Patent Publication Number: US-6902519-B2

Title: Folding device

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a folding device of a rotary printing press. The folding device includes at least one folding jaw cylinder and one folding blade cylinder. An electric motor can be used to drive the pair of cylinders. 
   BACKGROUND OF THE INVENTION 
   Folding devices for a rotary printing press, which have a folding jaw cylinder and a folding cylinder working together with the folding jaw cylinder are known from DE 195 09 947 A1, as well as from DE 195 25 169 C2. In connection with these folding devices, it is disadvantageous that the product guidance is complicated. Thus, a signature arriving from a cutting groove cylinder must first be transferred to a folding jaw cylinder, and from there to a transverse folding cylinder before it reaches a belt guidance system, which conveys the product to a delivery device. The transverse folding cylinder of these folding devices must continuously run during production, even if it is not used for creating a transverse fold, since it is needed for conveying the signatures. Transfer or hand-over errors between the cylinders can lead to so-called “paper plugs”, which can result in damage to the cylinders. 
   DE 43 18 133 A1 describes a folding device, which selectively creates products with a transverse fold in a first operating mode, and in a second operating mode, forms products with an additional second transverse fold. A first and second folding blade cylinder is arranged for this, wherein the signatures of the products of the second folding blade cylinder are selectively stripped off by means of belts. 
   DE 36 36 244 C2 discloses a folding device with a pivotable stapling cylinder, which selectively works together with a first or second folding jaw cylinder. 
   SUMMARY OF THE INVENTION 
   It is the object of the present invention to provide a folding device. 
   In accordance with the present invention, this object is attained by providing a folding device having at least one folding jaw cylinder and a folding blade cylinder that is working with it in a working position. The folding blade cylinder can be moved from a working position to a rest position. A second folding blade cylinder may also be provided. The first folding blade cylinder and the folding jaw cylinder can be mutually driven by one electric motor. The second folding blade cylinder is independently driven by a second electric motor. 
   The advantages to be attained by the present invention consist, in particular, in that damage to the folding device by paper plugs are prevented, and that the accessibility of the parts of the folding devices for maintenance purposes is simplified. 
   By shutting down cylinders which run unnecessarily, it is furthermore intended to achieve that the folding device becomes more energy-saving, wear resistant and quieter. 
   Because the displaceable cylinder is seated between two lateral elements, which can be pivoted against lateral frames of the folding device, a modular construction is made possible. The employment of a specifically assigned motor for driving the displaceable folding cylinder allows the decoupling of its movements from vibrations caused in the folding device by variably loaded other rotatably driven parts, such as a cutting and punching roller. 
   A further advantage of the specifically assigned motor is that, in a way different from a common drive of the folding cylinder and folding jaw cylinder by meshing, the phase position of the folding cylinder in respect to the folding jaw cylinder working together with it can be changed in a simple manner by a suitable control of this motor. Thus it is possible, in particular, to provide a coupling of the rotation of the motor to the width of the folding jaw gap in such a way that, with any width of the folding jaw gap, a folding blade of the folding cylinder enters the folding jaw gap centered. In this way, the folding device can be adapted very simply and rapidly to the processing of signatures of various thicknesses. 
   A further advantage lies in that the provision with a second transverse fold does not have any substantial effect on the design of the base unit of the folding device, i.e. that the otherwise customary bearing bores and the oil space required for the gear drive are omitted and do not require an increase in height of the frames of the folding device. 
   In accordance with a preferred embodiment, the folding device in accordance with the present invention furthermore has a folding cylinder that is seated fixed in place. In this case, the folding cylinder seated fixed in place can be used for creating a first transverse fold of the product, while the displaceably seated folding cylinder can be employed for creating a second transverse fold. While, for example, customarily a large portion of a printing of newspapers which are intended for delivery to subscribers or for street sale are produced with a single transverse fold, that portion of the printing intended for being sent by mail requires a second transverse fold in order to give the newspaper a format suitable for mailing. The folding device in accordance with the present invention permits the production of the newspaper with or without a second transverse fold, wherein the folding cylinder which can be displaced for the portion of the printing without a second transverse fold, can be pivoted into a position of rest and its drive mechanism can be shut off while the folding device is running. 
