EP1176110B1 - Method and winding core for avoiding winding errors in a material web - Google Patents

Abstract

The method for avoiding coiling damage to sheet material, in particular, paper and cardboard being coiled onto a coiling drum (2) consists of decoupling, as much as possible, at least the initial material layer from the drum surface. Also claimed is a coiling drum for implementation of the method. It comprises a coating (7) which covers end sections of the drum surface and is provided with at least one groove (8).

Description

The invention relates to a method for avoiding winding defects, in particular glossy areas, in a material web, in particular a paper or board web, according to the preamble of claim 1 and a winding core ("spool") for a continuous winding a web, in particular a paper - or board web, serving winding machine according to one of the preambles of claims 6 and 21st

A winding machine of the type mentioned here, for example, from PCT document WO 98/52858 A1 (PR10706 WO) of the Applicant well known and is used in particular at the end of machines that are used for the production of webs, such as paper or board webs, or Refinement of webs, such as paper webs serve.

A winding core, for example a spool for use in a winding machine or a winding tube for use in a slitter-winder, is disclosed in German Utility Model DE 296 12 786 U1 (PR10331 DEG) by the applicant. This winding core preferably consists of a hollow cylindrical winding core body and mounted at its two ends bearing journals, with which it rests during its use in bearings, which are usually supported movably on, for example, horizontal rails.

The winding process has a very great importance in both web production and in the material web finishing, because sometimes the danger exists that a previously produced material web is so impaired during winding by winding defects that parts of a manufactured wound roll are not for sale. Among the currently known winding defects include the so-called shiny spots, wrinkles or Platzer. The resulting winding defects are generally greater, the faster the winding machines are operated (order of magnitude 1,500 to 2,500 m / min) and the larger the diameter produced (order of magnitude 2.5 to 4.5 m) and finished weights (order of magnitude up to 135 t) the winding rolls ("finished reels") are.

There are a variety of theories for the formation of glosses, the most common is the following theory: When the web is wound onto a winding core and the resulting winding roll gradually reaches its finished diameter, the high weight forces cause a deflection of the winding roll , which ultimately causes relative displacements of individual material web layers (axial displacements) against each other. In other words: Adjacent material web layers slide with friction on each other so that "axial scratches" arise. These "axial scratches" eventually appear as undesirable highlights.

• sie entstehen hauptsächlich in einem Schwartenbereich von bis zu 150 mm, gelegentlich auch in einem größeren Schwartenbereich von bis zu 300 mm;
• sie treten bei einem Wickelrollendurchmesser meist von größer 2,5 m auf und werden mit zunehmendem Wickelrollendurchmesser gravierender;
• sie treten im wesentlichen im Randbereich zwischen 0,5 und 1,5 m auf;
• sie erstrecken sich meist nur über wenige Materialbahnlagen (circa 10 Materialbahnlagen);
• sie treten bei gestrichenen Papiersorten auf, sind aber meist nur bei den sogenannten Mattsorten störend.

The appearance of Glanzstellen is versatile:

• They occur mainly in a rind area of up to 150 mm, occasionally in a larger rind area of up to 300 mm;
• they usually occur with a winding roll diameter of more than 2.5 m and become more serious with increasing winding roll diameter;
• they occur essentially in the edge region between 0.5 and 1.5 m;
• they usually only extend over a few material web layers (about 10 material web layers);
• They occur in coated paper grades, but are usually disturbing only in the so-called mats.

With regard to the avoidance of the emergence of highlights, various efforts have been made in the past, which in the end remained without the hoped-for success.

For example, the winding roll was intentionally wrapped with a softening point (hanging edges) in the area of the possible highlights, or the wicketroils were wound harder in the core (hanging edges), which caused problems with the flatness of the material web. Furthermore, the winding core was provided with various crowns: For example, although there were no gloss spots with a crown of 2.4 mm, wrinkles formed in the core of the wound roll; With a crown of 1.1 mm gloss could not be safely avoided, also showed problems when winding, also the control of the profiles contributed to no problem solution: A normal profile (hanging edges) resulted in a lower winding hardness at the edge, a flat Profile, produced by calender and / or line, slightly reduced the risk of the emergence of highlights.

