Abstract:
Two webs of material, each rolled on a separate roll of material, are linked or spaced together during a web-roll change, without stoppage of the web travel. A linking or splicing device is used for linking, particularly by gluing the fresh web of material to the exhausting web. A cutting device is used to produce two web ends. The cutting device is located downstream of the linking or splicing device, as seen in a direction of travel of the expiring or exhausting web of material.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a device for connecting two webs of material during a flying roll change. A connecting device is used to connect the two webs and a cutting device is used to cut the exhausting web from its roll once the webs have been connected. 
     BACKGROUND OF THE INVENTION 
     A device for accomplishing a flying roll change is known from DE 42 18 825 A1. A fresh paper web can be glued to the paper web which is running-out in a printing press operating at production speed. After the fresh paper web has been glued on, the paper web which is running-out is cut by use of a cutting device and two web ends are formed in the process. The one web end, together with the fresh paper web, is conveyed through the printing press, and the second web end, together with the used up paper roll, can be removed from the roll changer. In the course of the roll change, both paper rolls rotate in the same direction, and the running-out paper web is moved past the fresh paper roll in such a way that, in the course of gluing it to the running-out paper web, the start of the fresh paper web is brought into contact with the running-out paper web in as tangentially a way as possible. 
     Another device for accomplishing a flying roll change is known from U.S. Pat No. 4,936,942, wherein a cutting device and a gluing roller are provided in a frame. For a roll change, the frame can approach the running-out paper web from one side, so that when the connecting device is triggered, a gluing roller, together with the running-out paper web, is pressed against a gluing spot of the fresh paper web. Thereafter, the running-out paper web is cut by the cutting knife. 
     Yet another device for accomplishing a flying roll change is known from EP 0 720 581 B1. The tension of the paper web can be kept substantially constant during the gluing or cutting process by a suitable kinematic movement process. 
     In connection with the generally known devices for connecting two paper webs in the course of a flying roll change, it is disadvantageous that, because of the arrangement of the connecting device, for example a gluing roller or gluing brush, downstream of the cutting device, in the feed direction of the running-out web of material, a so-called “slip” is necessarily formed. In this case, the length of this slip, i.e. the distance between the connecting point of the fresh and the old web of material and the cut-through web end of the old web of material, is essentially determined by the distance between the connecting device and the cutting device. Interferences are often caused by the slip in the course of conveying the web of material through a processing machine, for example a web-fed rotary printing press. To prevent these interferences, a device is proposed in WO 99/40004 A1, wherein, by use of an appropriate web guidance after the cutting of the old web of material, the slip is pushed outwardly by the centrifugal forces acting on the slip and is subsequently cut off by a cutter bar. It is possible with this to shorten the length of the slip to almost zero. However, a considerable additional structural outlay is required for an appropriate web guidance and for the downstream connected cutter bar. 
     SUMMARY OF THE INVENTION 
     The object of the present invention, is directed to providing a device for connecting two webs of material. 
     In accordance with the present invention, this object is attained by connecting the two webs of material, each wound on a separate roll, during a flying roll change. A connecting device is provided for connecting the fresh web of material with the exhausting web of material. A cutting device is used to cut the exhausting web once the connection has been made. The cutting device and the exhausting web, which is to be cut, are brought into engagement by changing the course of travel of the web to be cut. 
     The advantages to be obtained by the present invention lie, in particular, in that, because of the arrangement of the cutting device downstream of the connecting device, viewed in the feeding direction of the running-out web of material, the slip can be basically cut off as short as desired when the running-out web of material is cut. When connecting the fresh web of material to the running-out web of material, the result always is a Y-shaped structure, one of whose branches, namely the old web of material starting at the old roll of material up to the gluing point, can essentially be completely cut off by the cutting device which is arranged downstream of the connecting device. By arranging the cutting device downstream of the connecting device, no minimum slip length necessarily results, but the length of the slip can basically be shortened as desired. However, in the course of this, it should be noted that, if the slip length is selected to be too short, there is the potential danger that the fresh web of material is inadvertently damaged by the cutting device. 
     If the cutting device is arranged downstream of the connecting device, there is the potential danger that the fresh web of material is also inadvertently damaged in the course of cutting through the old web of material. To reliably prevent this danger, it is particularly advantageous if the cutting device is brought into engagement with the web of material to be cut by moving a web guide device, by which the course of the web of material to be cut can be changed. As a result, it is possible to accomplish that the fresh web of material and the web of material to be cut off are guided along different paths in the area downstream of the gluing point, so that only the old web of material is cut. By moving the web guide device, it is, in particular, possible for the fresh web of material and the web of material to be cut to form a defined angle with respect to each other. In this case, the cutting device for cutting the old web of material must be arranged in such a way that, after the gluing point has passed the cutting device, because of its course the old web of material can be cut by contact with the cutting edge of the cutting device. An advantage of this configuration resides, in particular, in that the cutting device for cutting the old web of material need not be moved, but can be arranged fixed in one place. 
