Abstract:
An apparatus for performing successively performable actuations in a printing press includes a pressure converter having an actuator formed with actuator surfaces which are successively able to be acted upon stepwise by pressure fluid; and a printing press in combination with the apparatus. Successively performed actuations in a printing press include switching or controlling, coupling, adjusting and tensioning operations, wherein machine or press parts are moved and/or held in a given position. Such actuations may be necessary in various devices of the printing press, a defined sequence of actuations having to be adhered to, depending upon the functions of the individual devices and to assure disruption-free cooperation of the devices. The actuations often require a transmission of comparatively strong forces to devices located at various places in the printing press which in terms of structural space are quite restricted. Pneumatic and hydraulic systems are therefore used for these purposes.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an apparatus for performing actuations or operations in a printing press. 
     By the term actuations or operations there is meant, for example, switching or controlling, coupling, adjusting and tensioning operations, wherein machine or press parts are moved and/or held in a given position. Such actuations may be necessary in various devices of the printing press, a defined sequence of actuations having to be adhered to, depending upon the functions of the individual devices and to assure disruption-free cooperation of the devices. The actuations often require a transmission of comparatively strong forces to devices located at various places in the printing press which in terms of structural space are quite restricted. Pneumatic and hydraulic systems are therefore used for these purposes. 
     In the published German Patent Document DE 44 01 684 A1 and U.S. Pat. No. 5,588,363, a method for performing successive work steps in a printing press by the application of a pressure medium in various pressure stages upon actuators preloaded in the opposite direction is proposed. Also proposed therein is an apparatus for performing the foregoing method which has a piston-cylinder unit with a differential piston. One piston face of the differential piston can be subjected in a cylinder chamber to a pressure medium of a first pressure medium system with a pressure stage regulation, and another piston face acts in another cylinder chamber on a pressure medium of a second pressure medium system which, in turn, acts upon the actuators. 
     An unfavorable aspect of this heretofore known method and device is that, in addition to the piston-cylinder unit, pressure stage regulation is required, for example, in the form of a switchable or controllable pressure regulator or pressure limiter, which is all the more complicated, the greater the number of work steps that have to be performed in succession. Another disadvantage is that the piston-cylinder unit produces relatively little output power relative to the structural size thereof, that is, if a low pressure is applied to the cylinder input side, a high pressure on the cylinder output side cannot be generated by the pressure conversion performed there. The preloading magnitude of the actuator which is preloaded with a maximal force can therefore be only comparatively slight, especially if the actuators are intended to be of small structural dimensions. On the one hand, actuations to be performed with great force, such as fastening cylinder coverings, can be achieved only at the cost of the disadvantage of a piston-cylinder unit with a large piston face that occupies a great deal of space in the radial direction. On the other hand, this complicates the adaptation to one another of the forces that preload the actuators and in terms of the pressure stage regulation, especially when a great number of switching operations on the part of the adjusting cylinders must be performed successively. Because there is only a slight difference between the minimal and maximal preloading of the adjusting cylinders, only a limited number of adjusting cylinders can be switched or controlled in succession, because assurance must be provided that any partial relief of the adjusting cylinders of a higher pressure stage is so slight that a switching operation cannot yet take place when the switching of the adjusting cylinders of a lower pressure stage is already occurring. 
     In the German Patent Document DE 39 25 110 A1, a cylinder of the tandem cylinder type is proposed which produces increased power without any increase in the dimensions or operating pressure thereof. The tandem cylinder is formed of a housing with openings acting alternatively as inlets or outlets for the pressure fluid, a central column; and a member in the form of an inverted beaker. The housing forms a first expansion chamber wherein a piston with a first annular, pressure-absorbing face reciprocates. The column extends upwardly from the bottom of the housing, the piston being disposed on the open end of the member. The inner surface of the cap of the member acts as a second pressure-absorbing face, and the interior of the member acts as a second expansion chamber. 
     An unfavorable aspect thereof is that, with this tandem cylinder, only two pressure stages can be achieved, and the construction principle of the tandem cylinder, which is formed of individual parts that are complicated to produce, entails a major production expense. 
     The brochure entitled “Leibfried Antriebseinheiten Anlagentechnik Schrift (“Leibfried Drive Units Installation Technology”) 7501175.05.03.093” published by the firm Leibfried Maschinenbau GmbH discloses a compressed air cylinder, type LMZT, of the tandem construction type in a bidirectional version. This tandem cylinder has two conventional piston-cylinder units disposed in alignment with one another in the axial direction of the cylinders, which form a common housing encompassing two expansion chambers that are subjectible to the application of pressure. One adjusting piston is disposed in each expansion chamber, and one adjusting piston rod, when pressure is imposed on the adjusting piston disposed thereon, acts to transmit force to the other adjusting piston rod. When pressure is imposed simultaneously in both expansion chambers, an increased output of power is achieved, and installation of the tandem cylinder in an apparatus in the radial direction requires only little installation space. 
     This tandem cylinder has the same disadvantages as those of the type of tandem cylinder described hereinbefore with respect to the aforementioned published German Patent Document DE 39 25 110 A1. 
     SUMMARY OF THE INVENTION 
     Based upon the foregoing prior art and the inadequacies of previous embodiments, it is accordingly an object of the invention to provide an apparatus for performing actuations in a printing press, with which, without a complicated, additional pressure stage regulation, a very large number of successively occurring actuations can be realized in a relatively simple manner. 
     With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, an apparatus for performing successively performable actuations in a printing press, comprising a pressure converter including an actuator formed with actuator surfaces which are successively able to be acted upon stepwise by pressure fluid. In accordance with another feature of the invention, the apparatus for performing actuations in a printing press include a control unit for remotely controlling a valve with which the pressure converter communicates. 
     In accordance with a further feature of the invention, the pressure converter communicates with two piston-cylinder units actuatable stepwise in succession. 
     In accordance with an added feature of the invention, the pressure converter has two expansion chambers connected to a first pressure fluid system, the expansion chambers being successively suppliable with a pressure fluid present in the first pressure fluid system. 
