Abstract:
A roll of material is unloaded from a roll changer of a web-processing machine. The roll changer includes a first arm having a first axle journal and a second arm having a second axle journal. The roll of material is rotatably supported between these two spaced axle journals. The first arm is moved axially outwardly until the first end of the roll is stripped off the first axle journal. The second arm is then also moved axially outwardly until the roll of material is stripped off the second axle journal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This U.S. patent application is the U.S. national phase, under 35 USC 371, of PCT/EP2005/050488, filed Feb. 4, 2005; published as WO 2005/108254 A1 on Nov. 17, 2005, and claiming priority to DE 10 2004 021 604.5, filed May 3, 2004, the disclosures of which are expressly incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is directed to methods for unloading a roll of material. The roll of material is unloaded from a roll changer which has spaced first and second arms, each with an axle journal. The roll of material is rotatably supported by these two arms. The first and second arms are each moved serially outwardly to strip the roll from the first arm and then from the second arm.  
       BACKGROUND OF THE INVENTION  
       [0003]     Methods for unloading a roll of material are used frequently, but by no means exclusively, in, for example, web-fed rotary printing presses to remove finished or partially used rolls of material from a roll changer. To ensure a reliable stripping of the roll of material from the axle journals of the roll changer, stripping devices, such as stripper rings, are provided in generally known roll changers.  
         [0004]     A method for unloading a roll of material from a roll changer of a web-fed rotary printing press is described in DE 101 50 810 A1. In this method, the stripping devices are actuated, in a position-controlled or a position-regulated manner. As the axle journals of the roll arms are being moved apart, the stripping devices move along the same path as the roll arm, but in the opposite direction relative to the axle journals. As a result, the residual roll does not change its position during the separation of the roll arms and the associated stripping of the residual roll from the axle journals of the roll arms.  
         [0005]     WO 02/40387 A1 describes a device for producing sleeveless paper rolls. In order to change such paper rolls, the two support journals are pulled back simultaneously.  
         [0006]     U.S. Pat. No. 4,903,910 A1 describes a process for unloading a roll of material in a roll changer. A distance between the support elements is greater than the length of a sleeve. For the safe unloading of the sleeves, strippers are provided.  
         [0007]     EP 0 391 061 A1 describes a device for aligning a new roll of material. An alignment device presses against the roll of paper, and thus can move an unlocked transport car on a sliding platform.  
       SUMMARY OF THE INVENTION  
       [0008]     The object of the present invention is to provide methods for unloading a roll of material.  
         [0009]     The object of the present invention is attained by provision of a roll changer with first and second roll arms, each of which has a roll end supporting axle journal on which one end of the roll of material is supported. The first roll arm is moved axially outwardly until the first side of the roll of material is stripped from the first axle journal. The second roll arm is then also moved axially outwardly until the second end of the roll of material is stripped from the second axle journal.  
         [0010]     The benefits to be achieved with the present invention consist especially in that a position control or a position regulation for a stripping device is not necessary. Instead, the unloading of the roll of material, in the correct position, is achieved because the stripping devices are pressed against the roll of material with specific levels of force, and in a predetermined process sequence.  
         [0011]     In a first process step, a first stripping device is pressed, with a first stripping force, against the roll of material. No relative movement between the roll of material and the axle journals initially occurs. This is due to the securely set distance between the roll arms of the roll changer. In a second process step, the roll arms are moved away from one another until the first side of the roll of material is stripped from the first axle journal. Thus, the correctly positioned stripping of the first side of the roll of material from the first axle journal is ensured by the application of a stripping force A by the first stripping device.  
         [0012]     Once the first side of the first roll of material is free, a second stripping device presses, with a second stripping force B, against the roll of material. As the two roll arms continue to move away from one another, the second side of the roll of material is now also stripped from the second axle journal.  
         [0013]     According to one preferred embodiment of the process in accordance with the present invention, the second stripping force B is greater in magnitude than the first stripping force A. This can be advantageous if the roll of material has not been completely consumed. If that is the case, the roll of material will therefore hang down on one side, under its own weight, once the first side has been stripped from the first axle journal. Because of the tilting moment that this tilting of one end of the roll causes, the frictional forces between the second side of the roll of material and the second axle journal are increased. A correspondingly greater second stripping force B, for stripping the second side of the roll of material from the second axle journal, is thus required.  
