Abstract:
A device for changing an operating state of a gripper-control device in a sheet-reversing device of a sheet-processing machine including a cylinder having an actuating shaft accommodated therein, includes an activating element cooperatively engaging with the actuating shaft for changing the operating state of the gripper control device. An actuating element is coupled mechanically with the actuating shaft. An adjusting element is movable relative to the cylinder. The adjusting element is disposed externally to the cylinder and cooperatively engages with the actuating element for moving the actuating element at least approximately synchronously with the cylinder during operation of the sheet-processing machine while the actuating shaft remains in a prescribed position with respect to the cylinder. The actuating element is changeable in position relative to the cylinder by the adjusting element, whenever the operating state is changed. A sheet-processing machine is provided with the operating-state changing device.

Description:
BACKGROUND OF THE INVENTION  
       FIELD OF THE INVENTION  
         [0001]    The invention relates to a device for changing the operating state of a gripper-control device in a sheet-reversing device of a sheet-processing machine. The invention also relates to a sheet-processing machine having the operating state changing device.  
           [0002]    In sheet-fed rotary printing machines, paper sheets which are to be printed are removed from a sheet pile and transported through individual printing units of the printing machine with the aid of grippers, which are accommodated on cylinders of the printing machine. In order to allow the sheets to be printed both on the upper side and on the underside thereof, sheet-fed printing machines are provided, in a heretofore known manner, with reversing or turning devices which are disposed, for example in the form of a reversing or turning drum, between two printing units of the printing machine. The reversing drum, in that regard, has a plurality of suction grippers by which the sheets that have been printed on one side and are guided on an upstream impression cylinder, are gripped at a trailing edge thereof, lifted from the circumferential surface of the impression cylinder and transferred to one or more pincer grippers or reversing grippers disposed in the interior of the reversing drum, and transfer the trailing sheet edge as a new leading edge to the gripper device of the impression cylinder of a downstream printing unit, wherein the sheet is printed on the reverse side thereof.  
           [0003]    In the case of the aforedescribed reversing or turning device, in order to switch over or convert between the operating state of single-side printing, wherein the sheets are printed on one side, and the operating state of first form and perfecter printing, wherein each of the sheets is printed on both sides thereof, it is necessary to activate reversing or turning grippers and/or suction grippers gripping the trailing sheet edge. That is accomplished, in a conventional manner, by actuating shafts which cooperate with activating elements by which the cam followers of the gripper-control devices, that are fixed by the activating elements during single-side printing, are released in order to activate the grippers. As a result, during the subsequent first-form and perfecting operation, the grippers are activated via the cam followers running along the associated gripper-control cams. In order to ensure further that, during the changeover between the operation of single-side printing and the first-form and perfecter printing operation, the gripper devices are located in the correct position for gripping the trailing sheet edge, with the heretofore known reversing or turning devices, the gear train for driving the cylinders disposed upstream of the reversing or turning device is coupled via a clamping coupling, which is disposed on the reversing or turning device, to the gear train for driving the cylinders which are disposed downstream of the reversing or turning device. In order to perform the changeover or conversion between the single-side printing operation and the first-form and perfecter printing operation, the coupling therein is opened and the gear train of the downstream printing units are rotated in relation to the gear train of the upstream printing units until such time as the gripper devices have assumed the correct position for the respective sheet format. The coupling is then closed, and printing is continued in the newly set operating state.  
