Abstract:
A printing press cylinder assembly is provided including a mandrel including an outer surface, a passage formed therein, at least one first conduit formed therein coupled to the passage and the outer surface, and at least one second conduit formed therein coupled to the passage and the outer surface. The printing press cylinder assembly also includes a guide piece located in the passage. The guide piece is movable in the passage between a first position where the guide piece guides air from the passage to the at least one first conduit and a second position where the guide piece guides air from the passage to the at least one second conduit. A method of installing a bridge sleeve and an outer sleeve on a mandrel of a printing cylinder assembly is also provided.

Description:
[0001]    The present invention relates generally to printing presses and more specifically to a method and apparatus for providing air to sleeves mounted on cylinders. 
       BACKGROUND OF INVENTION 
       [0002]    U.S. Pub. No. 2005/0257706 discloses an interchangeable printing cylinder including a cylindrical shaft, a sleeve supported on the shaft and a tube, whose face constitutes the active surface of the cylinder, received on the sleeve. The shaft includes therein a longitudinal channel and five radial conduits, with each conduit leading to one of five radial conduits formed in the sleeve. The radial conduits in the sleeve receive pressurized air from the radial conduits in the shaft and conduct the pressurized air between an internal surface of the tube and an external surface of the sleeve. In one embodiment, a valve is included between the radial conduits in the shaft and the radial conduits in the sleeve. The valve makes it possible to direct the flow pressurized air coming from the conduits either between the sleeve and the cover or between the tube and the sleeve. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    A printing press cylinder assembly is provided including a mandrel including an outer surface, a passage formed therein, at least one first conduit formed therein coupled to the passage and the outer surface, and at least one second conduit formed therein coupled to the passage and the outer surface. The printing press cylinder assembly also includes a guide piece located in the passage. The guide piece is movable in the passage between a first position where the guide piece guides air from the passage to the at least one first conduit and a second position where the guide piece guides air from the passage to the at least one second conduit. 
         [0004]    A method of installing a bridge sleeve and an outer sleeve on a mandrel of a printing cylinder assembly is also provided. The method includes providing a guide piece in a passage inside the mandrel, setting the guide piece in a first position and supplying air into the passage such that the air flows into at least one first conduit to an outer surface of the mandrel, sliding the bridge sleeve onto the mandrel, moving the guide piece into a second position and supplying air into the passage such that the air flows into at least one second conduit to an outer surface of the bridge sleeve and sliding the outer sleeve onto the bridge sleeve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The present invention is described below by reference to the following drawings, in which: 
           [0006]      FIG. 1  shows an exploded perspective view of a printing press cylinder assembly according to an embodiment of the present invention; 
           [0007]      FIGS. 2 and 3  show a longitudinal cross-sectional view of the printing press cylinder assembly with a guide piece of the printing press cylinder assembly inserted into a passage in a mandrel of the printing press cylinder assembly; and 
           [0008]      FIG. 4  shows a detailed view of the guide piece. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]      FIG. 1  shows an exploded perspective view of a printing press cylinder assembly  10  according to an embodiment of the present invention. Cylinder assembly  10  includes a mandrel  12  and a removable bridge sleeve  14  which may be slid onto an outer surface of mandrel  12 . A removable outer sleeve  16 , which in this embodiment is a blanket sleeve, is also included for sliding onto an outer surface of bridge sleeve  14 . In alternative embodiments, outer sleeve  16  may be a tubular printing plate. On a first or drive side  18  of printing press cylinder assembly  10 , an air source  20  may provide pressurized air into an axially aligned passage  21  ( FIG. 2 ) extending through an interior of mandrel  12 . Passage  21  may extend all the way from drive side  18  to a second or work side  22  of printing press cylinder assembly  10 . Mandrel  12  may include a stop  24 , preferably in the form of a pin protruding from an outer mounting surface  26 , for stopping bridge sleeve  14  as bridge sleeve  14  is slid axially onto mandrel  12 . Mandrel  12  also includes a plurality of first radial conduits  30  formed therein near work side  22  and a plurality of second radial conduits  32  formed therein spaced an axial distance D 1  ( FIG. 2 ) from first radial conduits  30 . First radial conduits  30  and second radial conduits  32  extend from passage  21  radially outward to outer mounting surface  26 . In the embodiment shown in  FIGS. 1 to 4 , mandrel  12  includes eight first conduits  30  and eight conduits  32 ; however, in other embodiments, the number of conduits  30 ,  32  may each be more or less than eight and do not have to be equal in number to each other. 
