EP0802026B1 - Perforating appparatus for foils, especially plastic foils - Google Patents

Abstract

A device for perforating webs of foil, in particular plastic foil, has at least one pair of rollers through which the foil is moved. The pair of rollers includes a spiked roller with spikes which extend radially from its outer surface, and a mating roller held against the spiked roller and whose outer surface has a lining which can be penetrated by the point of each spike, for example an elastic outer ply. The outer surface of the spiked roller has at least one recess in which a spike is arranged in such a way that only a section of its point protrudes by a predetermined extent beyond the outer surface.

Description

The invention relates to a device for perforating sheet-like foils, especially plastic foils, accordingly the preamble of claim 1, e.g. known from US-A-3760671.

For the production of packaging, such as Sacks or bags, plastic films used should be permeable to air at least in some areas if therein bulk goods, such as dusts, flours and granules, be packed so that, for example, when filling can escape with trapped air. included Air cushions can otherwise stack and Storage of the filled packaging for stacking difficulties to the bursting of sacks and bags to lead.

It is known to make air permeable areas by roughly piercing, punching or be slit. Since the foils as a web Raw material accumulate, that is continuous, i.e. endless, one Manufacturing plant for packaging is also fed a perforating station will be able to be endless Perforate foils. Because of the pass, in connection with the conveying speed of the foils arise when piercing the foils with conventional tools more or less widened holes that ensure that in the packaging produced trapped air can escape, but also undesirably Contents. Another disadvantage of yourself resulting, relatively large-format punctures to be seen in the fact that from the outside foreign substances in the packaging can penetrate, which in the Packaging filling is contaminated and even can become unusable. To avoid this, it is usual, the perforated areas in manufacturing technology complex and costly way with filter material cover.

The invention has for its object a device to create with which foils perforate so finely let them become air permeable, but not The product is leaking or foreign matter is not in the foils can penetrate.

This object is achieved according to the invention by the features of claim 1.

Films can be made with the device according to the invention perforate very finely, because the needles of the needle roller so are arranged so that they only with their tip in the suitably equipped outer surface of the counter roller can penetrate once through the perforated Are pushed through. The equipments include preferably a resilient design of the lateral surface. However, the equipment can also be used in grooves or the like formed in the lateral surface Include depressions in which one is pierced from the Protruding the film-replacing tip of a needle can. Since the counter roller and the needle roller during the Passing a film to be perforated in mutual Are kept, a deformation and tearing of the Puncture prevented when penetrating the needle because resulting distortions of the pierced film, which especially in the area of the puncture occur, were rolled practically smooth or even cannot occur. Even tears that occur when the needle will be prevented.

There is at least one needle roller for perforating films with an associated counter role required form a pair of roles. However, it is also possible to have several Keep needle rollers in contact with a counter roller. You can use both counter rollers and needle rollers Rotary bodies are assembled, the needle rollers or form counter rolls. It is particularly useful if each needle roller individually and within a needle roller remains stored separately. However, a counter roller can be formed in one piece, in which case several needle rollers or needle rollers abut this counter roller can.

The dimensioning of a puncture through the film depends depends essentially on the size of the piercing needle. The minimization of the diameter of a needle stands counter that the needle with decreasing needle diameter becomes more sensitive to mechanical loads. The goal, use the smallest possible needle diameter therefore by reducing the size of the needle rollers the needles used can hardly be reached.

In the device according to the invention, the desired small-sized puncture of foils, the one so-called "microperforation" results without risk of breakage for reached the needles in that the outer surface of the Has needle roller depressions, for example holes. A needle of the type is accommodated in each recess only a section of its tip by a predetermined amount protrudes over the lateral surface. Such a measure is included Advantage about four times the thickness of the film, creating largely round holes with smooth edges in the Foil arise. Preferably, namely by certain Achieving standardization can be the same as that Ratio of film thickness to protrusion of approximately 1: 3.33 to 1: 4.66, which also makes adjustments to the Punch the foil to the one with the perforated foil packing goods are possible.

