Abstract:
A drive for a rotary printing press has a clutch with improved reliability in the main drive gear train. The drive has a gearwheel mechanism for transmitting a rotational movement of transfer drums during delivery of a printing material. The gearwheel mechanism includes a gearwheel pair with a driving gearwheel and a driven gearwheel and the driven gearwheel, which is arranged coaxially with respect to the driving gearwheel, is coupled during delivery to a shaft journal of a transfer drum. A clutch is provided for selectively producing and interrupting the transmission of torque between the driving gearwheel and the driven gearwheel. At least one motor is provided for feeding a torque into the gearwheel mechanism. A stepup gear mechanism is arranged in the torque flow between a clutch half of the clutch and a gearwheel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the priority, under 35 U.S.C. §119, of German patent application DE 10 2006 019 035.1, filed Apr. 25, 2006; the prior application is herewith incorporated by reference in its entirety.  
       BACKGROUND OF THE INVENTION  
     FIELD OF THE INVENTION  
       [0002]     The invention lies in the printing technology field. More specifically, the invention relates to a drive for a rotary printing press, having a gearwheel mechanism for transmitting a rotational movement of transfer drums during delivery of a printing material, the gearwheel mechanism comprising a gearwheel pair having a driving gearwheel and a driven gearwheel and the driven gearwheel which is arranged coaxially with respect to the driving gearwheel being coupled during delivery to a shaft journal of a transfer drum, having a clutch for producing and interrupting the transmission of torque between the driving gearwheel and the driven gearwheel, and having at least one motor for injecting a torque into the gearwheel mechanism.  
         [0003]     Sheet-fed printing presses having a plurality of printing units in an inline construction are known, in which the impression cylinders which convey sheets and the drums are driven by way of a gearwheel mechanism. The cylinders and drums are held rotatably in bearings in side walls by way of shaft journals. Gearwheels of the gearwheel mechanism are arranged fixedly in terms of rotation on the shaft journals. The gearwheels form a main drive gear train, into which a torque is fed by a motor during printing. The cylinders and drums have a defined rotary phase position during printing, with the result that the sheets which are held in grippers can be transferred in register from a cylinder or a drum to an adjacent drum which lies downstream or a cylinder.  
         [0004]     Sheet-fed printing presses are known, the operating type of which can be set optionally to printing on only one side or to printing on both sides of the sheets. In order to set printing on both sides, a turning apparatus is set in operation in the conveying path of the sheets. The rotary phase positions of the cylinders and drums differ during printing on only one side and in perfecter operation. Commonly assigned German published patent application DE 42 23 189 A1 and its counter-part U.S. Pat. No. 5,398,606 describe an apparatus which makes it possible to divide the main drive gear train and to set the rotary phase of the cylinders and drums in front of the turning apparatus to the desired operating type with respect to the rotary phase position of the cylinders and drums after the turning apparatus. The apparatus comprises a clutch which can disconnect a gearwheel from the shaft journal of a turner drum. The clutch is configured as a friction clutch, friction faces of the disconnectable gearwheel and a gearwheel which is connected fixedly in terms of rotation to the shaft journal being pressed against one another during printing by means of a spring assembly. The disconnectable gearwheel and the gearwheel which is connected fixedly in terms of rotation to the shaft journal are permanently in engagement with the gearwheels of an adjacent storage drum and an impression cylinder.  
         [0005]     The torques which can be transmitted in the main drive gear train are limited by the construction of the gearwheels, the connection to the shaft journals and by clutches. In particular, in the case of machines having a multiplicity of printing units and large sheet formats which are to be printed, static and dynamic torques occur which can lead to failure of the clutch. If the clutch fails, the rotary phase position of the printing units changes, with the result that printing errors are produced or, in the extreme case, grippers collide with drum elements.  
         [0006]     It is possible to design a clutch of a turning apparatus of a sheet-fed printing press for a maximum torque which is to be transmitted. According to the commonly assigned published German patent application DE 102 02 386 A1 and its counter-part U.S. Pat. No. 6,695,114, a multiple disk clutch has been equipped both with friction elements and also with form-fitting elements. Clutches which are dimensioned in this way require a large amount of installation space which is not available in every case.  