     In accordance with an additional feature of the invention, the apparatus includes a second pressure fluid system, and the pressure converter has a third expansion chamber communicating with the piston-cylinder units via the second pressure fluid system. 
     In accordance with yet another feature of the invention, a first one of the piston-cylinder units is actuatable by a first actuating force, and a second one of the two piston-cylinder units is actuatable by a second actuating force having a different magnitude from that of the first actuating force. 
     In accordance with yet a further feature of the invention, the piston of the first piston-cylinder unit is preloaded with a first force different in magnitude from that of a second force with which the piston of the second piston-cylinder unit is preloaded. 
     In accordance with yet an added feature of the invention, a first spring for bringing the first force to bear is assigned to the first piston, and a second spring for bringing the second force to bear is assigned to the second piston. 
     In accordance with yet an additional feature of the invention, the first piston has a first piston face different in size from a second piston face of the second piston. 
     In accordance with still another feature of the invention, the first pressure fluid present in the first pressure fluid system has at least one characteristic different from that of a second pressure fluid present in the second pressure fluid system. 
     In accordance with still a further feature of the invention, the first pressure fluid system is embodied as a pneumatic pressure fluid system, and the second pressure fluid system is embodied as an hydraulic pressure fluid system. 
     In accordance with still an added feature of the invention, the pressure converter includes a housing formed with a partition, and the actuator is embodied as an adjusting piston rod carrying a first adjusting piston and a second adjusting piston, so that the partition and the second adjusting piston define an expansion chamber. 
     In accordance with still an additional feature of the invention, the first adjusting piston defines an expansion chamber formed with a vent opening. 
     In accordance with another feature of the invention, the pressure converter is embodied as a component-containing modular system for varying the number of expansion chambers therein during assembly of the pressure converter. 
     In accordance with a further feature of the invention, the modular system contains at least one component type that includes identically embodied components. 
     In accordance with an added feature of the invention, the modular system contains three different component types including a first component type embodied as a partition, a second component type embodied as an intermediate element, and a third component type embodied as an adjusting piston. 
     In accordance with an additional feature of the invention, the partition has a pressure fluid connection with a thread, the connection being formed of two bores opening into one another. 
     In accordance with yet another feature of the invention, the actuator is returnable in one direction of motion by the action of the forces for preloading the pistons. 
     In accordance with yet a further feature of the invention, the actuator is returnable by a restoring spring for reinforcing the return. 
     In accordance with yet an added feature of the invention, the actuator is returnable by an application of pressure fluid on at least one surface of the actuator. 
     In accordance with an additional feature of the invention, the apparatus includes a valve with which the pressure converter communicates, and the first pressure fluid is controllingly feedable into at least one of the expansion chambers via the valve. 
     In accordance with yet another feature of the invention, the valve is embodied as a multiway valve having various control positions and flow paths for feeding pressure fluid to both expansion chambers. 
     In accordance with yet a further feature of the invention, the pneumatic pressure fluid system is connected to a compressed air source for supplying compressed air to the printing press for a plurality of other functions. 
     In accordance with yet an added feature of the invention, the actuator is constructed for directly actuating another part of the printing press. 
     In accordance with yet an additional feature of the invention, the pressure converter has a pressure fluid conduit connecting at least two of the expansion chambers for supplying the at least two expansion chambers with the pressure fluid via a single common pressure fluid connection. 
     In accordance with still another feature of the invention, the apparatus includes a device for starting and stopping sheet turning in a sheet-fed printing press. 
     In accordance with another aspect of the invention, there is provided, in a printing press, in combination, an apparatus for performing successively performable actuations therein, comprising a pressure converter including an actuator formed with actuator surfaces which are successively able to be acted upon stepwise by pressure fluid. 
     With the apparatus according to the invention, the output pressure or output force of the pressure converter can be adjusted in stages, and a constant input pressure can be employed. With the constant input pressure, an actuator can be acted upon in such a manner that the input pressure can act selectively on different-sized portions of the face of the actuator. 
     The actuator may also additionally be acted upon by input pressures of various magnitudes. 
     The “effectiveness” of an actuator face or piston face is intended, in the context of this invention, to mean the cooperation of the pressure-absorbing face with a pressure fluid, and the term “piston-cylinder unit”, going beyond a so-called adjusting cylinder, is understood to mean a device with a component that may be acted upon by pressure fluid and thereby movable, preferably displaceable. 
     The actuator is constructed so as to be movable, in particular, movable by an application of pressure fluid and, for example, is rotatable. Preferably the actuator may be embodied so as to be displaceable, for example, as a displaceable unit made up of two adjusting pistons and one adjusting piston rod. Tandem cylinders, often called multi-power cylinders, with two or more adjusting pistons on two or more separate but cooperating adjusting piston rods, (the term actuator, in this case, being understood to mean a plurality of cooperating actuators) and preferably tandem cylinders with one or more adjusting pistons on a single common adjusting piston rod can be employed in accordance with the invention. The latter type of tandem cylinder may also have a stationary adjusting piston rod with adjusting pistons which, for example, is fixed to the machine frame; in that case, the actuator is formed by a tandem cylinder housing that is displaceable on the adjusting piston rod or on the adjusting piston. 
     The first expansion chamber of the pressure converter may be formed by a face belonging to the actuator, such as the pressure-absorbing face of a first adjusting piston, and a housing of the pressure converter, for example, in the form of a cylinder jacket. A second expansion chamber may communicate with switchable piston-cylinder units. A further expansion chamber, hereinafter called the third expansion chamber, may be formed by a face belonging to the actuator and by the housing and a partition. The partition may be embodied in the housing, for example, if the housing is formed in a single pouring, and it can belong to the housing, for example, if the housing is composed of various structural components. A multi-partite housing may, for example, be in the form of two piston-cylinder units of conventional type, disposed in alignment one after the other in the direction of the cylinder axis, with a single common adjusting piston rod connecting the adjusting pistons. Thereat, the end-face housing wall of one cylinder, through which the adjusting piston rod may be passed, forms a partition that defines the third expansion chamber formed in the cylinder. The end-face housing wall of the other cylinder in that case forms a further partition that defines a fourth expansion chamber formed in the other cylinder. The term partition will be used hereinafter both to mean two adjoining or two spaced-apart partitions and for a preferable embodiment in the form of a single partition. 
