Abstract:
A pair of synchronously rotating draw-in devices are placed in contact with an outer layer of a web of material wrapped on a supply roll. The outer layer is pulled between the two draw-in devices. This pulled-in outer layer can them be conveyed to a separate processing station where it can be given a fresh end.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and a device for grasping a part of an outer layer of a material on a supply roll. 
     DESCRIPTION OF THE PRIOR ART 
     A method, as well as a device, is known from DE 42 12 095 C1, by means of which a suction strip is placed on the outer layer of a supply roll. The outer layer is lifted by this suction strip and is transversely cut. The start of a web of material formed by means of this is subsequently lifted and moved away. 
     DE 195 40 689 C2 shows a work carriage for preparing a paper web tip for a flying paper web roll change. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a method for grasping an outer layer of a web of material from a supply roll, as well as providing a device for grasping the outer layer of a supply roll. 
     In accordance with the present invention, this object is attained by using a pair of draw-in devices, such as draw-in rollers that are driven together. These draw-in rollers are brought into contact with the outer layer of material on the supply roll and draw the outer layer off the supply roll. Once the outer layer of material has been drawn into the draw-in device, it can be moved in a pre-determined path away from the supply roll. 
     The advantages which can be obtained by means of the present invention reside in particular, in that no suction lifters must be employed, and that with the device no matching to the width of the supply roll is necessary. The device of the present invention is matched to a maximally possible width of a supply roll, so that any narrower supply roll can also be processed. Regarding air permeability, basically any material, for example paper or textiles, can be processed. The position of the start of the web of material is of no importance for further processing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Several preferred embodiments of the present invention are represented in the drawings and will be explained in greater detail in what follows. 
     Shown are in: 
     FIG. 1, a lateral side elevation view of a device in a schematic representation in accordance with first and second preferred embodiments, 
     FIG. 2, a side elevation view of a device in a schematic representation in accordance with a third preferred embodiment and in, 
     FIG. 3, a side elevation view of a device in a schematic representation in accordance with a fourth preferred embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A device for grasping an outer layer  1  or winding of a supply roll  2  of material, for example a supply roll, consists of two contacting gripping rollers or, forming a draw-in device rollers  3 ,  4  (draw-in), which draw-in rollers  3 ,  4  extend axis-parallel in respect to each other. They can be placed on the circumference  31  of the supply roll  2 , as seen in FIG.  1 . 
     The roller journals of the draw-in rollers  3 ,  4  are rotatably seated on both sides respectively in a two-armed lever  6 . Both draw-in rollers  3 ,  4  are driven by motors  7 ,  8 , for example asynchronous motors, so that the draw-in rollers  3 ,  4  rotate along with them. By means of this, an inlet wedge  9  is generated on a supply roll  2 . The outlet wedge  10  lies opposite to inlet wedge  9 . 
     It is also possible to embody the first draw-in roller  3  or  4  without its own motor drive and to place it into contact with the second motor-driven draw-in roller  4  or  3 . With this, the draw-in roller  3  would be driven by friction. In this case, the first draw-in roller  3  turns in the unrolling direction H, and the second draw-in roller  4  rotates, following the direction of rotation of the first draw-in roller  3  and in the winding direction I of the supply roll  2 . 
     A drive by traction means would also be possible. 
     The two-armed levers  6  can be pivoted around a pivot shaft  11 , which is arranged at the first end  13  between two pivot arms  14  extending parallel with each other. A gear motor  12  is used for pivoting the two-armed levers  6 . This gear motor  12  is arranged, fixed against twisting, on the first end  13  on one of the pivot arms  14 . 
     The second ends  16  of the pivot arms  14  are respectively pivotably seated in a bearing  17 , fixed in place on the machine frame. The pivot arms  14  can be pivoted by means of a gear motor  18 , fixed in place on the machine frame. In the process, the draw-in rollers  3 ,  4  move on a curved path  19 , shown in dashed lines in FIG. 1, for example on a circular path. The elements  18 ,  14 ,  6 ,  7 ,  8  are part of a pivot drive. 
     It is also possible to rotate the two-armed lever  6  by the use of a work cylinder, not specifically represented, which work cylinder is hingedly supported on the first end  13  of the pivot arm  14 . The work cylinder can also be used to press the draw-in rollers  3 ,  4  against the supply roll  2 . Moreover, the two-armed lever  6  can also be designed as a one-armed lever. 