           [0004]    German Patent DE 39 11 609 C2, corresponding to U.S. Pat. No. 5,076,164, discloses, in that context, the performance of activating and deactivating the gripper devices for gripping the trailing sheet edge in a reversing or turning operation with the aid of an actuating shaft which acts, via an activating element, on the gripper shaft in order to secure the latter and/or which, via a correspondingly configured activating element, brings the cam follower into engagement with differently configured gripper-control cams in order to open and close the gripper device. In the described device, the coupling for disconnecting the gear trains is disposed directly on the side of the reversing or turning drum and, as is generally customary, is formed by a fixed gearwheel, which is disposed coaxially with the reversing or turning drum and fastened on the latter, and an adjusting gearwheel, which has an annular construction, extending coaxially with the fixed gearwheel and, in order to close the coupling, is pressed axially against the side wall of the fixed gearwheel by a pressure-exerting element. In order to achieve automatic adjustment of the gripper device during format adjustment or when the operating state is changed, the actuating shaft, in the described device, is guided through a slot formed in the pressure-exerting element and is rotated via an adjusting element in the form of a toothed segment, which cooperates in a complex manner with the adjusting gearwheel, as well as a pinion, which is coupled to the actuating shaft. Apart from the mechanically very complex mechanism, the described device is beset by the problem that the strength or rigidity of the pressure-exerting element is vastly reduced as a consequence of forming the slot in the actuating shaft. Moreover, it is not possible, with the described device, for the actuating shaft to be disposed on a cylinder which is not provided with a coupling for disconnecting the gear trains.  
           [0005]    Furthermore, it has become known heretofore from German Patent DE 42 31 257 C2, corresponding to U.S. Pat. No. 5,365,846, to provide two cylinders in a reversing or turning drum of a sheet-fed rotary printing machine, which are coupled with one another drivewise via intermediate gearwheels revolving at an increased speed. In that regard, one of the intermediate gearwheels is constructed as a double intermediate gearwheel with two coaxially disposed individual gearwheels. One of the gearwheels engages with the driving gearwheel of a downstream printing unit, and the other engages with the gear train of the upstream printing units.  
         SUMMARY OF THE INVENTION  
         [0006]    It is accordingly an object of the invention to provide a device for changing the operating state of a gripper-control device in a sheet-reversing or sheet-turning device of a sheet-processing machine and a sheet-processing machine having the operating state changing device, in which the operating state changing device has a straightforward construction and which, when the operating state of the printing machine is changed, in particular during the switchover or conversion between a single-side printing operation and a first-form and perfecter printing operation, allows the operating state of the gripper-control device to be changed automatically.  
           [0007]    With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for changing the operating state of a gripper-control device in a sheet-reversing device of a sheet-processing machine. The sheet-reversing device includes a cylinder having an actuating shaft accommodated therein and the operating state changing device comprises an activating element cooperatively engaging with the actuating shaft for changing the operating state of the gripper control device. An actuating element is coupled mechanically with the actuating shaft. An adjusting element which is movable relative to the cylinder is disposed externally to the cylinder and cooperatively engages with the actuating element for moving the actuating element at least approximately synchronously with the cylinder during operation of the sheet-processing machine while the actuating shaft remains in a prescribed position with respect to the cylinder. The adjusting element serves for changing the position of the actuating element relative to the cylinder whenever the operating state is changed.  
           [0008]    In accordance with another feature of the invention, the actuating shaft is rotatably mounted coaxially with the axis of rotation of the cylinder. The actuating element and the adjusting element are respectively formed by a first and a second mutually meshing gearwheel. The first gearwheel is connected to the actuating shaft, and the second gearwheel is in drive connection with a further cylinder of the sheet-processing machine.  
           [0009]    In accordance with a further feature of the invention, the second gearwheel is disposed coaxially with the further cylinder and is connected thereto so as to be fixed against rotation relative thereto.  
           [0010]    In accordance with an added feature of the invention, the first gearwheel and the second gearwheel are disposed on the operator side of the sheet-processing machine.  
           [0011]    In accordance with an additional feature of the invention, the first-mentioned cylinder and the further cylinder are coupled with one another via a gear train having a double gearwheel including a fixed gearwheel in drive connection with the further cylinder, and an adjusting gearwheel coupled with the fixed gearwheel for forming a coupling. The coupling, when open, is rotatable relative to the fixed gearwheel for changing the mode of operation and/or adapting to different sheet formats.  
           [0012]    In accordance with yet another feature of the invention, the fixed gearwheel is disposed coaxially with the further cylinder and is connected thereto so as to be fixed against rotation relative thereto. The second gearwheel is disposed coaxially with the fixed gearwheel and is connected thereto so as to be fixed against rotation relative thereto.  
