Abstract:
A paper web is drawn into a printing and can be guided along a selected one of several paths. The paper web is weakened along a line of separation and is then held by a retaining system that can move the web in a conveying direction along a first path. The web is fed to a different conveying path and is separated ot torn along the line of separation. This line of separation or weakening is formed at an angle to the production direction.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and to a device for drawing in a paper web, as well as to a corresponding device. 
     DESCRIPTION OF THE PRIOR ART 
     It is known, from DE 25 32 168 C3, to draw in webs of material to be printed, for example paper webs, from a roll support to a folding apparatus of a web-fed rotary printing press by means of web draw-in devices. It is also possible to select different movement tracks for the webs of material to be printed. 
     U.S. Pat. No. 5,279,195 A describes a device for separating a defective section of a web. In the process, the web is cut, the fresh start of this web is guided to another web guide and this start is again cut off the web. The now fresh start is again guided to the original web guide. 
     EP 0 479 385 A1 discloses a device for cutting perforated sheets. Here, two pairs of rollers are arranged, between which the sheets are conveyed at different conveying speeds. 
     EP 0 297 282 A1 shows a device for dividing a flow of printed pieces. In this case, a web is cut into signatures by means of two eccentrically seated cutting cylinders and is alternatingly guided onto two tracks. 
     DE 196 26 014 A1 describes a device, having an air-permeable conveyor belt, for cutting a fleece into longitudinal sections. Here, a part of the fleece is held in place by means of suction air, and the other part is moved on in the conveying direction. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a method for guiding a paper web, as well as an associated device. 
     In accordance with the present invention, this object is attained by creating a fresh or new start on a paper web in a direction transverse to the web travel direction. The web is separated at this new start and the path of travel of the web subsequent to this new start can be changed to a second, different web travel path. 
     The advantages to be obtained by the present invention consist, in particular, in selectively rerouting one of a number of moving paper webs, or one or several partial paper webs, independently of each other onto predeterminable movement tracks, without it being required to stop the press, or the system, or for the operators to rehang the webs or the partial webs. In connection with a web-fed rotary printing press, for example, it might be possible to make a movement track change of a web, or of a partial web, while production is running. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the present invention is represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
     FIG. 1, a schematic representation of a side view of a device for directing a path of web or partial web travel in accordance with the present invention, 
     FIG. 2, a section taken along line II—II of FIG.  1  and in an enlarged representation, and in 
     FIG. 3, a view from above in accordance with FIG. 1, but without the conveyor belts. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A device  3  for reducing the tear resistance of a paper web  1  moving in the production direction E of the web is provided, as seen in FIG.  1 . This device  3  can consist, for example, of a transverse perforation device, or also of another similar device, for example a device, such as a plurality of nozzles for applying a liquid track of a solvent or water transversely over the width of the web  1 , or respectively over the widths of partial webs  16 ,  17 ,  18 ,  19  to be processed. Viewed in the production direction E of the web, the web tear resistance reducing device  3  can be arranged ahead of, or behind a longitudinal separating device  2 , known per se, of the moving paper web  1 . 
     The transverse tear resistance reducing device  3  can consist of forming rollers  4  and of bottom rollers  6 , which can be placed against each other. The paper web  1  in a first movement track A, can be rerouted out of the movement track A, or into a further movement track, for example the movement track B, or into a further movement track C. For example, the movement track A may extend essentially horizontally between two first forwarding systems  8 ,  8 . The movement track B may extend underneath the movement track A, wherein the paper web  1  is rerouted over two paper guide rollers  9 ,  11 . The movement track C may extend above the movement track A between two second forwarding systems  7 ,  7 . 
     The first and second forwarding systems  7 ,  8  are each devices for grasping and temporarily forwarding a part of the paper web  1 , or the partial paper webs  16 ,  17 ,  18 ,  19 . They can be, for example, so-called driven suction belts, suction rollers, or electrostatic belt devices. A plurality of deflection rollers  14  can be provided for rerouting. 