     The change of the course of the old web of material, which is required for cutting the old web of material, can be achieved in a particularly simple manner. The connecting device, for example a gluing roller or gluing brush, after it has pressed the running-out web of material against the fresh web of material, is displaced in such a way that the old web of material comes into engagement with the cutting device. 
     Alternatively to the displacement of a web guide device, by which the course of the web of material to be cut can be altered, it is also possible that the cutting device will come into engagement with the web of material to be cut by use of a suitable displacement of a web guide device, by which the course of the fresh web of material can be changed, and which will accomplish the simultaneous change of position of the cutting device. In other words, this means that by changing the web guide device, the fresh web of material is rerouted, at least briefly, in such a way that after the position of the cutting device has been changed, the fresh web of material does not come into engagement with the cutting device, and only the old web of material is cut by the change of position of the cutting device. 
     In order to reliably prevent an unintentional cutting of the fresh web of material by the cutting device, a spacing element can be provided on the cutting device. By use of the spacing element, a defined minimum distance between the cutting device and the fresh web of material is assured. 
    
    
     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 side elevation view of a device for connecting two webs of material in accordance with the present invention and in an initial position, 
     FIG. 2, the device of FIG. 1 after the running-out web of material has approached the fresh web of material, 
     FIG. 3, the device of FIG. 1 in the course of pressing the running-out web of material against the fresh web of material, and in 
     FIG. 4, the device of FIG. 1 in the course of cutting the old web of material. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A device  01  for linking two webs of material in accordance with the present invention and with a web connecting device  02 , that is embodied in the manner of a gluing roller, in particular a web guide device, and a web cutting device  03 , which web cutting device  03  is embodied in the manner of a severing cutter, are represented in FIG.  1 . Both the web connecting device  02  and the web cutting device  03  are fastened on a frame  04 , with frame  04  being formed by two lateral elements that are arranged parallel with each other. Two pivot arms  07 , which are each seated for pivoting around an axis of rotation  06 , are provided for use in displacing the web connecting device  02  in relation to the frame  04 . The web connecting device  02  can be rotatingly pivoted around the axis of rotation  06  by triggering a drive mechanism, which is not specifically represented. The web connecting device  02  is embodied in the manner of a gluing roller and is rotatably seated at the lower ends of the pivot arms  07 . The cutting device  03  is connected with the frame  04  and is fixed in place on it. The frame  04  itself is pivotably seated and can be pivoted around a frame axis of rotation  08 , which is the same as, and is aligned with an axis of rotation of a guide roller  09 . The frame  04  is pivotable about its axis of rotation  08  by use of a drive device, which is not specifically represented. 
     FIG. 1 represents the device for linking webs,  01  in its initial position. In the initial position, the device  01  has been pivoted to the right in such a way that neither the cutting device  03  nor the web connecting device  02  come into engagement with one of the webs of material. A running-out or exhausting web of material  11 , in particular a paper web, is wound off a depleted roll of material  15 , which depleted roll of material  15  is seated in a roll changer, not represented. Web of material  11  is conveyed into a downstream arranged device, for example a rotary printing press, over the web guide rollers  12 ,  09 . The conveying direction of the running-out or exhausting web of material  11  can be determined by the movement arrow  13 . 
     If the old or depleted roll of material  15  is used up to a large extent, and if therefore a flying roll change is to be performed, a fresh or full roll of material  14 , on which a fresh web of material  16 , in particular a paper web, is wound, is clamped into the roll changer, which is not specifically represented, and is rotationally accelerated in accordance with the movement arrow  17  until the circumferential speed of a web start  18  of the fresh web of material  16  matches the conveying speed of the running-out or exhausting web of material  11 . Adhesive labels  19  have been attached to the web start  18  of the fresh web of material  16 , so that the fresh web of material  16  can be connected with the running-out or exhausting web of material  11 . The passage of the adhesive labels  19  can be detected by utilization of a sensor  21 , which is only represented schematically, and can be passed on to the control of the roll changer. As soon as the fresh web of material  14  has reached the required circumferential speed, the frame  04  can be pivoted to the left in accordance with the movement arrow  22  so that the running-out or exhausting web of material  11  initially approaches the fresh roll of material  14 . 