     When a first pressure fluid is fed via a first pressure fluid system to the first and/or third expansion chamber, the actuator can be moved, for example, by being displaced or slid, in such a manner that an actuator face active in the second expansion chamber exerts a force relative to the size of the actuator face and thus exerts a pressure on a second pressure fluid carried in a second pressure fluid system. If the pressure fluid fed or applied to the first and/or third expansion chamber is interrupted, the actuator face can absorb the pressure exerted by the second pressure fluid and generated by the forces preloading the piston-cylinder units, so that, in this manner, the actuator can be returned indirectly via the pressure fluid. Restoring springs may also be provided, in addition, for returning the actuator directly. 
     The feeding of pressure fluid to the first and third expansion chambers can be controlled in a simple manner by shutoff valves assigned to the pressure fluid feed lines, the valves, for example, being in the form of stopcocks or slide valves. Remote control of individual valves or of a multiposition valve is especially advantageous. 
     The order in which the first and third expansion chambers are acted upon by pressure can be selected in various ways. What is essential is that first one of the expansion chambers is acted upon, so that the actuator in a first pressure stage moves a first distance counter to the action of the forces preloading the piston-cylinder units, the actuator, for example, being displaced. After that, a further expansion chamber can be acted upon by the first pressure fluid, so that in a second pressure stage the actuator is moved a further distance counter to the action of the preloading forces. Depending upon the magnitude of the preloading forces and upon the size of the piston face, a first piston-cylinder unit switches on in the first pressure stage, and a second piston-cylinder unit switches on in the second pressure stage. 
     The cross-sectional shape of the actuator and of the housing of the pressure converter and also of the switchable piston-cylinder units may be constructed axially symmetrically or circularly, which is advantageous from a production standpoint, but may also have a polygonal construction, for example. The adjusting piston or pistons forming the actuator or belonging to the piston-cylinder units may be embodied as differential pistons. 
     Precisely the same gaseous or liquid pressure fluid may be carried in the first and second pressure fluid system communicating with the pressure converter. It is equally possible for a hydraulic oil of a given nature to be carried in the first pressure fluid system, for example, and some other kind of hydraulic oil, in terms of its composition or its rheological properties, to be carried in the second pressure fluid system, so that the pressure converter acts as a pressure medium converter from one hydraulic medium to another. The pressure converter may also act as a pressure medium converter from gas to gas, liquid to gas, or preferably gas to liquid. 
     The apparatus according to the invention can be employed for various kinds of actuations in a printing press, for example, as will be described in further detail in an exemplary embodiment, to actuate a device for switching a sheet turning on and off or for actuating a clamping and tensioning device in printing presses. A clamping and tensioning device for printing plates actuatable by the apparatus of the invention is described and shown in the published German Patent Document DE 44 01 684 A1. Devices in other machines which process material to be printed can also be actuated with the apparatus of the invention. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in an apparatus for performing actuations in a 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. 
     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, wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic and schematic view of an apparatus according to the invention for successively performing actuations in a printing press; 
     FIG. 2 is a diagrammatic and schematic view, in section, of a device for turning on and off, i.e., starting and stopping sheet turning on one side of the printing press; 
     FIG. 3 is an enlarged fragmentary diagrammatic and schematic view, in section, of FIG. 1 showing a different advantageous embodiment of a pressure converter of the apparatus according to the invention, which has identical components; 
     FIG. 4 is a reduced side elevational view of the pressure converter shown in FIG. 3; and 
     FIG. 5 is a diagrammatic cross-sectional view of another different pressure converter which is provided with a rotatable actuator. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is shown therein an apparatus for successively performing actuations or operations in a printing press, the apparatus having a pressure converter  103  which includes at least one actuator  101  and a housing  102  which has a first expansion chamber  105  connected to a first pressure fluid system  107 , and a second expansion chamber  109  connected to a second pressure fluid system  111 , a first actuator face  104  being operative in the first expansion chamber  105 , and a second actuator face  108  being operative in the second expansion chamber  109 , the apparatus further having at least one first piston-cylinder unit  118 ,  218 , including a first piston  113 ,  213  preloaded with a first force represented by the arrow  115 ,  215  and being formed with a first piston face  112 ,  212  that is operative in a first cylinder chamber  117 ,  217  of a first cylinder  116 ,  216 , the first cylinder chamber  117 ,  217  being connected to the second pressure fluid system  111 , and the apparatus also having at least one second piston-cylinder unit  125 ,  225 , including a second piston  120 ,  220  preloaded with a second force represented by the arrow  122 ,  222  and being formed with a second piston face  119 ,  219  that is operative in a second cylinder chamber  124 ,  224  of a second cylinder  123 ,  223 , the second cylinder chamber being connected to the second pressure fluid system  111 . The apparatus according to the invention is distinguished in that the pressure converter  103  has a third expansion chamber  129  connected to the first pressure fluid system  107  and defined by a third actuator face  130  operative therein, and in that a pressure fluid  106  guided in the first pressure fluid system  107  can be conducted either to only one of the expansion chambers  105 ,  129  at a time or to both expansion chambers  105 ,  129  simultaneously, so that the actuator  101 , by successively effected and staggered application, respectively, of the pressure fluid  106  on the actuator faces  104 ,  108 , is displaceable in stages, and the piston-cylinder units  118 ,  125  and  218 ,  225  are switchable or controllable in succession and in staggered manner, respectively. 