   In connection with a folding device with two folding cylinders, it is furthermore preferred that the folding jaw cylinder have pairs of folding jaws, wherein the second folding jaw of a pair works respectively together with another folding cylinder. This permits the simplification of the product guidance, because with such a structure, a signature can be picked up by the holding device of one of the two folding cylinders and the signature can be folded by pressing it into the gap of the first folding jaw with the aid of the folding blade of the folding cylinder and can be transferred to the folding jaw cylinder. Subsequently, the product folded in this way can be pushed by the folding blade of the other folding cylinder into the gap of the second folding jaw of the pair and in this way can be provided with a second transverse fold without it being necessary to transfer it to another cylinder. Therefore, the finished folded product can be transferred directly from the folding jaw cylinder to a belt guidance system or the like, and product conveyance is simplified in this way. 
   To make possible a center fold in connection with each product, even of different formats, the two gaps of the two pairs of folding jaw working together are usefully adjustable in respect to each other in the circumferential direction; the grippers in the folding cylinder are distributed in the same way. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
       FIG. 1 , a schematic section through a folding device in accordance with the present invention during a first phase of the folding process, 
       FIG. 2 , a partial section corresponding to that in  FIG. 1  during a second phase of the folding process, 
       FIG. 3 , a partial section corresponding to  FIG. 2  during a third phase of the folding process, 
       FIG. 4 , a portion of the folding device with a folding cylinder displaced into a passive position, 
       FIG. 5 , a guide or pressure element, 
       FIG. 6 , a gripper regulating device, or folding jaw regulating device in axial section, 
       FIG. 7 , a partial lateral view of the folding device, 
       FIG. 8 , a schematized representation of the drive mechanism of the displaceable folding cylinder, 
       FIG. 9 , a further development of the folding device in partial section corresponding to FIG.  4 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A schematic section through a folding device of a rotary printing press, in accordance with the present invention, is represented in  FIG. 1. A  web  1 , or a strand consisting of a plurality of webs, coming out of a former (not represented) and entering the folding device, first passes over a pair of traction rollers  2  and thereafter reaches a first gap  3  between a cutting cylinder  4  and a first folding blade cylinder  7 , which is seated fixed in place. On its circumference, the cutting cylinder has blades which act together with blade grooves of the first folding blade cylinder  7  and cut the web  1  into individual signatures. The individual signatures are grasped by a holding device of the first folding blade cylinder  7 , such as a gripper or point needles, and in this way the signature is conducted in a counterclockwise direction in the drawing figure between the first folding blade cylinder  7  and a lower region of a first guide plate  6  extending around the first folding blade cylinder  7 . 
   The first guide plate  6  terminates in the vicinity of a second gap  8  between the first folding blade cylinder  7  and a folding jaw cylinder  9 . On its circumference, this folding jaw cylinder  9  has a number of first folding jaws  11 , which are evenly spaced apart from each other in the circumferential direction. In the example represented in  FIG. 1 , the folding jaw cylinder  9  has three first folding jaw pairs  11  at an angular distance of 120°. The distance between two first folding jaw pairs  11 , measured on the circumference of the folding jaw cylinder  9 , corresponds to the length of a not yet folded signature. Each of the first folding jaw pairs  11  has a strip-shaped cheek or jaw  12 , fixed in place on the folding jaw cylinder  9 , and a pivotable cheek or jaw  13  coupled with the rotary motion of the folding jaw cylinder  9 . The coupling of the movement of the pivotable cheek or jaw  13  to the rotation of the folding jaw cylinder  9  takes place with the aid of a cam plate, not represented in FIG.  1 . The latter opens the gap of the first folding jaw pair  11  shortly before it reaches the gap  8 , so that a folding blade mounted on the first folding blade cylinder  7  can press the signature carried along by the first folding blade cylinder  7  into the gap of the first folding jaw pair  11  during the passage through the gap of the first folding jaw pair  11 . A first center transverse fold is created in the signature in this way. While, after passage through the gap  8 , the folding blade of the first folding blade cylinder  7  is retracted, the cheeks or jaws  12 ,  13  of the first folding jaw pair  11  close, so that the signature remains stuck in the first folding jaw pair  11  and in this way is taken over by the folding jaw cylinder  9  and is conveyed on. 