         [0007]     German patent DE 41 32 250 C2 (corresp. to U.S. Pat. No. 5,249,521) and German published patent application DE 198 43 066 A1 describe devices for changing over to recto printing or recto and verso printing on a sheet-fed printing press. In those devices the main drive gear train on a turner drum is divided by way of a clutch and phase setting is performed by way of an additional gear mechanism and an auxiliary drive. A planetary gearwheel mechanism, a bevel gearwheel mechanism or a differential gear mechanism serve as additional gear mechanism. The construction having an additional gear mechanism is expensive in terms of material and cost and requires a large amount of installation space.  
       SUMMARY OF THE INVENTION  
       [0008]     It is accordingly an object of the invention to provide a drive for a rotary printing press which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which further improves the reliability of the clutch in the main drive gear train.  
         [0009]     With the foregoing and other objects in view there is provided, in accordance with the invention, a drive for a rotary printing press, comprising: 
    a gearwheel mechanism for transmitting a rotational movement of transfer drums during delivery of a printing material, the gearwheel mechanism including a gearwheel pair with a driving gearwheel and a driven gearwheel, said driven gearwheel being disposed coaxially with respect to said driving gearwheel and being coupled to a shaft journal of a transfer drum during delivery of a printing material;     a clutch for producing and interrupting a transmission of torque between said driving gearwheel and said driven gearwheel, said clutch having a clutch half;     at least one motor for injecting a torque into said gearwheel mechanism; and     a stepup gear mechanism disposed within a torque flow between said clutch half and a respective said gearwheel.    
 
         [0014]     In other words, the invention provides for a clutch for selectively closing or interrupting a transmission of torque between a driving and a driven gearwheel in the drive gear train of a sheet-fed printing press, with a stepup gear mechanism being arranged in the torque flow between a clutch half of the clutch and a gearwheel. In particular, coaxial gear mechanism types, such as planetary gearwheel mechanisms, cycloidal gear mechanisms or harmonic drive mechanisms, can be used as stepup gear mechanisms. In a sheet-fed printing press having a turning apparatus, the clutch can exist between double gears which are arranged coaxially with respect to a turner drum.  
         [0015]     In comparison with the solutions according to the prior art, the torque which is to be transmitted by the clutch during printing is reduced, which is achieved by the transmission ratio of the stepup gear mechanism. In addition to the use of the transmission ratio, a plurality of clutches which act in parallel can be used. The elements of the drive can be arranged coaxially and within the circumferential contour of a double gearwheel, as a result of which a small amount of installation space is taken up.  
         [0016]     In accordance with an added feature of the invention, the stepup gear mechanism is at least one planetary gearwheel mechanism.  
         [0017]     In accordance with an additional feature of the invention, the driving gearwheel and said driven gearwheel are spur gears having an external toothing system with an equal radius, said driving gearwheel is rotatably mounted and said driven gearwheel is rotationally fixedly with said shaft journal; said driving gearwheel has an internal toothing system in addition to said external toothing system, and at least one planetary gear is in permanent engagement with said internal toothing and a sun gear that is rotatably mounted relative to said shaft journal; said planetary gear is mounted on a journal that is fixedly connected to said driven gearwheel in an axially parallel manner; and one said clutch half of said clutch is fixedly connected in terms of rotation to said planetary gear and another said clutch half is fixedly connected in terms of rotation and axially displaceably to a journal.  
         [0018]     In accordance with another feature of the invention, the driving gearwheel is rotatably mounted and said sun gear is rotationally fixed on a shaft that is rotatably mounted with respect to said shaft journal. Preferably, the shaft can be coupled to an adjusting drive.  
         [0019]     In accordance with a further feature of the invention, the driving gearwheel and said driven gearwheel are spur gears having an external toothing system with an equal radius; said driving gearwheel and said driven gearwheels are rotatably mounted on a shaft coaxially with respect to said shaft journal; said driven gearwheel has an internal toothing system in addition to said external toothing system, at least one planetary gear is in permanent engagement with said internal toothing system and a sun gear that is seated rotationally fixed on said shaft; said planetary gear is mounted on a journal fixedly connected to said driving gearwheel in an axially parallel manner; and one said clutch half of said clutch is fixedly connected in terms of rotation to said driving gearwheel and another said clutch half is fixedly connected in terms of rotation and axially displaceably to said shaft.  