     The paper web  1  can also be longitudinally cut into several partial paper webs  16 ,  17 ,  18 ,  19 . A longitudinal cutting device  2 , or a plurality of longitudinal cutting devices  2 , as seen in FIG. 3, and which are known per se, can be used for this purpose. 
     Viewed in the production direction E of the paper web  1 , a device  13 , or devices  21  to  24  for grasping a start of a web  1  of material, or starts of partial webs of material  16  to  19 , respectively, at their upper and/or undersides and for their subsequent rerouting into a second movement track, for example B or C, and back, are provided in the first movement track A, after the device for reducing the tear resistance of the web  1 , or the partial webs  16 ,  17 ,  18 ,  19 , and before the forwarding systems  7 ,  8 . For example, this rerouting device can be used for rerouting webs from movement tracks A+C only into the movement track A, or from the movement tracks A+B back toward the movement track A, or from the movement tracks A+B toward the movement track A+C, etc. In this phase, the web, or a partial web, is clamped under tensile stress between two spaced-apart devices. For example, this can occur between two pairs of drawing rollers, between one pair of drawing rollers and cylinders (for example rubber blanket cylinders) of a print unit, or between cylinders of two spaced-apart print units. The web  1 , or the partial webs  16  to  19 , are therefore clamped between two such spaced-apart devices, while a web tension is maintained, and they are pulled apart or separated. 
     It is accordingly to select the number of partial webs per movement track (A, B, C), and therefore the composition and number of pages of the signatures, in a particularly simple manner. This is, of course, dependant on the occupation of the print units. Web transfers, known per se, are required for this. 
     The following actions take place: 
     The clamped paper web  1 , or the clamped partial web  16 , each move along a movement track, for example A. By the application of a force through the devices  13 ,  21  to  24  for rerouting a web on their upper and/or undersides, the web  1  or the partial web  16  are pulled out of their original movement track, for example A, and are directed onto another movement track, for example movement track B, or movement track C. Because the device  21  to  24  for rerouting has a device  44  for holding and conveying of the web or the partial web, as seen in FIG. 2, the held web  1 , or the partial webs  16  to  19  are therefore simultaneously moved along the former movement track, for example movement track A, and along the newly selected movement track, for example movement track C, and is or are accordingly separated at a predetermined breaking point or at a predetermined tear line formed by transverse perforations or by a water track made in the web  1 , or partial webs  16  to  19  by the device  3 . This occurs because the tear resistance is exceeded by the pulling force exerted on the web or the partial web at the predetermined transverse breaking point formed by the device  3 . The affected web or the partial web is completely separated in such a way, that a “fresh” web end  5  and a “fresh” web start  15  are created. Together with its “fresh” web end  5 , the web  1 , or respectively the partial webs  16 ,  19 , are pulled, for example, along their former movement track by drawing rollers, printing units, etc. The “fresh” web start  15  of the web  1 , or of the partial webs  16  to  19 , as well as the latter themselves, are held by the devices  21 - 24  for rerouting , are moved along the newly selected movement tracks, for example C, and are finally transferred to a forwarding system, for example  7 , and are transported to an intended destination, such as, for example, a pair of drawing rollers, a print gap of a print unit, and taken over by them. 
     The shape of the predetermined breaking point or of the predetermined tear point can actually be designed in almost any arbitrary manner. 
     For example, the break or of tear point can be embodied as an acute-angled tip in the shape of a right triangle starting at one of the lateral edge, or also as a simple, non-oblique, i.e. straight tear. 
     The devices  13 , or  21  to  24  for rerouting, which are suitable for rerouting, holding and conveying a web  1 , or a partial web  16  to  19 , for example can consist of a suction belt station, or of several suction belt stations  21  to  24 , arranged next to each other and each centered over one partial web  16  to  19  of material to be printed. The suction belt stations  21  to  24  are each constructed the same. Only the suction belt station  21  shown in FIGS. 1 and 3 will be described in what follows. 
