Abstract:
One or more issue web rolls are transferred from the core shaft on which they are carried by an apparatus that includes a roll change tube that is moved into coaxial alignment with one end of the core shaft and engages the end of the shaft to support it. A pusher device pushes the tissue web rolls from the core shaft onto the roll change tube. The roll change tube is then pivoted to move the roll change tube away from the core shaft to position the tissue web rolls for delivery to a downstream process, and simultaneously a core change tube is moved into coaxial alignment with the core shaft so that new cores can be pushed from the core change tube onto the core shaft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is a continuation of International Patent Application PCT/FI01/00372 filed Apr. 12, 2001, incorporated herein by reference, which designated inter alia the United States and was published in English under PCT Article 21(2).  
         FIELD OF THE INVENTION  
         [0002]    The present invention relates to a method for transferring rolls of soft paper grades, also known as tissue paper grades, that are rolled on core shafts to further processing. The invention also relates to an apparatus suitable for implementing the method.  
         BACKGROUND OF THE INVENTION  
         [0003]    In the art of papermaking, high bulk paper grades, also known as soft paper grades, are generally called tissue webs. Tissue webs also include silk paper grades. Tissue web finds particular use in various products requiring good absorbency, such as towels and napkins, diapers and the like. For these products, tissue web is subjected to further processing in order to make the absorbent pads or other liquid-receiving bulk portions needed in the final product. All of these raw material grades are characterized by high compressibility even under small compressive forces, as well as a low specific weight in regard to their volume.  
           [0004]    Due to their high compressibility, the handling of tissue web rolls is difficult. It is desirable that the large specific volume of the product per unit weight be retained as unchanged as possible through all the manufacturing steps up to the end user in order to maintain the qualities of the product at an optimally high level. As such web rolls tend to collapse easily, the handling of the rolls must be carried out with maximum caution to roll damage so that the rolls are not subjected to high forces nor supported on their outer plies. One problem in the handling of rolls is associated with the removal of the set of parent rolls from the core shafts. In the production of soft tissue webs wider than about 5000 mm, the web leaving the papermaking machine is slit into two or more partial-width webs prior to winding, and the partial-width webs are wound onto individual cores on the core shafts to form a plurality of partial-width parent rolls. Prior to the start of the winding, the cores are already threaded onto the core shafts and thus the tissue paper rolls wound from the slit web have a width which is directly suitable for the further processing steps. Herein, a problematic phase occurs in the removal of the set of parent rolls from the core shaft. If the parent rolls are still supported by the core shaft on the reel rail, the core shaft cannot be pushed out from the rolls without an external support of the rolls. The friction between the core and the core shaft caused by the weight of the parent rolls resting on the shaft would prevent free sliding of the core shaft. In one prior-art method, this problem has been solved by supporting the parent rolls by their outer plies, whereby the weight of the rolls is relieved from resting on the core shaft. However, this arrangement involves the risk of reducing the caliper of the tissue web as a result of the externally applied forces from the weight of the rolls. Additional problems can result from the elasticity of the wound web causing the wound parent rolls to expand after the compressive pressure of the core shaft is removed. The winder of a prior-art arrangement is provided with a lift table that supports the parent roll and a downward sloped rolling ramp for transferring the rolls from the winder. For the handling of the core shaft, this apparatus construction is provided with core shaft puller means and other means for threading new cores onto a free shaft. Obviously, such supporting of the tissue web parent roll and the free rolling off the rolling ramp can readily degrade the compressibility properties of the tissue web and thus impair parent roll quality.  
         SUMMARY OF THE INVENTION  
         [0005]    An object of the present invention is to provide a method and apparatus for supporting tissue parent rolls by their cores during their removal from the core shaft and, advantageously, also during their transfer to the further processing steps.  
           [0006]    The goal of the invention, to remove the set of parent rolls from the core shaft while maintaining the quality of the wound paper, is achieved by supporting the core shaft at one end by a support such as a rail and at the other end by a roll change tube whose outer diameter is equal to that of the core shaft and whose end is operable to engage and support the end of the core shaft. When the core shaft is connected to the roll change tube, the rolls wound on the core shaft can be pushed onto the roll change tube outside the reel and then transferred to a pole truck pick-up position for further processing or storage.  