         [0020]     In accordance with a concomitant feature of the invention, the clutch is a force or friction clutch that can be actuated by a pressure medium.  
         [0021]     Other features which are considered as characteristic for the invention are set forth in the appended claims.  
         [0022]     Although the invention is illustrated and described herein as embodied in drive for a rotary printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
         [0023]     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0024]      FIG. 1  is a diagram of a multi-color sheet-fed printing press having a turning apparatus;  
         [0025]      FIG. 2  shows a planetary gearwheel mechanism and a clutch in the torque flow between double gearwheels on a turner drum;  
         [0026]      FIG. 3  shows a planetary gearwheel mechanism and a clutch between double gearwheels with a possibility for phase adjustment on a sun gear;  
         [0027]      FIGS. 4 and 5  show pneumatic actuating apparatuses for a clutch between double gearwheels; and  
         [0028]      FIG. 6  shows a planetary gear mechanism and a clutch between a planetary gearwheel carrier and a sun gear. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     Referring now to the Figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a perfector printing press having eight printing units  1 - 8  and a varnishing unit  9  for printing on sheets  10 . In order to separate sheets  10  from a stack  11  and in order to convey them to the first printing unit  1 , there is provided a feeder  12  having a suction head  13 , a creeper table  14 , and swinging grippers  15 . In order to convey the sheets  10  through the printing press, transfer drums  16 - 49  are provided. The transfer drums  17 ,  21 ,  25 ,  29 ,  33 ,  37 ,  41 ,  45 ,  49  are configured as impression cylinders and interact with transfer cylinders  50 - 57 . The transfer cylinders  50 - 57  interact with form cylinders  58 - 65 . In the varnishing unit, the transfer drum  49  interacts directly with a form cylinder  66 . During the passage through a press nip between a transfer cylinder  50  to  57  and an impression cylinder  17 ,  21 ,  25 ,  29 ,  37 ,  41 ,  45 ,  49 , the sheets  10  are printed with a separated color. The separated color of a color separation is transferred by the respective form cylinder  58 - 65  onto a transfer cylinder  50 - 57 . The color separation is transferred by the respective transfer cylinder  50 - 57  onto a surface of a sheet  10 . In the varnishing unit, the sheets  10  are given in each case one terminating varnish coat on that side of a sheet  10  which was printed last. All transfer drums  16 - 49  which guide sheets  10  have gripper arrangements  67  for holding the sheets  10  at the front edge. The transfer drum  31  has additional gripper arrangements  68  for holding a sheet  10  at the rear edge. The transfer drums  16 - 49 , the transfer cylinders  50 - 57  and the form cylinders  58 - 66  are coupled to one another in a gearwheel mechanism. In order to drive the printing press, a motor  69  is provided which feeds a torque onto the shaft of the transfer drum  38  via a gear mechanism  70 . The sheets  10  which have been completely printed are conveyed onto a stack  73  in a delivery  71  by way of a chain gripper system  72 .  
         [0030]     The printing press can be changed over from printing on only one side of the sheets  10  to printing on both sides. In perfector operation, the printing units  1 - 4  serve to print onto the front side and the printing units  5 - 8  and the varnishing unit  9  serve to print onto the rear side of the sheets  10 . Between the printing units  4  and  5 , the transfer drums  31 ,  32  are configured as storage drum and turner drum. During printing on both sides, the phase positions of the gripper arrangements  67 ,  68  are set in such a way that the edge which trails in the printing units  1 - 4  is conveyed further as front edge from the printing unit  5 . In order to set the phase position, a clutch arrangement  74  which permits division of the gearwheel train of the gearwheel mechanism is provided at the turner drum  32 .  
         [0031]     The remote control clutch arrangement  74  is connected to a control device  75 . The phase setting is performed by way of the motor  69  or an additional adjusting motor on the transfer drum  31  and is monitored by way of a rotary encoder G on the shaft of the transfer drum  46  or the shaft of the transfer drum  17 . That part in the drive train which is not moved in each case during the phase setting is fixed so as not to rotate. The rotary encoder  76  and the motor  69  are likewise connected to the control device  75 .  