The tip angle of each needle tip should not be greater than 25 ° so that the needle tip is fine enough on the one hand remains, but on the other hand not too sensitive to mechanical loads. A has proven to be advantageous Point angle shown from 15 ° to 20 °.

There are relatively strong needles in Insert recesses in the needle roller, only the Tip the needles out of the desired size Project wells. The conical shape of the needle tips in connection with the constant protrusion of the needles over the lateral surface causes the perforation of the Plastic films with minimal puncture diameters becomes possible.

The needle roller can be spread over its surface Wells, for example holes, easily be equipped. Each depression can be a blind hole into which the shaft of a needle can be inserted. The Needles can be used with a press fit.

Means of adjusting and fixing the Insertion depth of a needle may be provided. Any means of Setting and fixing a needle in the blind hole can be used for Example, a spacer element that can be placed in the blind hole. The can be in the blind hole in plant standing surfaces of the needle and spacer mutually operable locking means be equipped.

However, it is also possible for each needle roller or needle roller to use a hollow roller or hollow roller and the Needles with the foot area in the inner cavity of the roller or to let the roller emerge with a projection or flush, so that corresponding holding, Fastening and adjustment elements can be attached through which the protrusion of the needle tips over the Can be adjusted outside surface of the roller or roller, and through which the set needles are then in the determine the relevant position and have it fixed.

Each counter roller or counter roller is a smooth roller or Smooth roller trained. A smooth roll or smooth roller is advantageously able to deal with faults in the marginal area of the Roll the perforations of the film smooth. this will enables in particular that the lateral surfaces of The needle roller and counter roller are practically free from each other are kept, thereby leading to the continuous perforating film exerted a not inconsiderable pressure becomes. Such an advantageous proof is for example achieved by equipment designed so that it consists of a material in which the through a foil can penetrate the needles. This is made, for example, by a hard elastic material reached. The outer surface of the counter roller or counter roller consists at least in sections of hard elastic Material. For example, hard rubber can be used. The hard elastic material can for example be in the form of a the opposed roller position. The one used Material has a Shore hardness of 90, preferably of 95, on. If the counter roller and the needle roller are placed together, that their lateral surfaces are in contact with each other, penetrate the needles projecting over the lateral surface the layer of hard elastic material. The one to punch Plastic film, which is relatively thin, runs between Counter roll and needle roll through and will, also by the elasticity of the outer surface of the counter roller, with a predeterminable rolling pressure rolled.

This is advantageous for the "microperforation" according to the invention Concerns of the rolls or rollers, namely that The previously described backlash-free concerns under pressure, also in is guaranteed in terms of design, is at Device provided that at least one of the roles of Pair of rollers, or one of the rollers of a pair of rollers, in Bearing is stored with an actuator for Adjustment of the center distance between the rollers of the Roller pair are equipped.

The adjustment of the center distance can be done with a correspondingly suitable actuating device also in cycles can be controlled, for example, intermittently Bring perforation into a film.

The setting device for the bearings is more advantageous Way with pressure elements, for example spring elements provided, which make it possible to roll the Flexible pair of rollers or rollers by the spring force but to hold each other with appropriate pressure. As Pressure elements can also replace the spring elements Working cylinders are used. To set the Installation of the rollers or rollers and the system pressure can a device for adjusting the bias of the spring members or to change the pressurization of the Working cylinders can be provided.

For perforating films with the invention Furthermore, it is particularly advantageous for the device if Deflection rollers are provided, which the film in front and / or after passing through the pair of rollers or rollers to the Place the outer surface of the counter roller or counter roller.