     The actuator  101  includes a first adjusting piston  136  and a second adjusting piston  137 , which are secured to an adjusting piston rod  138  by retaining rings  149 . The housing  102 , formed as a casting, for example, is in the shape of a circular cylinder and includes a partition  135  having a bore  179 , through which the adjusting piston rod  138  extends, as well as end-face walls  181  formed with bores  180  through which the adjusting piston rod  138  can extend. 
     This embodiment is especially advantageous if an actuation, such as a clamping  159 , is to be effected directly, i.e., not via the second pressure fluid system  111 , by the force exerted by the adjusting piston rod  138  of the pressure converter  103 . The clamping may be effected by two components which are to be held in frictional locking engagement, such as coupling halves, or by two components  160  and  161 , such as clamping jaws or claws, and a component  182 , such as a printing plate, to be clamped between them in a printing plate clamping and tensioning device. Provision may also be made for undoing or releasing, in this manner, any clamping effected by a spring force. 
     Either both or one of the end-face walls  181  may also be formed without bores  180 , so that in the absence of the adjusting piston shaft ends protruding beyond the actuator faces  104 ,  108 , the actuator faces  104 ,  108  are operative over the entire surface thereof in the first and/or second expansion chamber  105 ;  109 . 
     Damping of the actuator  101  in the terminal positions may be provided. This damping may be either singly adjustable in its action, that is, in only one terminal position, or doubly, or nonadjustable. Seals  148 , such as plastic rings guided in grooves, may as shown be provided on the bores  179 ,  180  of the housing  102  that guide the adjusting piston rod  138  and on the partition  135  as well as on the seat of the adjusting pistons  136 ,  137  on the adjusting piston rod  138  and at the sealing face between the adjusting pistons  136 ,  137  and the inside surface of the housing, so that it is possible to prevent an escape of pressure fluid out of the housing or to prevent pressure fluid from spilling over from one expansion chamber to the other. This can also be achieved by an appropriate accuracy in terms of fit and surface of the joined-together parts guided in one another. 
     The first expansion chamber  105  can be supplied with the first pressure fluid  106  carried in the first pressure fluid system  107  via a first pressure fluid connection  144  introduced into the housing, and the third expansion chamber  129  can be supplied with the same pressure fluid via a second pressure fluid connection  145 . A third pressure fluid connection  146  connects the second expansion chamber  109  to the second pressure fluid system  111 . A vent opening  147  enables the aeration and ventilation  162  of the fourth expansion chamber  152 . 
     The restoration of the actuator  101  in a second direction of actuator motion  132  can be effected by the action of the forces  115 ,  122 ,  215 ,  222 ; by an additional restoring spring  150 ; or by a pressure fluid application  163  to the fourth expansion chamber  152 ; as well as by a combination of a plurality of these options. The forces  115 ,  122 ,  215 ,  222  which preload the pistons  113 ,  120 ,  213 ,  220  may, as shown, be brought to bear by springs  133 ,  134 ,  233 ,  234 , or by elastic properties of components such as components to be clamped. 
     The restoring spring  150  may also be disposed in the interior of the pressure converter  103 , and the springs  133 ,  134 ,  233 ,  234  may be disposed in the interior of the piston-cylinder units  118 ,  125 ,  218 ,  225 , for example, being mounted on the piston rods. Instead of the helical springs  133 ,  134 ,  233 ,  234  shown as compression springs, other types of springs may also be employed, such as leaf springs, cup springs, tension springs and torsion springs, or gas pressure elements, as well as other springs that exert a corresponding force  115 ,  122 ,  215 ,  222  upon the pistons  130 ,  120 ,  213 ,  220 . 
     The pressure fluid source  143  feeding the first pressure fluid  106  into the first pressure fluid system  107  may be embodied as a compressor, when a pneumatic first pressure fluid system  107  is present, and as a hydraulic pump in the case of a hydraulic first pressure fluid system  107 . Instead of the pressure fluid source  143  embodied as a hydraulic pump in FIG. 1, a pneumatic pressure fluid source is used in a preferred embodiment. Other versions of the pressure fluid source  143  are also possible, for example, in the form of hydraulic or pneumatic reservoirs. It is useful to use a central pneumatic pressure fluid source that is present in any printing press for performing other functions, such as for guiding printed sheets with blown air. The pressure fluid source  143  may include a pressure adjuster or a pressure regulator  164 . However, in contrast with the prior art, this pressure regulator is not used to switch various pressure stages of the first pressure fluid system but rather to adjust a desired value, for example, in an infinitely graduated manner, or to regulate an actual pressure to a nominal or setpoint value. The pressure prevailing in the first pressure fluid system  107  is of such value that when a given number of expansion chambers are acted upon by the first pressure fluid  106 , a given number of piston-cylinder units is switched. For the embodiment of the invention shown in FIG. 1, the pressure may, for example, be so great that by or after action on the first and third expansion chambers  105  and  129 , all the piston-cylinder units  118 ,  125 ,  218  and  225  shown have been switched counter to the action of the preloaded forces  115 ,  122 ,  215  and  222 . The view shown, wherein the piston-cylinder units are presented in different switching positions, is helpful for the sake of a more-detailed explanation to be made hereinafter regarding the switching of the piston-cylinder units  118 ,  125 ,  218  and  225 . 
     The first pressure fluid system  107  may be embodied as a closed pressure fluid system or preferably as an open pressure fluid system. In the hydraulic first pressure fluid system  107  shown, a return flow of the first pressure fluid  106  into a pressure fluid reservoir  153  is contemplated. 
     The second pressure fluid system  111  is embodied according to the invention as a closed pressure fluid system; that is, the hollow chamber formed by the second expansion chamber  109 , the lines or conduits of the second pressure fluid system  111 , and the cylinder chambers  111 ,  124 ,  217 ,  224 , is filled with a given quantity of the second pressure fluid  110 . An hydraulic second pressure fluid  110  advantageously has a relatively low compressibility in comparison with a pneumatic pressure fluid, making this second pressure fluid quasi-incompressible. Thus, the piston-cylinder units  118 ,  125 ,  218 ,  225  to be switched on are switched on without delay via the second pressure fluid  110  upon actuation of the pressure converter  103 . An additional advantage associated with this is that, given the practical absence of a significant compression of the second pressure fluid  110  associated with the first transmission by the second pressure fluid  110 , very short reciprocating motions of the actuator  101  of the pressure converter  103  can be realized. The structural size of the pressure converter  103  can thus be kept small. 