           [0007]    The invention offers significant benefits. By virtue of the method, tissue parent rolls can be transferred so that they are supported by their cores in a continuous manner when they are pulled from the support of the core shaft, whereby there is no need to grab the roll or support the same by the outer plies of the roll. Hence, the risk of roll compression and damage can be eliminated from these steps of roll processing. The removal of parent rolls from the winder after being wound on a core becomes extremely fast and a new core shaft with the cores threaded thereon is rapidly placed into the vacant position of the just removed shaft. As the construction of the core-handling assembly is extremely uncomplicated, its cost as compared with its high roll-handling capacity remains very low. Furthermore, parent rolls removed from the core shaft can be handled by a lift truck having core chuck arms, whereby any post-processing of the rolls can be carried out without supporting the parent rolls by their outer plies. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0008]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:  
         [0009]    [0009]FIG. 1 shows a diagrammatic view of an embodiment according to the invention performing a first step of the method;  
         [0010]    [0010]FIG. 2 shows a diagrammatic view of the embodiment of FIG. 1 performing a second step of the method;  
         [0011]    [0011]FIG. 3 shows a diagrammatic view of the embodiment of FIG. 1 performing a subsequent step of the method;  
         [0012]    [0012]FIG. 4 shows a diagrammatic view of the embodiment of FIG. 1 performing a next subsequent step of the method;  
         [0013]    [0013]FIG. 5 shows a detail of the embodiment of FIG. 1;  
         [0014]    [0014]FIG. 6 shows another detail of the embodiment of FIG. 1;  
         [0015]    [0015]FIG. 7 shows a detail of a preferred embodiment of the invention;  
         [0016]    [0016]FIG. 8 shows a detail of the embodiment of FIG. 7 viewed from another direction;  
         [0017]    [0017]FIG. 9 shows a component of the embodiment illustrated in FIG. 7; and  
         [0018]    [0018]FIG. 10 shows one further embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.  
         [0020]    The assembly according to the invention is mounted to operate in conjunction with a winder of a tissue-making paper machine. In the arrangement illustrated in FIG. 1, parent rolls  10 ,  11  are transported along transfer reel rails  2 ,  3  starting from the winder to a changer of a core shaft  1 . The core shaft comprises a shell portion for supporting at least one roll core  9  and at least one coupling portion  20 . At the reel changer, the reel rails  2 ,  3  terminate at rotatable supports  15  having crosswise aligned rails  14  located below the supports  15 . A lift fork  4  is adapted to be movable on these crosswise rails  14 . The fork  4  has at its end a slot  16  suitable for supporting the end of the core shaft  1 . The rails  14  are adapted to extend beyond the width of the reel shaft  1  and the height of the lift fork  4  is dimensioned so that the fork  4  can move on the rails  14  underneath the core shaft  1  and the parent rolls  10 ,  11 . At the opposite end of the lift fork  4  transfer rails  14 , a roll core handler  12  is located adjacent to the core shaft reel rails  2 ,  3 . The core handler  12  comprises a roll change tube  5  and a core change tube  8  cantilever mounted thereon. The roll change tube  5  and the core change tube  8  are mounted at a mutual 90° angle on the body of the roll core handler  12  and adapted to be rotatable so that either one of tubular charger tubes  5 ,  8  can be rotatably aligned parallel to the rails  14  and the center axis  17  of the core shaft  1 . Additionally, the roll core handler  12  is made transferable, e.g., along the rails  14  of the lift fork in a parallel direction to the central axis  17  of the core shaft  1 . Further, the roll core handler  12  is complemented with a core-handling table  13  in a position meeting the core change tube  8  when the roll change tube  5  is aligned parallel to the central axis  17  of the core shaft  1 .  