When using rollers there may be deviations in parallelism occur, especially during long periods Make rollers noticeable. To make wider stripes in one Perforating foil, however, are more or less long Rolls required, the length of the perforation width equivalent. -Around the parallelism deviations that occur is to be avoided with the invention Invention provided that multiple needle rollers in Direction of travel of the film offset one behind the other are stored such that the work areas each neighboring needle rollers directly to each other limits. The contiguousness of the work areas worries a comprehensive perforation of the films, the Individual storage of several needle rollers, against each other are offset to reduce harmful effects due to deflection and manufacturing tolerances. In particular to avoid the deflection of a Counter roll it is expedient that of a common Counter roller or counter roller assigned needle rollers by 180 ° offset to each other radially to the counter roller or counter roller to arrange. In particular the not insignificant proof of the This will cause needle rollers on the counter roller or counter roller approximately compensated so that the risk of deflection the counter roll or counter roll to a still tolerable Minimum remains limited.

Are the needle rollers, each offset by 180 °, but in arranged in the same circumferential area, there is a risk of deflection causing pressure forces compensated. However, both needle rollers perforate same area of the film, which in the longitudinal direction of the Counter roller or counter roller staggered needle rollers not happened.

If there is an already perforated area of the film again Perforated by the following needle roller, this can happen adversely affect the perforation image. To do this can avoid the needles of the corresponding needle rollers so arranged that, for example, the needles the first needle roller passed first only one perforate such a film area that the other arranged needles of the second passing thereafter Do not reach the needle roller. For example, the needles arranged in rows along the circumference of each needle roller be, the rows of the second needle roller opposite the Rows of the first needle roller are laterally offset.

The use of single needle rollers, which also are stored individually has the further advantage that each needle roller is pressed in a controlled manner, i.e. also clocked can be, so that in the longitudinal direction of the film Perforation fields can be generated. It is the same through the Individual needle rollers can be arranged in the device, by swiveling predetermined needle rollers, continuously Perforations on the film in stripes there hide where a perforation creates application difficulties which could result in slides. It is also possible Summarize the needle roller with storage in one unit, causing a lateral shift of the entire Construction unit is possible in an advantageous manner. lateral Distances can be set so that work areas border exactly or the areas of the perforations are defined.

In addition, there is only one for needle or needle roller defects inexpensive replacement of the defective needle roller required.

When designing the device with individually stored Needle roller is the even pressure on the Counter pressure roller and the continuous film over the entire film width possible, which advantageously uniformly sized holes in the perforation leads.

When the needles are removed from the perforated film can lead to the formation of elongated holes. To do this avoid the diameters of needle roller and Counter roller or needle roller and counter roller relative low. For reasons of stability, the counter role or Counter roll with a larger diameter than that Needle roller or needle roller executed, namely for Example with a diameter of 200 mm, which turns out to be Has proven useful if the diameter of the The needle roller or the needle roller is not larger than, for example 120 mm, but preferably not less than 80 mm. The Passage of the film is directed so that it Counter roll or counter roll largely wraps around Example with a wrap angle of 270 °.

Films made from semi-crystalline materials, such as Polyethylene, have a stronger orientation in the direction of manufacture of the molecules as transverse to the direction of manufacture. This requires a higher sensitivity to tearing and tearing Foil webs in the longitudinal direction, the "production direction".

As already mentioned, there is a predetermined number of needles on a circumferential line of the needle roller or needle roller distributed in a row, each needle roller or Needle roller several rows of needles side by side having. To the tear and tear sensitivity of the perforated film in the longitudinal direction (production direction) is to reduce in the device according to the invention provided that the needles are next to each other Circumferential lines or adjacent rows in Direction of rotation of the needle roller or needle roller are offset from each other. This will make the distance between the holes of the perforation in the film and thus the tear length doubled.

For further increases in hole spacing, it is advisable with a permanent needle pattern and number of needles of the needle roller or Needle roller each circumferential line or row with needles in one Angle offset from the axis of rotation or radial direction to be aligned. The offset angle of one For example, the circumferential line or row can be about 15 ° Axis of rotation.

Another advantageous hole pattern of the perforation can also result from the fact that the needles remain the same Number of needles within a row or perimeter alternating or alternating on both sides of the Circumferential line are offset, especially in combination with the offset of the needles of adjacent rows or Perimeter lines, this results in a hole pattern Perforation that has little tendency to tear.

