EP2138436B1 - Device for centring, adjusting the width of and/or aligning a moved textile web and accompanying method - Google Patents

Description

The invention relates to a device for centering, spreading and / or straightening a moving web according to the preamble of claim 1 and an associated method according to the preamble of claim 11.

During the mechanical manufacturing and processing of particular textile webs, preferably fabric webs often occurs a delay in goods. Such delays of the web change the structure of the textiles made from these, which in turn reduces the utility of the goods and / or the further processing of the goods is impaired.

A textile material web consists in particular of threads crossed at right angles, which are produced during the weaving process in the loom or in the weaving machine. Here, a distinction is made between the longitudinal threads ("warp") and the transverse threads ("weft"). Due to the usually oblique to the running direction or arcuate distortion of the textile web, the orthogonal textile structure of warp and weft is deformed into a parallelogram. The originally orthogonal structure of warp and weft or their courses are thus changed obliquely or arcuately.

To restore the original orthogonal structure, the textile web is usually guided over a mechanical straightening arrangements, in which by means of straightening or arcuate to the direction of the textile web straightening roller units, the existing delays are compensated by appropriate application of compensating forces on the moving textile web. Such roll-based directing arrangements are preferably used to eliminate arcuate thread and stitch distortion.

Furthermore, a wide variety of roller assemblies for centering or positioning of textile webs, such as segmented control rollers, pivot-sliding rollers, etc. are known. Also, for spreading of textile webs so-called Lattenausbreiter, Schnurbreithalter and spreader rollers are used in various embodiments.

From the DE 43 22 114 A1 is a guide roller for an inclined incoming web, in particular a plastic web is known, which wraps around the guide roller partially, in which on the cylindrical roller surface parallel to the axis movably arranged rigid displacement rods are provided. DE 4 322 114 A1 discloses a device according to the preamble of claim 1 bw. a method according to the preamble of claim 11.

The US 2001/0023883 A1 discloses a device for spreading, upsetting or guiding a moving web, are used in the axially displaceable slats in a known manner in the widening. For axial adjustment of the slats two opposite swash plates are provided, in which the slats are each guided with a free end, and in turn.

Said devices are usually provided as separate machines which form mutually independent processing stations in the context of the mechanical manufacturing and processing process.

Proceeding from this, the present invention seeks to provide a multi-functional device for centering, spreading and / or straightening a moving web, which is flexibly adaptable to the respective required processing task and thus straightening, centering and / or spreading the moving web in one step allows. The object is achieved on the basis of an arrangement according to the preamble of claim 1 by its characterizing features.

The essential aspect of the arrangement according to the invention is to be seen in that the roller has a plurality of elastic connecting bands, which are axially movable relative to the longitudinal axis of the roller. Particularly advantageous allows the inventive, wherein the free ends of the elastic connecting bands with two opposing curves track mechanisms for the axial displacement of the elastic connecting bands along the longitudinal axis of the roller are in operative connection.

Forming the roller centering, spreading and / or straightening over this guided web. In the device according to the invention, the said functions can be integrated into a machine and thereby a reduction of mechanical components can be achieved, which in turn leads to a compact design. As a result, the described multifunctional device can be used for various machining processes even in very tight spaces. All the functions described can already be realized with a very low content of goods, which leads to the reduction of unwanted longitudinal expansion of the product, especially in elastic webs. In contrast to commercial directional arch rollers, which lead depending on the Umschlingungsposition to wrinkles in the web, this is Effect avoided by the integrated spreading function in the device according to the invention.

Particularly advantageously, the elastic connecting bands are evenly distributed over the roll surface and / or arranged concentrically to the longitudinal axis of the roll and / or independently movable.

The roller further comprises an elastic covering forming the roller surface, which comprises guide grooves which are designed to guide the elastic connecting belts along the longitudinal axis of the roller, wherein the roller comprises a preferably arcuate drive axle, which is surrounded by the elastic covering.

At least one drive mechanism for driving the roller around the longitudinal axis, which comprises at least one curved path mechanism, is particularly advantageously provided at the free ends of the drive axle. For this purpose, the curved path mechanism at least approximately forms a curved path comprising at least three curved path sections or sectors I, II, III, wherein the curved path in sector I has a neutral course, in sector II a preferably linearly increasing course and in sector III a preferably linearly falling course ,

In a particularly advantageous embodiment, the cam mechanism has at least one guide sleeve with at least one, the course of the curved path imaged free edge on which rest a plurality of cam rollers, the cam rollers are axially displaceable to the longitudinal axis of the guide sleeve and with the free ends of the elastic connecting bands, In particular expander belts are in operative connection.

