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

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

A preferred field of application of this device are winding machines in which a web is wound into a roll. a transverse to the web direction of circulation perforation in the web by means of the device produces - this is - for performing a role change. Thereafter, the web is severed along the perforation.

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

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, also a backing roll with an elastic sheath. When not operating the perforating means thereby is the perforation comb in a position that it does not come with the paper web into contact. If a perforation in the paper web are placed, so the shaft makes one revolution; so that the perforation comb is screwing in the paper web and moved back out of this, so that it leaves a perforation. This device has the disadvantage that their construction cost is very large. The controller has to work very precisely, because the shaft and the counter-roller must be synchronized with the paper web, as otherwise a premature path separation.

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

Document (2) shows and describes a device for severing a paper web. It is pressed during stop of the machine (eg winding machine) against which rests on a supporting roll sheet to squeeze and thus weaken the web. The complete transection is then carried out by increasing the web tension. This device has the disadvantage that the winding machine for the purpose of weakening the web must be stopped, whereby the roll changing operation requires a relatively long time. There is also the risk of damaging the surface of the support roller.

The invention has for its object to provide an apparatus for perforating a paper web, which is simple in construction, which does not require high control effort, and with a perforation across the web width can be set reliably and reproducibly.

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

The device according to the invention is simple in construction, requires no complicated control and works reliably. This is particularly true if the path is not particularly high tension in the running direction, ie with low web tension. Thanks to the invention it is possible, the perforation - despite continued running machine - bring to a precisely determinable spot in the web, premature tearing of the web is avoided with certainty.

Particularly good results are achieved if the invention by the features of at least one of the sub-claims will be further developed. It is important that the tips of Perforationskammes can delve into the recesses of the web supporting body without touching. The length of the recesses (measured transversely to the running direction) and thus their number has to be determined such that the web does not avoid the immersion of Perforationskammes. The length of the recesses depends on the web properties, especially the stiffness of the web. For example, thin paper webs having low stiffness requiring a large number of recesses less length, relatively thick and stiff paper webs on the other hand a smaller number of recesses with a correspondingly relatively large length (claim 5). The width of the transverse ribs which separate the recesses from one another, is chosen as small as possible, for example, only 2 to 4 mm, so that the free tips of the areas 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 backing roll may for example be part of a winding machine for winding a paper web.

A paper web 2 is brought in the present case from the bottom via a guide roller 3 to the backing roll. 1 She runs through the inventive perforation 4 and 5 at a device for applying a glue line. The gluing device is irrelevant for the invention.

As can be seen also from Figure 2 in detail, the device 4 according to the invention comprises a shaft 4.1. 4.2 whose axis runs parallel to the web 2, but transversely to the web running direction, ie transversely over 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 can rotate in the direction of the arrow 4.4.

On the wave of 4.1 opposite side of the web 2 to a supporting body is 4.5. This extends equal to the shaft 4.1 across the web width. It is crucial that the support body comprises 4.5 4.6 recesses, which are open towards the web. 2 In other words, the supporting body 4.5 in principle has the form of a trough, which is open against the web. The groove may have transverse ribs 4.8, which divide the interior of the trough, so that the said recesses emerge 4.6. The comb 4.3 on the one hand and the recesses 4.6 on the other hand are so shaped and arranged that the comb and the peak 4.7 in said recesses 4.6 then can engage when the shaft 4.1 rotates, and the crest comes into that position in which its tips 4.6 prick in the paper web. 2 And yet no contact between Crest 4.3 and 4.5 support body takes place.

Preferably, the shaft 4.1, the perforation comb mounted thereon 4.3 and 4.5 the support body over the entire web width extending across. Jedochh it may be sufficient in the individual case, if extending these three elements over only a portion of the web width.

The length L of the recesses 4.6 is - as explained above - made dependent on the type of paper. The width B of the transverse ribs 4.8 is chosen 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 is wound into a paper roll, the shaft 4.1 is in the shown in Figure 1 angular position of the comb in 4.3 the support body is 4.5 away. If a perforation in the paper web 2 are adopted, the shaft performs one revolution 4.1, so that comb 4.3 with its tips 4.7 is immersed in the paper web 2 and, according to the further circulation of the shaft 4.2 out of contact with the medium again.

The peripheral speed of the tips of 4.7 must not necessarily exactly equal to the speed of the web 2 to be. It is also both a slightly higher speed possible, as well as a somewhat lower. In the former case Perforationsschlitze be generated in the running direction of the paper web 2, 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, as diagrammatically indicated by means of double-headed arrow 4.9.

The support roller 1 is associated with a web holder (6), which (for retaining the new web start to the severing of the web) to the support roller is pressed.

An important advantage of the invention compared with the embodiment according to document (1), Figure 1, is as follows:

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

In the invention, this is not necessary. The shaft 4.1 has a corresponding distance from the paper web. 2

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