         [0021]    Now referring to FIGS. 5 and 6, there are shown some details of the construction of the lift fork  4 , the core shaft support  15  and the end of the roll change tube. The core shaft support  15  is implemented in the form of a rail as an extension of the transfer rail  3  and has a stop  18  at its end for stopping the movement of the reel shaft  1 . The support  15  is mounted on the end of the transfer rail  3  so as to be rotatable about a pivotal joint  19 . The lift fork  4  has a round slot  16  with a shape compatible with the outer shape of the core shaft  1 . An alternative technique is to use, e.g., a V-shaped slot, whereby a single lift fork can be used for supportably lifting core shafts of different diameters. However, papermaking factories generally use only core shafts of the same size. The height position of the lift fork  4  as seen from the level of the rails  14  is adapted such that the fork  4  may be moved under the largest roll  11  to be handled in the roll change position without interfering with the roll  11 .  
         [0022]    The outer diameter of the roll change tube  5  is dimensioned to be compatible with the inner diameter of the roll cores  9  used at the winder. The end of the roll change tube  5  is provided with an inner bushing whose inner diameter is compatible with the outer diameter of a coupling portion  20  adapted to the end of the core shaft, whereby the outer diameter of the coupling portion must be made smaller than the outer diameter of the core shaft shell. The end of the roll change tube  5  can be slidably fitted on the coupling portion  20  so that the end of the tube  5  remains resting on the end of the shell of the core shaft  1  that provides support to the roll cores  9 . The diameters of the roll-supporting shell portion of the core shaft  1  and the roll change tube  5  are preferably made equal. The end of the roll change tube  5  need not necessarily have a shaped bushing, but instead, the inner diameter of the tube  5  may be directly made compatible with the outer diameter of the core shaft coupling portion  20 .  
         [0023]    The function of the roll-handling system according to the invention is as follows.  
         [0024]    The core shaft  1 , which in the exemplifying embodiment is shown having two rolls  10 ,  11  resting thereon, is rolled off from the slitter of a tissue-web-making machine up to the end of the transfer reel rails  2 ,  3 . One of the transfer rails has its end equipped with the above-mentioned rotatable support  15 , whereby the core shaft  1  can remain resting on the end of the second transfer rail  3  and the support  15 . Next, the lift fork  4  is elevated to bear the load of the core shaft  1  at that end of shaft which is resting on the support  15 , that is, the shaft removal end, and the support  15  is rotated downward away from the core shaft  1  and the rolls  10 ,  11 . The roll change tube  5  is next moved by the roll core handler  12  against the shell end of the core shaft  1  (see FIG. 2), whereby the core shaft  1  remains resting by its coupling portion  20  on the end of the roll change tube  5 . It must be noted, that the lift fork  4  supports the core shaft  1  over its shell portion so that the roll change tube  5  can be threaded fully home against the end of the shaft shell. While the core shaft  1  is resting on the roll change tube  5 , the lift fork  4  moves down and travels on the rails  14  toward the other end of the core shaft  1  up to a position between the transfer rail  2  and the roll  11  resting on the core shaft  1 , and then rises against the shell of the core shaft  1 . The lift fork  4  is then moved on the rails  14  to push the rolls  10 ,  11  resting on the core shaft  1  onto the roll change tube  5  that essentially forms an extension of the shell portion of the core shaft  1 . The lift fork  4  pushes the rolls at the ends of the roll cores  9  and, as the cores are abutting each other, there is no need to impose the pushing force on the ends of the rolls  10 ,  11 . Even here, the lift fork  4  provides support to the end of the outermost roll  11 . Obviously, a separate fork-shaped pusher can be used in lieu of the lift fork. The core shaft  1  is prevented from moving with the roll cores  9 , since the stationary roll transfer reel rail  2  and the roll change tube  5  lock the core shaft  1  stationary in regard to its movement along its longitudinal center axis.  
         [0025]    Next, the lift fork  4  moves to provide support to the core shaft  1  at its change-side end and, simultaneously, the roll change tube  5  is withdrawn to disengage the coupling portion  20 . After the roll change tube has disengaged the coupling portion  20  and has rolls  10 ,  11  on it, the roll core handler rotates 90° about its pivot point which is located on the extension of the core shaft longitudinal axis, which causes the core change tube  8  with new roll cores  9  threaded thereon to be aligned with the roll shaft center axis  17  so that the core change tube can be threaded in until pushed against the shell end of core shaft  1 . Next, the lift fork  4  is lowered down and the roll cores  9  are pushed onto the core shaft  1 , then the lift fork  4  is elevated up again and the core change tube  8  is detached from the core shaft end by the movement of the roll core handler  12 . As the next step, the support  15  is free to be rotated into a position under the core shaft  1  and, simultaneously, the lift fork  4  is lowered, whereupon the core shaft  1  can be transferred with the new roll cores threaded thereon ready for the next operation at the winder of the papermaking machine.  
