Abstract:
A mechanism is used for mounting a dressing on a cylinder of a printing press. The mechanism is fitted with at least one stop which is effective in an axial direction of the cylinder. The stop allows the cylinder dressing to be arranged on the cylinder with pressure in the axial direction. The stop is situated outside of the cylinder.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a device for positioning a dressing on a cylinder of a printing press. At least one detent, or stop, which acts in an axial direction of the cylinder, is situated outside the cylinder. 
   BACKGROUND OF THE INVENTION 
   EP 0678 383 A1 shows a device for changing printing formes. Horizontally movable holding elements temporarily fix the printing plate to be positioned in place. Each holding element has a lateral detent, and can be moved in the axial direction by operation of an actuating unit. 
   A device has been disclosed in EP 1 084 838 A1, which is used in one position as a holding device for a printing plate to be fed in, and in a second positions as a protection device. It is pivotable around a pivot axis on the plate feeding surface and has a lateral guide plate. 
   Various embodiments of a device for use in arranging lateral detents for the axial positioning of a printing plate are disclosed in DE 196 20 997 C2. In one embodiment of the device, the detents themselves can be brought into various positions. In another embodiment, several detents assigned to a plate selectively act together with plates of different widths by a step-like offsetting of the detents. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is directed to providing a device for use in positioning a different number of dressings of various widths. 
   In accordance with the present invention, this object is attained by providing at least one detent or stop, which acts in an axial direction of the cylinder, outside of the cylinder. In a first operating situation, a first number of detents are arranged on a dressing feeding surface. In a second operating situation, a second number of detents, which second number is different from the first number, are provided. 
   The advantages which can be gained by the present invention lie, in particular, in that the introduction of a dressing, for example a printing forme, is possible, which dressing introduction is exact in the axial direction of a cylinder, without it being necessary to provide an adjustable detent in or on the cylinder. The device is accessible in a simple way, is adjustable, can be driven by a drive and can be exchanged when required, and in accordance with a further embodiment, assures a dependable and positionally correct removal of the printing plate. In this way, the prerequisites for an automatic or for a semi-automatic dressing change, in particular, are considerably improved. 

   
     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 side elevation view of the device in accordance with the present invention in a first operating situation, in 
       FIG. 2 , a side elevation view of the device in a second operating situation, in 
       FIG. 3 , a top plan view of the device in the operating situation depicted in  FIG. 1 , and in 
       FIG. 4 , a top plan view of the device in the operating situation depicted in FIG.  2 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A cylinder  01 , for example a forme cylinder or a transfer cylinder, as seen in  FIGS. 1 and 2 , is to be provided with a dressing  02  such as, for example, a printing forme or a rubber blanket, particularly one embodied as a metallic printing blanket, as seen in FIG.  2 . For this purpose, the dressing  02  is fed to the cylinder  01 , via for example, a table, so that a beveled first end of the dressing  02  can be introduced into a groove in cylinder  01 . In a particular embodiment, a dressing end clamping device  03  can be arranged in the groove. However, the dressing ends can also be held in cylinder  01  by the cooperative shaping of the dressing end and the cylinder groove and without the use of a clamping device  03 . To insure that that the dressing  02 , and in particular the printing forme, is fed in, in the axial direction of the cylinder  01 , in the correct position and, if required, is fixed in place, a device  04  for guiding the dressing, or for the axial alignment of the dressing, is provided outside the cylinder. 
   The dressing axial alignment or guiding device  04  has a pivot axis S, which pivot axis S is substantially parallel with the longitudinal direction of the cylinder. At least one detent  06 ,  07  can be pivoted about this pivot axis S. For example, this detent  06 , or  07  is pivoted away, or out of a use position, for an operating situation in which no dressing change is to take place, as depicted in  FIG. 1 , and pivoted in, or into a use position, if the dressing is to be fed in, as depicted in FIG.  2 . Four such detents  06 , one for each of four printing formes  02 , for example, are arranged on a shaft  11  or a pivotable cross bar  11 , which shaft or cross bar  11  extends over the length of the cylinder  01 , which cylinder length corresponds, for example, substantially to the width of four printed pages, for example four newspaper pages, as seen in FIG.  3 . The printing formes  02  are pushed, for example by a spring force, against the respective lateral detent  06 ,  07 . 
   Two detents  07  are provided over the length of the cylinder  01 , or the shaft  11 , as seen in FIG.  4 . Detents  07  can be pivoted into their use position for the case of double-wide printing formes  02 . 