           [0013]    In accordance with yet a further feature of the invention, the double gearwheel is constructed as a double intermediate gearwheel revolvable at a greater speed than that of the cylinder. The double intermediate gearwheel is in drive connection with a driving gearwheel of the further cylinder via a further intermediate gearwheel. The second gearwheel is disposed coaxially with the fixed gearwheel of the double intermediate gearwheel and is connected thereto so as to be fixed against rotation relative thereto.  
           [0014]    In accordance with yet an added feature of the invention, the actuating shaft is rotatably mounted coaxially with the axis of rotation of the cylinder. A tensioning gear mechanism includes the actuating element and the adjusting element. The actuating shaft is drivable via the tensioning gear mechanism by a further cylinder of the printing machine. The actuating element is formed by a first belt pulley connected to the actuating shaft or a first chain wheel. The adjusting element is formed by a second belt pulley that is in drive connection with the second cylinder or a second chain wheel.  
           [0015]    In accordance with yet an additional feature of the invention, the one of the second belt pulley and the second chain wheel is disposed coaxially with a cylinder disposed directly upstream of the further cylinder and is connected thereto so as to be fixed against rotation relative thereto.  
           [0016]    In accordance with still another feature of the invention, the tensioning gear mechanism is disposed on the operator side of the sheet-processing machine.  
           [0017]    In accordance with still a further feature of the invention, the first-mentioned cylinder and the further cylinder are coupled with one another via a gear train having a double gearwheel including a fixed gear wheel in drive connection with the further cylinder and an adjusting gearwheel coupled with the fixed gearwheel for forming a coupling. The coupling, when open, is rotatable with respect to the fixed gearwheel for changing the operating mode or the adaptation to different sheet formats. The double gearwheel is constructed as a double intermediate gearwheel revolvable at a greater speed than that of the first-mentioned cylinder and is in drive connection with the driving gearwheel of the further cylinder via a further intermediate gearwheel. The second belt pulley or the second chain wheel is disposed coaxially with the further intermediate gearwheel and is connected thereto so as to be fixed against rotation relative thereto.  
           [0018]    In accordance with still an added feature of the invention, changing the operating state of the gripper control device constitutes switching the gripper-control device over between single-side printing and first form and perfecter printing. The actuating shaft is supported relative to the cylinder via a thread for producing an axial movement of the actuating shaft when the actuating shaft is rotated relative to the cylinder. The activating element includes a lever for transmitting the axial movement of the actuating shaft to the gripper-control device to switch the gripper-control device over between single-side printing or first form and perfecter printing operating states. The gripper-control device is adapted for different sheet formats.  
           [0019]    In accordance with still an additional feature of the invention, the cylinder is the reversing drum of the sheet-reversing device.  
           [0020]    In accordance with another feature of the invention, the further cylinder is an impression cylinder of the sheet-processing machine. The impression cylinder is disposed upstream of the sheet-reversing device.  
           [0021]    In accordance with a further feature of the invention, the adjusting element is in permanent engagement with the actuating element.  
           [0022]    In accordance with an added feature of the invention, changing the operating state of the gripper control device constitutes switching the gripper-control device over between single-side printing and first form and perfecter printing.  
           [0023]    With the objects of the invention in view, there is also provided a sheet-processing machine, comprising a device for changing the operating state of a gripper-control device in a sheet-reversing device of the sheet-processing machine. The sheet-reversing device includes a cylinder having an actuating shaft accommodated therein and the operating state changing device includes an activating element cooperatively engaging with the actuating shaft for changing the operating state of the gripper control device. An actuating element which is coupled mechanically with the actuating shaft is movable relative to the cylinder. The adjusting element is disposed externally to the cylinder and cooperatively engages with the actuating element for moving the actuating element at least approximately synchronously with the cylinder during operation of the sheet-processing machine while the actuating shaft remains in a prescribed position with respect to the cylinder. The adjusting element serves for changing the position of the actuating element relative to the cylinder whenever the operating state is changed.  
           [0024]    In accordance with a concomitant feature of the invention, the sheet-fed processing machine is a sheet-fed rotary printing press.  