   To this point, the mode of operation of the folding device corresponds to that of conventional folding devices, for which reason a detailed representation of the cutting cylinder  4  and the first folding blade cylinder  7  has been omitted, also in FIG.  1 . 
   A second guide plate  14  closes the outlet nip of the second gap  8 . It is used to fold over the front half of the signature released from the holding device of the first folding blade cylinder  7 , so that the signature, with the fold leading, is conveyed on by the folding jaw cylinder  9 .  FIG. 1  shows a signature identified by  16  in this stage of processing, wherein the formerly leading part  17  of the signature  16  brushes along the second guide plate  14 . 
   A guide or contact element  18  follows the second guide plate  14 , and its construction will be shown in greater detail in FIG.  5  and will be described at a later time. This guide or contact element  18  is located in the entry nip of a third gap  10 , which is defined between the folding jaw cylinder  9  and a second folding blade cylinder  19 , as seen in FIG.  2 . On its circumference, this second folding blade cylinder  19  supports two holding devices placed diametrically opposite each other, in this case in the form of grippers  21 . Since the number of the grippers  21 , or of the folding blades  22 , is less than that of the first folding jaws  11 , the diameter of the second folding blade cylinder  19  is also comparatively less than that of the folding jaw cylinder  9 . This makes the arrangement of the two folding blade cylinders  7 ,  19 , and of a belt guidance system, on the circumference of the folding jaw cylinder  9 , described later, easier. 
   In the phase of the folding process represented in  FIG. 1 , one of these grippers  21  is just in the process of taking over the signature  16  in the area of its first transverse fold from the opening first folding jaw pair  11 . The second folding blade cylinder  19  furthermore has two folding blades  22 . The distance between the gripper  21  and the following folding blade  22  on the second folding blade cylinder  19  can be adjusted and is advantageously set to a quarter of the length of the signature  16  in order to place a second transverse fold centered into the already once transversely folded signature by use of the folding blade  22 . 
   On its circumference, this second folding blade cylinder  19  can have a plurality of holding devices, which are located at identical distances from each other, in this case in the form of grippers  21  and two in number. The folding blades are also placed in the same way as the holding devices, spaced apart from the holding devices at the same distance corresponding to the length of the format. The fewer the number of holding devices, or folding blades, the smaller the structure of the second folding blade cylinder can be. In the most simple case, one holding device and one folding blade can also be provided. 
   The phase of forming the second transverse fold is represented in  FIG. 2  by use of a partial section. In this phase, the first transverse fold of the signature  16  is lifted off the surface of the folding jaw cylinder  9  by the gripper  21 ; the first folding jaw pair  11  is empty and open. A second folding jaw pair  23  is arranged on the circumference of the folding jaw cylinder  9  at a distance from the first folding jaw pair  11  corresponding to the distance between the gripper  21  and the folding blade  22  on the second folding blade cylinder  19 . The spacing between the first and second folding jaw pairs  11 , or  23 , is also adjustable. 
   The folding blade  22  pushes the signature  16  into the open gap of the folding jaw pair  23 , and the signature  16  is clamped in the gap. At the same time the gripper  21  releases the first transverse fold of the signature  16 . 
   Guide brushes  24  are arranged in the outlet nip of the gap between the second folding blade cylinder  19  and the folding jaw pair  9 . As can be seen in  FIG. 3 , they are used to pivot the two legs of the now twice transversely folded signature  16  against the surface of the folding jaw cylinder  9  and thus to complete the folding process. The twice folded product  26 , finished after the passage between the guide brushes  24  and the folding jaw cylinder  9 , can be seen in FIG.  2 . 
   A belt guidance system  27 , schematically represented in  FIG. 1 , with belts  29  guided around rollers  28 , takes over twice folded the product  26 , which is released in the approximate position represented in  FIG. 2  from the second folding jaw  23 , and conducts it to a bucket wheel  31 , which in the customary manner places the product  26  overlappingly on a belt delivery device  32 , wherein the guide tongues  100  are pivoted toward the detent  101  at a distance approximately corresponding to the length of the twice folded product  26 . 