     The device for linking webs,  01 , is represented in FIG. 2 after the pivoting of the frame  04 , for letting the running-out web of material  11  approach the fresh roll of material  14 , has been accomplished. In the course of the pivot movement of the frame  04 , the web connecting device pivot arms  07  are also pivoted without their moving relative to the frame  04 . The result is that the web connecting device  02  now comes into contact with one side of the running-out or exhausting web of material  11  and, with an increasing pivot angle of the frame  04 , the web connecting device  02  pushes the running-out or exhausting web of material  11  farther and farther in the direction of the fresh roll of material  14 . Since the pivot arms  07  have not yet been displaced, damage to the running-out or exhausting web of material  11  by the cutting device  03 , which is fixedly mounted on the frame, is prevented because of the relative arrangement between the web cutting device  03  and the web connecting device  02 . 
     Once the web connecting device  02  has sufficiently approached the fresh roll of material  14  by effecting the pivoting of the frame  04 , it is possible to start the actual connection of the running-out web of material  11  with the fresh web of material  16 . To this end, a signal is passed on from the sensor  21  to the control device when the adhesive labels  19  pass, so that after receipt of this signal, the control device triggers the drive mechanism for displacing the pivot arms  07 . The pivot arms  07 , which support the web connecting device  02 , are pivoted to the left, in accordance with the movement arrow  23 , and, in the process, move the running-out or exhausting web of material  11  along until the running-out or exhausting web of material  11  comes to rest against the fresh roll of material  14  at the exact moment of the passage of the adhesive labels  19 . The web start  18  of the fresh web of material  16  is now connected with one side of the old running-out or exhausting web of material  11 . 
     The configuration of the device for linking webs,  01 , at the exact moment of the connection between the running-out or exhausting web of material  11  and the fresh web of material  16  is schematically depicted in FIG.  3 . It can be seen, by referring to FIG. 4, that, because of the connection of the fresh web of material  16  with one side of the running-out or exhausting web of material  11 , a Y-shaped structure results, two of whose branches are formed by the running-out or exhausting web of material  11 , and one of whose branches is formed by the fresh web of material  16 , and in whose juncture the adhesive labels  19  are located. An unintentional cutting of the running-out web of material  11  at this time is not possible since, because of the arrangement of the cutting device  03  on the frame  04 , the cutting device  03  extends essentially parallel with the course of travel of the running-out or exhausting web of material  11  in the area of the frame  04 . Furthermore, a circular spacing element  24  is provided on the web cutting device  03 , because of which, a defined minimum distance between the running-out or exhausting web of material  11  and the cutting edge of the cutting device  03  is maintained. 
     To finish the flying roll change, it is necessary to cut the old web of material  11 , which up to this time has constituted the running-out or exhausting web of material  11 . In order to cut the old web of material  11 , without any danger of damage to the fresh web of material  16 , the pivot arms  07  are controlled in such a way that they are now pivoted back toward the right in accordance with the movement arrow  26 , which arrow  26  is shown in FIG.  3 . The course of the old web of material  11  is changed in the area downstream of the gluing point by this pivot movement, so that, as a function of the setting angle of the pivot arms  07 , the fresh web of material  16  and the old web of material  11  together form a defined angle a, as seen in FIG. 4, in the area of the gluing point. 
     The device for linking webs,  01 , is depicted in FIG. 4 at the exact moment of the passage of the adhesive labels  19  past the cutting device  03 . At this time, the web connecting device pivot arms  07  have been pivoted back far enough so that the web connecting device  02  just rests against the old web of material  11 . The fresh web of material  16  extends under tension between the adhesive labels  19  and the fresh roll of material  14 . As soon as the adhesive labels  19  pass the cutting device  03 , the old web of material  11  is cut by the cutting device  03  because of the course of travel of this old web. The slip or trail of the now cut old web  11 , which is being created in the course of this cutting is only as long as the distance between the cutting edge of the cutting device  03  and the splice point for the fresh web of material  16 . 
     Thereafter, the fresh web of material  16  is conveyed into the downstream located device  01  and the old roll of material  15 , together with the cut off web end, is removed from the roll changer. The frame  04  is then pivoted back, in accordance with the movement arrow  27 , into its initial position, as represented in FIG.  1 . 
     While a preferred embodiment of a device for linking two webs of material in accordance with the present invention has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example, the type of printing press being used, the overall width of the web being cut and the like could be made without departing from the true spirit and scope of the present invention which is to be limited only by the following claims.