           [0025]    The operating-state changing device according to the invention offers the advantage that the coupling for the purpose of decoupling the gear train of the printing unit disposed upstream of the reversing or turning device from the gear train of the printing units disposed downstream of the reversing or turning device need not necessarily be disposed on the reversing or turning drum in order to allow an automatic changeover, advancement or withdrawal of the gripper-control device when one gear train is rotated in relation to the other gear train.  
           [0026]    Furthermore, the operating-state changing device according to the invention offers the advantage that it is very compact and is constructed from only a small number of components which are relatively simple and cost-effective to produce. Furthermore, there is no need for any additional couplings or individual clamping devices in the reversing or turning drum, as are necessary, for example, in the case of corresponding devices of the prior art.  
           [0027]    Additionally, due to the numerous possible variations upon which the principle according to the invention is based, the operating-state changing device according to the invention is able to be adapted optimally to the installation space that is available and to other conditions in a sheet-processing machine. It is thus possible, for example, in the case of the actuating shaft being driven via a tensioning gear mechanism, for the installation space available in the region of the reversing or turning drum to be filled with other components, for example with components of a coupling for decoupling the gear train during format changeover.  
           [0028]    Other features which are considered as characteristic for the invention are set forth in the appended claims.  
           [0029]    Although the invention is illustrated and described herein as embodied in a device for changing the operating state of a gripper-control device in a sheet-reversing device of a sheet-processing machine and a sheet-processing machine having the operating state changing device, 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.  
           [0030]    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 DRAWINGS  
       [0031]    [0031]FIG. 1 is a diagrammatic, plan view, partly in section, of a first embodiment of the invention, wherein an actuating shaft is driven via a meshing gear mechanism including a first gearwheel fastened to the actuating shaft, and a second gearwheel fastened to a fixed gearwheel of a coupling for disconnecting gear trains during format changeover;  
         [0032]    [0032]FIG. 2 is a view like that of FIG. 1 of a further embodiment of the invention, wherein the actuating shaft is rotated, from the operator side of the printing machine, via a first gearwheel coupled to the actuating shaft, and a second gearwheel driven by an upstream cylinder;  
         [0033]    [0033]FIG. 3 is a side-elevational view of either FIG. 1 or FIG. 2 for more clearly illustrating the operative connection;  
         [0034]    [0034]FIG. 4 is another view like those of FIGS. 1 and 2 of yet a further embodiment of the invention, wherein the movement of the actuating shaft is effected via a drawing or tensioning gear mechanism or transmission disposed on the operator side of the printing machine;  
         [0035]    [0035]FIG. 5 is a side-elevational view of FIG. 4;  
         [0036]    [0036]FIG. 6 is a slightly enlarged, fragmentary view similar to those of FIGS. 1, 2 and  4  of an additional embodiment of the invention, wherein the reversing or turning drum and the further cylinder are coupled via a double intermediate gearwheel revolving at an increased speed and via an intermediate gearwheel, and wherein the second gearwheel is driven via a fixed gearwheel of the double intermediate gearwheel, which is connected to the driving gearwheel of the further cylinder via a further intermediate gearwheel;  
         [0037]    [0037]FIG. 7 is a side-elevational view of FIG. 6, showing the operative connection;  
         [0038]    [0038]FIG. 8 is a view like that of FIG. 6, showing a further modification of the additional embodiment of FIG. 6, wherein the second gearwheel is fastened to the outside of the driving gearwheel of the further cylinder;  
         [0039]    [0039]FIG. 9 is a side-elevational view of FIG. 8 with an appertaining point of interaction between the first and the second gearwheels;  
         [0040]    [0040]FIG. 10 is a view similar to that of FIG. 8, for example, of yet a further embodiment of the invention which uses a double intermediate gearwheel and a further intermediate gearwheel, wherein the actuating shaft is driven via a drawing or tensioning gear mechanism, a belt pulley or a chain wheel of which is fastened onto the further intermediate gearwheel;  
         [0041]    [0041]FIG. 11 is a side-elevational view of FIG. 10 wherein the drawing or tensioning gear mechanism is replaced by a belt, for example a toothed belt, or a chain;  