As a summary of these various efforts can be stated: The risk of the emergence of shiny spots when winding webs of material on a winding core could be hardly or only slightly reduced.

It is therefore an object of the invention to improve a method and a winding core of the aforementioned type such that winding defects, in particular gloss spots, are largely avoided, without negatively affecting the winding process in terms of effectiveness and not significantly increase the acquisition and operating costs of the winding core increase.

This object is achieved according to the invention in a method of the type mentioned in that at least the material web layer, which is initially wound on the winding core ("empty drum"), as far as possible decoupled from the winding core on the outer peripheral surface for effecting a smaller relative axial displacement of individual material web layers gegenelnander becomes. The material web layer is preferably substantially in the axial direction of the Winding core selectively decoupled. This results in the advantage that due to the decoupling of the material web layer from the winding core, the deflection of the same exerts a greatly reduced influence on the web position. This in turn causes the lower relative displacement of individual material web layers against each other (axial displacements) and thus the emergence of fewer "axial scratches", which are ultimately the reason for the emergence of glossy spots.

Since the high gloss occurs primarily in the edge region of the winding roll, it is sufficient under economic and constructive aspects, if the web position is decoupled in the two-sided edge regions of the winding core, and preferably in a respective width of up to one third of the web width, preferably from to to a quarter of the web width.

In a preferred embodiment, the material web layer is decoupled by means of at least one applied to the winding core coating, which has a high elastic compliance in the axial direction of the winding core. The high elasticity of the coating ensures axial elasticity.

This object is achieved in a winding core of the aforementioned type according to the invention that the winding core body in the two-sided edge regions of its outer peripheral surface each having at least one coating which is provided with at least one groove, preferably with a plurality of grooves. This at least one groove reduces the axial stiffness of the applied coating such that an axial elasticity between the winding core and the initial material web layers is formed, which ultimately prevents an axial displacement of the initial material web layers against each other despite bending of the winding core due to high weight forces as far as possible. This results in more or less no "axial scratches" that appear as unwanted highlights. The at least one groove may be formed, for example, as at least one spiral groove or at least two grooves with parallel, perpendicular to the axial direction of the winding core progressions.

With regard to both the axial compliance of the coating and the structural features of the winding core, it is sufficient and readily advantageous if the respective coating has a coating thickness which assumes a value of up to 100 mm, preferably of up to 50 mm.

• die Beschichtung besteht aus einem Gummi oder aus einem gummielastischen Kunststoff, vorzugsweise aus Polyurethan;
• die Beschichtung besteht aus einer Vielzahl an nebeneinander angeordneten Ringen mit abgestuften Außendurchmessern, die an den Zylinderflächen einen Bezug aus einem Gummi oder aus einem gummielastischen Kunststoff aufweisen und die in Achsrichtung des Wickelkerns fixiert sind;
• die Beschichtung besteht aus einer Vielzahl an nebeneinander angeordneten Ringen, wobei mindestens jeder zweite Ring an seiner Zylinderfläche einen Bezug aus einem Gummi oder aus einem gummielastischen Kunststoff aufweist und wobei alle Ringe in Achsrichtung des Wickelkerns fixiert sind.

Bei der zweiten und dritten Möglichkeit weist der Bezug in geeigneter Weise eine Bezugsdicke von 2 bis 10 mm, vorzugsweise von 5 bis 8 mm, auf, die Fixierung der Vielzahl an Ringen erfolgt mittels mindestens eines Spannrings, einer Vielzahl an Nieten, mindestens einer Klebung oder mindestens einer Schweißung.There are three preferred ways of designing the coating:

• the coating consists of a rubber or of a rubber-elastic plastic, preferably of polyurethane;
• the coating consists of a plurality of juxtaposed rings with stepped outer diameters, which have on the cylindrical surfaces a cover made of a rubber or of a rubber-elastic plastic and which are fixed in the axial direction of the winding core;
• the coating consists of a plurality of juxtaposed rings, wherein at least every second ring has on its cylindrical surface a cover made of a rubber or of a rubber-elastic plastic and wherein all rings are fixed in the axial direction of the winding core.

