The invention pertains to a winding arrangement for a web of paper or the like, for which at least one drum rests against the winding roll to be wound as a carrier, backup or load drum with a portative drum body having a cylindrical outer circumference, a radially deformable intermediate layer of elastomeric material, attached to the outer circum¬ ference of the drum body and a cylindrical run casing at¬ tached to the outer surface of the intermediate layer con¬ centric with the axis of the drum body, of a material sever- al millimeters thick which can be elastically deformed under contact pressure, such that the run casing cannot be, or can scarcely be deformed in an axial direction by the weight of the winding with which it is in contact, such that the run casing is also indented in a radial direction lateral to the support region influencing the windup roll. Moreover, the invention pertains to a corresponding drum itself.

This kind of winding arrangement and corresponding drums are known from DE-A1-4,035,054. This publication pro- poses the use of a compact elastomeric material having a hardness of 30-80° Shore A for the intermediate layer and, for the run casing, thin-walled spring steel having a radial

thickness of 1-5 mm, in order to produce by this means, windings which have less hardness and which otherwise do not noticeably impair winding quality. On the basis of the abi¬ lity of the run casing to indent, a drum of this kind en- ables a desired reduction in specific nip pressure with a relatively hard surface at the same time. The latter pre¬ vents that due to fluctuations in the thickness profile of the web being wound extreme variations in diameter may deve¬ lop in relatively narrow zones of the windup roll over the width of the roll, as with a softer surface. Grooves placed on the radial outer surface of the soft intermediate layer enable a certain compressibility of the intermediate layer and prevent an excessive piling of the drum covering, and thus prevent surface strains in the drum covering in the nip and changes in the tension of the web material caused by said piling. Without grooves, the drum covering would yield, due to the pressure, in the nip in the peripheral direction. Thereby, a drum covering would receive an elastic deforma¬ tion which can cause a substantial change in web tension. Elastomeric material used for the intermediate layer, such as rubber, polyurethane or the like are more or less not compressible without inclusion of compressible agents such as air. In principle, however, grooving or other inclusion of gas in an intermediate layer can be omitted; that is, if the production of additional tension in the web material is expressly desired. For details, reference is made to the disclosure of DE-Al-4,035,054 hereby made with the content of the present application.

These known rolls and winding arrangements fulfill the purpose of decreasing specific nip pressure while simultane¬ ously preventing, as desired, disturbance of the winding structure in the border zones of the contact surface with the windup roll. Nevertheless, producing such a drum is not without problems, since the production of a run casing out of spring steel and also the assembly of the drum body, in-

termediate layer and run casing are extraordinarily diffi¬ cult. An additional problem exists in precisely adapting the mechanical properties of the intermediate layer and of the run casing to each other. For example, even the smallest change in the material thickness of the run casing can sub¬ stantially influence mechanical properties. In addition, the range of alloys with respect to the desired mechanical prop¬ erties is relatively narrow. Finally, drums of this kind are somewhat sensitive to wear if the bond between the radial outer surface of the intermediate layer and the radial inner surface of the run casing is insufficiently or not adequate¬ ly stable over time.

Therefore, the underlying purpose of the invention is to find, for the intermediate layer and run casing of a generic drum for a generic winding arrangement, a material pairing which permits a comparatively simple manufacture of the drum coating and which, for use, enables a simple accom¬ modation of the mechanical properties of the intermediate layer and run casing.

This problem is solved with respect to a winding arran¬ gement of this generic class and also with respect to a drum of this generic class by a run casing composed of elastomer- ic material, which is radially elastically deformable and has a hardness two to one-hundred times the hardness of the material radially elastically deformable intermediate layer, the material of the intermediate layer being in general in compressible and the intermediate layer comprising cavities or void spaces being distributed over its circumference and making the intermediate layer, as a whole, compressible.

According to the invention the materials used for the intermediate layer and for the run casing as such are more or less incompressible. However, the intermediate layer material having itself a lower hardness than the run casing

material and including the cavities in the intermediate layers makes the intermediate layers, as a whole, becoming compressible.