         [0042]    [0042]FIG. 12 is a view similar to that of FIG. 1 of still another embodiment of the invention wherein, in addition to the embodiment of FIG. 1, a further actuation shaft is disposed on the operator side, the shaft being displaceable, during rotation thereof, in the axial direction of the cylinder, via a thread formed in the journal pin of the cylinder; and  
         [0043]    [0043]FIG. 13 is a fragmentary, side-elevational view of the cylinder with appertaining activating elements for switching over the gripper-control devices.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]    Referring now to the figures of the drawings in detail and first, particularly, to FIGS.  1  to  3  thereof, there is seen a sheet-processing machine  1  including a reversing or turning device  2  which is disposed between a first, upstream printing unit  6  for printing the upper side, and a second printing unit  4 , disposed downstream of the turning configuration  2 , for printing the underside, of a sheet  18  processed in the machine  1 . In the case of the embodiment of the invention illustrated in the side-elevational view of FIG. 3, the reversing or turning device  2  operates in accordance with the single-drum reversing or turning principle and has a first cylinder  8 , which is also referred to hereinbelow as a reversing drum, that is provided with gripping devices  10 , for example pincers-type grippers or suction grippers. One or more gripper-control devices in the form of cams  12 , and cam followers  14  cooperating with the cams  12 , which are illustrated diagrammatically in FIG. 3, respectively open and close the gripper devices  10  and pivot them in order to grip the printed sheets  18  at the trailing edges thereof and to respectively transfer the sheets to respective gripper configurations of a downstream cylinder  20 .  
         [0045]    The gripping device  10  grips the trailing edge of a sheet  18  which has been printed on one side, and is guided on a second or further cylinder  16  of the sheet-processing machine, in particular the impression cylinder of the upstream printing unit  6 . The gripping device  10  transfers the trailing edge as the new leading edge to a gripper device (illustrated without a reference numeral) of the impression cylinder  20  of the second, downstream printing unit  4 , wherein the reversed or turned sheet  18  is printed, in a conventional manner, on the reverse side thereof.  
         [0046]    Mounted preferably rotatably within the cylinder  8  is an actuating shaft  22 , which extends preferably coaxially with or along the axis of rotation of the cylinder  8  and cooperates with one or more activating elements  24 , via which the operating state of the gripper-control devices, which include the cams  12  and the cam followers  14 , can be changed when the printing machine  1  is switched over between the single-side printing and first form and perfector printing operating states.  
         [0047]    According to FIG. 13, the activating elements  24  may include further control cams and cam followers as well as transmission levers, which deactivate, for example, the gripper devices  10  in the single-side printing operation by bringing the appertaining gripper shafts  26  to a standstill and/or fixing them, as is shown by way of example in FIG. 13. The rotation of the actuating shaft  22  makes it possible, during the changeover from the single-side printing operation to the first form and perfecter printing operation, where the deactivation of the gripper-control device to be subsequently cancelled again, which is represented in phantom in FIG. 13.  
         [0048]    With respect to the embodiment of the invention shown in FIG. 1, an actuating element in the form of a first gearwheel  28  is fastened to the end of the actuating shaft  22 . The first gearwheel is in meshing engagement with an adjusting element in the form of a second gearwheel  30 .  
         [0049]    According to the embodiment of FIG. 1, the second gearwheel  30  is disposed coaxially with the further cylinder  16  and is fastened, for example, on the end of a driving gearwheel. The fastening may take place in this case, for example, on a fixed gearwheel  32  of a coupling  34  via which the gear train  36  of the upstream printing units  6  can be decoupled from the gear train  38  of the downstream printing unit  4  for format adjustment of the reversing or turning device.  
         [0050]    According to FIG. 3, the operative connection  40 , indicated by the dot and the arrow, for driving the actuating shaft  22  is located directly between the cylinder  8  and the further cylinder  16 . By the operative connection  40  between the cylinders  8  and  16 , or between the first gearwheel  28  and the second gearwheel  30 , the actuating shaft  22  is driven at the same rotational speed as the cylinder  8  during operation of the printing machine  1 , with the result that there is no change in the angular position or setting of the actuating shaft  22 , and thus the position of the activating element  24 , relative to the cylinder  8  during the operation of the printing machine  1 . The size of the two gearwheels  28  and  30  here corresponds at least approximately to the diameter of the cylinder  8  and of the further cylinder  16 , respectively.  
