Method in connection with a slitter- winder

The invention relates to a method according to the preamble of claim 1.

As known from prior art, in connection with slitter-winders, a full-width web coming from an unwinder is cut with the slitter-winder into partial webs which are wound by a windup into partial web rolls. A partial-web windup can be a windup of carrier roll type in which the partial web rolls are wound supported by carrier rolls by means of a winding nip between the forming web roll and a second carrier roll. In the windup of carrier-roll type, the second carrier roll can be a set of belt rolls in which an endless belt loop is arranged around two rolls. The partial -web windup can also be a centre-driven windup in which the partial web roll is rotated from the centre and winding takes place by means of the nip between the forming web roll and the winding drum.

When unwinding the web from the unwinder, when the roll being unwound, the so-called spool i.e. machine roll, is emptying, a machine-roll change is performed which in many windups is still done totally manually. Known is also the so-called automatic machine-roll change, whereby in methods known from prior art the slitter-winder is stopped and the old web is picked up with a pick-up device, e.g. a suction device, and cut after which the emptied machine roll is taken away and a next machine roll to be unwound is brought to its place. The web end of the new machine roll is brought to a joining position and the ends of the old web and the new web are joined to each other by applying different joining methods, the slitter-winder and the unwinder being stopped. Such an arrangement known from prior art is described in European patent specification 1163178,

A disadvantage of methods known from prior art in connection with the roll change of an unwinder has been that the machine is stopped for several minutes

during handling the machine rolls and joining the web, whereby costs are accrued because the production is stopped.

Furthermore, in methods known from prior art, the joint between the web ends is formed in a known manner perpendicularly in relation to the longitudinal direction of the web, which can cause problems in handling rolls in a printing machine and other further-processing devices when the joint being thicker than the other web goes simultaneously full-wide e.g. through a nip.

Also arrangements in connection with continuous unwinders are known from prior art in which the joining is performed for threading the web in which the joining takes place at creep or run speed. These known arrangements are poorly applicable to be used in connection with slitter-winders, because in these arrangements the joint provided is only applicable for threading requirements, and thus the slit- ter- winder has to be stopped after this event and the joint has to be removed from all rolls, because it is not suitable for further processing, e.g. for printing, and machine time is again spent on this work. Such embodiments are described in e.g. patent specifications FI74678, FI 100323 and FI96299.

The object of the invention is to provide a method in which the above-described disadvantages related to the machine-roll change have been eliminated or at least minimised.

An object of the invention is to provide a method using which is provided a joint suitable for further processing, e.g. a printable joint.

To achieve the above-mentioned objects and those which come out later, a method according to the invention is mainly characterised by what is presented in the characterising part of claim 1.

According to the invention in the machine-roll change stage, the speed of the slitter-winder is decelerated to creep speed and, when the slitter-winder decelerates, the emptying machine roll is transferred away from the unwinder as it is still unwinding, and a new machine roll is transferred to the unwinding position, and the web end of the new machine roll is brought to a joining position into connection with a joining apparatus the old machine roll still unwinding, and the web speeds are adjusted uniform. After this when the slitter- winder operates at creep speed, the web ends are joined together. When the machine-roll change is performed as the machine is operating at the creep speed of 5-15 m/min, a considerable time- saving is achieved. Alternatively, the slitter- winder can be stopped for a very short while i.e. only for the time of the joining end travelling across the web and making a joint splice. About 10-30 seconds is passed in this. Also in this case, the time-saving is great compared to methods used today. On the other hand, when performing the joining of the ends of the old web and the new web by means of a method according to the invention, a joint is provided which is not perpendicular in relation to the longitudinal direction of the web but oblique, whereby the joint causes no problems in printing machines or other further-processing devices and the joint splice is thus suitable for further processing.

Into connection with the slitter- winder are arranged means for transferring the old machine roll during deceleration away from the new machine roll, means for transferring the new machine roll to the unwinding position, means for bringing the web end of the new machine roll into the joining position, and an arrangement for joining at creep speed. Joining the web ends can be performed with joining means known as such whereby is provided a joint suitable for further processing.

The invention will now be described in more detail with reference to the figures of the accompanying drawing, to the details of which the invention is, however, by no means intended to be narrowly confined.

Fig. 1 schematically shows a situation in which a machine roll on an unwinder is just emptying.

Fig. 2 schematically shows a situation in which an old machine roll is transferred from an unwinding position to a change position.

Fig. 3 schematically shows a situation in which a new machine roll is brought to the unwinding position.

Fig. 4 schematically shows a situation in which the web end from the new machine roll is guided to a joining position.

Fig. 5 shows a situation in which the ends of the old web and the new web are joined and the web coming from the old machine roll is cut.