     The draw-in rollers  3 ,  4  are made of a material with a high coefficient of friction, for example of a rubber-elastic material of a hardness of  50  Shore A, for example. 
     It is essential for the present invention, that at least the friction number μG 1  for the sliding friction between the material of the web  5  of material, for example paper, and the surface of the shell or cover  21  of the draw-in means  3 ,  4  is greater than either the friction number μH 2  for the static friction, and the friction number μG 2  for the sliding friction of the end part  38  of the outer winding or layer  1  of the supply roll  2  on its winding or layer  40  directly below it. 
     The draw-in means device  3 ,  4  such as, for example the draw-in rollers  3 ,  4 , therefore have a shell or outer cover  21  with a high friction number for sliding friction μG 1  with the outer layer  1  of the web  5  of material, for example between 1.0 and 1.7, or greater. 
     This is achieved, for example, by the type of the rubber mixture or of the polish or roughness of the shell or outer cover  21 . 
     The friction numbers for paper on paper are approximately 0.25 for the static friction μH 2 , and approximately 0.2 for the sliding friction μG 2 . 
     The rubber can extend over the entire shell or cover surface, or along the entire circumference of the draw-in rollers  3 ,  4 , or only over individual sections of the shell or cover  21 . In sections means, that the rubber of a high coefficient of friction is arranged, for example, in strips along the circumference of the cover  21 , or in strips in the axial direction of the draw-in rollers  3 ,  4 , and alternates with a material of a lesser coefficient of friction. 
     A further possibility for embodying the draw-in device  3 ,  4  lies in employing two touching, driven endless conveyor belts, which belts, or respectively their surfaces, are made of the aforementioned rubber-elastic material. 
     Another possibility for embodying the draw-in device  3 ,  4  consists in that the shells or covers  21  of the draw-in rollers  3 ,  4  have radial bores, and the draw-in rollers  3 ,  4  can be charged with suction air. 
     As alternative to the draw-in rollers  3 ,  4 , which can be charged with suction air, endless conveyor belts which have holes can also be used as the draw-in device  3 ,  4 . With their facing surfaces, the conveyor belts are each conducted over a suction box having slits or elongated holes, so that at least half of the holes located in the area of the elongated holes respectively correspond with the elongated holes for letting air pass through. 
     Finally, the draw-in device  3 ,  4  embodied as draw-in rollers or as conveyor belts can be designed so that they can be electrostatically charged, for example from a high voltage d.c. current source. In this case, the first draw-in device  3  is connected to a negative pole, and the second draw-in device  4  is connected to a positive pole, or vice versa. 
     In connection with the aforementioned draw-in device  3 ,  4 , which can be pneumatically or electrostatically charged, it is essential that the holding forces of the draw-in device  3 ,  4  be greater than the forces of the outer layer  1  of the web  5  of material resulting from the static friction μH 2  or the sliding friction μG 2 . 
     A processing station  20  is arranged within the curved path  19  of travel of the draw-in devices  3 ,  4 , as may also be seen in FIG  1 . 
     This processing station  20  consists, for example, of a height-adjustable table  22 . A work carriage  23 , which can be moved back and forth, is arranged in the axis-parallel direction Z in respect to the supply roll  2  above the table  22 . The work carriage  23  can be moved, for example, on cross bars fixed in place. The work carriage  23  takes up a position of rest, for example, outside of the width of the supply roll  2 . 
     A waste receptacle  24  is provided below an end position G of the supply roll  2 . 
     A height-adjustable device for driving the supply roll  2  is provided below a grasping position F. The drive is provided, for example, by means of spreading cones, or support rollers, not specifically represented. An axis of rotation  29  of the supply roll  2  is located in the vertical direction Y underneath the inlet wedge  9  of the draw-in rollers  3 ,  4 . 
     The supply roll  2  can be rotated in the winding direction I, as well as in the unwinding direction H. 
     A transverse cutting device  32 , which is known per se, is provided in the vicinity of the circumference  31  of the supply roll  2 . It is used to cut open the transport packaging of a supply roll  2 . 
     A pressure roller  33 , which can be placed against the circumference  21  of the supply roll  2 , is arranged upstream of the first draw-in roller  3 , viewed in the unwinding direction H of the supply roll  2 . It has a shell or cover consisting of a material, which is a so-called anti-adhesive material, for example a silicon-containing, or Teflon-containing material. As represented in FIG. 1, the pressure roller  33  is guided by means of pivot arms  34 , which are seated, fixed in place on the machine, and which can be pivoted by means of a motor  36 . 