     The first pressure fluid system  107  may preferably be embodied as a low-pressure system, and the second pressure fluid system  111  as a high-pressure system; that is, if a low pressure is applied to the first pressure fluid system  107 , a higher pressure prevails in the second pressure fluid system  111 , at least in certain pressure stages. In the embodiment of the invention shown in FIG. 1, the first, second and third actuator faces  104 ,  108 ,  130  are all the same size. Upon the imposition or application of pressure solely in the first expansion chamber  105  in accordance with a first pressure stage, and disregarding the restoring spring  105 , an action which is acceptable in this example, the same pressures would prevail in the first and second pressure fluid systems  107 ,  111 , or in other words a pressure conversion ratio of the input to the output of 1:1 would prevail. If pressure is additionally imposed on or applied in the second expansion chamber  129  in a second pressure stage, then the pressure applied in the first pressure fluid system  107  would be maintained unchanged, while the pressure prevailing in the second pressure fluid system  111  would rise to twice that value, resulting in a pressure conversion ratio of 1:2. Provision may also be made, even in the first pressure stage, or in all the pressure stages, for a higher pressure to prevail in the second pressure fluid system  111  than in the first pressure fluid system  107 . This may be attained, for example, by an effective first actuator face  104  that is larger than the effective second actuator face  108 , as is similarly shown in the aforementioned published German Patent Document DE 44 01 684 A1 for a differential piston, which has a larger piston face on the inlet side, functionally similar to the first actuator face  104 , and a smaller piston face on the outlet side, functionally similar to the second actuator face  108 . In this manner, high preloading forces  115 ,  122 ,  215 ,  222  can be overcome. In addition, provision may also be made for the first pressure fluid system  107  to be embodied as a high-pressure system, and the second pressure fluid system  111  as a low-pressure system. 
     Also shown in FIG. 1 is a multiway valve  139 , which can be actuated by a remotely controllable actuating device, such as an electromagnet  151 . The multiway valve  189  includes the switching positions U through Z, and each switching position  140  includes flow courses a through d. A flow course  156  may be provided in the form of an open flow course  157  or a closed flow course  158  or a non-illustrated throttling flow course in the respective switching position  140 . A spring that returns the multiway valve  139  from the switching positions  140  and a retainer, such as a detent that keeps the multiway valve  139  in switching positions  140 , may be provided. The Remotely-controllable actuating device  151  is controlled by a control unit  142 , which is preferably embodied in the form of an electrical control unit with a microprocessor, in accordance with other actuations and processes in the printing press or on the periphery of the printing press, which are controlled by the control unit  142 . In the illustrated switching position U, an application solely of the first pressure fluid  106  into the first expansion chamber  105  is contemplated; this fluid can take the flow course a, while the flow courses b, c and d are blocked. In the switching position V, an application is effected solely into the third expansion chamber  120  via the open flow course b. The switching position U or the switching position V may correspond to a first stage, in which the actuator  101 , by the application of pressure fluid to the first actuator face  104  or the third actuator face  130 , is displaced out of the basic position for a first stroke course distance in a first direction  132  of actuator motion, and in which a first pressure stage is applied to the second pressure fluid  110  as a result of the displacement and action of the second actuator face  108  in the second expansion chamber  109 . Any volume of air that may be displaced positively out of the fourth expansion chamber  152  by this actuator displacement can escape via the vent opening  147 . The second pressure fluid  110  has a force-transmitting effect and exerts a force, which can assume the magnitude of a switching force  183 ,  184 ,  283 ,  284 , on the piston faces  112 ,  119 ,  212 ,  219 . 
     In the exemplary embodiment shown, the first piston face  112  of the first piston-cylinder unit  118  is larger than the second piston face  119  of the second piston-cylinder unit  125 , and the forces  115 ,  122  which preload the pistons  113 ,  120  are of equal magnitude, assuming that the types of springs  133 ,  134  are identical. The pressure of the second pressure fluid  110  acts upon the first piston face  112  of the first piston-cylinder unit  118  and upon the second piston face  119  of the second piston-cylinder unit  125 . The lesser switching force  183 , in this pressure stage, switches the first piston-cylinder unit  118 , first, by displacing the first piston  113  in a second direction of piston motion  126 , counter to the action of the first force  115 , over a defined travel distance until it meets a stop, for example. This also effects a partial relief of the second piston  120  of the second piston-cylinder unit  126 . The partial relief is so slight, however, that no switching operation occurs yet; that is, the second piston  120  is virtually not displaced or not adequately displaced counter to the action of the second force  122 . In this partial relief, the function of the partially relieved piston-cylinder unit can still be either fully operative, an example being the clamping of two coupling halves in frictional engagement with one another, or not yet established, an example being the release of the coupling halves. This can depend upon whether the clamping or release, for example, is effected by the preloading spring. 
     Once the actuation of the first piston-cylinder unit  118  in a first stage corresponding to one of the switch positions U or V has been performed, then in a second stage in a switch position W the first and third expansion chambers  105 ,  129  can be jointly acted upon by the first pressure fluid  106  via the pressure fluid feed line  154 . In this process, the actuator  101  is displaced farther, over a second stroke distance, in the first actuator motion direction  131 , and a higher pressure than in the first pressure stage can be imposed upon the second pressure fluid  110 , so that the second switching force  184  resulting therefrom assumes a sufficient magnitude for complete relief of the second piston  120 , and the second piston-cylinder unit  125  is switched, in that the second piston  120  is displaced a given distance in a second direction of piston motion  121 , counter to the action of the second force  122 . 