Is preferably between two adjacent to each other Needles in a row about 8 mm and between the rows about 4 mm distance. The degree of dislocation, based on a circumferential line, is about 2 mm.

Fig. 1

eine schematische Seitenansicht eines Rollenpaares im Schnitt,

Fig. 2

eine Einzelheit der Nadelrolle des Rollenpaares gemäß Fig. 1 im Schnitt in vergrößertem Maßstab,

Fig. 3

eine schematische Seitenansicht einer Vorrichtung mit einer Gegenrolle und zwei daran angelegten Nadelrollen,

Fig. 4

eine schematische Seitenansicht eines Abschnitts einer Gegenwalze mit mehreren daran angelegten Nadelrollen,

Fig. 5

die schematische Seitenansicht eines Abschnitts einer Gegenwalze mit daran angelegten Nadelrollen, die versetzt zueinander angeordnet sind,

Fig. 6

eine schematische Ansicht eines Abschnitts einer Folie, die mit einer Vorrichtung entsprechend Fig. 4,
erzeugte streifenförmige Perforierungen aufweist,

Fig. 7

einen Abschnitt einer Folie, der einen Perforationsbereich aufweist, welcher mit einer Vorrichtung entsprechend Fig. 5 hergestellt ist,

Fig. 8

eine schematische Seitenansicht einer Nadelwalze mit in Reihen angeordneten Nadeln,

Fig. 9

ein durch Einkreisung in Fig. 8 gekennzeichnetes, vergrößertes Detail zur Verdeutlichung der Nadelanordnung,

Fig. 10

eine schematische Seitenansicht einer Nadelrolle, deren Nadeln in Reihen angeordnet sind, die zur Rotationsachse um einen Winkel geneigt sind,

Fig. 11

eine durch Einkreisung in Fig. 10 gekennzeichnete Detailansicht in vergrößertem Maßstab und

Fig. 12

eine schematische Ansicht einer weiteren Möglichkeit der Nadelanordnung auf der Mantelfläche einer Nadelrolle.

Exemplary embodiments from which further inventive features result are shown in the drawing. Show it:

Fig. 1

a schematic side view of a pair of rollers in section,

Fig. 2

2 shows a detail of the needle roller of the roller pair according to FIG. 1 in section on an enlarged scale,

Fig. 3

2 shows a schematic side view of a device with a counter roller and two needle rollers placed thereon,

Fig. 4

FIG. 1 shows a schematic side view of a section of a counter roll with a plurality of needle rollers placed thereon,

Fig. 5

the schematic side view of a portion of a counter roller with needle rollers attached to it, which are arranged offset to one another,

Fig. 6

3 shows a schematic view of a section of a film which is provided with a device according to FIG. 4,
has produced strip-shaped perforations,

Fig. 7

a section of a film which has a perforation area which is produced with a device according to FIG. 5,

Fig. 8

2 shows a schematic side view of a needle roller with needles arranged in rows,

Fig. 9

8 shows an enlarged detail indicated by the encirclement in FIG. 8 to illustrate the needle arrangement,

Fig. 10

2 shows a schematic side view of a needle roller, the needles of which are arranged in rows which are inclined at an angle to the axis of rotation,

Fig. 11

a detailed view characterized by encirclement in Fig. 10 on an enlarged scale and

Fig. 12

is a schematic view of another possibility of the needle arrangement on the outer surface of a needle roller.

Fig. 1 shows a schematic side view Slide 1, which runs through a pair of rollers, which is a needle roller 2 and a counter roller 3 comprises. The lateral surface 4 of the Counter roll 3 consists of a layer of hard elastic Material 5, for example hard rubber. The needle roller 2 has Wells 6, in each of which a needle 7 such is recorded that only a predetermined section the needle tip 8 over the lateral surface 9 of the needle roller 2 protrudes. When the film 1 passes through the pair of rollers needle roller 2 and counter roller 3 become the film pierced what's through in the right section of the slide drawn punctures 10 is clarified.