         [0026]    As shown in FIG. 4, the rolls  10 ,  11  can be removed from the roll change tube  5  by using, e.g., a transfer truck  21  equipped with core chucks. After the removal of the rolls  10 ,  11 , the roll core handler  12  is rotated back into its home position, whereupon the roll change tube  5  is ready to receive new rolls and the new cores can be threaded onto the core change tube  8 . The loading of the core change tube  8  can be made manually or by an automatic core loader.  
         [0027]    In FIGS.  7 - 9  is shown a simplified embodiment of the invention. Due to its streamlined design, this embodiment is in many applications more cost-efficient than the arrangement described above. However, the above-described assembly is more suitable for use in locations where extremely heavy rolls are handled on core shafts, because it allows the lift fork to be designed sufficiently rugged. The simplified embodiment illustrated in FIG. 7 is, however, preferred in the handling of tissue web rolls on core shafts, because these rolls are relatively lightweight as compared with the heavy rolls of printing paper grades, whereby the handling of tissue web rolls does not require such rugged handling equipment.  
         [0028]    In the embodiment shown in FIG. 7, at the region where the roll change tube  5  reaches the rotatable support  15 , the end of the tube is provided with a cut-out relief portion  22  made by removing a portion of the tube  5  shell. Longitudinally, the cut-out relief portion  22  extends from the end of the roll change tube  5  up to a given portion of the width dimension of the coupling portion  20  of the core shaft  1  so that the support element has a sufficient space to support the core shaft  1  from below by engaging its coupling portion  20 . However, the width of the cut-out relief portion  22  must be made shorter than the longitudinal width of the core shaft coupling portion  20  so that the full-bore end of the roll change tube  5  can reach despite the cut-out relief portion  22  below the coupling portion  20 , thereby being capable of supporting the core shaft  1 . Due to this requirement, the length of the cut-out relief portion must be made shorter than the length of the coupling portion  20 . The upper side of the roll change tube  5  must be contiguous at least at the highest position of the tube surface in order to allow the roll cores to slide smoothly away from the shell of the core shaft  1  onto the roll change tube  5 . On the other hand, the underside of the roll change tube can be provided with a very short cut-out relief portion only, because the support  15  only makes touching contact with the underside of the coupling portion  20 . Hence, the dimensioning of the cut-out relief portion within this region is chiefly determined by the dimensions and structure of the coupling portion  20  and the support  15 . As to the strength of the shaft-engaging end of the roll change tube, it is obviously advantageous to make the cut-out relief portion as narrow as possible in the radial direction of the tube  5 , because then the stiffness of the tube end is retained as high as possible.  
         [0029]    The function of the above-described embodiment is as follows.  
         [0030]    The core shaft  1  with the rolls  10 ,  11  resting thereon moves to the end of the transfer rails  2 ,  3  and the roll change tube  5  is moved against the shell end of the core shaft  1 . The cut-out relief portion  22  at the end of the roll change tube  5  facilitates the engagement of the tube  5  with the coupling portion  20  while the support  15  mounted to the end of the transfer rail  3  continuously supports the end of the core shaft  1  at the coupling portion  20 . Once the end of the roll change tube  5  meets the shell end of the core shaft  1  at the upper edge of the tube, the uncut full-bore portion of the roll change tube  5  surrounds the end of the coupling portion  20  thus allowing the roll change tube  5  to support the core shaft. In this position, the support  15  can be rotated down and thereby the core shaft  1  remains resting on the roll change tube. Subsequently, the rolls can be pushed by a pusher means onto the reel change tube. In this embodiment, the pusher does not need be a rugged lift fork, but a less rugged pusher means may serve as well. After the rolls  10 ,  11  have been moved onto the reel change tube, the support  15  is rotated upward to re-support the end of the core shaft and the reel change tube  5  is withdrawn away from surrounding the coupling  20  of the core shaft. Next, the roll core handler  12  is rotated, whereby the core change tube  5  and the rolls  10 ,  11  are moved into the roll delivery position, and simultaneously the core change tube  8  with new roll cores  9  threaded thereon is aligned with the longitudinal axis of the reel shaft  1  and then pushed onto the end of the core shaft  1 . The core change tube  8  has a similar cut-out relief portion as that made on the roll change tube  5 . After the support  15  is again lowered, the roll cores can be pushed onto the reel shaft, whereupon the support may again rise and the core shaft is again ready for the next winding steps and the core change tube can be withdrawn from the end of the core shaft.  
