Abstract:
A printing plate or decorator cylinder has a tapered bore for engaging the tapered outer surface of a sleeve member which is mounted on an untapered rotatable drive shaft and the sleeve is adjustably coupled to the shaft to permit accurate registration of the printed indicia when a printing plate is changed.

Description:
FIELD OF THE INVENTION 
     This invention is directed toward adjustably mounting a printing plate cylinder, for example a magnetic cylinder to a rotatable drive shaft of a printing press or the like. 
     DESCRIPTION OF THE PRIOR ART 
     U.S. Pat. No. 5,819,648 by Megyesi point out some of the problems encountered in using a printing plate cylinder, such as a magnetic cylinder, in printing presses and decorator machines and the like. In practice the printing plate or decorator plate usually has to be changed often which in many cases requires that the printing plate cylinder with attached plate has to be removed from the drive shaft and a new plate installed, or a different cylinder with an attached printing plate installed on the drive shaft. Each time the printing plate is changed it may require some small amounts of adjustment both axially and circumferentially to bring the indicia on the new printing plate into proper registration with respect to other printed indicia. The Megyesi &#39;648 patent describes some of the problems associated with removal and replacement of the printing plate cylinders on a decorator machine and the need to have adjustments available to bring the indicia on the printing plate into close registration with the other printed indicia. As is well-known in the commercial field and as mentioned in the &#39;648 patent, some printing presses or decorator machines have straight or right angle cylindrical rotatable shafts and others have tapered shafts. The untapered shaft generally allows for easier adjustability but repeated replacement usually causes some wear to the bore of the printing plate cylinder and/or the shaft. The tapered shaft has the advantage of minimizing the amount of wear caused by repeated replacements but lacks adjustability. The &#39;648 patent utilizes an inner member or sleeve which has a tapered or conical shaped axial bore to engage a tapered rotatable drive shaft. The outer surface of the sleeve is untapered to engage the untapered axial bore of an outer sleeve or printing plate cylinder. In this arrangement to bring the printing plate into registration the outer printing plate cylinder is adjusted with respect to the inner sleeve which remains mated to or engaged with the tapered shaft. To gain the advantage of a tapered shaft when the printing plate or decorator plate has to be changed the entire combination of the inner member or sleeve and the outer member or printing plate cylinder (as well as the attached printing plate) is removed from the shaft and replaced with a new similar combination with a new printing plate or a new printing plate is replaced on the printing plate cylinder and the same unit or assembly is then reinserted on the tapered drive shaft. 
     Another embodiment of an adjustable printing plate cylinder by the same applicants as the instant application is a printing plate cylinder with a linear bearing press-fitted into the bore for engaging an untapered rotatable printing press drive shaft. The linear bearing minimizes the wear which normally is encountered when mounting the cylinder on an untapered drive shaft and also allows for both axial and circumferential adjustment of the printing plate cylinder as needed. 
     SUMMARY OF THE INVENTION 
     A sleeve member has an untapered bore for engaging and surrounding an untapered rotatable drive shaft of a printing press or the like and fits snugly but adjustably on the untapered drive shaft. The outer surface of the sleeve is tapered. A printing plate cylinder has a correspondingly tapered axial bore for engaging the outer surface of the sleeve member. When replacing a printing plate, only the printing plate cylinder, with attached printing plate, is removed from the sleeve member which remains engaged with the drive shaft. The tapered coupling between the sleeve member and the printing plate cylinder produces some benefits attributable to a tapered shaft yet at the same time, the untapered bore of the sleeve member engaging the untapered shaft retains the benefit of the adjustability feature associated with an untapered drive shaft. When a printing plate is changed only the printing plate cylinder (with attached printing plate) is removed. Because of the tapered bore of the printing plate cylinder it can then be replaced onto the outer tapered surface of the sleeve member so that the printing place is close to the ultimate registration. The sleeve member can then be adjusted both axially and circumferentially with respect to the drive shaft to bring the printing plate into precise registration. 
     In the aforementioned Megyesi device, because of the weight of the assembly which has to be removed from and replaced on the shaft when replacing a printing plate, the outer sleeve of the Megyesi device preferably is made out of a lighter weight metal such as aluminum. By comparison, since the instant invention requires only that the outer printing plate cylinder be removed and replaced for changing the printing plate it can be made out of a heavier metal such as steel. The parts made of steel are more uniform and are more stable (hold their dimensions better) and can be machined more accurately and precisely. This results in a significant savings in manufacturing costs and registration can be more accurate and precise. 