   Together with the guide or contact element  18  and the guide brushes  24 , the second folding blade cylinder  19  constitutes a modular unit, which can be displaced from a working position of the second folding blade cylinder  19 , represented in  FIGS. 1  to  3 , into a passive position represented in FIG.  4 . In this passive position, the second folding blade cylinder  19  has been pivoted at an angle of approximately 105° around a shaft  33  in respect to the working position, in its place a third guide plate  34  has been pivoted up against the folding blade cylinder  9  and in this way constitutes a continuous guide gap  36  for the signature  16 , which extends substantially without interruption from the second guide plate  14  to a guide body  37  and further as far as the first roller  28  of the belt guidance system  27 . In this way, the third guide plate  34  prevents the freshly folded signature  16  from unfolding again during its travel from the end of the second guide plate  14  to the tip of the guide body  37  when the second folding blade cylinder  19  is in its passive position. The guide tongues  100  are pivoted away from the detent  101  at a distance approximately corresponding to the length of the product  26 . 
   In this way, it is possible, by simple pivoting of the component consisting of the guide or contact element  18 , the second folding blades  19  and the guide brushes  24 , to switch between a production with single or with double transverse folds. Since the second folding blade cylinder  19  no longer has a conveying function in the production of a single transverse fold, its drive mechanism can be switched into the passive mode, even if the folding device is operated. 
     FIG. 5  shows in detail the structure of the guide or contact element  18 . It is comprised of a carrier  38 , which is fixedly connected with a not specifically represented lateral element  74  as seen in  FIG. 7 , which simultaneously constitutes a holder for the shaft  33  of the second folding blade cylinder  19  and supports the guide brushes  24 . A pivot arm  39  hinged on the carrier  38  supports on one end a rotatable roller  41  and on the other end two bores for a screw  42  and a threaded pin  43 . The threaded pin  43  can be axially adjusted and has a tip  44  located opposite the carrier  38 . This tip  44  constitutes a detent, which limits a pivot movement of the roller  41  in a counterclockwise direction. The screw  42  extends through a bore of the carrier  38  and on its distal end has two knurled nuts  46 ,  47 , of which the one knurled nut  46  is used for setting the pivotal freedom of movement of the roller  41 , and the other knurled nut  47  is used for checking the first knurled nut  46 . A spring  48 , for example a helical spring  48 , exerts a torque in a clockwise direction on the pivot arm  39 . 
   The setting of the threaded pin  43  defines the maximum distance over which the roller  41  can be spaced from the folding jaw cylinder  9  by pivoting the pivot arm  39  in the course of a passage of a signature  16  between the roller and the folding jaw cylinder. Usefully, this maximum distance has been set to a value which corresponds to the expected maximum thickness of the singly transversely folded signature  16 , plus a slight play. If, in the case of a paper plug, the thickness of the signature  16  is greater and the roller  41  is pushed upward past the amount predefined by the threaded pin  43 , the entire component is pivoted by this from the working position upward, and damage to the sensitive movable parts of the folding jaw cylinder  9  and the second folding blade cylinder  19  is prevented. 
   It is alternatively possible to also provide a servo mechanism, which measures the force transferred from the roller  41  to the carrier  38  and which, when a threshold value is exceeded, drives an actuating member for pivoting the second folding blade cylinder  19  out of its working position. 
   As  FIG. 7  shows, the pivoting in and out of the folding blade cylinder  19  can also be caused by use of an electric motor  73 , which acts on the shaft  33  and, by means of an electrical standstill moment against a gas pressure spring  75 , keeps the folding blade  19  down in the working position, and in case of an overload because of a paper backup, the pivoting away can be triggered by a limitation of the moment. 
   In case of an electrical outage, the gas pressure spring  75  takes on the function of the lift off by itself in order to achieve a safe distance between the folding jaw cylinder  9  and the folding blade cylinder  19 , which protects the grippers  21  and folding blades  22 , even at the time of spinning down of the electric motor. Up to the time of spinning down, the synchronous braking is fed by the remaining voltage from the intermediate circuit. 