         [0031]    [0031]FIG. 10 shows a further embodiment of the invention. In this embodiment the end of the roll change tube  5  is left on the end of the core shaft  1 . This leaves a gap of 500-600 mm between the end of the roll change tube  5  and the end of the core shaft  1  shell. Since the parent rolls  10 ,  11  are usually several even up to 5 meters long, the rolls can be easily pushed over the gap. Or course, it is clear that this embodiment is not suitable for processes handling very short rolls. On the operation of this embodiment it must be noted that the core shaft must be locked in the axial direction either by a stopper built within the roll change tube  5  or a suitable restraining apparatus at the opposite end of the core shaft  1 .  
         [0032]    Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.  
         [0033]    For example, it is to be understood that a non-split web can be wound on a single core threaded on the core shaft, and if the web is split more than twice, the number of cores can be three or greater.  
         [0034]    Furthermore, the mutual position of the tubes  5 ,  8  may be arranged different from what is described above. The tubes  5 ,  8  may be located on the same axis for instance, whereby the rotational movement of the roll core handler may cover an angle of, e.g., 90° or 180°. However, the exemplifying embodiment described above can offer smaller movements combined with a short transfer time. The roll core handler need not necessarily be designed movable, but instead the movements of the roll change tube and the core change tube in the direction of the core shaft longitudinal axis can be implemented by virtue of moving the tubes on guides or supported on telescoping cylinders or the like. Obviously, the lift fork could be moved above the core shaft, but this arrangement makes connection to the core shaft more difficult. A single lift fork may be replaced by a combination of two separate fork ends, whereby their movement toward the core shaft ends can be implemented in different manners. It is even possible to omit the lift fork totally. In such an embodiment the roll change tube is pushed over the end of the core shaft so that it engages the outer end of the coupling means and supports the core shaft. When the support at the end of the transfer rail is removed, the roll change tube can be pushed further over the end of the core shaft to make the support more secure. The roll change tube can be pushed against the shell end of the core shaft or left at a distance thereof. The disadvantage of this embodiment is that the weight of the parent rolls and the shaft rests largely on the end of the roll change tube whereby it is heavily stressed and moving it requires high force because of friction.  
         [0035]    Furthermore, an additional separate roll core handler can be placed close to the other end of the core shaft, thus achieving a reduced core change time. Correspondingly, the core change tube and the roll change tube can be located on different sides of the core shaft. The roll change tube may also be made movable only in the direction of the core shaft longitudinal axis, whereby it can also serve as the core change tube. Instead of running on the transfer rails, the core shafts may be introduced into the roll change position by lifting and then placed there on suitable support blocks or directly on the lift forks. Although certain elements in the foregoing text have been called as a “tube”, it is obvious that these elements may as well be implemented using bar cages or other similar constructions known in the art. Hence, their outer surface need not necessarily be defined by a cylindrical shell inasmuch as an equivalent element with a prismatic or even a radially outwardly ridged envelope of an elongated shape will serve the desired-purpose as long as the longitudinal projections of the element mate in the desired manner with the inner diameter of the core. Similarly, all other terms used to describe the different elements must be understood as descriptive and general names of the elements only, rather than as technical terms limiting to the implementation of the invention. For instance, the construction of the lift fork may in reality have any other form of a support element instead of being a forked structure. Instead of utilizing rotation, the support element or elements mounted at the end of the transfer rail can be arranged to be movable in the horizontal or vertical direction, or along an inclined trajectory, or the support(s) may be located on the opposite side of the core shaft in regard to the transfer rails.