Apparatus for producing a perforated track in a travelling web, e.g. a paper web

The invention relates to an apparatus for producing a perforation in a web, such as paper web. is on the preamble of claim 1 referenced.

A preferred application of this device are wrappers, wherein a web is wound into a roll. It is - to Performing a role change - by means of the apparatus transversely to Bahn direction of rotation produces extending perforation in the web. Thereafter, the web is severed along the perforation.

Such devices are known from:<sl><li>(1) DE 36 11 895 C2</li><li>(2) DE 40 34 997 C1</li></sl>

The known devices for perforating a running paper web have significant disadvantages. The perforating apparatus of FIG. 2 in Document (1) has a shaft with a comb, further comprising a backing roll with an elastic sheath. When not operating the perforating is doing the perforation comb in a position that he with the Paper web does not come into contact. If a perforation in the Paper web are placed, so the shaft makes one revolution; in order to the perforation comb is in screwing in the paper web and out of it again moved so that it leaves a perforation. This device has the disadvantage that its construction cost is very large. The controller must be very precise work because the shaft and the counter-roll in synchronism with the must run the paper web, as otherwise a premature path separation.

In the embodiment of Figure 1 in document (1) the wave travels in Opposite direction to the paper web. This leads to an undefined perforation and the risk of web break during Perforationsvorganges.

Document (2) shows and describes an apparatus for separating a Paper web. Here, during the stoppage of the engine (eg Winding machine) is pressed against the surface mounted on a support roller train, to squeeze around the track and thus weaken. full By separation is then carried out by increasing the web tension. This device has the disadvantage that the winding machine for the purpose of must be stopped weakening the web, whereby the Roll changing operation relative is time consuming. It is also Danger of damaging the surface of the support roller.

The invention has for its object to provide an apparatus for perforating to provide a paper web, which is simple in structure, no high Control effort required, and with a perforation on the Web width can be set reliably and reproducibly.

This object is achieved by the characterizing features of claim 1 dissolved.

The device according to the invention is simple in construction, requires no elaborate control and works reliably. This is particularly even if the track is not particularly high tension in the running direction, ie with low web tension. Thanks to the invention, it is possible that Perforation - despite continuing to run the machine - at a precisely introducing determinable point in the path, said premature is tearing the web safely avoided.

Particularly good results are achieved if the invention by the Characteristics is least developed further one of the dependent claims. It is important that the tips of the Perforationskammes into the recesses can touch to immerse the web supporting body without it. The Length of the recesses (measured transversely to the running direction) and thus their number must be determined in such a way that the path of the immersion Perforationskammes not evade. The length of the recesses depends of the train characteristics, particularly on the stiffness of the web. For example, thin paper webs having low stiffness requiring a large number of Recesses short length, relatively thick and stiff paper webs however, a smaller number of recesses with accordingly relatively large length (claim 5). The width of the transverse ribs, which the Recesses separate, choosing as small as possible, for example, only 2 to 4 mm, so that the free tips of areas of the Perforationskammes could be as short as possible (claim 6).

The invention is explained in more detail with reference to the drawing.

1 shows a support roll 1, which has a perforated roll shell. The back-up roll, for example, part of a winding machine for be winding a paper web.

A paper web 2 is in the present case from below over a guide roll 3 brought up to the support roller first She runs through the invention Perforation 4 and 5 at a device for applying a Glue line. The gluing device is irrelevant for the invention.

As can also be seen from Figure 2 in detail, including the 4 device according to the invention a shaft 4.1. Their runs axis 4.2 parallel to the web 2, but transversely to the web running direction, ie across the entire web width. Wave 4.1 has a perforation comb 4.3. The Shaft 4.1 is rotatably supported. She has a drive, so that it in the direction the arrow can revolve 4.4.

On the wave of 4.1 opposite side of the web 2 is a located Supporting body 4.5. This extends equal to the shaft transversely to 4.1 Web width. It is crucial that support body 4.5 cutouts 4.6 which are open towards towards the web. 2 In other words, the Supporting body 4.5 has basically the shape of a groove, the back against the web is open. The groove may have transverse ribs 4.8, that of the interior Channel is divided so that the said recesses emerge 4.6. Of the Comb 4.3 on the one hand and the recesses 4.6 on the other hand are such designed and arranged such that the comb and the peak 4.7 in the said recesses 4.6 then be able to intervene when the shaft 4.1 rotates, and the crest reaches that position, in which its peaks in 4.6 the paper web 2 Prick. And yet is no contact between Crest 4.3 and 4.5 support body instead.

Preferably, the shaft extending 4.1, the fortified it, Perforation comb 4.3 and 4.5 the support body over the entire web width away. However, it may be sufficient in the individual case, if these three Elements over only a part of the web width extend.

The length L of the recesses 4.6 is - as explained above - of the Paper made dependent. The width B of the transverse ribs is 4.8 as small as possible, for example, only 2 to 4 mm.

The device operates as follows:

In the normal state, that is when the paper web 2 to form a paper roll is wound, the shaft 4.1 is in the position shown in Figure 1 Angular position, facing away from the supporting body 4.5 in the comb 4.3. Should a Perforation be placed in the paper web 2, the shaft carries a 4.1 Revolution, so that comb 4.3 with its peak 4.7 in the paper web 2 dips and according to the other round the shaft 4.2 of this again contact with the medium.

The peripheral speed of the tips of 4.7 must not present absolutely exactly equal to the speed of the web 2 to be. It is also both an slightly higher speed possible, as well as a somewhat lower. in the former case are Perforationsschlitze in the running direction of the paper web 2 produced which are relatively short, while in the second case is relatively long.

The distance between the shaft 4.1 and the supporting body 4.5 is adjustable, indicated schematically by double arrow 4.9.

The support roller 1 is associated with a web holder (6) (to hold the new web start after the severing of the web) to the back-up roll is pressed.

An important advantage of the invention over the embodiment according to Document (1), Figure 1, is as follows:

In the said document, the equipped with a knife roller must 9 8 are departed from the paper web to be disengaged to will.

In the invention, this is not necessary. The shaft 4.1 has a corresponding distance from the paper web second

The invention is applicable preferably (but not exclusively) when Reel change process according to Patent Application 195 19 306.7 (PA 10169 = R 05355).