         [0014]     If clamping devices, for use in securing the roll of material, are provided on each of the axle journals, such as, for example, in the form of clamping jaws, these clamping devices should not simply be simultaneously opened prior to unloading the roll of material. Rather, initially only the first clamping device on the first side of the roll of material should be opened. The second side of the roll of material is thus still secured and cannot separate from the second axle journal. Only after the first side of the roll of material has been completely stripped from the first axle journal is the second clamping device also opened, so that the second stripping device can now strip the second side of the roll of material.  
         [0015]     Once the first side of the roll of material has been unloaded from the first axle journal, a potential danger exists that the stripping of the second side of the roll of material, during the outward movement of the second stripping device, may cause the first side of the roll of material to undesirably be pushed back onto the first axle journal. This undesired pushing of the first side of the roll of material back onto the first axle journal can be prevented, in a reliable manner, by securing the first stripping device in its final position once the first side of the roll of material has been stripped from the first axle journal. In this final position, the first stripping device then acts as a stop, which stop reliably prevents the first side of the roll of material from being pushed back onto the first axle journal.  
         [0016]     In principle, the first stripping device can be secured in its final position in any manner. One particularly simple manner and method results from the first stripping device being pressed against an end stop with a securing force C, for securing it in its final position. Essentially all other supplementary structural measures can thereby be omitted, since a device for applying the securing force C to the first stripping device must be provided in any case, such as, for example, in the form of a pneumatic or a hydraulic operating cylinder, and an end stop is customarily provided anyway.  
         [0017]     It is particularly advantageous for the securing force C to be greater than the second stripping force B. The pushing back of the first stripping device, while the second stripping device is being moved out, is reliably excluded.  
         [0018]     If the material on the roll which is being unloaded has not been completely consumed, the weight of the roll of material frequently causes its first side to tilt downward at an angle with respect to the second axle journal during unloading. This downward tilting of the roll of material can cause damage to the second stripping device. This damage is likely to occur because, due to the frictional forces at work between the second end surface of the roll of material and the second stripping device, a downward tilting of the roll of material causes a substantial force load on the second stripping device, which force load the second stripping device is frequently unable to bear. If, for example, the stripping device is structured as a stripper ring, which is moved out in the direction of the longitudinal axis of the roll of material by multiple operating cylinders, the downward tilting of the roll of material can frequently cause the connecting rods of the operating cylinders to bend.  
         [0019]     This problem can be prevented by reducing the frictional force between the second end surface of the roll of material to be stripped and the associated stripping device, prior to the downward tilting of the roll of material. These frictional forces are to be reduced to the extent that the second end surface of the roll of material is able to slide along the contact surface of the stripping device. It is therefore particularly advantageous for the second stripping force to be decreased from an initial, higher value to a final, lower value during unloading of the roll of material from the second axle journal. In the selection of an initial value B 1  for the second stripping force B, it must be ensured that the second stripping force B is sufficient so that the roll of material can be moved, relative to the second axle journal, at the start of the stripping. By decreasing such a second stripping force B, during the unloading of the second end of the roll from the second axle journal, it is ensured that the frictional force between the second end of the roll of material and the stripping device is decreased. Accordingly, when the roll of material tilts downward, its second end surface is able to slide along the contact surface of the second stripping device, so that no damage to the stripping device will occur.  
         [0020]     In principle, the stripping force can be decreased, during unloading, from the initial value B 1  to the final value in any manner. According to one preferred embodiment of the present invention, the second stripping force B takes on two values in two respectively assigned phases of the unloading, wherein the values for the stripping force B 1  and B 2  are each held constant during the two successive phases.  
         [0021]     A downward tilting of the roll of material typically occurs when the roll of material has essentially been completely stripped from a cylindrical portion of the second axle journal, and is supported only on the tapered end of the second axle journal. The two successive phases for applying the second stripping force B should therefore be oriented in a transition between the cylindrical portion of the second axle journal and the tapered portion of the second axle journal.  