In the second and third possibility, the cover in a suitable manner, a reference thickness of 2 to 10 mm, preferably from 5 to 8 mm, the fixation of the plurality of rings by means of at least one clamping ring, a plurality of rivets, at least one gluing or at least one weld.

In order to positively support the coating in terms of its elastic compliance in the axial direction of the winding core, the at least one groove of the respective coating is inclined at an angle to the adjacent bearing journal. The angle advantageously assumes a value between 0.01 ° and 10 °, preferably between 2 ° and 5 °.

In a further embodiment according to the invention, the coating has a high degree of flexibility over a substantial part of its coating thickness, corresponding to a rubber hardness of from 20 to 200 P & J, preferably from 50 to 150 P & J. This high flexibility in turn promotes the already described axial compliance between the winding core and the initial material web layers.

Within the framework of the desired axial elasticity, in a preferred embodiment, the groove of the coating essential to the invention has a groove width of 1 to 4 mm, preferably of 2 to 3 mm, and a groove depth of 2 to 15 mm, preferably of 5 to 12 mm. The web mounted between two adjacent grooves has a land width of 2 to 5 times, preferably 3 to 4.5 times, the two adjacent groove widths. In the case of the aforementioned structural ranges, the best possible functionality of the invention is ensured.

Furthermore, the groove has two side walls, which run either parallel or substantially parallel or conical or concave and / or convex to each other. Further, the groove has a groove bottom, which merges either by means of at least one curvature or by means of at least one bevel in the two adjacent side walls. Both the shape of the side walls and the shape of the groove bottom significantly affect the axial compliance of the coating. The forms mentioned support the axial elasticity in an excellent manner.

Furthermore, this object is achieved in a winding core of the type mentioned according to the invention that the winding core body in the two-sided edge regions of its outer peripheral surface each having at least one coating which consists of a plurality of juxtaposed rings or hoses so axially fixed in the axial direction of the winding core are that between them ever a gap or a groove exists. These rings or hoses reduce the axial stiffness of the applied coating so that an axial elasticity between the winding core and the initial material web layers is formed, which ultimately prevents an axial displacement of the initial material web layers against each other despite bending of the winding core due to high weight forces as far as possible. Consequently more or less no "axial scratches" occur which appear as unwanted highlights.

• die jeweilige Beschichtung besteht aus einer Vielzahl an jeweils mindestens zwei koaxial angeordneten Ringen, in deren Abstandsbereich mindestens ein nachgiebiges Teil eingebracht ist;
• die jeweilige Beschichtung besteht aus einer Vielzahl an jeweils zwei koaxial angeordneten Ringen, die mittels mindestens eines Stegs miteinander verbunden sind (Doppel-T-Profil);
• die jeweilige Beschichtung besteht aus einer Vielzahl an nebeneinander angeordneten Schläuchen mit vorzugsweise rechtwinkliger Kontur, die mit einer inkompressiblen Flüssigkeit, vorzugsweise Öl oder Wasser, gefüllt sind;
• die jeweilige Beschichtung besteht aus einer Vielzahl an nebeneinander angeordneten Ringen, die mindestens je eine Aussparung aufweisen, in die eine Passfeder, welche in einer in dem Wickelkernkörper angebrachten Passfedernut gelagert ist, eingelegt ist;
• die jeweilige Beschichtung besteht aus einer Vielzahl an nebeneinander angeodneten Ringen, insbesondere an Laufringen, die mittels je mindestens eines O-Rings auf je einem auf dem Wickelkernkörper angebrachten Lagerring gelagert ist.

Hinsichtlich den weiteren bevorzugten Ausgestaltungen der einzelnen Beschichtungen wird auf die entsprechenden Unteransprüche verwiesen.For the preferred embodiment of the coating, there are several advantageous possibilities:

• the respective coating consists of a plurality of at least two coaxially arranged rings, in the distance region at least one resilient part is introduced;
• the respective coating consists of a plurality of two coaxial rings, which are connected to each other by means of at least one web (double T-profile);
• the respective coating consists of a plurality of juxtaposed tubes with preferably rectangular contour, which are filled with an incompressible liquid, preferably oil or water;
• the respective coating consists of a multiplicity of rings arranged next to one another, which have at least one respective recess into which a feather key, which is mounted in a keyway mounted in the winding core body, is inserted;
• the respective coating consists of a multiplicity of rings which are arranged next to one another, in particular of races, which are mounted by means of at least one O-ring on each bearing ring mounted on the winding core body.