         [0032]     During printing operation, the clutch arrangement  74  is closed, with the result that, starting from the motor  69  via the clutch arrangement  74 , a torque is transmitted to the elements which are to be driven in the printing units  1 - 4 .  
         [0033]     In the following text, exemplary embodiments for clutch arrangements  74  are to be described using FIGS.  2  to  6 . If designations which have already been introduced are used in the following description, they relate to elements with an equivalent function.  
         [0034]      FIG. 2  shows, in a section transversely through the printing unit  5 , the turner drum  32  which is held by way of a shaft journal  77  in a bearing  78  of a side wall  79  of the sheet-fed printing press, such that it can rotate about the shaft axle  80 . Gearwheels  81 ,  82  which are arranged coaxially with respect to the axle  80  and have the same radius R 1  serve to drive the turner drum  32 . The gearwheel  82  is connected fixedly to the shaft journal  77 . The gearwheel  82  is coupled by means of a spring  83  to a shaft  84  which is arranged coaxially with respect to the axle  80 . Journals  86  are fastened to that end face  85  of the gearwheel  82  which faces the gearwheel  81 , at a spacing R 2  from and parallel to the axle  80 . A first half  88  of the clutch  77  is arranged fixedly in terms of rotation on each journal  86  by way of a spring  87 . A second half  89  of the clutch  74  is connected to a planetary gear  90  which is held rotatably in bearings  91 ,  92  on the journal  86 . In addition to an external toothing system on the radius R 1 , the gearwheel  81  has an internal toothing system on a radius R 3 . The gearwheel  81  is arranged rotatably in bearings  93 ,  94  on the shaft  84 . The external toothing system of the planetary gear  90  is in engagement with the internal toothing system of the gearwheel  81 . Furthermore, the planetary gear  90  is in engagement with a sun gear  95  which is arranged rotatably in bearings  96 ,  97  on the shaft  84 .  
         [0035]     The planetary gear  90  can be connected rigidly in terms of rotation to the journal  86  in each case by way of a clutch  74 . This affords the advantage that the torque which is to be transmitted at the clutch  74  is additionally reduced in a multiplied manner by the transmission ratio in the planetary gearwheel mechanism and by the number n of planetary gears  90 . The torque M K  which acts at the clutch  74  results from 
 
 n*M   K   =M   setp   *R 4/ R 2, 
 
 wherein M setp  is the overall torque which is to be transmitted and R 4  is the radius of the planetary gear  90 . The smaller the radius R 4  of a planetary gear  90  is designed to be, the lower the torque which is to be transmitted via a clutch  74 . 
 
         [0036]     In printing operation, the clutches  74  are closed, with the result that there is a rotatable connection between the gearwheels  81 ,  82  without a transmission ratio. In order to set the phase position, the clutches  74  are released and the driven gearwheel  82  or a gearwheel which is connected to the gearwheel  82  is fixed in position. The rotary position of the driving gearwheel  81  and the elements which are connected to it can therefore be adjusted in an infinitely variable manner relative to the driven gearwheel  82 .  
         [0037]     In one variant according to  FIG. 3 , the driving gearwheel  81  and the sun gear  95  are arranged coaxially with respect to a sleeve  98  which is held rotatably in bearings  99 ,  100  on a shoulder of the shaft  84 . The sun gear  95  is connected fixedly in terms of rotation to the sleeve  98  by means of a spring  101 . The gearwheel  81  is arranged rotatably on the sleeve  98  by way of bearings  102 , 103 . All further details correspond to the details which are described with respect to  FIG. 2 .  
         [0038]     In order to adjust the phase of the gearwheel  81  including the elements which are connected to it, the sleeve  98  can be coupled to a drive. If the sleeve  98  is rotated about the axle  80  when the clutches  74  are open, the sun gear  95  is corotated and a transmission ratio i=1+Z I /Z S  acts on the gearwheel  82 , wherein Z I  and Z S  are in each case the number of teeth of the internal toothing system of the gearwheel  81  and that of the sun gear  95 . The transmission ratio i reduces the required adjusting moment and increases the sensitivity of the changeover.  