   It is a second object of the guide or contact element  18  to assure a low-friction guide of the signature  16 . Because of its ability to rotate, the roller  41  exerts a substantially reduced friction on a passing signature  16  than would be the case with an immovable guide plate, such as the second guide plate  14 . Therefore, at the moment of the transfer of the first transverse fold to the gripper  21  of the second folding blade cylinder  19 , at best only small braking frictional forces act on the signature  16 , which simplifies the transfer and improves accuracy. 
   As already mentioned, the mutual distance between the first and second folding jaw pairs  11 ,  23  of the folding jaw cylinder  9 , and of the grippers  21  and the folding blades  22  of the second folding blade cylinder  19 , can be adjusted.  FIG. 6  shows in schematic section a structure of a rotatable suspension, by use of which such an adjustment can be controlled. The structure is described here with respect to the folding jaw cylinder  9 , but can be applied to the second folding blade cylinder  19 . The suspension is comprised of a flange  50 , which is fastened by one of its front faces, in this case the inner front face  49 , on a lateral frame  51  of the folding device. A cylindrical extension  52  projects through an opening of the lateral frame  51  into the interior of the folding device; a spindle  53  is guided in an axial bore of the extension  52 . On its end pointing into the interior of the folding device, the spindle  53  has a screw thread  54  on which a nut  56  is seated. A torsion prevention pin  57 , which is rigidly connected with the nut  56 , engages a blind bore  58  of the extension  52 . By use of this, the nut  56  is held fixed against relative rotation, but can be moved back and forth by rotating the spindle  53 . 
   On its exterior circumference, the nut  56  has a bearing  59 , for example a deep groove ball bearing  59 . Axial regulating forces can be transferred from the nut  56  to a rotatable regulating drum  61 ,  77  via the deep groove ball bearing  59 . The regulating drum  61 ,  77  is furthermore supported by an axially displaceable bearing  62 , for example a needle bearing, on the exterior circumference of the extension  52 . On its exterior circumference, the regulating drum  61 ,  77  has two helical gearings  63 ,  64 ,  82 ,  83 , each with different helix angles. The two helical gearings  63 ,  64 ,  82 ,  83  mesh with two crown gears  66 ,  67 ,  84 ,  86 , of which one crown gear  67 ,  86  supports the surface shell of the folding jaw cylinder  9 , as well as the first folding jaws  11 , which are fixedly connected with the shell surface, the other crown gear  66 ,  84  is connected with the adjustable second folding jaws  23 . 
   A rotation of the spindle  53  causes an axial displacement of the regulating drum  61 ,  77  and, along with it, a turning of the two crown gears  66 ,  67 ,  84 ,  86  in relation to each other, depending on the helix angles of the helical gearings  63 ,  64 ,  82 ,  83 . The length of the turning is a function of the difference between the helix angles, as well as the diameter of the folding jaw cylinder  9 . A length of a few centimeters in respect to the circumference of the folding jaw cylinder  9  is fully sufficient for most practical applications. 
   To achieve the radian measure between the folding jaw pairs  11  and  23 , and the one between the grippers  21  and the folding blade  22 , simultaneously and at the correct ratio, each of the two displacement devices in  FIG. 6 , which are engaging the folding jaw cylinder  9  and the folding blade cylinder  19  with teeth, is equipped with a regulating drive, which acts on the spindle  53 . 
   An adjustable detent  78 ,  80 , as seen in  FIG. 7 , each is attached at two positions remote from the shaft  33  on the lateral frame  51 . While the contact of the lateral element  74  with the detent  78  activates the working position of the second folding blade cylinder  19 , the contact of the lateral element  74  with the detent  80  triggers the position of rest of the second folding blade cylinder  19 . 
   The position of the second folding blade cylinder  19  in relation to the folding jaw cylinder  9  can be set in the working position regardless of the regulating accuracy of the electric motor  73 , or of the reduction gear, with the aid of the detent  78 . 
   The detents  78  and  80  furthermore contain an initiator, or switch, which upon contact with the lateral element  74  triggers a stop of the electric motor  73  and releases other drive motors of the folding device again, including the second electric motor  76 . 
   A contactless state of the lateral element  74  with the detents  78  and  80  triggers, besides the electric motor  73 , a stop of all drive motors in the folding device, including the second electric motor  76 . 