     In the &#39;648 patent, when changing printing plates both the inner and outer members are removed from the shaft and the assembly is usually cleaned (to remove ink and other materials). The cleaning process may result in dissolving surface lubrication between the members which is used to keep the members from binding up. Therefore, the usual practice is to separate the members after they are removed from the shaft and then relubricate after cleaning. In the instant invention only the printing plate cylinder is removed and cleaned before replacing on the sleeve. The lubrication is between the shaft and the bore of the sleeve which remains untouched and unchanged during replacement of a printing plate. Therefore, relubrication is not required. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial section side view of a preferred embodiment of the invention; 
     FIG. 2 is an end view of an end cap which is attached to the sleeve and used for adjustment of the printing plate cylinder; 
     FIG. 3 is an end view of a push/pull block utilized for adjustment of the printing plate cylinder; 
     FIG. 4 illustrates a shouldered bolt; 
     FIG. 5 is an end view of the mounting ring for attaching the printing plate cylinder to the sleeve; and 
     FIG. 6 is an end view of the printing plate cylinder. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a cylindrical untapered printing press drive shaft  10  is attached in conventional fashion at one end to a conventional driving source identified generally by reference numeral  11  for rotatably driving the shaft in a conventional and well-known fashion. A sleeve  12  has a central or axial untapered cylindrical bore  13  for engaging shaft  10  with its outer surface  14  tapered generally inward from the attached end of shaft  10  to the open or distal end of the shaft for a significant length and continues with a cylindrical or untapered length identified by reference numeral  15 . The outer end of sleeve  12  has an inward extending flange. The bore  13  of sleeve  12  fits over and surrounds shaft  10  snugly yet it can be adjusted both circumferentially and axially a small amount as necessary with respect to the shaft, as will be described later. Fitting over the outer tapered surface  14  of sleeve  12  is the tapered inner bore  16  of a printing plate cylinder  17 . Conventionally a printing plate, not shown, is mounted on the untapered outer surface  18  of printing plate cylinder  17 . A mounting ring  19  is attached to the outer end of printing plate cylinder  17  by threaded bolts engaged in the threaded openings  20 , see FIG.  5 . The cylinder  17  may be a magnetic cylinder or a type which holds the printing plate in place by mechanical means. 
     The outer or unattached end of shaft  10  is counter sunk to form a depression or recess identified by reference numeral  22 . Resting in recess  22  is a push/pull block  23 . Preferably recess  22  is cylindrical in shape and push/pull block  23  is in the form of a disk which rests in recess  22 . Disc or block  23  is free to move axially within the recess, within limits, but not circularly or circumferentially. Certain restraints are places on the movement of block or disk  23  as part of the necessary adjustment to bring the printing plate cylinder into correct registration each time the printing plate is changed. 
     FIG. 5 illustrates greater detail of the cylinder mounting ring  19 . Openings  24  are for threaded bolts which engage threaded openings  20  for attaching the mounting ring to the end of the printing plate cylinder  17 . Slotted openings  25  are access openings for allowing access to bolts which may have to be loosened and then retightened during circumferential adjustment of the printing plate. Slotted opening  26  allows access to adjustment screws which are used for axial adjustment of the printing plate. Slotted opening  27  allows access to an adjustable cam or gear which is used in the circumferential adjustment. The adjustments are done in a conventional and well-known fashion. The central or axial opening  28  is for a threaded bolt for attaching the mounting ring  19 , with the attached printing plate cylinder  17 , to end cap  30  which is attached to sleeve  12 . Threaded opening  38  is merely used for assisting in removing or disengaging the mounting ring with attached printing plate cylinder from sleeve  12 . A screw, not shown, is threaded into opening  38  to make contact with or butt against end cap  30 . As the screw advances it helps dislodge the printing plate cylinder from the sleeve. Opening  39  receives a dowel pin, not shown, which acts as a keyway for aligning mounting ring  19  to end cap  30  when the printing plate cylinder is being placed on sleeve  12 . 