With regard to the further preferred embodiments of the individual coatings, reference is made to the corresponding subclaims.

The fixation of the plurality of rings or the plurality of tubes is carried out in a general manner by means of at least one clamping ring, a plurality of rivets, at least one bond or at least one weld, since these types are known and proven prior art.

Since the axial displacements occur primarily only in the two-sided edge regions of the winding roll, the respective coating advantageously has a coating width which assumes a value of up to one third of the material web width, preferably of up to a quarter of the material web width.

The division of the plurality of grooves or rings or hoses in the coating can also be varied: it can be constant across the width of the respective coating, it can vary across the width of the respective coating, it can vary across the width of the respective coating be sectioned and the sectioned divisions assume different values, wherein the sectioned divisions can assume smaller values in the outer region of the respective coating of the winding core body than in the inner region. The possible embodiments of the divisions allow an optimal adaptation of the axial compliance of the coating to the particular requirement.

It is understood that the features of the invention mentioned above and to be explained below can be used not only in the respectively specified combination but also in other combinations or alone, without departing from the scope of the invention.

Further features and advantages of the invention will become apparent from the dependent claims and the following description of preferred embodiments with reference to the drawings.

Figur 1:

eine schematisierte Ansicht einer Wickelrolle;

Figuren 2 bis 11:

verschiedene Teilschnitte von Wickelkemen mit erfin-dungsgemäßen Beschichtungen.

Show it

FIG. 1:

a schematic view of a winding roll;

FIGS. 2 to 11:

various partial sections of winding cores with inventive coatings.

The winding roll 1 shown schematically in Figure 1 consists of a hollow cylindrical winding core 2 and wound thereon, only sketchy and partially illustrated material web layers 3a a web 3, preferably paper or board webs. The winding core 2 in turn consists of a Winding core body 4 and mounted at its two ends, only sketchy and partially illustrated bearing pin 5 in a known design of the winding core body 4 made of a metallic material, such as steel; However, it is also the use of fiber composites alone or in combination with other materials, such as steel conceivable.
The winding core 2 may further, as in the already cited German Utility Model DE 296 12 786 U1, be executed: winding core 4 and a jacket whose surface having reference with high compliance. In other words, the present invention is limited in a further embodiment not only to a winding core with at least one coating in the two-sided edge regions of its outer peripheral surface, the winding core may also have over its entire length, in particular in the middle region, having coating, for example Rubber or rubber-elastic plastic.
Under the effect of recorded by the two journals weight and contact forces the bobbin 1 and the winding core 2 bends slightly during operation, namely they will sag somewhat below the weight in the middle and due to the contact forces with their end portions press more strongly against the carrier drum, not shown, as in the middle section. This deviating from the ideal line position of the winding core 2 is indicated in the figure 1 in dotted lines.
According to the invention, it is now provided that the winding core body 4 in the two-sided edge regions 6 of its outer peripheral surface A has at least one coating 7 which is provided with a multiplicity of grooves 8. The two-sided edge regions 6 are each shown as an area which is surrounded by a dash-dotted line.

FIG. 2 shows a partial section of a winding core 2 with a coating 7 according to the invention, mounted in the winding core body 4, represented by a circle in FIG.
The abstracted coating 7 consists of a rubber or of a rubber-elastic plastic, preferably of polyurethane.