         [0039]      FIGS. 4 and 5  show various possibilities for actuating the clutch  74 . The clutches  74  are configured as friction clutches having disks  104 . During printing, the clutches  74  are closed by means of spring elements  105  in an operationally reliable manner. In order to release the clutches  74 , pneumatic elements, by way of example, are provided. As an alternative, hydraulic elements can also be used to release the clutches.  
         [0040]     According to  FIG. 4 , the clutch halves  88  of the clutches  74  are coupled to an annular piston  106 . The annular piston  106  interacts with a working cylinder  107 . A ventilation bore  108  leads radially and in the direction of the axle  80  through the gearwheel  82  and the shaft  84  from the working cylinder  107 . The ventilation bore  108  leads to a compressed air unit  109 . During phase setting, all actuating elements of the clutches  74  are situated in fixed parts in the drive gear train, as a result of which the clutch halves  88 ,  89  can be released from one another from outside by way of the working cylinder  107  being loaded with pressure.  
         [0041]     In the variant according to  FIG. 5 , a working cylinder  110 ,  111  having a piston  112 ,  113  is assigned to each clutch  74  for actuation. The working cylinders  110 ,  111  are connected to a common line  114 . The actuating energy is fed to the working cylinders  110 ,  111  from a compressed air unit  109  via a ventilation bore  108 . The pistons  112 ,  113  are coupled in each case to the clutch half  88  which is arranged fixedly in terms of rotation on the journal  86 .  
         [0042]      FIG. 6  shows a further variant for a drive of a sheet-fed rotary printing press. A driven gearwheel  82  of a turner drum  32  is held by way of bearings  114 ,  115  rotatably on a shaft  84  which is arranged coaxially with respect to the axle  80  of the turner drum  32 . Furthermore, a second gearwheel  81  is held rotatably on the shaft  84  by way of bearings  93 ,  94 . The gearwheels  81 ,  82  have the same radius R 1 . Journals  116  which lie parallel to the axle  80  are fastened to the gearwheel  81  at a spacing R 2 . The journals  116  carry planetary gears  117  which are rotatable by way of bearings  118 ,  119 . The gearwheel  82  has an internal toothing system with the radius R 3 . The planetary gears  117  are in engagement with the internal toothing system and a sun gear  120  with the radius R 4 . The sun gear  120  is connected fixedly in terms of rotation to the shaft  84  by way of a spring  121 . A half  122  of the multiple disk clutch  74  is fastened on that side of the gearwheel  81  which faces the gearwheel  82 . The associated second half  123  is arranged fixedly in terms of rotation on the shaft  84  by way of a spring  124 .  
         [0043]     During printing, the clutch  74  is closed, with the result that the gearwheel  81  is connected rigidly in terms of rotation to the sun gear  120 . A torque M K  acts on the clutch  74  as a result of a transmission ratio in the planetary gearwheel mechanism, where 
 
 M   K   =M   setp   *R 4/ R 3. 
 
         [0044]     M setp  is the torque which is fed by the driving gearwheel  81  from the drive gear train. The smaller the radius R 4  of the sun gear  120  is selected to be, the lower the torque M K  which is to be transmitted.  
         [0045]     During the setting of the phase of the turning apparatus, the clutch  74  is released and the gearwheel  82  and the elements which are connected to it in the drive gear train are fixed in position. The gearwheel  81  and the elements of the drive gear train which are connected to it can therefore be adjusted relative to the gearwheel  82  in an infinitely variable manner by way of the motor  89  or an auxiliary motor.  
         [0046]     As an alternative to the adjustment on the side of the gearwheel  81 , an adjustment can take place by rotation of the sun gear  120 . Here, a transmission ratio i is active, where 
 
 i= 1 +Z   I   /Z   S , 
 
 wherein Z I  and Z S  are the numbers of teeth of the internal toothing system of the gearwheel  82  and of the sun gear  120 . The transmission ratio i reduces the required adjusting torque and increases the sensitivity of the changeover. If an adjustment is provided on the sun gear  120 , a form-fitting clutch  74  is also possible because, as a result of the transmission ratio i, a sufficiently high rotary angle resolution is ensured for an adjustment of the turning apparatus to a defined sheet format.