     The suction belt station  21  consists of several suction chambers  26 ,  27 ,  28 ,  29  which, viewed in the production direction E of the web, are arranged one behind the other. Each chamber  26 ,  27 ,  28 ,  29  is closed on five sides and has, for example, a trapezoidal cross section as seen in FIGS. 1 and 2. On their lower, wider bases  31 , these chambers are flexibly connected with each other, for example by hinges. The narrow upper bases  32  are slightly convexly arched and have a plurality of holes. The narrow upper bases  32  are held apart adjustably by means of turnbuckles  33 . Such an arrangement of the chambers  26  to  29  selectively makes a straight, a convexly curved, or a concavely curved suction track possible. 
     A start  34  and an end  36  of each suction belt station  21  has, viewed in the production direction E, a holder  37 ,  38 , which is connected with its respective chamber  26 ,  29  and which supports a front belt roller  39 , or a rear belt roller  41 , respectively. All cylinders, rollers, and the like are seated in lateral frames  45 ,  50 , as seen in FIG. 3 the same as the holder  37 . 
     On their lower, wider bases  31 , the chambers  26  to  29  have, viewed in the production direction E, guides  42 ,  43  on the left and right, respectively for a revolving suction belt  44 . The suction belt  44  has spaced apart holes  46 ,  47 ,  48 ,  49 ,  50  over its entire length and width, which intermittently and alternatingly overlap holes  52 ,  53 ,  54 ,  55 ,  56  made in the lower, wide base  31  of the chambers  26  to  29 , all as seen in FIG.  2 . 
     The suction belt  44  is guided over both belt rollers  39 ,  41 . The belt roller  39  is driven, for example, in such a way that on its side close to the web, the suction belt  44  travels at the speed of the press and in the production direction E. This drive is provided, for example, via toothed belts from the device  3  for reducing tear resistance, for example by means of an rpm-controllable electric motor. 
     Each chamber  26  to  29  has a connector  58  on its side, to which air lines  60 ,  61 ,  62 ,  63  respectively are connected. These air lines can be selectively connected with a suction air source or with a compressed air source. In this way, a plurality of chambers  26 ,  27 ,  28  can be charged with suction air, and at least the last chamber  29  can be changed with compressed air. 
     The delivery end  36  of the suction belt station  21  can be adjusted in height, for example by means of a work cylinder  64  which, at one end, is fixed in place on the suction belt station, and whose opposite support  45  is seated on a cross bar  51 , which is fixed in place on the lateral frame. 
     In accordance with another preferred embodiment, the device  13  for rerouting, having a device for holding and conveying, can also be designed as a rotatable suction roller  13  air is provided to it via a rotating connector, not represented. In this case, it is possible to charge either the entire width of the suction roller  13  corresponding to the width of the web  1  of material to be printed, or to charge only one of several portions of the width of suction roller  13 , corresponding to the width of a partial web or webs  16 ,  17 ,  18  or  19 , with suction air. Approximately 270° of the interior circumference of the suction roller  13  is covered with a sealing coat  20 , so that the suction only becomes effective at the circumference of the suction roller  13  against which the web  1  or the corresponding partial web or webs  16 ,  17 ,  18  or  19  is resting and at an amount of an angle β of approximately 90°. From a vertex line  71  on the surface of suction roller  13 , which is a line where a change in the movement direction of the web  16  from one direction—for example a horizontal direction—into another direction—for example a vertical direction—takes place, the web  1  or the partial web  16  tears transversely along a predetermined cutting or tear line  68 . The fresh web end part  5  of the partial web  16  continues to run over the paper guide rollers  9 ,  11  in the movement track B. The torn off part of the partial web with the fresh web start  15  continues to run along the movement track A and possibly from there onto another movement track, for example movement track C. In the process, the “fresh” start  15  of the partial web  16  is still aspirated in the area of the next to the last chamber  28 , and in the area of the last chamber  29  it is pushed away by means of compressed air, and in this way is brought between the upper and lower belts of a forwarding system  7  and from there onto a preselected movement track, for example movement track C. 