Fig. 2 shows a detail of the needle roller 2 in enlarged scale. The same components are the same Designated reference numbers.

The needle 7 is inserted into the recess 6. The deepening is drilled as a blind hole. The deepening is expediently cylindrical, so that needles with cylindrical shaft can be used. At the bottom of the Well 6 is a spacer 11, through the length of the protrusion of the needle tip 8 from the The lateral surface 9 of the needle roller 2 can be determined. The needle 7 is slotted in the foot area. A slot can be inserted into the slot Press in the conical mandrel 12 of the spacer 11, whereby the shaft of the needle 7 is expanded and the needle one receives a tight fit in the recess 6 of the needle roller 2.

3 is a side view of a schematically represented Device shown. The device includes a Machine frame 13 in which a counter roller 3 in not is shown rotatably mounted, such that that the counter roller 3 can rotate about the axis 14 if the film 1 in the direction of the arrows 15 over the counter roller 3 running. Deflection rollers 16, 16 'are provided ensure that the film 1 in its passage through the device wraps around the counter roller 3, as is the case here is shown.

On the machine frame in the spherical bearings 17, 17 ' Bearing traverses 18, 18 'mounted. Working cylinder 19, 19 ' are supported on the machine frame 13 and engage their piston rods 20 on the bearing cross members 18, 18 '. Each crossbeam can be used with the Working cylinders 19, 19 'independently of each other Bearing traverse around the associated spherical bearing 17 or 17 ' be pivoted. The pivotal movement is through the Double arrows 21 and 21 'indicated.

At the free end of each bearing crossbeam 18 or 18 'is one Needle roller 2 or 2 'stored. Fig. 3 illustrates that the two needle rollers 2, 2 'using the working cylinder 19th or 19 'to the counter roller 3 with predeterminable pressure be created. The film 1 passing between them becomes perforated by means of the needle roller 2, 2 '.

Fig. 3 illustrates that the needle rollers 2 and 2 'one assigned common counter roller 3 and thereby by 180 ° offset radially to the counter roller are. The pressure force of the needle roller 2, this on the Counter roller 3 exerts, is thereby by means of the counteracting The contact pressure of the needle roller 2 is compensated. This is particularly advantageous in order to avoid deflections, which have particularly serious effects if several needle rollers side by side at the same time press on a longer counter roller.

4 shows a schematic view of a device, where several needle rollers 2, 2 'or 2' ', 2' '' one in Form of a longer counter roll present counter roll 3 have in common. Each needle roller 2, 2 'or 2' ', 2' '' is 3, stored separately and independently, and pressed against the counter roller 3. In the work area of Needle roller is the counter roller with hard elastic Material 5 coated, with which the outer surface 4 of the Counter roll 3 at least in sections made of hard elastic Material 5 is made.

Fig. 4 illustrates that a deflection of the counter roll 3rd could occur if only those next to each other Needle rollers 2 and 2 '' with the counter roller 3 'in contact would stand.

Due to the fact that the needle rollers 2, 2 '' spatially offset by 180 ° needle rollers 2 'and 2' '' the deflection due to the loads reduced.

5 shows a schematic view of a counter roll 3 ', with the needle rollers 2 'and 2' '' so that border their work areas.

During the formation of the device according to FIG. 4 leads to that on a film 1 in the direction of passage perforated strip areas can be formed with 5 a film over a wide area be perforated.

4a illustrates in an enlarged detail view Cuts through the outer surfaces of the two needle rollers 2 and 2 'in Fig. 4, which are offset by 180 ° face each other and the formation of the strip-shaped Get the perforation area 22 in the film (Fig. 6).

4a indicates how the needle tips 8 of the needle roller 2 opposite the needle tips 8 'of the needle roller 2' laterally are offset. Each needle roll therefore perforates one different row of holes in the film than each opposed to the counter roller 3 'pressed Needle roller.