The intermediate layer and run casing can be composed of the same or different base materials, e. g., of rubber, polyrethane, or similar elastomeric materials.

Since elastomeric materials in a non-expanded (non- foamed) state are almost incompressible, this property would lead to a case in which a drum covering, as a whole, which is radially elastically deformable, in particular its radial interior, i. e., the intermediate layer, under the influence of a roll resting thereupon, in particular the weight of a roll to be wound, would build up a hill of material which runs ahead of the nip, since the material yields under the nip pressure in the direction of the periphery. This would cause a drum covering to undergo an elastic deformation which causes a considerable change in the tension of a mate- rial web being wound to a roll supported on the drum. As these changes in web tension should be undesired - which is frequently the case - the intermediate layer is provided with cavities or void spaces, such that the intermediate layer, as a whole, becomes compressible. The cavities can be realized in the form of coarser and/or finer pores, on aver¬ age uniformly distributed over the circumference, which contain air, for example. However, it is also possible to place recesses, e.g., grooves, in particular, helicoidal grooves, as known in principle from DE-Al-40 35 054, on the outer circumference of the intermediate layer.

To divide of the intermediate layer into a radial inner incompressible layer and a radial outer layer, provided with cavities and therefore becoming compressible, has proven to be particularly advantageous.

Most advantageous - from a practical point of view - are the cavities or void spaces in the form of recesses on the outer circumference of the intermediate layer, especial¬ ly if circular or not too steep helical web-like or fin-like elements are formed between circular (or helical) grooves, as this makes the intermediate layer circumferentially near¬ ly incompressible and radially behaving like a compressible material and thereby avoid building up material hills at both sides of the nip. Further, the intermediate layer can also totally consist of said web-like or fin-like elements in form or rings or in form of a not too steep helix being axially spaced by leaving void spaces between them.

Also coming into consideration as a radial outer co - pressible partial layer of the intermediate layer are, in particular, one or more layers of expanded material, with the pore size and/or distribution capable of forming a gra¬ dient in the radial direction. In particular, it is possible to manufacture such intermediate layers as a single piece of the same material. Particularly simple to manufacture and preferred in this respect, however, is an intermediate layer which in itself is built up of several layers, with the radial inner part, in essence incompressible, capable of being composed of one or more layers of an elastomeric ate- rial having the desired hardness, whereas the radially out¬ er, compressible region of the intermediate layer can be initially independent and also composed of several layers, with the layer material used and, as such, incompressible, itself featuring the desired hardness - with, however, this part of the intermediate layer having, as a whole, i.e., including its cavities, a less hardness and being compress¬ ible.

It is particularly desired to first apply a radial outer region of the intermediate layer having cavities on to the radial inner surface of a run casing and to deposit the

same jointly with the latter on the radial inner region of the intermediate layer featuring no cavities, or fewer or smaller cavities.

Both the potentially several partial layers of the intermediate layer together and the intermediate layer and the run casing as well as, if necessary, the intermediate layer and the drum body, after being mutually attached in order to form a drum covering, can be interconnected subse- quently or simultaneously by means of vulcanization. Layers of coupling agent suitable for this purpose can be deposited in advance on the surface for later contact. For example, an interconnection of the layers can also be achieved by subse¬ quent heating. Likewise, elastomeric material can be charged as a foam between the incompressible layers of the interme¬ diate layer and run casing in order to harden afterwards.

A foam material can also be applied advantageously if recesses in the outer circumference of the intermediate layer are filled with a relative soft foam to ease to apply the run casing onto the intermediate layer.

The deflection resistance of a run casing parallel to the drum axis, hence, in a direction transverse to the ma- chine, can be increased by means of a fiber reinforcement, e.g., by means of carbon fiber incorporated roughly parallel to the axis. In order to prevent an undesired stretching of the run casing in the direction of the periphery, a rein¬ forcing element, fiber in particular, is provided, which is oriented essentially in the direction of the periphery.

