Printing plates lifting apparatus having storing function
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a printing plates lifting apparatus in a rotary press having upper and lower press units requiring a printing plate and arranged in tiers, an upper work floor corresponding to the upper press unit and a lower work floor corresponding to the lower press unit, for transferring unused and used printing plates between the two work floors and temporarily storing the printing plates. 
     2. Description of the Prior Art 
     Prior-art apparatus for transferring printing plates toward a printing machine are described, for example, in Japanese Patent Application Laid-Open Nos. 59-165659 and 60-52343. These apparatus comprise a conveying apparatus located between a plate making room and the vicinity of a printing machine for conveying prepared printing plates to the vicinity of the printing machine. 
     Prior-art apparatus for vertically transferring printing plates are described, for example, in Japanese Patent Application Laid-Open Publication No. 2-26584 and Japanese Utility Model Application Laid-Open Publication No. 5-1395. These apparatus are usually located in a plate making room for automatically loading prepared printing plates onto the conveying apparatus described in Japanese Patent Application Laid-Open Nos. 59-165659 and 60-52343. 
     The prior-art apparatus described in Japanese Patent Application Laid-Open Nos. 59-165659 and 60-52343 are for conveying printing plates to the vicinity of a printing machine located therewith on the same floor level and are not intended to convey printing plates to the upper press unit of a rotary press having upper and lower press units arranged in tiers. The prior-art apparatus, therefore, are unable to carry out such conveyance to the upper press unit and to store printing plates. 
     According to the prior-art apparatus described in Japanese Patent Application Laid-Open Publication No. 2-26584 and Japanese Utility Model Application Laid-Open Publication No. 5-1395, prepared printing plates transferred to a predetermined position are transferred one by one to a predetermined position where the printing plate is unloaded from vertically transferring means and then loaded onto a conveying apparatus for conveyance to the vicinity of a printing machine. The prior-art apparatus, therefore, are unable to convey printing plates to a press unit and to store printing plates. 
     Accordingly, it is necessary for a worker to bring up/down a printing plate to be used on an upper press unit and a printing plate having been used on the upper press unit. This labor of bringing a printing plate up and down between upper and lower work floors is quite wasteful, and going up and down the stairs with a printing plate is a problem in terms of the work efficiency and the safety of labor. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to solve the above-mentioned problems. 
     According to the present invention, there is provided a printing plates lifting apparatus having storing function in a rotary press having upper and lower press units arranged in tiers and upper and lower work floors corresponding to the press units, comprising upper rotating bodies located higher than the top surface of the upper work floor and supported rotatably, lower rotating bodies located higher than the top surface of the lower work floor by more than the length of a printing plate and opposed each other at a spacing greater than the width of the printing plate, opposed endless flexible bodies which are engaged with the vertically opposed upper and lower rotating bodies, driving means for rotating the rotating bodies to run the endless flexible bodies in a circulating fashion, and printing plate hanging members extending between the opposed endless flexible bodies and arranged vertically along the opposed endless flexible bodies at a spacing greater than the length of the printing plate, which upper rotating bodies are rotatably supported on shafts which are mounted such that the opposed ends thereof are spaced greater than the width of the printing plate. 
     When a worker starts a drive source on the upper or lower work floor for hanging the printing plate on the printing plates lifting apparatus, either lower or upper rotating shafts are rotatively driven. Accordingly, rotating bodies of the rotating shafts cause the endless flexible bodies to run in a circulatory fashion, and consequently, printing plate hanging members circulate up and down. When an appropriate empty printing plate hanging member reaches an appropriate position, the worker stops the drive source to stop the empty printing plate hanging member in the position. The worker hangs a desired printing plate on the empty printing plate hanging member. Thus, the printing plate PP is hung on the printing plates lifting apparatus PL. 
     For repeatedly hang the printing plate on the printing plates lifting apparatus, the above-mentioned operation is repeated. 
     In the printing plates lifting apparatus, a printing plates is hung on each of printing plate hanging members arranged along the endless flexible bodies in front and rear columns; thus, a plurality of printing plates are stored hung from printing plate hanging members. 
     Likewise, for removing a desired printing plate from the printing plates lifting apparatus on the upper or lower work floor, a worker first starts the drive source, as in the case of hanging a printing plate, for vertically circulating printing plate hanging members, i.e. stored printing plates. When a printing plate hanging member carrying a desired printing plate reaches an appropriate position, the worker stops the drive source for stopping the printing plate hanging member in the position. Then, the worker removes the printing plate from the printing plate hanging member. 
     Thus, the desired printing plate is removed from among a plurality of printing plates stored on the printing plates lifting apparatus in the front and rear columns. As in the case of hanging a printing plate, the work of removing a printing plate is repeated as needed. 