6 and 7 show corresponding perforation areas in a film 1. The stripe-shaped perforation areas are designated in Fig. 6 with 22 and 22 '. On both sides of the strip-shaped perforation areas 22 and 22 ' unprocessed foil areas. The film can be used Example in the direction of arrow 15.

Fig. 8 shows a schematic side view of a Needle roller 2, the outer surface 9 equipped with needles is. A predetermined number of needles is on each Circumferential line of the needle roller 2 arranged in a row, each needle roller having multiple rows of needles has side by side.

In Fig. 9 is the one marked by encirclement in Fig. 8 Detail from the view of the lateral surface 9 of the Needle roller 2 according to FIG. 8 on an enlarged scale shown. Fig. 9 shows that the needles 7 in Rows are arranged. One of the rows is through the arrow 23 illustrates.

10 shows a schematic side view of a needle roller 2 on the lateral surface 9 also needles in series are arranged, although the rows in one Angle to the axis of rotation 24 or radial direction of the Needle roller are aligned offset.

FIG. 11 shows the encirclement in FIG. 10 again designated section of the lateral surface in enlarged Scale and illustrated by the arrow 23 in turn Angular displacement of the rows of needles 7 with respect to Axis of rotation 24 of the needle rollers.

Fig. 12 shows schematically another possibility of Arrangement of needles on the outer surface 9 of a Needle roller or needle roller. The needles 7 are inside a row or circumferential line 25, again through the Arrow 23 is shown, alternating or alternating offset on both sides of the circumferential line 25. To do this To illustrate, the needles of a row are simply by Lines 26 drawn here connected to one another.

Claims (37)

