present invention with the provision of a cylinder that includes a non-rotatable shaft or axle and a casing or jacket that is rotatably supported on the shaft or axle using a plurality of bearings. A flexible sleeve can be slid over the casing or jacket. A lubricant chamber is provided between the shaft and the casing or jacket and extends, in sections, in an axial direction. A compressed gas chamber, with outlet openings, and which extends in a cylinder axial direction, is provided on the casing. The lubricant chamber and the compressed gas chamber may be in fluid communication with lubricant channels and gas bores in the shaft. 
         [0008]    The benefits to be achieved with the present invention consist especially in that with this cylinder, both an effective lubrication of the movable components and an easy exchange of the sheathing or sleeve is possible using compressed air. 
         [0009]    With the adjacent arrangement of two sealing rings, the sealing edges of which are turned away from one another, and which sealing edges thus are respectively turned toward the lubricant chamber on one side and toward the compressed gas chamber on the other side, an improved sealing between these two chambers, which conduct different media, is achieved. It is thereby ensured that no lubricant can be lost via the compressed gas chamber, nor can any lubricant escape with the compressed gas from the cylinder. The two sealing rings can be made of different materials and can have different shapes, thereby allowing them to each be optimally adjusted to the respective medium contained in the chamber being sealed by each such sealing ring. 
         [0010]    It is particularly advantageous for the compressed gas chamber to be supplied with compressed gas, and especially with compressed air, via a compressed gas bore that extends at least partially in the shaft. A compressed gas supply line can be particularly easily connected at the end-surface opening of the compressed gas bore in the non-rotating shaft. Starting from the compressed gas bore extending in the shaft, multiple supply bores can lead from that bore to the compressed gas chamber. 
         [0011]    To accomplish an efficient lubrication of the bearing, and to accomplish a simultaneous adequate cooling of the cylinder casing, it is advantageous for the lubricant, such as, for example, oil, to be brought to a specific volume rate of flow during the rotation of the casing. The heat that is generated by the flexing action of the sleeve or the jacket or casing can be rapidly drawn off from the interior side of the casing. Furthermore, the lubricant flow can preferably extend through the individual bearings, which bearings are arranged between the shaft and the casing, in order to ensure optimal lubrication conditions there as well. Because the individual bearings each acts to inhibit a free flow of lubricant in an axial direction, the lubricant must be purposely accelerated in an axial direction. Once the lubricant has passed through such a bearing, it must also be returned to the starting side of the chamber. For this purpose, it is advantageous to pass a lubricant channel through the shaft, and extending at an angle with respect to the longitudinal or axial direction of the shaft, with the ends of the lubricant channel lying in areas of the lubricant chamber that are separated from each other by the bearing that is to be lubricated. 
         [0012]    To purposely accelerate the lubricant, so that it is able to pass through a rotating bearing, and particularly through roller bearing which is the type of bearing being especially used here, an oil deflector, which is arranged at an angle, is preferably positioned near the interior surface of the casing. When the casing is rotated, this first oil deflector scrapes off the oil which has been adhering to the interior surface of the casing, and accelerates it in an axial direction. It is also advantageous for a second oil deflector to be provided, which second oil deflector, once the stream of lubricant has passed through a bearing, diverts that stream, which is initially running in an axial direction, essentially to a radial direction, to both complete the lubricant circuit and to minimize the oil pressure that is acting on the sealing ring on the lubricant side. To accomplish this result, the second oil deflector is preferably positioned very close to the lubricant-side sealing ring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    One preferred embodiment of the cylinder in accordance with the present invention is depicted in the set of drawings and will be described in greater detail below. 
           [0014]    The drawings show in 
           [0015]      FIG. 1  a cross-sectional top plan view of a cylinder in accordance with the present invention, wherein only individual sections of the cylinder are shown; in 
           [0016]      FIG. 2  a cross-sectional, detailed representation of two sections of the cylinder, the cutting plane of  FIG. 2  extending axially parallel with, but perpendicular to the cutting plane of  FIG. 1 ; and in 
           [0017]      FIG. 3  a variation of the two sections of the cylinder shown in  FIG. 2 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    As may be seen by initially referring to the longitudinal cross-section representation of a first preferred embodiment of the present invention, as seen in  FIG. 1 , an impression cylinder or a cylinder generally comprises a shaft  01  that may be structured either as a single piece or as multiple pieces. Shaft  01  is non-rotatably mounted with one end in a fixed bearing and the other end in an axially or radially movable bearing, which is not specifically shown. A printing machine, in which the cylinder of the present invention is intended for use, is preferably a gravure printing press, in which the cylinder, which may be an impression cylinder, acts as a printing cylinder or as a forme cylinder for printing on a substrate. The cylinder, and especially a sleeve that is positioned on the cylinder, can also have one or more printing formes on its circumferential surface. The second principal component of the cylinder, in addition to the shaft  01 , is a tubular casing or jacket  02 , which is rotatably mounted on the shaft  01 . Multiple bearing assemblies  03  are used to rotatably mount the casing  02  on the shaft. These bearing assemblies, and are preferably structured as ball bearing assemblies or as similar roller bearing. 