         [0022]     In order to be able to transport the roll of material away from the roll changer, following its unloading and without manual intervention to the greatest extent possible, a correspondingly suited transport assembly can be used. To accomplish this roll of material transport, the transport assembly may be arranged beneath the roll of material, before the roll of material has been stripped from the first axle journal, or before the roll of material has been stripped from the second axle journal. In this manner, the transport assembly can receive the unloaded roll of material, and can then transport it back to a material storage area, or can transport an emptied material roll to a disposal area.  
         [0023]     The downward tilting of the roll of material, after only one side has been unloaded, can be prevented in a simple manner by providing a height-adjustable support device on the transport assembly. This height-adjustable support device can be structured, for example, in the manner of a scissor lift platform. Either before, or both before and during unloading of the roll of material, the support unit is brought close to, or is placed against the circumference of the roll of material. The downward tilting of one side of the roll of material is correspondingly reduced or is entirely eliminated.  
         [0024]     An automatic advancement of the transport assembly is accomplished by the provision of a correspondingly suited drive mechanism, such as, for example, a chain conveyor which can be arranged beneath the floor. In this arrangement, it is particularly advantageous for a coupling device to be provided between the transport assembly and the drive mechanism. Once the transport assembly has been placed in the correct position beneath the roll of material, the coupling device can be uncoupled. This allows the transport assembly, once it is in contact with the roll of material, to follow any longitudinal movements of the roll of material during unloading. Damage to the circumference of the roll of material, which may be caused by an unintended relative movement between the transport assembly and the roll of material is thus prevented. Furthermore, in this manner the optimal position for the roll of material on the transport assembly is maintained during unloading of the roll of material, without any additional steps. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     A preferred embodiment of the present invention is represented in the set of drawings and will be described in greater detail below.  
         [0026]     The drawings show in:  
         [0027]      FIG. 1 a  schematically represented front elevation view of a roll changer in a first phase of unloading a roll of material; in  
         [0028]      FIG. 2  the roll changer according to  FIG. 1  in a second phase of unloading a roll of material; in  
         [0029]      FIG. 3  the roll changer according to  FIG. 1  in a third phase of unloading a roll of material; and in  
         [0030]      FIG. 4 a  diagram of the forces of pressure on the stripping devices of the roll changer depicted in  FIG. 1 , during the various phases of unloading of a roll of material, as depicted in  FIGS. 1-3 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0031]     Referring initially to  FIG. 1  there may be seen a roll changer  01 , for example a roll changer  01  which is intend for use with a web-fed rotary printing press, with two roll arms  02 ;  03 . It will be understood that roll changer  01  is schematically represented in  FIG. 1 . On a first roll arm  02  of the roll changer, a first axle journal  04  is provided, and on a second roll arm  03  of the roll changer, a second axle journal  06  is provided, which axle journals  04 ;  06  are each inserted into one end of a cylindrical recess  07  in a roll of material  08 . The roll of material  08  can thus be rotatably mounted on the roll changer  01 . To secure the roll of material  08  on the axle journals  04 ;  06 , the axle journals  04 ;  06  are each equipped with clamping devices  09  on their respective cylindrical sections. The clamping devices  09  are structured in the manner of clamping jaws  09  and can each be pressed against an inner circumference of the cylindrical recess  07  by actuating corresponding actuation devices on the roll arms  02 ;  03 .  
         [0032]     The roll changer  01  is equipped with a second pair of roll arms, which are not shown in  FIG. 1 , and which are provided for the purpose of accommodating a second roll of material and/or a residual roll. This second pair of roll arms is preferably identical in structure to the first pair of roll arms  02 ;  03 . The two roll arms  02 ;  03  are mounted so as to pivot around a pivoting axis.  
         [0033]     The clamping devices  09  are equipped with elements that can be moved in a radial direction. The clamping devices  09 , such as the clamping jaws  09  can be radially spread by the radially movable elements.  
         [0034]     A first stripping device  11  is provided on the first roll arm  02 , and a second stripping device  12  is provided on the second roll arm  03 . The two stripping devices  11 ;  12  are both structured in the manner of stripper rings  11 ;  12  and can be pressed, by the operation of pneumatic operating cylinders  13 , as may be seen in  FIGS. 2 and 3 , against the end surfaces  14  of the roll of material  08 .  
