Abstract:
A rubber blanket is provided with reinforcement rails on one or both of its ends. These reinforcement rails are positionable in a narrow channel in a rubber blanket cylinder. The reinforcement rail or rails extend beyond the ends of the channel. Rubber blanket cylinder tensioning devices engage the extending ends of the rubber blanket reinforcement parts.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a rubber blanket and to a device for fastening a rubber blanket on a rubber blanket cylinder of a rotary printing press. The blanket has at least one reinforcement rail at one of its ends. This reinforcement rail extends beyond the width of the blanket and is useable to secure the blanket to a cylinder. 
     DESCRIPTION OF THE PRIOR ART 
     A rubber blanket tensing device is known from DE 196 16 337 A1. Each end of the rubber blanket is provided with a suspension rail. Here, a first, or leading, end is brought into a lateral cutout of the cylinder channel, and a second, or trailing, end is radially pulled into the channel by a tensing strip and is tensed in this way. 
     DE 78 20 773 U1 discloses a rubber blanket with suspension rails. The suspension rails protrude past the width of the rubber blanket. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is directed to providing a rubber blanket and a device for fastening a rubber blanket. 
     In accordance with the present invention, this object is attained by providing the rubber blanket with at least one reinforcement rail at one end. Both blanket ends can have reinforcement rails. These reinforcement rails may have a height that is at least twenty times the thickness of the blanket. The rail or rails have a length greater than the width of the blanket. This length extends past the width of the blanket. The protrusion works with a blanket fastening device. 
     The advantages which can be achieved by the present invention reside, in particular, in that only a narrow visible tensioning or securement channel is provided, so that a large printing length can be achieved with the rubber blanket cylinder. Neither a tensioning spindle nor a tensioning strip are required for this simply and dependably operating device. 
    
    
     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 partial cross section view through a cylinder with the device of the invention and taken along the section line I—I of FIG. 2, and in 
     FIG. 2, a top plan view on the end of a cylinder with the device corresponding to the representation in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A rubber blanket  03 , for example of a thickness “a” of approximately 2 mm and a width “b” of approximately 1000 mm, rests on the surface  01  of a rubber blanket cylinder  02 . A first—for example U-shaped—reinforcement rail  07  and a second reinforcement rail  08  are interlockingly attached to or incorporated into the material of the rubber blanket  03  at the first and second ends  04 ,  06 , respectively of the rubber blanket  03 . They are sufficiently bending-resistant in respect to their longitudinal axis. Cross-sectional, form and section modulus have been appropriately selected. On the left and on the right ends of the rubber blanket  03 , the reinforcement rails  07 ,  08  each protrude with their first or left ends  12  and their second or right ends  13  laterally past the rubber blanket  03  by at least five millimeters, as seen in FIG.  2 . The reinforcement rails  07 ,  08  are longer than the rubber blanket  03  is wide. 
     As stated, the first and second ends  04 ,  06  of the rubber blanket  03  are fastened to the reinforcement rails  07 ,  08 , for example by rivets, or by gluing, vulcanizing, etc. The reinforcement rails  07 ,  08  can each have a height “f”, which height “f” is twenty to forty times the thickness “a” of the rubber blanket  03 . 
     The ends  12 ,  13  of the reinforcement rails  07 ,  08 , whose edges have been inserted into a cylinder channel  14  formed in the blanket cylinder  02 , protrude past the width “b” of the rubber blanket  03 , as well as laterally out of the cylinder channel  14 , again as seen in FIG.  2 . 
     The ends  04 ,  06  of the rubber blanket  03 , with the part of the reinforcement rails  07 ,  08  fastened on them, are inserted into the narrow cylinder channel  14 , which extends in approximately the radial and axial direction of the rubber blanket cylinder  02 . The opening  16  of the channel  14  facing toward the surface  01  of the blanket cylinder  02  is in the form of a gap having an inside width “g”. The cylinder channel  14  has been widened trapezoidally in cross section to an inside width “h”. A trapezoidal cross-sectional shape of the cylinder channel  14  is advantageous because it is possible, in this way, to position the reinforcement rails  07 ,  08  away from each other in the interior of the cylinder channel  14 . 
     The width “g” of the surface opening  16  of the channel  14  can be kept very narrow. It approximately corresponds to the thickness “a” of the rubber blanket  03 , plus the thickness “c” of a reinforcement rail  07 , plus a small added amount. 
     The cylinder channel  14  can be longitudinally divided into two compartments  19 ,  21  by a guide strip  18 , as represented in dashed lines in FIG. 1, which guide strip  18  is fastened on the channel bottom  17 , extends upward and is wedge-shaped. Because of this guide strip  18 , it becomes possible for each end  04 ,  06  of the rubber blanket  03  to be guided into its own compartment  19 ,  21 . In the course of this, the reinforcement rails  07 ,  08  are conducted away from each other. 
     A device  20  for generating a pressure force on the free ends  12  and  13  of the reinforcement rails  07 ,  08  is provided to the left and right on the blanket cylinder  02  next to the start and end of the cylinder channel  14 . Device  20  is situated, with respect to the free ends of the reinforcement rails  07 ,  08  directly next to them or distanced from them. The device  20  is supported on the rubber blanket cylinder body and generates a pressure force on the free ends  12  and  13  of the reinforcement rails  07 ,  08  acting in the radial direction; i.e. in the direction toward the axis of rotation of the rubber blanket cylinder  02  and in this way holds and tensions the rubber blanket  03 . 
     Devices  20  for generating a pressure force are provided for each free end  12 ,  13  of the reinforcement rails  07 ,  08 . They comprise, for example, respective tensioning blocks  24 ,  26 , each of which can be moved in the direction toward or away from the axis of rotation of the cylinder, or radially up and down, by a releasable interlocking connection, for example respective screws  27 ,  28 , at the side of the cylinder channel  14  of the rubber blanket cylinder  02 , and in this way can exert pressure force on the free ends  12 ,  13  of the reinforcement rails  07 ,  08 . 
     Each tensioning block  24 , 26  fixed against relative rotation, and for example each has a projection  29  extending around and resting against the free ends  12 ,  13  of the reinforcement rails  07 , or  08 , as shown most clearly in FIG.  1 . 
     In the radial direction of the blanket cylinder  02 , the tensioning blocks  24 ,  26  also have distances of different length from the surface  01  of the rubber blanket cylinder  02 , as seen in FIG.  1 . Thus, both tensioning blocks  24  of the first or leading end  04  of the rubber blanket  03  are farther distanced from the surface  01  than the tensioning blocks  26  of the second or trailing end  06  of the rubber blanket  03 . 
     The devices  20  are each fastened in a cutout  23  on the barrel of the rubber blanket cylinder  02 . One wall of this cutout  23  can be used as a torsion guard. However, the devices  20  can also be fastened on both front faces  22  of the rubber blanket barrels. 
     While a preferred embodiment of a rubber blanket and of a device for fixing a rubber blanket to a blanket 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 overall size of the cylinder, the drive for the cylinder 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.