A winding arrangement and a drum in accordance with the invention have - amongst others - the advantage of being manufactured more simply than a metal run casing as known from DE-A1-4,035,054. For example, a run casing can be con¬ nected to an intermediate layer in a non-positive connection

by means of vulcanization, with the material of the run casing being produced as an oblong belt from which a length corresponding to the periphery of the casing is severed. This causes a seam to arise in the forming of a surrounding casing, which seam, for its part, can be closed in a non- positive manner by adhering, vulcanizing or the like. In principle, it is also possible to manufacture a seamless running casing and connect it to an intermediate layer.

A non-positive connection between an intermediate layer and run casing leads to favorable properties during opera¬ tion of the drum, since the material layers of intermediate layer and run casing, on the basis of the material pairing, do not shift or otherwise detach with respect to each other, even with long use.

The mechanical properties of the new material pairing can be varied within a wide range, e.g., by means of placing recesses such as grooves in the surface by means of gas inclusions - hence, in general, by means of a porous materi¬ al layer or by varying the material hardness and/or material thickness. In addition, the expansion behavior and flexural behavior of the intermediate layer easily adapt to the run casing.

Further advantageous configurations of the object of the invention which, in the winding of material in the form of a web, paper in particular, particularly make further improvement of the winding structure possible, are contained in additional claims.

No specific conditions underlie the aforementioned com¬ ponents - as well as the components claimed and described in the embodiment - to be used in accordance with the inven- tion, with respect to their size, design, material selection and technical conception, such that selection criteria known

in the particular field of application can be used without limitation.

Additional details, features and advantages of the subject of the invention follow from the following descrip¬ tion of the associated figure, which represents - exemplary - a preferred embodiment. Shown are:

Figure 1: A winding arrangement, schematically simplified, for winding rolls from material in the form of a web, paper in particular, by means of two carrier drums - in end view;

Figure 2: An alternative embodiment of the winding arrange- ment in accordance with Figure 1;

Figure 3: From the winding arrangement in accordance with Figure 1 or 2, part of a carrier drum in axial section - cut along line III-III in accordance with Figure 4; and

Figure 4: The same carrier roll as in Figure 3, in section along line IV-IV with a paper roll supported the¬ reupon.

Figure 1 represents a double carrier drum winding ar¬ rangement 20, which serves to wind a paper web 1 to a wind¬ ing 2. The material web 1 is fed under a certain longitudi¬ nal web tension. It wraps around, from below, a driven, first carrier drum 4 in the web running direction, having a horizontal axis, next to which a second carrier drum 5 is arranged at the same height, or, as represented in the em¬ bodiment and preferred in this respect, at an unequal height with a clearance which permits the development of a winding bed for the roll 2 to be wound. The forming roll 2 rests on the locations 6, 7 (=A) on the carrier drum 4, 5, at a nip

pressure 8 resulting from the weight of the roll 2 and the bearing pressure 9 of a load drum 11 (rider roll), which is arranged over the carrier drums 4, 5 symmetrically or asym¬ metrically to the latter and is powered by at least one pis- ton/cylinder unit 12. The drums 4, 5, 11 influence, by means of their surface behavior, the winding hardness of the roll 2.

In accordance with Figures 1 and 2, the first carrier drum 4 in the web running direction features a drum cover¬ ing, non-rigid in a radial elastic deformable sense, the cross section and longitudinal section of which are ex¬ plained in greater detail in connection with Figures 3 and 4.

As shown in Figure 3 and 4, a drum 4 is composed, in essence, of a portative drum body 24 of steel or another very deflection-resistant material, e.g., fiber-reinforced plastic, such as carbon-fiber-reinforced plastic with a bearing journal 23. An radially elastically compressible intermediate layer 26 of elastomeric material, being more or less incompressible per se, is attached to the cylindrical outer circumference 25 of the drum body 24, if necessary with the addition of an intermediate layer of bonding agent 22. Likewise, an additional radially elastic layer of an elastomeric material and several millimeters thick, is at¬ tached to the preferably cylindrical outer circumference of the intermediate layer 26. This layer forms a circular cy¬ lindrical run casing 33 on the outer circumference.