     In connection with the vertical circulation of printing plates on the printing plates lifting apparatus, there is formed a printing plate hanging zone slightly longer than the length of a printing plate between the rotating shafts and the top floor of the lower work floor, and also the spacing between printing plate hanging members forms a printing plate hanging zone slightly longer than the length of a printing plate. Accordingly, printing plate hanging members are able to pass upper and lower limit positions in a circulatory fashion without any interruption even when a printing plate is hung therefrom. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevation showing a printing plates lifting apparatus having storing function according to an embodiment of the present invention; 
     FIG. 2 is a side elevation showing a printing plates lifting apparatus having storing function according to an embodiment of the present invention; 
     FIG. 3 is an enlarged view showing the essential portions of a printing plates lifting apparatus having storing function according to an embodiment of the present invention; 
     FIG. 4 is an enlarged view showing a different type of the essential portions of a printing plates lifting apparatus having storing function according to an embodiment of the present invention; and 
     FIG. 5 is a perspective view showing a printing plate to be stored on a printing plates lifting apparatus having storing function according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A press plates lifting apparatus having a press plates storing function according to an embodiment of the present invention will hereinafter be described with reference to the drawings. 
     As shown in FIGS. 1 and 2, in the printing plates lifting apparatus PL located along the height of a rotary press RP comprising upper and lower press units arranged in tiers, there is provided two posts 1a and 1b standing upright from a lower work floor F1, passing the vicinity of an upper work floor F2 and extending above the upper work floor, which two posts are spaced greater than the width of a printing plate PP to be used on the press units. The posts 1a and 1b are preferably secured to the upper work floor and the like at the intermediate and top end portions thereof. 
     Both end portions of a through-shaft 2 are rotatably supported on the posts 1a and 1b, respectively. Lower sprocket wheels 3a and 3b of the same specification are spaced slightly greater than the width of the printing plate PP and mounted on the through-shaft 2 so as to rotate therewith as a unit. Also, upper sprocket wheels 5a and 5b are opposed each other at the same level near the top ends of the poles 1a and 1b and rotatably supported on short shafts 4a and 4b, respectively, which short shafts are mounted such that the opposed ends thereof are spaced greater than the width of the printing plate PP. The spacing between the upper sprocket wheels 5a and 5b is identical to that between the lower sprocket wheels 3a and 3b. The endless chain 6a, 6b is engaged with vertically opposed upper sprocket wheel 5a, 5b and lower sprocket wheel 3a, 3b, respectively. 
     A follower sprocket wheel 7A is mounted on the through-shaft 2 outside the lower sprocket wheel 3a so as to rotate therewith as a unit. An endless chain 7D is engaged with a driving sprocket wheel 7C mounted on the output shaft of a drive source located underneath, such as a geared motor 7B equipped with a brake, and with the follower sprocket wheel 7A mounted on the through-shaft 2, thereby constructing driving means 7. 
     Press plate hanging members 8, 8, . . . are mounted between the endless chains 6a and 6b and spaced slightly greater than the length of the printing plate PP along the endless chains. 
     In an embodiment shown in FIGS. 1 and 2, a linking pitch 6Pa, 6Pb of a link 61a, 61b of the endless chain 6a, 6b is double the linking pitch of ordinary chains (for example, BI-PITCH CHAIN (trademark) is a chain of such double-pitch type). A through-bar 8a of the printing plate hanging member 8 is rotatably supported on opposed links 61a and 61b at the intermediate portion thereof, and the axial displacement of the through-bar is prevented with a pin 8d (e.g. split pin). In place of the through-bar 8a, used may be opposed short bars 8b and 8c which are mounted such that the base ends thereof are rotatably supported on the opposed links 61a and 61b at the intermediate portion of the links as for both ends of the through-bar 8a, the opposed ends thereof are spaced smaller than the width of the printing plate PP, and the axial displacement thereof is prevented with the pin 8d (e.g. split pin). The short bars 8b and 8c may be unequal in length. A retaining ring may be used as means for preventing the axial displacement of the through-bar 8a and the short bars 8b and 8c. 
     Preferably, as shown in FIGS. 3 and 4, a drop preventing member 9 is fit onto one end of the through-bar 8a and/or either of the short bars 8b and 8c (the short bar 8b in the illustrated example). An elastic nail-like holder 9a is formed on the drop preventing member 9. To maintain the elastic nail-like holder 9a in such an angular position in the rotating direction as to readily hold a printing plate, a weight 9c is mounted on the drop preventing member 9 through an arm portion 9b projecting in an appropriate angular direction. 
     When the through-bar 8a and the short bars 8b and 8c are of a round bar or a near-round polygonal section bar, the through-bar 8a and the short bars 8b and 8c may be supported on the links 61a and 61b in a nonrotatable fashion. If the bars are supported in a nonrotatable fashion, the drop preventing member 9 will not be provided. 
     Operation switches SW1 and SW2 are located on the printing plates lifting apparatus PL (e.g. the post 1a or 1b) or in the vicinity thereof so that a worker can start/stop the geared motor 7B equipped with a brake on the lower work floor F1 and the upper work floor F2, respectively, using the switches. 
     Actions of the above-mentioned printing plates lifting apparatus will hereinafter be described. 
