DE1090070B - Device for cross-line perforation of running webs of paper, plastic or the like. - Google Patents

Description

Od for Querstrichperforieren of running webs of paper, plastic or the like, it is known, the railway between a fixed and a circulating or rotating between two knives · ^*.:. To pass blank. One of these two knives has a large number of notches. As a result, the web is only available to the. Cut points where the knife sections interact with the counter knife, while it remains uncut at the notch points. This results in cross-line perforations, the cutting lengths of which correspond to the width of the individual knife sections, while the webs that remain in between are equal to the width of the notch.

With such devices only cross-line perforations can be made can be produced with constant cutting and web lengths. Should be with such a Device different types of paper or, for example, multi-layer webs of different thicknesses and number of tracks are perforated, then it is mostly desirable and often necessary that the Degree of perforation, d. H. the ratio of the cutting length to the web length is changed. With the known Devices of this type can only be achieved in that the knife provided with the notches is replaced by a knife in which the width of the knife sections and the notches is different.

This disadvantage is to be avoided by the invention and the degree of perforation is to be avoided without replacing a knife can be changed. According to the invention this is achieved in that not only one Knife has notches, but that also the cutting edge of the counter knife with a multitude of notches is the same Division provided and relative to the cutting edge dej other knife is adjustable in the longitudinal direction of the cutting edge.

The concept of the invention is explained in more detail in the figures, in which only a section both knives and the perforation that can be achieved in different knife positions in one opposite the reality very much enlarged scale is.

In Fig. 1, two knife sections of the knife 1 and of the counter knife 2 can be seen, the width of which is denoted by s. The width of the notch in between is denoted by k. The sum of j and k gives the division t of the knife edge. For the sake of clarity, the two knives have been pulled apart a little. In reality, of course, they have to touch each other if a cut is to be created in the path running between them.

From the consideration of Fig. 1 it can be seen that the web is cut at the points at Device for cross-line perforation of running webs of paper,

Plastic or the like

Applicant:

Maschinenfabrik Goebel GmbH,
Darmstadt, Goebelstr. 21

Willy Säuberlich, Darmstadt-Eberstadt,
has been named as the inventor

which the two knife sections face each other in width. It remains uncut at the points at which the notches k face one another. This creates a cross-line perforation in the web, which is indicated by the two horizontal lines below the knife 2.

If the knife 2 is now displaced in relation to the knife 1 in the direction of the cutting edges, as indicated in Fig. 2, then there is no cut of the web at those points where either the upper knife 1 or the lower knife 2 has a Notch location. This means that the bridge is getting longer. But since the pitch t does not change, the cut becomes shorter. If the displacement is half as large as the width k of the notches, which is assumed in Fig. 2, then the length of the cut is no longer

but only

> while the web length ³ A ₂ k

amounts to. The degree of perforation has changed accordingly. '

A borderline case is shown in Fig. 3, namely that the displacement of the notch width is the same. The cutting length is thereby reduced to s-k , while the web width is 2 k .

By further displacement of the knife 2 with respect to the knife 1, the one achieved in accordance with FIG. 3 can be achieved Do not change the degree of perforation. But it arises from the fact that there are then two knife sections of the one knife cooperate with a knife section of the other knife, the double the number of perforation cuts, which are, however, correspondingly shorter. For example, is According to Fig. 4 every notch in the middle of the knife section of the counter knife, then every cut has

only a length of

while the intermediate web of the notch k is the same. On a

0D9 609/131

Pitch t is then again omitted, a total cutting length of s-k, while the two webs together have a length of 2 k .

From the above explanations it follows that the degree of perforation can be changed within wide limits and adapted to the respective type of paper to be perforated. The ratio of the achievable degrees of perforation results from the ratio of j to k at the knife division. However, the above formula values apply to all ratios of s to k, provided that this ratio is the same for both knives 1 and 2. However, it is also possible that the two knives differ from one another in this respect, only the division t must be the same.

The invention is applicable to such devices that operate in the manner of a scissor cut. However, it can be used in the same way for those devices in which - as already proposed - one of the two knives is fixed, the cutting edge of this knife and the rotating counter knife being parallel to its axis of rotation.
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Claims (1)

Claim: Device for cross-line perforation of running webs of paper, plastic or the like. ίο between a fixed and a umlau fenden or two rotating knives, the cutting edge of one knife by a multitude is interrupted by notches, characterized in that the cutting edge of the counter knife with provided a plurality of notches of equal pitch and relative to the cutting edge of the other Knife is adjustable in the cutting direction. 1 sheet of drawings