         [0051]    When a conversion or changeover of the operating state of the printing machine  1  occurs, the coupling  34  is opened, for adapting the position of the gripper device  10  to the respective sheet format, and the gear train  36  is rotated in relation to the gear train  38  until such time as the desired position of the gripper device  10  has been reached. The opening or release of the coupling  34  here preferably takes place with the aid of an adjusting gearwheel  42  which is disposed coaxially with the fixed gearwheel  32 , is forced axially, via otherwise non-illustrated pressure-exerting devices, against a correspondingly formed seat of the fixed gearwheel  32 , and is in meshing engagement with the driving gearwheel  44  of the cylinder  8 . The fixed gearwheel  32  and the adjusting gearwheel  42  here form a double gearwheel  48 .  
         [0052]    Due to the coupling via the first gearwheel  28  and the second gearwheel  30  and due to the coupling between the second gearwheel  30  and the fixed gearwheel  32 , rotation of the adjusting gearwheel  42  in relation to the fixed gearwheel  32  of the double gearwheel  48  automatically results in a corresponding rotation of the actuating shaft  22 , as a result of which the operating state or operating mode of the gripper-control device  10  of the cylinder  8  changes correspondingly without requiring the printer himself or herself to be actively engaged in bringing this about.  
         [0053]    According to the embodiment of FIG. 2, the first gearwheel  28  and the second gearwheel  30  are disposed on the operator side  46  of the printing machine, and the actuating shaft  22  extends through the operator-side drive journal of the cylinder  8  into the interior of the cylinder  8 . Apart from the fact that additional space is attained on that side of the printing machine  1  of the embodiment of FIG. 2 which is located opposite the operator side  46 , the embodiments of FIGS. 1 and 2 do not differ from one another in terms of function and operation.  
         [0054]    In the embodiment of the invention illustrated in FIGS. 6 and 7, and wherein the cylinder  8  and the further cylinder  16 , for illustrative reasons, has been depicted as being drawn apart from one another, the releasable coupling of the gear trains  36  and  38  takes place via a double gearwheel which is formed as a double intermediate gearwheel  148  and, in the same way as the double gearwheel  48 , includes an adjusting gearwheel  142  and a fixed gearwheel  132 , the latter engaging, via an additional intermediate gearwheel  150 , with the driving gearwheel  152  of the further, upstream impression cylinder  16 . The intermediate gearwheel  150  and the double intermediate gearwheel  148  here preferably have a smaller diameter than the cylinders  8  and  16 , for example, merely half the diameter, and have a correspondingly increased speed. Using the double intermediate gearwheel  148  and the intermediate gearwheel  150  provides the advantage of a considerable reduction in the tendency towards ghosting which results from the lack of roundness of the double intermediate gearwheel when use is made of a double-sized impression cylinder  16 .  
         [0055]    In the embodiment of the invention illustrated in FIG. 6, the second gearwheel  30  preferably has the same diameter as the adjusting gearwheel  142  and/or the fixed gearwheel  132 , and is preferably disposed coaxially with the fixed gearwheel  132  of the double intermediate gearwheel  148 , and fastened thereon.  
         [0056]    According to FIG. 7, in the case of the previously described embodiment of the invention, the operative connection  40  for synchronously driving the actuating shaft  22  is provided between the double intermediate gearwheel  148  and the cylinder  8 .  
         [0057]    In the same way, however, in the case of an embodiment of the invention which uses a double intermediate gearwheel  148  and an additional intermediate gearwheel  150 , it is likewise possible for the second gearwheel  30  to be disposed coaxially with the further cylinder  16  and to be connected so as to be fixed against rotation relative thereto, for example on the driving gearwheel  152  thereof, as is shown in FIGS. 8 and 9. In this embodiment of the invention, the operative connection  40  is provided directly between the cylinder  8  and the further cylinder  16 . It is produced by the meshing engagement between the first and second gearwheels  28  and  30 , which have at least approximately the same diameter as the cylinders  8  and  16 . In FIG. 8, the meshing engagement between the first and second gearwheels  28  and  30  cannot be seen because this is a sectional view wherein the two gearwheels are drawn apart from one another, the sectional view serving predominantly for illustrating the function of the double intermediate gearwheel  148  and of the further intermediate gearwheel  150 .  