   As also described, in the working position of the second folding blade cylinder  19 , the electric motor  73  exerts a pressure via a predetermined standstill moment on the detent  78 , as well as on the gas pressure spring  75 , which is therefore compressed and represents a counter-force. If thereafter the pressure between the two cylinders  9  and  10  becomes too great because of a paper backup and the danger of damage to the press arises, the standstill moment on the electric motor  73  is overcome, the electric motor  73  is then set into operation and lifts the second folding blade cylinder  19  upward out of the work area via the gear and with the aid of the gas pressure spring  75 . All motors of the folding device, including the second electric motor  76 , are stopped. 
     FIG. 7  shows a schematic lateral view of a portion of the folding device. An upper edge  68  of the lateral frame  51  of the folding device can be seen. The cutting cylinder  4 , the first folding blade cylinder  7 , the folding jaw cylinder  9 , the belt guidance system  27  and the bucket wheel  31  are arranged between the lateral frame  51  and an oppositely located lateral frame, not represented. The circumference of the folding jaw cylinder  9 , which is hidden by the lateral frame  51  in  FIG. 7 , is indicated by a dashed line  71 . A housing  72  with an electric motor  73  is mounted on the lateral frame upper edge  68 . The housing  72  contains, for example, a reduction gear for transferring the drive force of the electric motor  73  to the shaft  33  so that, as already explained, the second folding blade cylinder  19  can be pivoted out of its working position into a passive position. The second folding blade cylinder  19  is rotatably seated between two lateral element  74 , one of which is visible in the drawing figure. Actually, in the working position the lateral element is represented by a solid outline, and in the passive position by a dashed outline; the shaft  33  is fixedly connected with both lateral elements  74 . A second electric motor  76 , indicated by a dashed outline, is mounted on the side of the lateral element  74  facing away from the viewer, which drives the second folding blade cylinder  19  in a rotating manner by means of a pinion gear  81  via a regulating drum  61 ,  77 , also indicated by dashed lines. Moreover, the guide or contact element  18  and the guide brushes  24  are mounted between the two lateral elements  74 . 
   Together, the elements  74 ,  76 ,  77 ,  78 ,  18 ,  19  and  24 , together with the housing  72  and the electric motor  73 , constitute an independent module which, when not used, can be removed from the folding device. This modular construction also permits the building of simple and cost-efficient folding devices which lack the module, but which are equipped for the retroactive mounting of such a module. This makes it possible for a print shop to keep the investment for a folding device low as long as there is no requirement for products with double transverse folds; but if such a requirement arises, the folding device can be made suitable in a cost-efficient and simple and space-saving manner for the production with double transverse folds by purchasing the module. 
   A control circuit, not specifically represented, controls the rotary movement of the second electric motor  76 , and therefore that of the second folding blade cylinder  19 , exactly synchronous with the rotary movement of the folding jaw cylinder  9 . In this case, the relative phase position of the folding jaw cylinder  9  and of the second folding blade cylinder  19  are regulated, taking into consideration the gap width set at the second folding jaw pairs  23  for receiving the signature  16 , so that it is assured that a folding blade  22  of the second folding blade cylinder  19  always enters centered in an associated folding jaw gap. 
     FIG. 8  shows, greatly schematized, the drive mechanism of the second folding blade cylinder  19 . The second electric motor  76  drives a pinion gear  81  via a coupling  79 , which is used to shield the second electric motor from irregularities in the rotary movement of the downstream-arranged gear. This gear includes, besides the pinion gear  81 , the regulating drum  61 ,  77  driven by it, which had already been mentioned in respect to FIG.  7 . As can be seen in  FIG. 8 , this regulating drum  61 ,  77  has two helical gearings  63 ,  64 ,  82 ,  83 , of which only one helical gearing  82  meshes with the pinion gear  81 . The construction of the regulating drum  61 ,  77  corresponds to the construction described in connection with FIG.  6 : the gearings  82 ,  83  are helical gearings with different helix angles than those of the helical gearings  63 ,  64 , and they are axially displaceable by use of a mechanism which can be driven with the aid of a rotary spindle. An angular offset between the two gear wheels  84 ,  86  driven by the helical gearings  82 ,  83  can be adjusted by that axial displacement. The gear wheel  84  drives the rotary movement of the folding blades  22  via a hollow shaft  87  and two arms  88 , more clearly visible in  FIG. 1 , which are connected with each other in the axial direction by cross pieces  90 ; the gear wheel  86  drives the rotation of the shell surface of the second folding blade cylinder  19 , as well as the grippers  21 , via a shaft  89  passed through the hollow shaft  87 . 