1. Device for perforating web-like films, in particular plastic films, having at least one pair of rollers through which the film (1) passes, comprising a needle roller (2) which has needles (7) which are aligned radially with respect to the outer surface (9) of said needle roller (2), are in each case accommodated in a depression (6) formed as a blind hole in the outer surface and project with tips (8) by a predetermined amount beyond the outer surface (9), and comprising a backing roller (3), which is held in contact with the needle roller (2) and whose outer surface (4) is provided with a finish permitting a tip (8) of a respective needle (7) to penetrate, characterized in that each needle (7) is plugged by its shank into the respectively associated depression (6), present as a blind hole, to such an extent that it still projects only with a section of its tip (8) by a predetermined amount beyond the outer surface (9).
2. Device according to Claim 1, characterized in that means of adjusting and fixing the penetration depth of a needle (7) are provided.
3. Device according to Claim 2, characterized in that each means of adjusting and fixing a needle (7) is a spacer element (11) that can be set into the depression (6).
4. Device according to Claim 3, characterized in that the surfaces of needle (7) and spacer element (11) that are in contact with each other in the depression (6) are equipped with fixing means which can be brought mutually into operative connection.
5. Device according to one of Claims 1 to 4, characterized in that a plurality of needle rollers (2) are mounted offset one behind the other in the passage direction of the film (1), in such a way that the working areas of respectively mutually adjacent needle rollers (2) adjoin one another directly.
6. Device according to Claim 5, characterized in that one backing roller (3) is common to a plurality of needle rollers (2) offset one behind another.
7. Device according to Claim 6, characterized in that the needle rollers (2) associated with a common backing roller (3) are arranged to be offset by 180° from one another radially in relation to the backing roller (3).
8. Device according to one of the preceding claims, characterized in that at least some of the backing rollers (3) are replaced by a backing roll (3') that is common to a plurality of needle rollers (2).
9. Device according to one of the preceding claims, characterized in that a plurality of needle rollers (2) are combined to form a needle roll.
10. Device according to Claim 9, characterized in that each needle roller (2) is mounted individually or separately within the needle roll formed.
11. Device according to one of the preceding claims, characterized in that each backing roller (3) is designed as a smoothing roller.
12. Device according to one of Claims 1 to 10, characterized in that each backing roll (3') that replaces a plurality of backing rollers (3) is designed as a smoothing roll.
13. Device according to one of Claims 1 to 11, characterized in that the finishes of the outer surface (4) of each backing roller (3) comprise a configuration in which the outer surface (4) consists of a hard elastic material, at least in some sections.
14. Device according to one of Claims 1 to 12, characterized in that the finishes of the outer surfaces (4) of each backing roller (3) or backing roll (3') comprise a configuration in which the outer surface (4) consists of hard elastic material (5), at least in some sections.
15. Device according to Claim 13, characterized in that the hard elastic material (5) is present in the form of a layer placed around the backing roller (3) or backing roll (3').
16. Device according to Claim 14, characterized in that the hard elastic material (5) is present in the form of a layer placed around the backing roller (3) or backing roll (3').
17. Device according to one of Claims 13 to 16, characterized in that the hard elastic material (5) has a hardness of more than 90 Shore, preferably 95 Shore.
18. Device according to one of the preceding claims, characterized in that at least one of the rollers (2, 3) of a pair of rollers or the rolls of a pair of rolls is mounted in bearings which are equipped with an actuating device for adjusting the axial spacing between the rollers of the pair of rollers or the rolls of the pair of rolls.
19. Device according to Claim 18, characterized in that the actuating device has an actuating drive with which a cyclic control system is associated.
20. Device according to either of Claims 18 and 19, characterized in that the actuating device has at least one pressing element.
21. Device according to Claim 20, characterized in that the pressing element is a spring element.
22. Device according to Claim 21, characterized in that the pressing element is an operating cylinder (19, 19').
23. Device according to Claim 20, characterized in that a device for adjusting the prestress of the spring elements is provided.
24. Device according to one of the preceding claims, characterized in that deflection rollers (16, 16') are provided, which place the film (1) on the outer surface (4) of the backing roller (3) or backing roll (3') before and after the said film (1) runs through the pair of rollers or rolls.
25. Device according to one of the preceding claims, characterized in that the projections of the tips (8) of the needles (7) beyond the outer surface (9) of the needle roller (2) or the needle roll are approximately equal to four times the thickness of the film (1).
26. Device according to Claim 25, characterized in that the ratio between the thickness of the film (1) and the projection of the tips (8) of the needles (7) is between 1:3.33 and 1:4.66.
27. Device according to one of the preceding claims, characterized in that each needle roller (2) or each needle roll has a diameter of no more than 120 mm, preferably 80 mm.
28. Device according to Claim 27, characterized in that each backing roller (3) or each backing roll (3') has a diameter of about 200 mm.
29. Device according to one of the preceding claims, characterized in that a predetermined number of needles (7) is arranged distributed in a row on a circumferential line on the needle roller or needle roll, each needle roller (2) or each needle roll having a plurality of rows of needles (7) beside one another.
30. Device according to Claim 29, characterized in that the needles (7) of circumferential lines (25) located beside one another or mutually adjacent rows are offset with respect to one another in the circumferential direction of the needle roller (2) or the needle roll.
31. Device according to Claim 29 or Claim 30, characterized in that each circumferential line (25) or each row is aligned so as to run offset at an angle to the axis of rotation (24) or radial running direction.
32. Device according to Claim 31, characterized in that the offset angle of a circumferential line (25) or row is approximately 15° with respect to the axis of rotation (24).
33. Device according to one of Claims 29 to 32, characterized in that the needles (7) within one row or circumferential line (25) are alternatingly or alternately offset on either side of the circumferential line (25).
34. Device according to one of Claims 29 to 33, characterized in that there is a spacing of about 8 mm between two mutually adjacent needles (7) in a row and about 4 mm between the rows.
35. Device according to Claim 33, characterized in that the amount of the offset, as based on a circumferential line (25), is about 2 mm.
36. Device according to one of the preceding claims, characterized in that the tip angle of each needle tip (8) is not greater than 25°.
37. Device according to Claim 36, characterized in that the tip angle of each needle tip (8) is 15° to 20°.

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