         [0019]    A compressed gas inlet bore  04  extends, axially in shaft  01  in the first preferred embodiment depicted in  FIG. 1 , and beginning at the fixed bearing end of the shaft  01 , or on the left, as seen in  FIG. 1 . The compressed gas inlet bore  04  extends axially to preferably multiple compressed gas supply bores  05 , which extend essentially radially through the shaft  01 , with each such radial bore  05  opening up into a compressed gas chamber  06 . The compressed gas chamber  06  in turn communicates with multiple compressed gas outlet openings  07 , which are distributed around the outer circumferential periphery of the casing or jacket  02 . When a sheathing or sleeve that is not specifically shown in the drawings, is applied to the outer circumference of the casing or jacket  02 , compressed air is forced out of the compressed gas outlet openings  07  from the compressed gas chamber  06 , thus making it easier to pull the sleeve onto the casing or jacket  02  or to remove the sleeve from the casing or jacket  02 . 
         [0020]    In each of the end areas of the cylinder, a lubricant chamber  08  is provided for lubricating the bearings  03  and the rotatable casing or jacket  02 . As is shown more clearly in  FIG. 2 , lubricant chamber  08  is extending in an axial direction, in sections, between the shaft  01  and an interior wall of the casing or jacket  02 . A suitable lubricant, especially oil, is held inside the lubricant chamber  08 . 
         [0021]    Referring now particularly to the detailed drawing of the cylinder in accordance with the present invention, as presented in  FIG. 2 , the structural details of the cylinder can be seen in greater detail. The flow of compressed air, which may be introduced into the compressed gas bore  04  at, for example, a pressure of 15 bar, is indicated by a bold, dot-dashed line. The compressed air flow runs through the compressed gas inlet bore  04  and the connected compressed gas supply bore  05  into the compressed gas chamber  06 , and from there through the outlet openings  07  in the casing or jacket  02  to the outside circumferential peripheral surface of the casing or jacket  02 . 
         [0022]    To achieve an effective, sealed separation between the compressed gas chamber  06  and the lubricant chamber  08 , these two chambers are separated from one another by a lubricant-side sealing ring  09  and by a compressed gas-side sealing ring  10 , as may be seen in  FIG. 2 . The two sealing rings  09 ;  10  are preferably both annular rings which are arranged, for example, directly adjacent to one another, as seen in  FIG. 2 , and are each preferably made of a material that is suited to the medium which is contained in the adjacent chamber, typically either oil or compressed air. Furthermore, the adjacent cooperating pairs of sealing rings  09 ;  10  are each positioned as close as possible to one of the bearings  03  on which the casing or jacket  02  is supported. The various mechanical stresses which act on the sealing rings  09 ;  10 , and that result from the possible bending of the impression cylinder casing can be kept low by the placement of these sealing rings  09 ;  10  adjacent the bearing assemblies  03 . The sealing edges of the respective sealing rings  09 ;  10  are each turned toward the respective bordering lubricant chamber  08  or compressed gas chamber  06 , as is indicated by the arrows shown in the sealing rings  09 ;  10  depicted in  FIGS. 2 and 3 . In this manner, a separate sealing of the lubricant chamber  08  and of the compressed gas chamber  06  is accomplished, so that the corresponding stress acts on only one side, on the respective sealing ring  09 ;  10 . In this manner, an effective sealing of each of the two chambers  06 ;  08  can be achieved over a substantially longer period of time as compared with the sealing of the two chambers  08 ;  06  which could be accomplished by the use of a single, common sealing ring  09  or  10  for the two chambers  08 ;  06 , which single, common sealing ring would then be stressed from both sides by different media. 
         [0023]    In a second preferred embodiment of the present invention, which is shown in  FIG. 3 , a spacer ring is positioned between the lubricant-side sealing ring  09  and the compressed gas-side sealing ring  10  to form an oil chamber between the lubricant-side sealing ring  09  and the compressed gas-side sealing ring  10 . This oil chamber is for the purpose of lubricating the compressed gas-side sealing ring  10 . 