     In certain applications, such as clamping  159  or in the case of piston-cylinder units  118 ,  125  with very stiff counteracting springs  133 ,  134 , for example, the stroke distances of the actuator  101  may be so short that in the individual pressure stages practically only an increase or decrease in the effective clamping forces or in the forces acting upon the pistons  113 ,  120  is perceptible. 
     The magnitude of the switching forces  183 ,  184 ,  283 ,  284  required for the switching is determined by the magnitude of the forces  114 ,  122 ,  215 ,  222  preloading the pistons  113 ,  120 ,  213 ,  220  and by the size of the piston faces  112 ,  119 ,  212 ,  219 . It will now be shown, in terms of further piston-cylinder units  218 ,  225  illustrated in FIG. 1, how a successively effected switching can also be achieved by a different preloading of the first piston  213  and the second piston  220 . The first piston  213  is preloaded by a first spring  233 , which brings to bear a greater first force  215  and requires a greater switching force  282  for the switching than does the second spring  234  that preloads the second piston  220  and requires a lesser switching force  284 . Thus, in the switch position U or V of the multiway valve  139 , switching of the second piston-cylinder unit  225  can be accomplished first, followed by switching of the first piston-cylinder unit  218 , as well, in the second switch position W. 
     It is readily apparent that a combination of the two different embodiments is also possible; that is, the first and second piston-cylinder units can differ from one another both in having piston faces of different areas and in having preloading forces of different magnitudes. In this way, assuming suitable adaptation or adjustment, both successive and simultaneous switching of the first and second piston-cylinder units can be achieved. For example, the piston-cylinder unit  118  can be switched or actuated jointly with the piston-cylinder unit  225  in a first stage, and in a subsequent second stage, the piston-cylinder unit  125  can be switched or actuated jointly with the piston-cylinder unit  218 . 
     The imposition or application of the first pressure fluid  106  into the expansion chambers  105 ,  129  can be undone successively as well, by moving the multiway valve  139  from the switch position W to one of the switch positions X or Y. In the switch position X, for example, the imposition or application into the first expansion chamber  105  via the open flow course a is maintained, while the imposition or application into the third expansion chamber  129  is undone by the blocked flow course b. One or more piston-cylinder units  125 ,  218  that were switched in the second stage now switch back again, before one or more other piston-cylinder units  118 ,  225  subsequently switch back again as well. The piston-cylinder units  118 ,  225  are partially loaded again in this process. However, the pistons  113 ,  220  are not yet returned to the original outset position thereof and, thus, no switching takes place. The preloading forces  122 ,  215  now act, by displacing the pistons  120 ,  213  in a first direction of piston motion  121 ,  214 , upon the actuator  101  via the second pressure fluid  110 , thereby returning the actuator in a second actuator motion direction  131 . 
     The volume of first pressure fluid  106  positively displaced by the return of the actuator  101  from the third expansion chamber  129  can be delivered to a pressure fluid reservoir  153  through the open flow course d and via outgoing pressure fluid lines  155 . Compressed air acting as the first pressure fluid  106  can simply be vented. 
     From the switch position X or Y, the multiway valve  139  can be set into the switch position Z. In the latter position, because the flow courses a and b are blocked, the pressure imposed on both the first and the third expansion chambers  105 ,  129  is undone. In the switch position Z, one or more previously first partially re-loaded piston-cylinder units  118 ,  225  can be switched completely back again, and consequently a further displacement of the actuator  101  in the second actuator motion direction  132  back into the outset position thereof can be effected. The volume of first pressure fluid  106  positively displaced in the process out of the last expansion chamber to be relieved of the pressure which is imposed can be fed back into the pressure fluid reservoir  153  by way of a second flow course c or d that is now open as well, an example being the flow course c. The flow course c or d, in this example, the course d, that was open in the previous switch position X or Y now remains open, so that the volume of pressure fluid, now having been positively displaced even more, can be diverted out of the outer expansion chamber that in the previous stage was the first to be relieved of the pressure which was imposed. It is understood that the expansion chambers  105 ,  129  can be supplied jointly and simultaneously with the pressure fluid  105 , so that a major force is immediately operative, if a previous switch position X or Y is skipped, and the switch position W is activated immediately. 
     The displaceable multiway valve  139  illustrated in FIG. 1 is shown only diagrammatically and schematically. A practical version assures tightness of the parts movable relative to one another. Check valves may also be disposed in the first pressure fluid system  107  or in the multiway valve  139 , thus simplifying the construction of the multiway valve  139  and requiring fewer flow courses per switching position, because one flow course can act as an open flow course in one direction and simultaneously as a closed flow course in the other direction. 
     Another exemplary application of the features of the invention is shown in FIG.  2 . This exemplary application is shown in vertical section through a storage drum  13 , a turning or inversion drum  14 , and an impression cylinder  15  which, for recto/verso printing, are rotatably supported or journalled on both sides of a printing press in a respective side wall  16  thereof. The storage drum  13  is formed of two segments  17  and  18  which are adjustable in the circumferential direction relative to one another; bearings  19  for a gripper shaft  20  are located on the segment  17 , and grippers  21  for the front edge of the sheet are disposed on the gripper shaft. The segment  18 , which is rotatable relative to the segment  17  about a common pivot axis, has suction devices  22  for the trailing edge of the sheet being guided on the circumference of the storage drum  13 . The printing cylinder  15 , the turning drum  14 , and the storage drum  13  having twice the diameter of the standard printing-unit cylinders are all driven by the train of wheels of a toothed wheel gear mechanism. Beginning at a gear wheel  23  of a preceding transport drum, the drive of the storage drum  13  is effected by a gear wheel  24 ; the drive of the turning drum  14  is effected by a toothed ring (gearwheel)  25  and a gearwheel  26 ; and the drive of the printing cylinder  15  is effected by a gearwheel  27 . The gearwheels  24 ,  26  and  27  are each disposed solidly on ends of the respective storage drum  13 , turning drum  14  and impression cylinder  15 , those ends being journalled in the side wall  16 . 