     It is also possible to arrange the pressure roller  33  on an extension, not represented, of the two-armed lever  6 . 
     A method for grasping an outer layer or winding  1  of a supply roll  2  proceeds as follows: 
     The draw-in devices for example the draw-in rollers  3 ,  4 , and the supply roll  2  can be relatively moved toward each other. This can take place by only the movement of the supply roll  2 , or only the move of the draw-in rollers  3 ,  4 , or by a mutual movement of the supply roll  2 , as well as the draw-in rollers  3 ,  4 . 
     After the draw-in rollers  3 ,  4  and the outer layer or winding  1  of the supply roll  2  have come into contact in the grasping position F, i.e. after the draw-in device  3 ,  4  have been placed on the outer layer  1 , portions, parts  15  of the outer layer  1  are grasped by the draw-in rollers  3 ,  4  moving together in the draw-in direction of rotation K. The supply roll  2  rotates in the unwinding direction H. Based on the different coefficients of friction of the outer layer  1 , of the web material  5 , and the draw-in rollers  3 ,  4  rotating along together, the outer layer  1  is pulled from the direction of the temporary end  38  of the outer winding  1 , as well as from the opposite direction as material parts  15 , into the inlet wedge  9  and the outlet wedge  10 . The formation, or completion of the formation of a loop  37  of web material located in the outlet wedge  10  is reported by sensors, not specifically represented. The draw-in rollers  3 ,  4  come to a stop, the pressure roller  33  is pushed against the supply roll  2 , if necessary, and the draw-in rollers  3 ,  4  transport the loop  37  of web material clamped between the draw-in rollers  3 ,  4  to a processing station  20 . 
     In the process, the draw-in devices, for example the draw-in rollers  3 ,  4 , move along a straight line or a curved path. The movement path can take place on a straight line  26 ,  27  in the radial direction Y, T in relation to the axis of rotation  29  of the supply roll  2 , or on a differently designed curved path  19  in relation to the outer layer or winding  1  of the supply roll. The curved path  19  can be designed to be circular, elliptical, etc. 
     The movement of the draw-in means  3 ,  4 —along with the preliminary material start  38  passes the “work place” of the processing station  20 . The processing station  20  has, for example, a work carriage  23  with the devices for transverse cutting of the web  5  of material, for the application of adhesive labels, a transverse glueing device and the like, as well as a work table  22 . There are now the following options: 
     1. The draw-in devices  3 ,  4  pass through the “work place” of the processing station  20 . In this case, the work carriage  23  and the work table  22  have been moved out of the area of the “work place”. This can take place by longitudinal displacement along the longitudinal axes Z of the draw-in devices  3 ,  4 , or vertically or perpendicularly in the direction X in respect to the longitudinal axes of the draw-in devices  3 ,  4  the direction Z. After passing the “work place”, they are stopped. Thereafter the work carriage  23  and the work table  22  move in such a way, that the web  5  of material rests on the work table  22 . 
     2. The draw-in devices  3 ,  4  pass through the “work place” along a curved path  19  on their way into a final or work position G. In the course of this, the web  5  of material loosens. The web  5  of material is tightened over the work table  22  by the continued rotation of the draw-in devices  3 ,  4 . Subsequently, the work carriage  23  forms a “fresh” start of the material web or a new material web tip by a movement above the work table  22 . This can occur by devices of transverse cutting of the web  5  of material, by the application of adhesive strips and adhesive labels. In the course of this, the work carriage  23  moves back and forth, for example from a position outside of the width of the supply roll  2 , in the axial direction Z of the supply roll  2 . The freshly created start of the material web is placed on the supply roll  2  in the winding direction I by rotating the supply roll  2 , and is pressed against it, for example by devices of the pressure roller  33 . Waste material being created is conducted into the waste receptacle  24  by continuing the rotation of the draw-in devices  3 ,  4 . 
     It is, of course also possible to bring the draw-in rollers  3 ,  4  into a grasping position F, as shown in FIG. 1 on a supply roll  39  of small diameter in order to form a fresh start of the outer layer of the supply roll  39 . 