         [0035]     The process for unloading the roll of material  08  from the roll changer  01 , in accordance with the present invention is set forth, as follows:  
         [0036]     Initially, the first stripping device  11  is pressed, with a first stripping force A, against the left end surface  14  of the roll of material  08 . The clamping device  09  on the first axle journal  04  is then opened or released. To unload the left end surface  14  of the roll of material  08  from the first axle journal  04 , the first roll arm  02  is moved axially toward the outside in the direction of the movement arrow  16  shown in  FIG. 1 , in order to increase the distance between the roll arms  02  and  03 . Because the right side of the roll of material  08  is still secured by the clamping device  09  of the second axle journal  06 , the separation of the roll arms  02  and  03  from one another causes the first axle journal  04  to be drawn out of the left end of the cylindrical recess  07 , as seen in  FIG. 1 . This withdrawing movement is supported by an outward movement of the first stripping device  11  with the first stripping force A. An unintended withdrawal of the right side of the roll of material  08  from the second axle journal  06  is thus excluded.  
         [0037]      FIG. 2  shows the roll of material  08 , after its left side has been unloaded from the first axle journal  04 . It is apparent that the first stripping device  11  has now been completely withdrawn from the roll core or cylindrical recess  07 . The stripping device  11  is secured in this withdrawn position by an impingement of the operating cylinder  13  at a higher operational pressure of, for example, 6 bar. In this manner, an unintended shifting of the left side of the roll of material  08  back onto the first axle journal  04 , during the continued unloading process is prevented. At this point, at the latest, a transport  17  assembly is arranged beneath the roll of material  08  for the purpose of transporting the roll of material  08  away from the roll changer after unloading of the roll of material  08 .  
         [0038]     To now also unload the right side of the roll of material  08 , the second stripping device  12  is acted upon by the initial value B 1  of a second stripping force B, and the clamping device  09  of the second axle journal  06  is opened. As a result of the stripping force B which is exerted by the second stripping device  12 , the roll of material  08  is first pressed against the now secured first stripping device  11 . The second roll arm  03  is then moved toward the right, as indicated by the movement arrow  18  shown in  FIG. 2 , in order to thus further increase the axial spacing distance between the roll arms  03  and  02 . Because of the now greater axial spacing distance between the roll arms  02  and  03 , the right side of the roll of material  08 , in response to the outward movement of the second stripping device  12 , is now stripped from the second axle journal  06 . Shortly before the roll of material  08  is completely stripped from the cylindrical portion of the second axle journal  06 , the stripping force B of the second stripping device  12  is reduced to the final value B 2 . The frictional force between the right end surface  14  and the second stripping device  12  is decreased and any damage to the operating cylinder  13 , which might be caused by a downward tilting of the roll of material  08 , is thus prevented.  
         [0039]     In  FIG. 3  the now completely unloaded roll of material  08  is shown. The roll of material  08  lies with its full surface on the transport  17  assembly, and can now be automatically transported away from the roll changer  01 .  
         [0040]     In  FIG. 4 , the drive pressures for the stripping devices  11 ;  12 , during the unloading of the roll of material  08 , are schematically represented. The drive pressure for the first stripping device  11  is represented by a continuous line, and the drive pressure for the second stripping device  12  is represented by a dashed line.  
         [0041]     As is illustrated in  FIG. 4 , during the unloading of the left side of the roll of material  08 , the first stripping device  11  is acted upon by a positive pressure of 1.5 bar, in order, in this manner, to generate the first stripping force A. After the complete stripping of the left side of the roll of material  08 , the first stripping device  11  is then acted upon by a positive pressure of 6 bar, in order to generate the subsequent securing force C.  
         [0042]     During the unloading of the left side of the roll of material  08 , the second stripping device  12  is initially not pressurized. Once the first stripping device  11  has been provided with the securing force C, the second stripping device  12  is then initially acted upon by a positive pressure of 3 bar, in order, in this manner, to generate the initial value B 1  for the second stripping force B. In a second phase of the stripping of the right side of the roll of material  08  from the second roll arm  03 , the pressure of the second stripping device  12  is then reduced to a positive pressure of 1.5 bar, which positive pressure corresponds to the final value B 2  for the second stripping force B.  
         [0043]     While a preferred embodiment of a method for unloading a roll 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 overall structure of the roll changer, the structure used to move the transport assembly, 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 appended claims.