     As mentioned earlier, the present invention results in benefits usually attributed to a tapered shaft while at the same time achieving benefits of the circumferential and axial adjustments which are normally experienced by using an untapered or a cylindrical shaft. This is achieved by using a sleeve  12  having an untapered bore for engaging an untapered rotatable drive shaft  10  so that the sleeve  12  can be moved slightly as necessary with respect to the shaft to obtain the circumferential and axial adjustments as needed for accurate registration. For removable attachment of printing plate cylinder  17  the outer surface of sleeve  12  is tapered to engage the tapered bore  16  of cylinder  17 . Mounting ring  19  attaches cylinder  17  to end cap  30  which in turn is attached to sleeve  12  whereby moving sleeve  12  circumferentially and/or axially with respect to shaft  10  results in circumferential and/or axial adjustment of cylinder  17 . As described earlier, to change a printing plate, cylinder  17  is removed from sleeve  12  by unthreading the bolt (not shown) in opening  28  of mounting ring  19  and sliding cylinder  17 , with attached mounting ring  19 , off sleeve  12  using a dislodging screw in opening  38  if necessary. A new printing plate is then placed on the printing plate cylinder  17  which is then replaced on sleeve  12  and bolted on. Alternatively, a new or different printing plate cylinder  17  with attached printing plate is slipped over sleeve  12 . In any event, only the printing plate cylinder with its attached printing plate and mounting ring is removed and replaced as compared to the aforementioned Megyesi device in which the entire assembly including the inner sleeve and the outer sleeve and printing plate and adjustment mechanism is removed from the shaft for replacement of the printing plate. Because the components are made of metal, they are quite heavy so to lighten the load the Megyesi components are made out of lighter weight metal such as aluminum or something similar. This can result, and has resulted, in some manufacturing problems, e.g., the aluminum components may not hold tolerances. Since the instant invention requires fewer component parts be removed and replaced when changing printing plates, cylinder  17  and sleeve  12  can be made out of a heavier and stronger metal, such as steel or similar, which hold tolerances more closely thereby achieving a significant manufacturing benefit. 
     One of the components or elements utilized for adjustment is the push/pull block or disk  23  which rests within the recess  22  at the end of shaft  10 . Referring to FIG. 3, push/pull block  23  is attached to the end of shaft  10  by four shouldered bolts inserted through counter-sunk openings  31 . As illustrated in FIG. 4, the bolts have a partially threaded length identified by reference  29  to engage corresponding threaded openings in the end of shaft  10 , not shown, and have an unthreaded shoulder  35  which permits push/pull block  23  to move longitudinally or in an axial direction while still attached to shaft  10 . In this fashion, then, push/pull block  23  is attached to shaft  10  yet has some degree of freedom of movement in an axial direction with respect to shaft  10  but cannot rotate or move circularly or in a circumferential direction with respect to shaft  10 . Opening  32  is to accommodate and accept a pin for attaching a cam or gear to make a circumferential adjustment of sleeve  12  with attached cylinder  17  which is done in a conventional fashion. Openings  33  and  34  are utilized for axial adjustment which is also done in a conventional fashion. A bolt or threaded screw, not shown, is threaded through opening  33  and the end of the bolt makes contact with or butts against the end of shaft  10  at the bottom of recess  22 . The other axial adjustment opening  34  contains a screw, not shown, with clearance between opening  34  and the screw but with the screw threaded into a threaded opening, not shown, in the end of shaft  10 . When the bolt in opening  33  is threaded inwardly or advanced it moves push/pull block  23  axially outward or toward the free end of shaft  10  and when the screw in opening  34  is advanced it serves to pull push/pull block  23  inwardly or in the opposite direction toward the attached end of the shaft, i.e., toward the bottom of recess  22 . Push/pull block  23  is linked to sleeve  12  via end cap  30  and printing plate cylinder  17  with attached printing plate is coupled to sleeve  12  via mounting ring  19  so that the printing plate can be adjusted axially as needed to bring it into proper axial registration by axially adjusting push/pull block  23 . The two threaded openings  36  are to receive threaded bolts, not shown, which attach push/pull block  23  to the end cap  30  and thereby transfer the adjustments as described to the printing plate cylinder. Threaded openings  37  are to receive threaded bolts, not shown, for loosely attaching push/pull block  23  to end cap  30  for precaution to prevent the remote possibility of the two becoming disengaged during circumferential adjustment. Opening  46  in push/pull block  23  is merely to provide clearance for the bolt which attaches mounting ring  19  to end cap  30 . 
     Referring now to FIG. 2, end cap  30  is used for attaching push/pull block  23  to sleeve  12 . The seven outer peripheral shouldered openings  40  are for screws or bolts for attaching end cap  30  to the end of sleeve  12 . The central threaded opening  41  is to receive a bolt which passes through opening  28  on mounting ring  19  for attaching the mounting ring, along with the printing plate cylinder  17 , to end cap  30  thereby connecting printing plate cylinder  17  to sleeve  12 . When the printing plate is to be changed the bolt is unthreaded from opening  41  and the mounting ring  19  and printing plate cylinder  17  are slipped off sleeve  12 . An indexing hole  42  receives the dowel pin that fits into opening  39  in mounting ring  19  for alignment purposes when the printing plate cylinder is being placed on sleeve  12 . Slotted openings  43  are for the bolts which thread into openings  36  of push/pull block  23  and slotted openings  44  are for the bolts which thread into openings  37  on push/pull block  23 . Slotted opening  45  provides access to the axial adjustment screws or bolts which are in openings  33  and  34  in push/pull block  23 .