     When a worker wants to hang the printing plate PP on the printing plate lifting apparatus PL on the lower work floor F1, the worker first operates the operation switch SW1 to start the geared motor 7B equipped with a brake. When the motor is started, the through-shaft 2 is rotatively driven (e.g. clockwise in FIG. 2) through the driving sprocket wheel 7C, the endless chain 7D and the follower sprocket wheel 7A. Then, the endless chains 6a and 6b run in a circulatory fashion through the lower sprockets 3a and 3b, thereby vertically circulating the printing plate hanging members 8, 8, . . . . When an appropriate empty printing plate hanging member 8 reaches an appropriate position, the worker operates the operation switch SW1 to stop the geared motor 7B equipped with a brake, thereby stopping the empty printing plate hanging member 8 in the position. 
     Next, the worker manually hangs the printing plate PP on the empty printing plate hanging member 8. In the illustrated example, a bend portion PP1 formed by bending the edge of the printing plate across the width thereof is hung on the through-bar 8a or the short bars 8b and 8c. When the drop preventing member 9 is provided, a weight 9c thereof maintains the rotative through-bar 8a or the short bar 8b in such an angular position in the rotating direction that the elastic nail-like holder 9a is held in a predetermined position (e.g. top position). The worker slides the printing plate PP toward the drop preventing member 9 to retain one corner portion thereof under the elastic nail-like holder 9a of the drop preventing member 9. 
     Thus, the printing plate PP is hung on the printing plates lifting apparatus PL. 
     For repeatedly hanging the printing plate PP on the printing plates lifting apparatus PL, the worker repeats the above-mentioned operation. As a result, the printing plate PP is hung on each of the printing plate hanging members 8, 8, . . . (eight members in the illustrated example) arranged in the front and rear columns along the endless chains 6a and 6b, thereby hanging eight printing plates PP for storage. 
     When the worker wants to remove the printing plate PP from the printing plate lifting apparatus PL on the lower work floor F1, the worker first operates the operation switch SW1 to start the geared motor 7B equipped with a brake as in the case of hanging the printing plate. When the motor is started, the printing plate hanging members 8, 8, . . . , i.e. the printing plates PP, PP, . . . are circulated vertically. When the printing plate hanging member with a desired printing plate PP hanging therefrom reaches an appropriate position, the worker operates the operation switch SW1 to stop the geared motor 7B equipped with a brake, thereby stopping the printing plate hanging member 8 in the position. 
     Next, the worker detaches the bend portion PP1 of the printing plate PP from the through-bar 8a or the short bars 8b, 8c, thereby removing the printing plate PP from the printing plate hanging member 8, i.e. from the printing plates lifting apparatus PL. When the drop preventing member 9 is provided, the worker slides the printing plate PP laterally to move the printing plate away from the drop preventing member 9, thereby detaching the corner portion of the printing plate from the elastic nail-like holder 9a of the drop preventing member 9. Then, the worker detaches the bend portion PP1 of the printing plate PP from the through-bar 8a or the short bars 8b and 8c to remove the printing plate PP from the printing plates lifting apparatus. 
     Thus, the desired printing plate PP has been removed from among a plurality of printing plates PP (eight printing plates in the illustrated example) stored on the printing plates lifting apparatus PL in the front and rear columns. 
     As in the case of the hanging work, the above-mentioned removing work is repeated as needed. 
     In connection with the vertical circulation of the printing plates PP, PP, . . . on the printing plates lifting apparatus PL, there is formed a printing plate hanging zone slightly longer than the length of the printing plate PP between the through-shaft 2 and the top floor of the lower work floor F1, and also the spacing of the printing plate hanging members 8, 8, . . . forms a printing plate hanging zone slightly longer than the length of the printing plate PP. Also, the upper sprocket wheels 5a and 5b are rotatably supported on the short shafts 4a and 4b, respectively, which short shafts are mounted such that the opposed ends thereof are spaced greater than the width of the printing plate PP. Hence, even when the printing plate PP is hung from the printing plate hanging members 8, 8, . . . , the printing plate hanging members can pass the position of the lower sprocket wheels 3a and 3b and the position of the upper sprocket wheels 5a and 5b without any interruption. 
     When the worker wants to hang the printing plate PP on or remove from the printing plates lifting apparatus PL on the upper work floor F2, the worker operates the operation switch SW2 in place of the operation switch SW1 and carries out the same work as that on the lower work floor F1. 
     When work is carried out in parallel on both the lower work floor F1 and the upper work floor F2, the workers on both floors need to cooperate with each other to secure safety. For securing safety in such parallel work, for example, it will be effective to provide each of the operation switches SW1 and SW2 with a safety circuit to lock the operation of the geared motor 7B equipped with a brake. 
     A printing plates lifting apparatus having storing function of the present invention in a rotary press having upper and lower printing units arranged in tiers allows an appropriate number of printing plates to be stored and lifted up and down in the stored state. Accordingly, printing plates used on the upper printing unit can be stored in sequence, and also a desired printing plate can be selected and removed from among stored unused printing plates for use on the upper printing unit. 
     Hence, it is not necessary for a worker to bring down a printing plate used on the upper printing unit from the upper work floor to the lower work floor or to bring up a printing plate for use on the upper printing units from the lower work floor to the upper work floor, thereby improving the work efficiency and the safety of labor.