Furthermore, the coating has a coating thickness D which assumes a value of up to 100 mm, preferably of up to 50 mm. Both the coating width B and the coating thickness D depend on the material of the selected coating 7 and are ultimately determined by them and the force relationships prevailing in the winding roll.
The coating 7 also has a high compliance, corresponding to a rubber hardness of 20 to 200 P & J, preferably from 50 to 150 P & J, since this high flexibility in turn promotes the already described axial elasticity between the winding core and the initial material web layers.
The grooves 8 of the coating 7 have, within the desired axial elasticity, a groove width R _B of 1 to 4 mm, preferably of 2 to 3 mm, and a groove depth R _T of 2 to 15 mm, preferably 5 to 12 mm. The web 9 mounted between two adjacent grooves 8 has a web width S _B of 2 to 5 times the value, preferably of 3 to 4.5 times the value of the two adjacent groove widths R _B.
Furthermore, each groove 8 has two side walls 10 which extend either parallel or substantially parallel or conical or concave and / or convex to each other. Moreover, each groove 8 has a groove bottom 11, which merges into the two adjacent side walls 10 either by means of at least one curvature or by means of at least one bevel. These constructive embodiments are well known to the skilled person and require no further explanation.
The pitch T of the multiplicity of grooves 8 in the coating 7 can also be varied: In FIG. 2, it is constant over the width B of the respective coating 7. On the one hand, however, it may also be different across the width B of the respective coating 7; on the other hand, it may also be sectioned across the width B of the respective coating 7 and the sectioned divisions T assume different values, the sectioned divisions T being in the outer region of the respective Can accept coating 7 of the winding core 2 of smaller values than in the interior. The possible embodiments of the pitches T allow an optimal adaptation of the axial compliance of the coating 7 to the respective requirement.

3 shows a partial section of a winding core 2 with inventive, mounted in the winding core 4 coating 7 according to a second embodiment.
The schematically illustrated coating 7 consists of a plurality of stepped rings 12 which have a reference 14 made of a rubber or of a rubber-elastic plastic on the cylindrical surfaces 13 and which are fixed in the axial direction AR, represented by a double arrow, of the winding core 2. The shape of the stepped rings 12 is not limited to those of the illustrated shape; On the contrary, they can have any shape adapted to the particular application.
The rings 12 have a reference thickness B _D of 2 to 10 mm, preferably from 5 to 8 mm. The axial fixation of the rings 12 takes place by means of at least one known and prior art clamping ring 15. Alternatively, the axial fixation by means of a plurality of rivets, at least one bond or at least one weld done, wherein the Fixierungsart not on the types mentioned limited.

4 shows a partial section of a winding core 2 with inventive, mounted in the winding core 4 coating 7 according to a second embodiment.
The schematically illustrated coating 7 consists of a plurality of rings 12, wherein at least each second ring 12 'on its cylindrical surface 13 has a cover 14 made of a rubber or of a rubber-elastic plastic and wherein all rings 12 and 12' in the axial direction AR, represented by a double arrow, the winding core 2 are fixed by means of a schematic clamping ring 15. The rings 12 and 12 'have different outside diameters in FIG. 4; However, they can also have the same outer diameter, wherein the rings 12 ', however, on their cylindrical surfaces 13 have a reference 14.

Also, Figure 5 shows a partial section of a winding core 2 with inventive, mounted in the winding core 4 coating 7 according to a further embodiment.

The coating 7 consists of a plurality of juxtaposed hoses 16 with preferably rectangular contour which are filled with an incompressible liquid 17, preferably oil or water. The hoses 16 are reinforced in their mutual contact surfaces 18 by means of incorporated stabilizers 19, for example sheet metal and / or plastic rings. The contact surfaces 18 may also be only alignment surfaces, wherein between the tubes 16 each have a gap or a groove 8 is. Furthermore, tubes 16 are reinforced at their webs contacting surfaces 20, preferably by means of introduced bands 21st

FIGS. 6a and 6b show, in two sections corresponding to one another, a winding core 2 with a coating 7 according to the invention and attached in the winding core body 4.
The coating 7 consists of a plurality of two coaxially mounted rings 12 and 12 ', which are interconnected by means of at least one web 22 (double T-profile). The resulting cross-sectional profile does not have to be of symmetrical contour; it can rather be adapted to its stress.
The web 22 of the rings 12 and 12 'is, as shown in Figure 6b, provided with a plurality of perforations 23 (apertures), preferably in a circular contour. However, further, with respect to the strength of optimal perforations can be realized.
In Figure 6a is further seen that the outer rings 12 have smaller ring widths b than the inner rings 12 ', whereby grooves 8 arise, which in turn promote the axial displaceability.