   The drawing figure of  FIG. 8  furthermore schematically shows pivot arms  69 , which are each connected with one of the respective folding blades  22 , or grippers  21 , and which roll off on a cam disk  70 , fixedly connected with one of the lateral elements  74 , and in this way assure an opening and closing movement of the gripper  21 , or a pivoting-out movement of the folding blade  21  coupled to the respective rotary position of the second folding blade cylinder  19 . 
   Coupled electric motors can be provided for the respective rotary drive of the spindle  53  on the folding jaw cylinder  9 , as well as the functionally equivalent spindle of the regulating drum  61 ,  77 , wherein it is assured by use of the coupling that the distances between the first and second folding jaw pairs  11 ,  23  on the one hand, and between the grippers  21  and folding blades  22  on the other hand are always varied in the identical way. 
     FIG. 9  shows a further embodiment of the folding device in partial section analogous to the one in FIG.  4 . Components which had already been described in respect to  FIGS. 1  to  8  here have the same reference symbols and will not be described again. In  FIG. 9  the second folding blade cylinder  19  is in the passive position, in which a wide space exists between it and the folding jaw cylinder  9 . A belt guidance system  91  has two movable rollers  92 ,  93  which, when the second folding blade cylinder  19  is in the working position, are in an inactive, not represented position, behind the guide brushes  24  and which are coupled to the position of the second folding blade cylinder  19  in such a way that, when the second folding blade cylinder  19  is pivoted into its passive position, they advance opposite the conveying direction of the signature  16  on the folding jaw cylinder  9  in the direction of the arrow  94  into the positions represented in  FIG. 9. A  further roller  96  of the belt guidance system  91  can be displaced transversely to the general orientation of the belt guidance system  91  in the direction of the arrow  97  against a spring force in order to maintain the belt  98  guided by the rollers  92 ,  93  tightly stretched regardless of the position of the rollers  92 ,  93 . In the position of the belt guidance system  91  indicated in  FIG. 9 , this belt  98  touches the circumference of the folding jaw cylinder  9 , on that portion of its circumference, where the first folding jaw pairs  11  open for releasing the signature  16  guided from the inside. The guide body  37  is pivotably suspended and touches the surface of the folding jaw cylinder  9  under the pressure from the belt  98 . The signature  16  released from the first folding jaw  11  is lifted off the folding jaw cylinder  9  in this way and is conveyed on between the guide body  37  and the belt  98 . A second belt  99  of the belt guidance system  91  adjoins the end of the guide body  37  which is at the rear in the conveyance direction. The signature  16  is conveyed between the two belts  98 ,  99  to the inlet of a folding device, not specifically represented for forming a second longitudinal fold. In this way, the embodiment in accordance with  FIG. 9  selectively allows, depending on the position of the second folding blade cylinder  19 , the formation of a second transverse fold or of a second longitudinal fold in the product  26 . 
   A further development, which is not represented in a separate drawing figure, comprises the pivotable third guide plate  34  from  FIG. 4 , as well as the belt guidance system  91  from FIG.  9 . With this structure, the movement of the rollers  92 ,  93  is coupled to the pivot movement of the folding blade cylinder  19 , as well as to the movement of the third guide plate  34 . This coupling achieves that, when the folding blade cylinder  19  is in its passive position, either the guide plate  34  can be folded against the folding jaw cylinder  9 , as represented in  FIG. 4 , or the belt guidance system  91  enters into the intermediate space  95 . With this structure, the selective production with simple transverse folds, with double transverse folds, or with a single transverse and a second longitudinal fold is therefore possible. 
   While preferred embodiments of a folding device in accordance with the present invention have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that changes, in, for example, the specific printing press used, the specific structure of the grippers and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.