         [0058]    According to the embodiment of the invention shown in FIGS. 4 and 5, the actuating shaft  22  is driven synchronously with the first cylinder  8  via a tensioning or drawing gear mechanism  200  including the actuating element and the adjusting element. The tensioning gear mechanism  200  here has a first belt pulley, which forms the actuating element, or a first chain wheel  228  and a second driving belt pulley, which forms the adjusting element, or a second chain wheel  230 , which, according to FIG. 4, are preferably disposed on the operator side  46  of the printing machine  1 . In this embodiment of the invention, the second driving belt pulley or the second chain wheel  230  is connected to the operator-side shaft journal of a third cylinder  17 , which is disposed upstream of the further cylinder  16  and may be, for example, a transfer cylinder or a transfer drum. In this embodiment of the invention using the tensioning gear mechanism  200 , the operative connection  40 , depending upon the configuration of the tensioning gear mechanism, is produced either via a belt, for example a toothed belt, or, if chain wheels  228  and  230  are used, via a link chain identified by reference numeral  232  in the drawings.  
         [0059]    As can further be gathered from FIGS. 10 and 11, it is also possible, in the case of this embodiment of the invention using a tensioning gear mechanism  200 , for coupling of the cylinder  8  and of the further cylinder  16  to take place via a double gearwheel in the form of a double intermediate gearwheel  148  and via a further intermediate gearwheel  150  disposed upstream of the latter.  
         [0060]    In this embodiment of the invention, the second driving belt pulley  230  and the second chain wheel  230 , respectively, are preferably disposed coaxially with the further intermediate gearwheel  150  and fastened for example via a protrusion  233 , formed on the further intermediate gearwheel  150 , so that the tensioning or drawing device  232  runs past the double intermediate gearwheel  148  at a sufficient distance therefrom. In this case, the operative connection  40 , which gives rise to the in-phase rotation of the actuating shaft  22  synchronously with the cylinder  8 , takes place, via the chain and the toothed belt  232 , respectively, between the further intermediate gearwheel  150  and the cylinder  8 .  
         [0061]    This embodiment of the invention and the embodiment of the invention illustrated in FIGS. 4 and 5, respectively, offer the advantage that the driving belt pulleys  228  and  230  may have a smaller diameter than the cylinders  8 ,  16  and/or the intermediate gearwheels  148 ,  150 , which results in additional space being gained and costs being reduced.  
         [0062]    As is shown, furthermore, in FIG. 12, the actuating shaft  22  may be supported on the cylinder  8  via a thread  23  so that rotation of the actuating shaft  22  relative to the cylinder  16 , via the first and second gearwheels  28 ,  30  or via the tensioning or drawing gear mechanism  200 , results in an axial movement of the actuating shaft  22 , which, by the correspondingly formed activating element  24 , is transmitted to the gripper-control device in order to switch over the latter in the aforedescribed manner between the different single-side printing and first form and perfecter printing operating states and to carry out adaptation to different sheet formats, respectively. For this purpose, the activating element  24  may include, for example, a lever  25  which is pivotable about a point of rotation (not otherwise specifically identified) and one end of which is forced, via a resilient device  27 , against the axial end surface of the actuating shaft  22 . The other end of the lever  25  here is coupled to the gripper-control device, for example via a diagrammatically illustrated connecting lever element  29 , so that the lever element  29  is displaced in the direction of the double arrow  33  if the first gearwheel  28  is displaced axially in the direction of the double arrow  31 , via the thread  23 , by being rotated relative to the cylinder  8 .  
         [0063]    This embodiment of the invention can be used either as an alternative to the embodiment of the invention illustrated in FIGS.  1  to  11  and  13 , or else in addition thereto, as is illustrated in FIG. 12, in order to provide an additional manner of adjustment. The embodiment of the invention according to FIG. 12 here may be disposed both on the drive side, and on the operator side  146 , of the printing machine  1 .