     The method for transversely separating and changing the direction of a moving web of material to be printed, for example a paper web  1 , operates as follows: a full-width paper web  1  moving in the production direction E is longitudinally cut into four quarter-width partial paper webs  16  to  19  by means of the longitudinal cutting devices  2  and is guided by the paper guide rollers  9  onto a first movement track A. The for example, left partial web  16  is provided with a predetermined separation or tear line  68  or  69 , as depicted in FIG. 3, for example in the form of a transverse perforation line or a transverse water track, at a predetermined angle±α, for example 0° to 60°, and preferably 45°, in respect to a lateral edge  66  or  67 , or in respect to the partial paper web  16 , by means of a device  3  for reducing the tear resistance of the web, for example the transverse perforation device  3 . Following the separation of the web  1 , or the partial web  16 , in the manner discussed above, a “fresh” web end  5  and a trailing “fresh” web start  15  of the web  1 , or of the partial web  16 , is created. 
     It will be understood that+α a means that the angle a is in reference to the right lateral edge  67  of the partial web  16 , and that−α means that the angle a is in reference to the left lateral edge  66  of the partial web  16 . 
     The suction belt station  21  arranged above the partial web  16 , for example at a short distance “d”=one millimeter, is charged with compressed and suction air. The first chambers  26  to  28  are charged with suction air, and at least the last chamber  29  is charged with compressed air. The web or the partial web is aspirated and is held against the suction belt  44 . 
     The web  1  or the partial web  16  is to be rerouted from the movement track A onto the movement track C in the following discussion. The web  1  or the partial web  16  moving, for example, in the movement track A, has a speed which is equal to the circumferential speed of the suction belt  21 . The suction belt  21  aspirates the partial web  16 , which is to be rerouted, in such a way, that it does not slip, if possible, and attempts to move or to draw it onto the new, preselected movement track, for example the movement track C. This means that the partial web  16  is moved in the movement track A, as well as in the movement track C. Because of this, the tensile stress exerted on the partial web  16  increases until the artificially generated reduction of the tear resistance of the partial web  16 , created by the device for reducing tear resistance  3 , is exceeded and the partial web  16  is transversely separated along a preselected or predetermined break line or tear line  68  or  69 . A part of the partial web  16  continues to run in the movement track A, and the torn off part is conveyed on in the movement track C. 
     After the termination of the transverse separation and direction changing process, the air supply is cut off and the suction air station  21  is removed by means of the work cylinder  64  from the vicinity of the paper web  1  or the partial web  16 , i.e. the suction air station  21  is pivoted up. 
     It is also possible to transfer one or several other partial webs downward onto a different movement track. This can take place by displacing the chambers  26  to  29  and the suction belt stations  21  to  24  in respect to each other in such a way, that the suction belt stations  21  to  24 , and thus the suction belts  44  now have a concave shape in place of a convex shape. Therefore, separation of the paper webs or partial paper webs takes place by holding them and changing their direction. 
     A device for the complete transverse separation of the paper web  1 , or for all of the partial webs  16  to  19  can also be provided. For example, this device may consist of a cutter holder, which can be moved up and down and which has a cutter that works together with a counter cutter fixed in place on the frame. The paper web  1 ,  16  to  19  is stopped or moves slowly, and is then transversely cut. During this process, the paper web  1 ,  16  to  19  is held by suction belts  44  via chambers, as described above. Two suction belt systems  44  are provided, which can both be driven and which are arranged one after the other, viewed in the production direction. The cutter moves up and down between the two suction belt systems  44  and transversely cuts the paper web  1 , or the partial paper webs  16  to  19 . In the process, a fresh web end  5  and a fresh web start  15  are created. The fresh web end  5  is held by the front suction belt system  44  and is conveyed on. The fresh web start  15  is held by the rear suction belt system  44 , as viewed in the production direction E, and is subsequently conveyed on. 
     While preferred embodiments of a device for drawing-in paper webs, and a method for its use 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 a number of changes in, for example, the source of supply of the paper web or webs, the type of printing press used, and the like can 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.