Furthermore, FIGS. 7 a and 7 b each show a partial section of a winding core 2 with a coating 7 according to the invention and mounted in the winding core body 4.
The coating 7 consists of a plurality of each two coaxially mounted rings 12 and 12 ', in the distance region 24 at least one resilient member 25 is introduced. In FIG. 7a, a plurality of resilient parts 25, which have a substantially truncated pyramidal shape, are in the distance range 24 introduced; however, the compliant parts 25 may also have other forms serving the stress types.
It can also be seen in FIG. 7a that the outer rings 12 have smaller ring widths b than the inner rings 12 ', as a result of which grooves 8 are formed, which in turn promote the axial displaceability.

FIG. 8 shows a partial section of a winding core 2 with a coating 7 according to the invention, mounted in the winding core body 4, represented by a circle in FIG. With regard to the further properties of the coating 7, reference is made in principle to FIG.
The plurality of grooves 8 of the coating 7 is inclined at an angle α to the adjacent, only schematically indicated bearing pin 5. The angle α assumes a value between 0.01 ° and 10 °, preferably between 2 ° and 5 °, thereby positively supporting the elastic compliance of the coating 7 in the axial direction AR (arrow) of the winding core 2. However, the individual grooves can also assume different angles α which lie in the stated range.

FIGS. 9a and 9b also show, in two sections corresponding to one another, a winding core 2 with a coating 7 according to the invention and attached in the winding core body 4.
The coating 7 consists of a plurality of rings 12, each having a recess 26, in which a feather key 27, which is mounted in a mounted in the winding core body 4 keyway 28 is inserted. The unit of rings 12 is acted upon in Figure 9a on both sides by a respective return element 29, preferably a spring. FIG. 9b shows FIG. 9a according to the section line AA.

The two Figures 10 and 11 show further partial sections of a winding core 2 with inventive, mounted in the winding core 4 coating 7 according to a further embodiment.

The coating 7 of Figure 11 consists of a plurality of outer races 32, each mounted by means of an O-ring 30, preferably made of one of the aforementioned materials (rubber or rubber-elastic plastic), each mounted on the winding core 4 bearing ring 31 are. In FIG. 10, each race 32 is supported by means of two O-rings 30 on the bearing rings 31 mounted on the winding core body 4.
Generally, the O-rings 30 are supported by means of bearings 33 in the bearing rings 31 and in the races 32, wherein the bearing shells 33 have a symmetrical or asymmetrical contour. The bearing shells 33 have the same or larger radii than the inserted O-rings 30, which in turn promotes the axial displaceability.
Furthermore, in a particular embodiment, the bearing rings 31 and the races 32 have different ring widths b, whereby grooves 8 are formed, which in turn promote the axial displaceability.

In FIGS. 6a to 11, the plurality of rings 12 and 12 'or tubes 16 are fastened by means of at least one clamping ring 15. However, they can also be effected by means of a plurality of rivets, at least one gluing or at least one welding.

All coatings 7 of FIGS. 2 to 11 have a coating width B which assumes a value of up to one third of the material web width, preferably of up to a quarter of the material web width.

In summary, it should be noted that the invention provides a method and a winding core of the type mentioned, the winding defects, especially shiny spots, largely avoid without affecting the winding process in terms of effectiveness and negligible to increase the acquisition and operating costs of the winding core ,

LIST OF REFERENCE NUMBERS

1

reel

2

winding core

3

web

3a

Web location

4

Winding core body

5

pivot

6

border area

7

coating

8th

groove

9

web

10

Side wall

11

groove bottom

12, 12 '

ring

13

cylindrical surface

14

reference

15

clamping ring

16

tube

17

liquid

18

Touchpad

19

stabilizer

20

area

21

tape

22

web

23

perforation

24

distance range

25

part

26

recess

27

Adjusting spring

28

keyway

29

Return element

30

O-ring

31

bearing ring

32

race

33

bearing shell

A

Outer circumferential surface

AR

axially

B

coating width

b

ring width

B _D

reference thickness

D

coating thickness

R _B

groove width

R _T

groove depth

S _B

web width

T

division

Claims (39)