In the situation shown in Fig. 1, an old machine-roll 10 in the unwinding position is emptying and arrow SlO shows its transfer direction towards the change position. Simultaneously, a guide roll 27 and a counter part 26 of the joining end are transferred towards the change position, arrows S27, S26. Furthermore, simulta- neously a suction roll 21 of a web pick-up device 20 is started to transfer towards the stand-by position to receive the web end coming from a new machine roll, arrow S21. In the situation of Fig. 1, a web WlO is unwound from the old machine roll 10 and the speed of the slitter- winder is started to decelerate towards creep speed.

Fig. 2 schematically shows a situation in which the old machine roll 10 is transferred to the change position and the web WlO is still unwinding from the old machine roll 10 via a guide roll 28. The web pick-up device 20, the counter part 26 of the joining end and the guide roll 27 of the web are transferred to the stand- by position.

In the situation shown in Fig. 3, a new machine roll 15 is transferred to the unwinding position, and with the suction roll 21 of the web pick-up device 20 the web end coming from the new roll 15 is picked up, after which the web pick-up device 20 is started to transfer, as shown with arrow S 15, towards the joining po- sition. The web being guided to the slitter-winder is still unwinding from the old machine roll 10.

In the situation shown in Fig. 4, the end of a web Wl 5 coming from the new machine roll 15 is brought with the suction roll 21 of the web pick-up device 20 to the joining position, after which the guide roll 27 and the counter part 26 of the joining end are transferred to the joining position. The web being guided to the slitter- winder is still coming from the old machine roll 10 and the slitter- winder operates at creep speed.

In the situation shown in Fig. 5, as the machine operates at creep speed or alternatively is stopped for the movement of the joining end, the joining of the end of the web Wl 5 coming from the new machine roll 15 is performed to the web WlOA coming from the old machine roll 10 with a joining end 25, in which connection the web WlO coming from the old machine roll is cut and the winding continues from the new machine roll 15. The joining as such can be performed by applying arrangements known as such for those skilled in the art in which the joining end, when moving across the web, cuts the webs and a joint splice is made between the ends of the webs Wl 5 and WlOA intended for joining. The joining end 25 transfers during joining in the cross-machine direction and, when moving, cuts both webs, guides the extra tails aside and pulls tapes to the joint on both sides of the web. After the joining is performed, the joining position is opened by transferring the guide roll 27 and the counter part 26 of the joining end towards the change position. After the joining, tape tails possibly remaining on the edges of the web are cut away in connection with the cutting of edge trims performed later in the process. After the joining, the slitter- winder is accelerated to run speed and the

cutting of the partial webs and the winding of the partial webs is continued at run speed.

According to the invention, when the slitter- winder decelerates to creep speed, the emptying i.e. old machine roll 10 is transferred away from the new machine roll 15 to an upper position, and simultaneously the web pick-up device 20 is transferred to the change position, and the new machine roll 15 is brought to the unwinding position. After this, the slitter-winder operating at creep speed, the end of the new web Wl 5 is picked up with the web pick-up device 20, e.g. a suction roll beam or e.g. with the suction roll 21 of the web pick-up device 20, and is brought to the joining position into connection with the web WlO coming from the old machine roll 10. After this, the webs W15, WlOA moving at creep speed are joined together with the joining end 25, and the web WlO coming from the old machine roll 10 is cut. Alternatively, the slitter- winder can be stopped for the time of the across movement of the joining end. When performing joining at creep speed, the joint formed is oblique in relation to the longitudinal direction of the web. After joining, the speed of the slitter- winder is increased to run speed for continuing normal run.

The joining devices comprise, known as such from prior art, a frame and the joining end 25 and the counter part 26 of the joining part. The frame consists of a machine-wide beam with its end structure. Furthermore, into connection with the frame are arranged the guide rolls 27, 28 for guiding the new web and the old web for joining in the joining position. The joining part comprises a guide guiding the travel of the joining end 25, the transfer devices of the joining end and the cutting blades of tape. The counter part 26 of the joining end is transferred to the joining position against the frame beam by means of an actuator, e.g. a hydraulic cylinder. The joining end comprises rotating disc blades which cut the webs being joined during the movement of the joining end. Simultaneously, the joining end guides the extra web tails aside and the web ends being joined against each other and tapes them together from both sides of the webs forming a so-called butt-joint. In

the joining end, there are reels for the tape rolls and for collecting the back tapes of the tape. The cutting blades of the tape are located at both ends of the joining beam for cutting the tape. By means of a suction roll or a corresponding means, the new web is picked up from the surface of the new machine roll and the fasten- ing of the web on the suction roll takes place by means of a vacuum zone provided with the suction roll. For turning, the suction roll is provided with an actuator, e.g. a hydraulic cylinder, and into connection with the roll is arranged means for rotating it and the roll can be rotated in both directions.

The invention was described above only referring to one of its embodiments, to the details of which the invention is, however, by no means intended to be narrowly confined.