Device and method for a job change in a system for the lengthwise cutting of a weblike material

#The present invention relates in general to a device for the lengthwise cutting of a weblike material, such as, for example and in particular, corrugated cardboard, which is subdivided into a plurality of strips having a desired width, from which individual sheets having the desired dimensions are then produced by means of transverse cuts.

#In cutting and creasing plants for the production of sheets of corrugated cardboard intended, for example, for the manufacture of boxes, it frequently becomes necessary to change the job being processed. The job change normally requires a change in the positions of the lengthwise cutting lines and/or of the lengthwise creasing lines. This occurs because different jobs performed in succession by the same plant are characterized by different dimensions of the final sheets produced.

#During the job change phase, certain problems arise that are well known to those skilled in the art, in particular when the plant is of the type having two or more levels, in other words of the type in which the strips cut lengthwise from a single weblike material are conveyed to transverse cutting devices disposed at different heights. In this case, one of the lengthwise cutting lines subdivides the weblike material into one or more strips that are conveyed to a first level and one or more strips that are conveyed to a different level to be subdivided into sheets. On the occasion of a job change, the intermediate cutting line that subdivides the strips being conveyed to the two levels is normally shifted in position, so that it becomes necessary to connect the two intermediate cutting lines in order to avoid the tearing of the weblike material.

#FIG. 1 shows a diagram—in a lateral view—of a plant for cutting and creasing a web of corrugated cardboard according to the invention;

#FIG. 2 shows a diagrammatic view of an embodiment of the transition zone between two successive jobs in the weblike material;

#FIG. 3 shows a diagrammatic lateral view of a simplified plant;

#In FIG. 1, a general view is shown of the structure of a device for cutting and creasing a weblike material N coming, for example, from a corrugated cardboard production line. The device has a first creasing station 1, a second creasing station 3, a first cutting station 5 and a second cutting station 7. The four stations (forming what is known as a slitter-scorer) may be disposed in various ways, and in the example shown the two creasing stations are positioned upstream of the cutting stations, but this is not obligatory. It is also possible to provide arrangements in which the creasing and cutting stations are disposed alternately, or with the cutting stations upstream of the creasing stations. As will be clear from the description that follows, moreover, it is also possible to provide a single cutting station and/or a single creasing station.

#The invention is described with reference to a complex device also equipped with creasing tools, but it is understood that the invention may also be applied to different machines or devices, for example those lacking creasing tools. Furthermore, the configuration of the cutting and creasing stations is not critical, the method of the present invention being capable of being used on any type of slitter-scorer able to produce a weblike material cut lengthwise into portions intended to be passed to two or more levels for the subsequent transverse cut.

#In the situation shown in FIG. 1, the creasing tools of the station 1, designated 2A, 4A, are in operation while those of the station 3, designated 2B, 4B, are disengaged from the weblike material N and can be positioned by a suitable positioning robot (not shown). The cutting tools 25B of the station 7 are idle and may be positioned by the positioning robot generally designated 9, while the tools 25 of the station 5 are in operation.