1. Method for avoiding winding defects, in particular shiny spots, in a material web (3), in particular in a paper or board web, which is wound onto a core (2) in a winder to form a roll (1) consisting of a large number of material web layers (3a), characterized in that at least the material web layer (3a) which is initially wound onto the core (2) is specifically decoupled as far as possible from the core (2) on the outer circumferential surface (A) of the latter in order to effect a lower relative axial displacement of individual material web layers (3a) in relation to one another.
2. Method according to Claim 1, characterized in that the material web layer (3a) is decoupled substantially in the axial direction (AR) of the core (2).
3. Method according to Claim 1 or 2, characterized in that the material web layer (3a) is decoupled in the edge regions (6) on both sides of the core (2).
4. Method according to Claim 3, characterized in that the material web layer (3a) is decoupled in a respective width of up to one third of the material web width, preferably of up to one quarter of the material web width.
5. Method according to one of the preceding claims, characterized in that the material web layer (3a) is decoupled by means of at least one coating (7) which is applied to the core (2) and which has a high level of elastic compliance in the axial direction (AR) of the core (2).
6. Core (2) for a winder used for the continuous winding of a material web (3), in particular a paper or board web, having a preferably hollow- cylindrical core body (4), characterized in that, in the edge regions (6) on both sides of its outer circumferential surface (A), the core body (4) has in each case at least one coating (7) which is provided with at least one groove (8), preferably with a plurality of grooves (8).
7. Core (2) according to Claim 6, characterized in that the respective coating (7) has a coating thickness (D) which assumes a value of up to 100 mm, preferably of up to 50 mm.
8. Core (2) according to Claim 6 or 7, characterized in that the respective coating (7) consists of a rubber or of a resilient plastic, preferably of polyurethane.
9. Core (2) according to Claim 6 or 7, characterized in that the respective coating (7) consists of a large number of rings (12) arranged beside one another and having stepped external diameters, which have a covering (14) of a rubber or of a resilient plastic on the cylindrical surfaces (13) and which are fixed axially in the axial direction (AR) of the core (2).
10. Core (2) according to Claim 6 or 7, characterized in that the respective coating (7) consists of a large number of rings (12, 12') arranged beside one another, at least every second ring (12') having a covering (14) of a rubber or of a resilient plastic on its cylindrical surface (17), and all the rings (12, 12') being fixed in the axial direction (AR) of the core (2).
11. Core (2) according to Claim 9 or 10, characterized in that the covering (14) has a covering thickness (B_D) of 2 to 10 mm, preferably of 5 to 8 mm.
12. Core (2) according to one of Claims 6 to 11, characterized in that the groove (8) of the respective coating (7) is inclined at an angle (α) with respect to the adjacent bearing journal (5).
13. Core (2) according to Claim 12, characterized in that the angle (α) assumes a value between 0.01 ° and 10°, preferably between 2° and 5°.
14. Core (2) according to one of Claims 8 to 13, characterized in that the respective coating (7) has a high compliance over a substantial part of its coating thickness (D), corresponding to a rubber hardness of 20 to 200 P&J, preferably of 50 to 150 P&J.
15. Core (2) according to one of the preceding Claims 6 to 14, characterized in that the groove (8) has a groove width (R_B) of 1 to 4 mm, preferably of 2 to 3 mm.
16. Core (2) according to one of the preceding Claims 6 to 15, characterized in that the groove (8) has a groove depth (R_T) of 2 to 15 mm, preferably of 5 to 12 mm.
17. Core (2) according to one of the preceding Claims 6 to 16, characterized in that, between two adjacent grooves (8), a land (9) is fitted which has a land width (S_B) of 2 to 5 times the value, preferably of 3 to 4.5 times the value, of the two adjacent groove widths (R_B).
18. Core (2) according to one of the preceding Claims 6 to 17, characterized in that the groove (8) has two side walls (10), which either run parallel or substantially parallel or conically or concavely and/or convexly in relation to each other.
19. Core (2) according to one of the preceding Claims 6 to 18, characterized in that the groove (8) has a groove base (11) which merges into the two adjacent side walls (10) by means of at least one curvature.
20. Core (2) according to one the preceding Claims 6 to 19, characterized in that the groove (8) has a groove base (11) which merges into the two adjacent side walls (10) by means of at least one chamfer.