     In accordance with a third preferred embodiment as seen in FIG. 2, the draw-in device, for example the draw-in rollers  3 ,  4 , together with the clamped web  5  of material, are not moved along a path such as a straight line or curve. Next to a draw-in roller, for example the second one  4 , an obliquely downwardly extending table  47 , as well as a working carriage displaceable in an axis-parallel direction Z over the table  47 , are arranged in a common component  49 . A paper guide device  51  is arranged in the outlet wedge  10  of the draw-in roller  3 ,  4 , which paper guide device  51  guides a paper web loop  37  drawn between the draw-in rollers  3 ,  4  to the table  22  via one, for example the second, draw-in roller  4 . 
     In order to bring the component  49  with the draw-in devices, for example the draw-in rollers  3 ,  4 , into contact with the supply roll  2 , the latter can be moved up and down in the vertical direction Y, or respectively back and forth in the horizontal direction X by devices of a linear drive  43 . 
     It would also be possible to leave the table  47 , as well as the component  49 , in the radial direction T at a fixed distance from the supply roll  2 , and to only displace the draw-in rollers  3 ,  4  in the vertical direction Y, or also in the horizontal direction X, by devices of a linear drive  43 . 
     It is furthermore possible to turn the entire component  49  in a clockwise direction B, for example by an angle of approximately 45°, so that the straight line  26  of the linear drive  43  extends in the radial direction T—approximately 45° removed from the Y-axis in the 1st quadrant of the right-angled coordinate system—congruently with the straight line  27 . 
     Therefore the component  49  would be displaced from its position in the 2nd and 1st quadrants into a position in the 1st and 4th quadrants of the right-angled coordinate system. Then the component  49  would be movable back and forth in the radial direction T in respect to the supply roll  2 . 
     Finally, it is also possible to install the component  49  fixed in place and to additionally move the paper web roll  2  in the vertical Y-direction back and forth, for example by devices of a lifting device. 
     With the fourth preferred embodiment, which is shown in FIG. 3, in addition to what has been described above, there is provided a paper guide device  54  which is directed into the outlet wedge  10 , as well as onto the second draw-in roller  4  and which acts, or example, pneumatically in the manner of a nozzle strip, and a work carriage  23  arranged above the paper guide device  54  and, for example, matching the surface which faces away from the supply roll  2  of the curvature of the second draw-in roller  4 . The paper guide device  54 , and the work carriage  23  are arranged in a common component. On its side facing the draw-in roller  4 , the work carriage  23  can also be embodied straight. The work carriage  23  is arranged above or next to the draw-in roller  3  or  4 . Furthermore, a waste removal device  57 , following the second draw-in roller  4  and extending obliquely downward, is a part of the component  58 . 
     One, for example the second, draw-in roller  4  has a counter-cutting strip  59  extending in the axis-parallel direction on its surface, which can be exactly positioned in respect to the work carriage  23 . 
     The component  58  can be moved back and forth in the vertical Y-direction by devices of a linear drive  43  can be brought toward a rotatable and drivable supply roll  2 . 
     The outer layer  1  of the supply roll  2  is pulled into a paper web loop, not specifically represented, by devices of the draw-in rollers  3 ,  4 , which are in the work position. The supply roll  2  is rotated in the unwinding direction H in the course of this movement of the outer layer. A pressure roller  33  in accordance with FIG. 1 can also be placed against the supply roll  2 . The outer layer  1  of the supply roll  2  is pulled between the draw-in rollers  3 ,  4 , and is guided in the outlet wedge  10  onto the surface of the second draw-in roller  4  by devices of the paper guide device  54 . Because of its back-and-forth movement guided in the axis-parallel Z-direction, the work carriage  23  provides the completion of a fresh paper web start. Here, the curved surface of the draw-in roller  4  is used as the work table. Following the completion of the fresh material web start, the supply roll  2  is rotated back in the winding direction I, and the fresh start is fixed in place on the supply roll  2 . 
     The surface of the draw-in rollers  3 ,  4  is provided with a soft material coated with an anti-adhesive layer. 
     There is also the possibility of keeping the component  58  in its fixed position, and of giving the supply roll  2  only a lifting movement in the vertical direction Y in addition to the rotating movement. 
     The draw-in devices  3 ,  4  are in operative connection with each other. This means that the oppositely located draw-in devices  3 ,  4  can touch each other, or a gap can be provided between them. In this case the gap has sufficient dimensions, so that a web  5  or  1  of material, or respectively a loop  37  of web material, can be drawn in. 
     While preferred embodiments of a method and device for grasping pail of an outer layer of a strip of material on a supply web 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 drive for the supply roll, the type of printing press with which the supply roll may be used, and the like could be made without departing from the true spilit and scope of the present invention which is accordingly to be limited only by the following claims.