     The segments  17  and  18  are joined to one another by a clamping device. In this clamping device, the short arm of a clamping lever  28  presses the adjustable segment  18  against a countersupport  31  secured to the shaft end of the storage drum  13  by a securing ring  29  and screws  30 . The clamping lever  28  is supported with a cam  32  on a flat or planar face  33  of the segment  17 . The cam  32  is disposed off-center, so that the clamping lever  28  has one short lever arm and one long lever arm. The inner end of a thrust rod  34  that is guided axially displaceably and coaxially in the storage drum and extends out therefrom at an end face thereof is directed towards an end of the long lever arm. This thrust rod  34  is loaded by a spring  37 , which is braced at one end against a bridge  35  and at the other end against a thrust rod flange  36 , in such a way that the segments  17  and  18  of the storage drum are joined firmly to one another by frictional engagement as a consequence of the lever ratio of the clamping lever  28 . The resultant clamping of the segments  17  and  18  can be undone with the aid of a hydraulic piston-cylinder unit  12 . 1  which, when pressurized, presses the piston of the work cylinder thereof against a stop ring  38  secured to the thrust rod  34 , so that the spring  37  is compressed and the clamping between the two segments  17  and  18  is undone. Via the line  11 , the piston-cylinder unit  12 . 1  communicates with the symbolically represented pressure converter  1 . The relative adjustment of the segments  17  and  18  is performed manually or by machine. For gripper control, a roller lever  39  is secured to the gripper shaft  20 ; a cam roller  40  is rotatably supported or journalled on a free end of the roller lever  39  and rolls along a cam  41  disposed on an adjustable toothed rack segment  42 . The rack segment  42  is clamped to the side wall  16  by a clamping piece  43  that is disposed on the inner end of a bolt  44  that, in turn, is axially displaceably guided in the side wall  16 . In the clamping direction, the bolt  45  is loaded by a spring  45  which, in turn, is braced at one end against the side wall  16  and at the other end against a flange ring  46  on the bolt  44 . To undo this clamped connection, a piston-cylinder unit  12 . 2  is disposed between the bolt  44  and a bracket  47  secured to the side wall  16 ; its piston and work cylinder are braced against the bolt  44  on one side and against the bracket  47  on the other. This piston-cylinder unit  12 . 2  likewise communicates through a line  11  with the hydraulic pressure system of the pressure converter  1 . Once the clamping has been undone, the rack segment  42  is angularly adjusted in a conventional manner, either by hand or automatically via an adjusting shaft, not shown in the drawing, whereon a pinion engaging the teeth is disposed and which is supported in the side wall  16 . 
     Gripper tongs  48 , for example, constructed in a conventional manner, are disposed on a gripper shaft  49  on the turning drum  14 . Control of the gripper tongs  48  on the gripper shaft  49  of the turning drum  14  is effected by double cams  50 , preferably secured to the side wall  16  on both sides of the machine, a respective cam roller  51  rolling on each cam of the double cams  50  and moving a gripper control segment  52 . This gripper control segment  52  is secured at an end face thereof to a carriage  53  guided axially displaceably along the turning drum  14 , so that the cam roller  51  is adjustable by axial carriage motion from one cam to the other of the double cam  50 . The carriage  53  is radially clamped to the turning drum  14  by a further clamping device. To that end, a thrust rod  64  is axially movably supported coaxially in the turning drum  14  and a free end thereof is directed towards one arm of a bellcrank  55 , which is pivotably supported in the turning drum, the other arm of the bellcrank  55  engaging a tie rod  56  from below, the tie rod  56  being radially movably guided and being connected to the carriage  53 . The other end of the thrust rod  54 , which is directed outwardly at the end face thereof, passes through both a spring  57  and a thrust ring  58 . The spring  57  is braced at one end thereof against the thrust ring  58  and at the other end against a flange  59  of the thrust rod  54 . The abutment of the thrust ring  58  is formed by a plurality of clamping levers  60  and by a printing plate  61  that is firmly connected to the gearwheel  26 . The thrust ring  48  presses against the inner ends of the clamping levers  60  which, with the outer ends thereof press the gearwheel  25  against the gearwheel  26 , and cams provided in the vicinity of these outer ends are braced against the printing plate  61 . A sleeve  63  is slipped axially movably onto the outward-extending end of the thrust rod  54 , one of the end faces of which rests on the thrust ring  58 , and the other end face of which cooperates with the piston-cylinder unit  12 . 3 , which in turn is braced at the other end thereof against a flange ring secured to the free end of the thrust rod  54 . By suitably activating the piston-cylinder unit  12 . 3 , the sleeve  63  is displaced on the thrust rod  64  until it meets a shoulder  65  on the thrust rod  64 , so that the clamping action between the gearwheels  25  and  26  and of the carriage  53  on the turning drum is undone. This adjusting cylinder  12 . 3 , also communicates through a line  11  with the pressure converter  1 . 
     Another piston-cylinder unit  12 . 4  is secured to the outside of the side wall  16 ; the piston thereof, when subjected to the pressure fluid in the adjusting cylinder, presses against the end face of the gearwheel  27  and firmly holds it thereat for the duration of the readjustment operation. The piston-cylinder unit  12 . 4  again communicates through the line  11  with the pressure converter  1 . By the action of the pressure converter  1 , upon its actuation in the first pressure stage P 1 , the piston-cylinder unit  12 . 4  is acted upon first, so that the drive of the drums in the zero position is blocked. At the same time, the piston-cylinder unit  12 . 1  can be suitably activated to undo the clamping in order to adjust the format at the storage drum. In a further pressure stage P 2 , the piston-cylinder unit  12 . 1  is then acted upon, to undo the clamping of the rack segment  42  so as to adjust the gripper opening, and at the same time the piston-cylinder unit  12 . 3  is acted upon, to undo the clamping in order to adjust the toothed ring and also the carriage of the turning drum. Once these readjustment operations have been performed, a pressure relief of the pressure converter first relieves the pressure in the piston-cylinder units  12 . 2  and  12 . 3  which are combined in the pressure stage P 2 , so that the associated clamps become operative again, before relief of the piston-cylinder units  12 . 1  and  12 . 4  is effected in the pressure stage P 1 , so that the release of the driving gearwheel  27  does not occur until after all the clamps are again operative. 