         [0024]    To achieve an efficient lubrication in the lubricant chamber  08 , during the rotation of the casing or jacket  02 , a directed lubricant flow is accomplished as follows. In an idle state of the cylinder, the lubricating oil collects in the lower portion  8   a  of the lubricant chamber  08 , as seen in  FIG. 2 . When the casing or jacket  02  is rotated, a layer of oil forms on an interior surface of the casing or jacket  02 , which oil layer has a certain thickness, with that thickness depending primarily upon the speed of rotation of the casing or jacket  02  and the viscosity of the oil. To also direct the lubricating oil through the bearing  03 , a first, outer oil deflector  11  is located in the lubricant chamber  08 . This first, outer oil deflector  11  scrapes off part of the layer of oil that has adhered to the interior surface of the casing  02 . The first, outer oil deflector  11  is positioned at a slight angle with respect to a diametral plane extending through the casing or jacket  02 , in order to accelerate the scraped off oil in the axial direction of the cylinder. The resulting flow of lubricant is represented by a dashed line in  FIG. 2 . Because the first, outer oil deflector  11  is located in the lubricant chamber  08  near the bearing  03 , the lubricant flow is directed axially through the bearing  03 , as seen in  FIG. 2 . Axially interiorly of the bearing  03 , in the direction of oil flow, as seen in  FIG. 2 , a radial oil layer again forms on the interior surface of the casing  02  in an axially interior lubricant chamber which is defined by the bearing assembly  03  and the lubricant-side sealing ring. 
         [0025]    To keep the pressure of the oil acting on the lubricant-side sealing ring  09  low, a second, inner oil deflector  12  is provided in the interior lubricant chamber, which second, inner oil deflector  12  scrapes the lubricating oil off of the interior surface of the casing  02  and directs it toward the shaft  01 . 
         [0026]    In the embodiment of the present invention which is depicted in  FIGS. 2 and 3 , the lubricant circuit is completed by a lubricant channel  13 , which extends generally diametrically through the shaft  01  and at an angle in relation to the axial direction of the cylinder. In this depicted configuration, the two ends of the lubricant channel  13  open into the interior and outer or exterior sections of the lubricant chamber  08  that are separated by the bearing  03 . The oil passes through the lubricant channel  13 , by the force of gravity, from the rear or interior side of the bearing  03  back to the front or exterior or outer side of the bearing  03 , where it is redistributed over the interior surface of the casing  02  by the force of the rotation of the casing  02 . 
         [0027]    Because the lubricant channel  13  extends through the center of the shaft  01 , and thus is intersecting with the axially centrally located compressed gas bore  04 , a seal must be provided between the lubricant channel  13  and the compressed gas bore  04 . This is accomplished, for example, by inserting a tube  14  into a corresponding bore in the shaft  01 . It would also be within the scope of the present invention for the lubricant channel  13  to extend offset radially, in relation to the compressed gas bore  04 , thereby avoiding an intersection of these two hollow conduits. 
         [0028]    To seal the outer side of lubricant chamber  08  toward the outside of the cylinder, additional end sealing elements  15  are provided in the end areas of the cylinder. To be able to fill the oil into the lubricant chamber  08  and to be able to measure the oil fill level, an oil fill bore  16  that is accessible from the outside of the cylinder is provided. This oil fill bore  16  extends, for example, through the shaft  01 . It must also be sealed by a tube  14  if it intersects with the compressed gas bore  04 . The oil fill bore  16  extends from an oil fill opening  17 , at the exterior of the shaft  01 , to the lubricant chamber  08 . The oil fill bore  16  can also be used to vent the lubricant chamber  08 . In addition, an oil level gauge, which is not specifically shown can be inserted into the oil fill bore  16  and, with which oil level gauge the oil fill level of the lubricant chamber  08  can be checked. 
         [0029]    It should be noted that, in accordance with the present invention and based upon the intended use of the cylinder, multiple lubricant chambers  08  and, as needed, multiple compressed gas chambers  06  can be constructed in the cylinder. These lubricant chambers  08  and gas chambers  06  would be configured and sealed against one another in a comparable manner, as has been described above. 
         [0030]    While preferred embodiments of cylinders of machines that process continuous lengths of material, in accordance with the present invention, have been described fully and completely hereinabove, it will be apparent to one of skill in the art that various change in, for example, the type of sleeve positionable on the cylinder casing or jacket, the source of the compressed gas, 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.