   The device  04  for the axial alignment of dressings is embodied in such a way, that in a first operating situation, a first defined number of n detents  06  can be brought onto a use position, or are arranged on a feeding surface of the dressing  02 , and in a second operating situation, a second defined number m of detents  07 , which is different from the number first defined n can be brought into the use position. FIGS.  3  and  4  show these two operating situations by the example of a printing press, or of a cylinder  01 , whose length is configured for the printing of four pages arranged next to each other, in particular for four newspaper pages. In  FIG. 3 , four printing forms  02 , each having, for example, a width of a printed page, and in particular for a newspaper page, can be fed to the cylinder and are laterally guided by four detents  06 . In  FIG. 4  only two detents  07  have been brought onto an operative position with respect to the feeding surface of two double-width printing formes  02 , each having, for example, a width of two printed pages, in particular two newspaper pages, for example two panorama printing formes  02 . If the cylinder  01  is embodied with a length adapted for the printing of six side-by-side arranged printed pages, in particular for six newspaper pages, in an embodiment which is not specifically depicted, in the one operating situation six detents  06  can be brought onto the feeding surface, and in the other operating situation three detents  07  can be positioned on the feeding surface. For k printed pages which can be arranged side-by-side on the cylinder  01 , n=2*m, and n=k applies. 
   Depending on the operating situation, in the above mentioned embodiments one detent  06 , or  07  is assigned to each one of the dressings  02 , respectively for one-sided guidance of each dressing  02 . The detents  06 ,  07  are advantageously each arranged on the same side of the respective dressing  02  to be fed in, in particular on a left side of a script located on the dressing. 
   In another preferred embodiment, which is not specifically depicted, a common detent  06 ,  07 , which has two detent faces facing away from each other and respectively facing the dressings  02  to be fed in, is arranged between each of two dressings to be fed in. Thus, for a cylinder  01  whose width is configured for four side-by-side arranged printed pages, the device has three such detents  06 ,  07  in the one operating situation, and in the other operating situation only one detent  06 ,  07 . For six side-by-side arranged printed pages there are five, or two detents  06 ,  07 . Here, n=k−1 and n=2*(m+1)−1 generally applies. 
   In a further development of the present invention, the device can also be embodied in such a way that, although in the second operating situation fewer than n detents  06 ,  07  are used, more than the above mentioned number m can be introduced onto the feeding surface. For example, this can be the case if only a portion of the length of the cylinder  01  should be covered for printing with dressings  02  of a width of two printed pages. Thus, in a variation of  FIGS. 3 and 4  for example, in the first operating situation four detents  06 , corresponding to the four dressings  02 , could be supplied. In the second operating situation, two dressings  02  of single width and one dressing  02  of double-width would be aligned, if the device in  FIG. 4 , viewed from the left side, additionally would utilize the first or third detent  06  from FIG.  3 . This should be correspondingly applied to the embodiment of even wider cylinders  01 , as well as to the non-represented, previously mentioned embodiment with common detents  06 ,  07 . 
   The device for positioning a cylinder dressing and for the pivoting of the device can be integrated into a full-or a semi-automated plate change. The axial position of the detents  06 .  07 , which may be, for example, arranged as thin plates or “wings” on a cross bar  11  to be pivoted, for example a square tube, can be individually adjustable, if required. The entire device  04  can be axially adjustable, if desired. 
   In a further embodiment of the present invention, the device  04  has one or several rollers  08 , which rollers  08  are different from the detents  06 ,  07 , and which rollers  08  are situated on a side of shaft or bar  11 , which rollers  08  hold down the printing forme  02  to be installed or during removal of the printing forme  02  from the cylinder  01 , after the appropriate pivoting of the device  04 , so that it comes to rest in the correct position on the table, for example against a detent. A further aid device  09  for use in pulling on the dressing  02 , or for removing it, can have one or several rollers, which can be placed against the dressing. 
   The selective placing of detents  06 ,  07  onto the feeding surface can also take place in another way. For example, a first set of detents  06  and a second set of detents  07  can be brought onto the feeding surface independently of each other by respective linear or pivoting movements. In a different variant, single detents  06 ,  07 , or groups of detents  06 ,  07  can be moved onto or out of the feeding surface, for example by their own drive mechanisms. For example, all of the detents  06  can be brought onto the surface in the first operating situation, while some ones of these detents  06  can be moved out of the surface in the second operating situation. Then, the number of detents  07  becoming effective in the second operating situation correspond to a partial number of detents  06 . This embodiment can then be appropriately controlled, for example by the use of a control device, which is not specifically represented, so that, in the one selectable operating situation, all detents  06 , for example, are effective, and in another operating situation a partial number of the detents  06  are used as detents  07 . 
   In connection with all of the embodiments of the present invention, it is applicable that the device advantageously has an operating situation in which none of the detents  06 ,  07  are arranged on the feeding surface. 
   While preferred embodiments of a mechanism for positioning a cylinder dressing, 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 type of material to be printed, the specific type of printing press, 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.