     A pressure monitor  87  in the line  11  of the second pressure medium system stops the press during the press readjustment, or does not allow the press to run until the line  11  is pressureless. 
     FIG. 3 shows an especially advantageous embodiment of the pressure converter  103  of the invention in the form of a modular system that includes components  165 ,  166 ,  167 . As a result of this construction, the pressure converter  103  is readily adaptable to various requirements in use, because the number of expansion chambers  172  acted upon by the pressure fluid supplied from a non-illustrated pressure fluid source, can easily be varied during assembly. For example, depending upon the intended purpose, a different adjusting piston rod  185  that carries a different number of adjusting pistons  165  can be provided. The adjusting pistons  165  may be different in construction; for example, adjusting pistons  165  of the embodiment shown may be used jointly with adjusting pistons embodied as differential pistons. 
     In terms of production effort and expense, a modular system that includes at least one component type having identically embodied components is advantageous. For example, an identical embodiment of the partition  166  and a different embodiment of the adjusting piston  165  and the intermediate element  167  may be contemplated. By dimensioning the intermediate element  167  and/or the adjusting pistons  165  differently, the size of the expansion chambers and the stroke length of the actuator  165 ,  186  can be varied, and the partition  166  that defines the expansion chambers can essentially continue to have the same construction in all cases. In FIG. 3, an advantageous embodiment of the modular system shows which three component types, namely, the adjusting piston  165 , the partition  166 , and the intermediate element  167 , are provided with respectively identical components. The partitions  165  and the intermediate elements  167  can be connected to one another during assembly by a non-releasable connection, such as an adhesive bond, or by a releasable connection, such as one or more screw fastenings  168 ,  169 . The pressure converter  103  may preferably have a circular-cylindrical or parallelepipedal (note FIG. 4) outer form and jacket surface, respectively. If the outer form is circular-cylindrical, then the intermediate elements  167  may be circular-ringshaped, and may be joined, for example, by three screw fastenings each offset 120° from one another. In the case of a parallelepipedal form, four screw fastenings  168 ,  169  may be provided. The position of the components relative to one another can be assured not only by the screw fastenings, but also by position-securing elements, such as pins. Form-lockingly interengaging embodiments of the components, such as shoulderlike offsets made on a lathe, so that the components can be inserted partly into one another, can also contribute to the positional securing. In this regard, it is noted that a form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements. In the embodiment shown in FIGS. 3 and 4, only bores  170  in which the screws  168  are guided, are necessary. The play of the bores  170  allows for the alignment of the components in accordance with the adjusting piston rod  185 . 
     Sealing of the gaps formed by the faces of joined-together components can be achieved by a smooth, flat embodiment of the sealing faces, which is effected by grinding or precision turning, for example, or by seals, such as rubber washers, placed between the sealing faces  171 . 
     In accordance with the invention, the intermediate element  167  and the partition  165  may already form a structural unit because of how they are produced, for example, making this component in the form of a flangelike or cup-shaped turned part. 
     An embodiment that is advantageous in terms of both production and function includes a partition  165  which has a pressure fluid connection  173 ,  186 ,  189  formed of two bores  174  and  175  which open into one another. This preferred embodiment makes good pressure fluid feeding feasible, even when the stroke lengths of the actuator  165 ,  185  are very short. The bore  174  extending perpendicularly to the central axis of the adjusting piston rod  184  may, as shown in FIG. 3, be formed as a stepped bore with a thread  176  for connecting the pressure converter  103  to pressure fluid delivery lines and/or drain lines, which are not illustrated. The supply of pressure fluid to the expansion chambers may, however, also be effected via recesses  188  formed in some other manner. 
     Depending upon the installed position of the partition  166  and the orientation of the bore  175 , the pressure fluid connections  173  and  189  may serve for the first pressure fluid system and the pressure fluid connections  186  for the second pressure fluid system. 
     In at least one pressure stage, two or more expansion chambers may be acted upon by the first pressure fluid, in addition to the number of expansion chambers acted upon in the previous pressure stage. To that end, the control of pressure fluid in the first pressure fluid system may be constructed accordingly, so that a plurality of additional expansion chambers  172  per pressure stage can be supplied with the first pressure fluid, via individual pressure fluid connections  173  associated with these expansion chambers. A transverse conduit  187  which connects a plurality of expansion chambers, for example, two of them, may also be provided, so that the two expansion chambers can be supplied via a single common pressure fluid connection  189 . Furthermore, more than one expansion chamber may be connected to the second pressure fluid system. 
     FIG. 5 shows the application of the features according to the invention to an apparatus for performing actuations that are to be performed in succession in a printing press, the apparatus having a pressure converter  190  operating on the rotary principle. The pressure converter  190 , including rotary parts, has an actuator  198  embodied as a vane wheel which, in a housing  210  of circular-cylindrical outer contour, is supported rotatably relative to the housing. The pressure converter  190  also includes expansion chambers  192 ,  196 ,  197  of circular sector-like cross section, which can be acted upon by pressure fluid and are defined by actuator faces  200 ,  202 ,  204  operative therein and by partitions  199 . The actuator  198  is rotatable relative to the housing  210  in one rotational direction  296  by an application of pressure fluid into expansion chambers, for example, three expansion chambers  192 ,  196  and  197 . The mode of operation of the apparatus that includes this pressure converter  190  may be equivalent to that of the apparatus described in conjunction with FIG. 1 but, instead of the pressure converter  103  with a displaceable actuator  101  shown therein, the rotationally acting pressure converter  190  is integrated with the apparatus, so that the cooperation of individual components of the apparatus as described in conjunction with FIG. 1 is applicable in the same manner to the pressure converter  190  operating on the rotary principle.