21. Core (2) for a winder used for the continuous winding of a material web (3), in particular a paper or board web, having a preferably hollow- cylindrical core body (4), characterized in that in the edge regions (6) on both sides of its outer circumferential surface (A), the core body (4) has in each case at least one coating (7) which consists of a large number of rings (12, 12'; 31, 32) or hoses (16) arranged beside one another, which are fixed axially in the axial direction (AR) of the core (2) in such a way that in each case there is a gap or a groove between them.
22. Core (2) according to Claim 21, characterized in that the respective coating (7) consists of a large number of in each case at least two coaxially arranged rings (12, 12'), in the region (24) of whose spacing at least one compliant part (25) is introduced.
23. Core (2) according to Claim 22, characterized in that a plurality of compliant parts (25) which have a substantially truncated pyramidal shape are introduced in the region (24) of the spacing.
24. Core (2) according to Claim 22 or 23, characterized in that the respective coating (7) consists of a large number of in each case at least two coaxially arranged rings (12, 12'), which are joined to one other by means of at least one land (22) (double T profile).
25. Core (2) according to Claim 24, characterized in that the land (22) of the rings (12, 12') is provided with a large number of perforations (23), preferably in a circular contour.
26. Core (2) according to Claim 21, characterized in that the respective coating (7) consists of a large number of hoses (16) arranged beside one another with a preferably rectangular contour, which are filled with an incompressible liquid (17), preferably oil or water.
27. Core (2) according to Claim 26, characterized in that the hoses (16) are reinforced in their mutual contact areas (18) by means of introduced stabilizers (19).
28. Core (2) according to Claim 26 or 27, characterized in that the hoses (16) are reinforced in their areas (20) touching the material web (3), preferably by means of introduced bands (21).
29. Core (2) according to Claim 21, characterized in that the respective coating (7) consists of a large number of rings (12) arranged beside one another, which each have at least one cutout (26) into which there is inserted a key (27) which is mounted in a key groove (28) fitted in the core body (4).
30. Core (2) according to Claim 29, characterized in that the unit comprising rings (12) is acted on by means of a restoring element (29), preferably a spring, on at least one side, preferably on both sides.
31. Core (32) according to Claim 21, characterized in that the respective coating (7) consists of a large number of rings (31, 32) arranged beside one another, in particular running rings (32), which are mounted by at least one O ring (30) in each case on at least one bearing ring (31) in each case fitted to the core body (4).
32. Core (2) according to Claim 31, characterized in that the running rings (32) are mounted by means of two O rings (32) on the bearing rings (31) fitted to the core body (4).
33. Core (2) according to Claim 31 or 32, characterized in that the O rings (30) are mounted in the rings (31, 32) by means of bearing shells (33), the bearing shells (33) having a symmetrical or asymmetrical contour.
34. Core (2) according to one of Claims 21 to 23, characterized in that the large number of rings (12, 12', 31, 32) or the large number of hoses (16) is fixed by means of at least one clamping ring (15), a large number of rivets, an adhesive bond or a weld.
35. Core (2) according to one of Claims 6 to 34, characterized in that the respective coating (7) has a coating width (B) which assumes a value of up to one third of the material web width, preferably of up to one quarter of the material web width.
36. Core (2) according to one of the preceding Claims 6 to 35, characterized in that the at least one groove (8) or the large number of rings (12, 12', 31, 32) or the large number of hoses (16) is arranged with a pitch (T), the pitch (T) being constant over the width (B) of the respective coating (7).
37. Core (2) according to one of the preceding Claims 6 to 35, characterized in that the at least one groove (8) or the large number of rings (12, 12', 31, 32) or the large number of hoses (16) is arranged with a pitch (T), the pitch (T) being different over the width (B) of the respective coating (7).
38. Core (2) according to one of the preceding Claims 6 to 35, characterized in that the at least one groove (8) or the large number of rings (12, 12', 31, 32) or the large number of hoses (16) is arranged with a pitch (T), the pitch (T) being sectioned over the width (B) of the respective coating (7) and the sectioned pitches (T) assuming different values.
39. Core (2) according to Claim 38, characterized in that the sectioned pitches (T) in the outer region of the respective coating (7) of the core body (4) assume smaller values than in the inner region.

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