         [0010]    In order to selectively couple air source  20 , via passage  21  inside of mandrel  12 , to either first conduits  30  or second conduits  32 , a guide piece  34  is provided in passage  21  at a valve end  40  of mandrel  14 , which is at work side  22  of cylinder assembly  10 . Guide piece  34  is configured to (a) block air from flowing into first conduits  30  and direct air into second conduits  32  or (b) block air from flowing into second conduits  32  and direct air into first conduits  30 . In the preferred embodiment shown in  FIGS. 1 to 4 , guide piece  34  is configured as a two position spool valve. Guide piece  34  allows for a single air supply, provided here by air source  20  through passage  21  in mandrel  12 , to accommodate independent removal/installation of bridge sleeve  14  and outer sleeve  16 . Guide piece  34  may be provided with a circumferentially extending valve retention groove  38  on an outer surface of guide  34 , which receives a fastener  42 , in the form of a set screw, passing through a radial hole  44  in mandrel  12  to hold guide piece in passage  21 . A resilient element  46 , in the form of a compression spring, forces guide piece  34  axially away from mandrel  12  towards work side  22  to press valve retention groove  38  against fastener  42 . 
         [0011]      FIGS. 2 and 3  show a longitudinal cross-sectional view of printing press cylinder assembly  10  with guide piece  34  inserted into passage  21 . In  FIG. 2 , guide piece  34  is selectively positioned to block air from flowing from passage  21  into first conduits  30  and direct air into second conduits  32 , which allows outer sleeve  16  to be slid off or onto bridge sleeve  14  (i.e., outer sleeve  16  installation/removal position). In  FIG. 3 , guide piece  34  is selectively positioned to block air from flowing from passage  21  into second conduits  32  and direct air into first conduits  30 , which allows bridge outer sleeve  14  to be slid off or onto mandrel  12  (i.e., bridge sleeve  14  installation/removal position). Set screw  42  is holding guide piece  34  in position as compression spring  46  provides constant force against guide piece  34  to keep guide piece  34  in position against set screw  42 . 
         [0012]    Guide piece  34  includes an axial cavity  50  formed therein at a head end  52  thereof and eight first radial holes  54  connected to axial cavity  50 . Guide piece  34  also includes eight second radial holes  56  formed therein which are spaced from first radial holes  54  by an axial distance D 2 , which is greater than distance D 1 . First radial holes  54  are configured to connect axial cavity  50  to first radial conduits  30  when guide piece  34  is in the bridge sleeve installation/removal position shown in  FIG. 3 , allowing air to flow from passage  21  through axial cavity  50  and first radial holes  54  into first radial conduits  30 . In the position shown in  FIG. 3 , air flowing into first radial conduits  30  creates an air cushion between the outer surface of mandrel  12  and the inner surface of bridge sleeve  14 , allowing for bridge sleeve  14  to be slid off of mandrel  12 . 
         [0013]    Similarly, second radial holes  56  are configured to connect axial cavity  50  to second radial conduits  32  when guide piece  34  is in the outer sleeve  16  installation/removal position shown in  FIG. 2 , allowing air to flow from passage  21  through axial cavity  50  and second radial holes  56  into second radial conduits  32 . Bridge sleeve  14  also includes a plurality of radial bridge holes  58  formed therein that align with second radial conduits  32  formed in mandrel  12 . In the position shown in  FIG. 2 , air flowing into second radial conduits  32  enters into radial bridge holes  58  and creates an air cushion between the outer surface of bridge sleeve  14  and the inner surface of outer sleeve  16 , allowing for outer sleeve  16  to be slid off of bridge sleeve  14 . 
         [0014]    O-rings  60  may be provided on the inner surface of bridge sleeve  14  on opposite sides of radial bridge holes  58  to isolate radial bridge holes  58  and second radial conduits  32  utilized for the installation/removal of outer sleeve  16 . Additional o-rings  62  may also be provided on opposite sides of second radial holes  56  to seal the connections between second radial holes  56  and second conduits  32  and o-rings  64  may be provided on the downstream side of first radial holes  54  to prevent air from leaking into second conduits  32  in the bridge sleeve  14  installation/removal position and to prevent air from leaking into first conduits  30  in the outer sleeve  16  installation/removal position. 