One of the essential differences between the intermedi¬ ate layer 26 and run casing 33 consists in the varying hard¬ ness of the material used, with the hardness of the run casing capable of being two to one-hundred times as great as the hardness of the intermediate layer. It is preferable for the intermediate layer to have a PJ (Pussey Jones) value of

80-110 (hardness measure of a P & J Plastometer) and prefer¬ able for the thickness of the intermediate layer to be be¬ tween 10 and 20 mm. In contrast, it is preferable for the PJ value of the run casing to be 5-15 and for the thickness of the running casing to be 5-15 mm. In this regard, an overall thickness of both radially elastic layers of elastomeric material of 20-30 mm, preferably approximately 25 mm, is particularly preferred.

For the embodiment in accordance with Figure 3 and 4, such helical grooves 27, having a width of approximately 1 mm and a depth of 3 mm, and are placed in the outer periph¬ eral surface of the intermediate layer 26, while the radial inner regions of the intermediate layer 26 are formed with- out cavities, i.e., fundamentally incompressible. The later¬ al groove clearance is preferably between 6 and 15 mm, but can also be of a size similar to the groove depth, as in the embodiment.

It is possible to make a run casing somewhat compress¬ ible as a whole with a means similar to that used for the intermediate layer. For this purpose, grooves 37 are provid¬ ed also on the radial outer surface of the run casing 33, hence, the running surface. As a rule, however, such an effect is not desirable for a run casing. Grooves 37 never¬ theless provided on its outer surface principally must serve a different function, namely, that of air discharge grooves, such that air cushions which influence the frictional behav¬ ior between a material web wrapping around a drum and the surface of the drum cannot form between both materials. For the embodiment represented in Figures 3 and 4, and preferred in this respect, the width and depth and distance between these grooves 37 are provided somewhat smaller than for the grooves 27 of the intermediate layer.

When winding a material web, in particular of paper, in order to stretch the material web to the greatest extent possible, and also to wind this stretching into the winding 2, it has proven to be especially advantageous to provide the running surface of the run casing 33 with a low-friction layer 38. A lower coefficient of friction allows, namely, the effective range of influence for stretching to be in¬ creased. As shown using Figure 1 as an example, the length of the range of influence would be, e.g., as great as the web length between Nip A, between the winding 2 and second carrier drum 5 and Point B, drawn onto a first carrier drum 4. By means of a surface having a lower coefficient of fric¬ tion, this length could be increased, e.g., up to Point B'. For an embodiment in accordance with Figure 2, this range of influence would be greater still. The coefficient of fric¬ tion μ must not be so small, however, that in an extreme case, the web slides over the first carrier drum 4. Suitable for a low-friction layer is, e.g., a Teflon coating, which can be deposited by spraying onto the running surface. Other low-friction materials can also be used. A typical thickness of a low-friction layer is between 0.05 and 2 mm, although it can be less thick. Varying roll-coating materials can also be used to wind different web-like materials. As a rule, material webs of paper, film and the like can be wound with the same surface coating, for example. Teflon.

As seen in Figure 2, a nip roller 14 can be provided such that an incoming material web 1 is pressed against the carrier drum 4 around which it wraps. Among other things, this can enlarge the effective range for influencing the amount of stretch which can be wound in. The nip roller 14 can also feature a roller covering in accordance with the invention.

List of reference numbers

1 Material web

2 Roll

4 First carrier drum

5 Second carrier drum

6 First nip

7 Second nip

8 Nip pressure

9 Bearing pressure

10 Drum covering

11 Load drum

12 Piston/cylinder unit 14 Nip roller

20 Double carrier drum arrangement

22 Layer of bonding agent

23 Bearing journal

24 Drum body

25 Outer circumference

26 Intermediate layer 27 Helical grooves

33 Running casing

37 Grooves

38 Layer