         [0015]      FIG. 4  shows a detailed view of guide piece  34 , illustrating the spacing of first and second radial holes  54 ,  56 . Guide piece  34  may be beveled at head end  52  for ease of insertion into passage  21  and may be flat at a handle end  48  thereof to aid in turning. Valve retention groove  38  includes a circumferentially aligned portion  38   a  and two axially aligned portions  38   b,    38   c  extending from circumferentially aligned portion  38   a  toward head end  52 , with portion  38   b  extending further towards head end than portion  38   c.  As shown in  FIG. 4 , guide piece  34  may include a step  66  between valve retention groove  38  and second radial holes  56 , where guide piece  34  gets radially wider to provide a surface for compression spring  46  to contact. 
         [0016]    Referring to  FIGS. 2 to 4 , to switch between the outer sleeve  16  installation/removal position shown in  FIG. 2  and the bridge sleeve  14  installation/removal position shown in  FIG. 3 , guide piece  34  only needs to be rotated ninety degrees manually by an operator of press cylinder assembly  10 . Beginning in the outer sleeve  16  installation/removal position shown in  FIG. 2 , with set screw in axially aligned portion  38   c,  the operator may slightly press guide piece  34  towards drive side  18  ( FIG. 1 ) to overcome the force of compression spring  46  and bring circumferentially aligned portion  38   a  into contact with set screw  42 , then turn handle end  48  in a first direction  68  (e.g., clockwise). Once set screw  42  is aligned with axially aligned portion  38   b,  compression spring  46  forces guide piece  34  towards work side  22  and set screw  42  enters into contact with the edge of axially aligned portion  38   b,  setting guide piece  34  in the bridge sleeve  14  installation/removal position shown in  FIG. 3 . From this position, to enter back into the outer sleeve  16  installation/removal position shown in  FIG. 2 , the operator may press guide piece  34  towards drive side  18  ( FIG. 1 ) to overcome the force of compression spring  46  and bring circumferentially aligned portion  38   a  into contact with set screw  42 , then turn handle end  48  in a second direction  70  (e.g., counterclockwise). Once set screw  42  is aligned with axially aligned portion  38   c,  compression spring  46  forces guide piece  34  towards work side  22  and set screw  42  enters into contact with the edge of axially aligned portion  38   c,  setting guide piece  34  back into the outer sleeve  16  installation/removal position shown in  FIG. 2 . 
         [0017]    The embodiment of printing press cylinder assembly  10  disclosed herein may allow for easy installation and removal of both bridge sleeve  14  and outer sleeve  16  using a single air source  20  and passage  21 . To effect a plate or blanket change, guide piece  34  may be set in the outer sleeve  16  installation/removal position and air may be provided from air source  20  through passage  21 , axial cavity  50 , second radial holes  56 , second radial conduits  32  and radial bridge holes  58  to between the outer surface of bridge sleeve  14  and the inner surface of outer sleeve  16 . Outer sleeve  16 , which may be a tubular blanket or printing plate, is then slid off of bridge sleeve  14 . If a next print job requires a tubular blanket or printing plate of the same inner diameter as outer sleeve  16 , guide piece  34  is kept in the outer sleeve installation/removal position and a new outer sleeve is slid onto bridge sleeve  14  while air is provided to the outer surface of bridge sleeve  14 . If the next print job requires a tubular blanket or printing plate having a larger or smaller inner diameter than outer sleeve  16 , guide piece  34 , which is easily accessible to the operator because of its placement at the axial end of assembly  10  at work side  22 , is easily rotated into the bridge sleeve  14  installation/ removal position and bridge sleeve  14  is removed and replaced with a new bridge sleeve having a larger or smaller diameter than bridge sleeve  14  by sliding the new bridge sleeve onto mandrel  12  while air is provided from air source  20  through passage  21 , axial cavity  50 , first radial holes  54  and first radial conduits  30  to the outer surface of mandrel  12 . After the new bridge sleeve is mounted onto mandrel  12 , guide piece  34  is easily accessed and rotated back into the outer sleeve installation/removal position. Then, the new tubular blanket or printing plate that is of a larger or smaller diameter than outer sleeve  16  is slid onto the new bridge sleeve while air is provided to the outer surface of the new bridge sleeve. Accordingly, a simple rotational adjustment of guide piece  34  allows the press operator to switch between the outer sleeve and bridge sleeve installation/removal positions. 
         [0018]    In an alternative embodiment, an automatically controlled actuator may be coupled to at least one of guide piece  34  and mandrel  12  for rotating guide piece  34  based on instructions from a controller. 
         [0019]    In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.