In addition, further developments, advantages and possible applications of the invention result, in particular a method for centering, spreading and / or straightening a moving, in particular textile, web of further claims and will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination are fundamentally the subject of the invention, regardless of their summary in the claims or their dependency. Also, the content of the claims is made an integral part of the description.

Fig. 1a

eine Frontansicht der erfindungsgemäßen Vorrichtung zum Zentrieren, Breitstrecken und/oder Richten einer bewegten Warenbahn,

Fig. 1 b

eine Draufsicht auf die erfindungsgemäße Vorrichtung gemäß Fig. 1a,

Fig. 2

einen Schnitt entlang der Linie A-A durch die Vorrichtung gemäß Fig. 1 a,

Fig. 3

eine Seitenansicht der Walze mit stirnseitigen Antriebsmechaniken,

Fig.4

einen Schnitt entlang der Linie A-A durch die Walze mit stirnseitigen Antriebsmechaniken gemäß Fig. 3,

Fig. 5

eine vergrößerte Ausschnittsdarstellung des Schnittes durch die linke Antriebsmechanik,

Fig. 6

eine weitere vergrößerte Ausschnittsdarstellung des Schnittes durch die rechte Antriebsmechanik,

Fig. 7

eine perspektivische Ansicht eines Schnittes entlang der Linie B-B durch die Walze,

Fig. 8a

einen Querschnitt durch den elastischen Belag der Walze mit elastischen Verbindungsbändern,

Fig. 8b

einen Querschnitt durch den elastischen Belag der Walze ohne elastische Verbindungsbänder,

Fig. 8c

einen Querschnitt durch ein elastisches Verbindungsband,

Fig. 9

ein Diagramm zur Veranschaulichung der Sektoren I, II, III der Kurvenbahn und der Auswirkungen auf die bewegte Warenbahn und

Fig. 10

eine perspektivische Ansicht der Antriebsmechanik mit integrierter Kurvenbahnmechanik.

The invention will be described in more detail below with reference to drawings of an embodiment. Show it:

Fig. 1a

a front view of the device according to the invention for centering, spreading and / or straightening a moving web,

Fig. 1 b

a plan view of the inventive device according to Fig. 1a .

Fig. 2

a section along the line AA through the device according to Fig. 1 a,

Fig. 3

a side view of the roller with frontal drive mechanisms,

Figure 4

a section along the line AA through the roller with front drive mechanisms according to Fig. 3 .

Fig. 5

an enlarged sectional view of the section through the left drive mechanism,

Fig. 6

a further enlarged detail of the section through the right drive mechanism,

Fig. 7

a perspective view of a section along the line BB through the roller,

Fig. 8a

a cross section through the elastic lining of the roller with elastic connecting bands,

Fig. 8b

a cross section through the elastic lining of the roller without elastic connecting bands,

Fig. 8c

a cross section through an elastic connecting band,

Fig. 9

a diagram illustrating the sectors I, II, III of the curved path and the effects on the moving web and

Fig. 10

a perspective view of the drive mechanism with integrated cam mechanism.

In Fig. 1a is an example of a front view and in Fig. 1b a plan view of an inventive device 1 for centering, spreading and / or straightening a moving, in particular textile web W shown.

The device 1 has at least one roller 2 conveying the moving web W, which can be driven about its longitudinal axis L via a drive axle 3, via a respective drive mechanism 4, 4 provided on the opposite free ends 3 ', 3 "of the drive axle 3 The roller 2 and the end drive mechanisms 4, 4 'can be accommodated, for example, in a machine frame.

In addition to the roll, in particular centering, spreading and / or straightening roll 2, the device 1 can have a plurality of further roll units, preferably two deflection rolls 5, 5 ', which are provided for supplying or removing the moving fabric W to the roll 2. These are preferably mounted rotatably about a perpendicular to the direction LR of the web W extending axis of rotation. Alternatively, these can also be rigid.

The in the Fig. 1a, b illustrated device 1, for example, an arcuate roller 2, which is designed for straightening and simultaneous centering and / or widening of a moving web W. In the device 1 according to the invention with straightening roller arrangement, the paths of the material web W over the width of the roller 2 can be designed to be different, for example, by pivoting in or out of the roller 2, whereby a correction of, for example, arcuate distortion, in particular of the weft thread is possible.

By means of the device 1 according to the invention can thus be carried out simultaneously up to three processing steps, namely straightening, centering and spreading. Alternatively, the device 1 may also be in the form of a centering and / or spreading device with at least one straight roll 2, via which the conveyed web W is centered and / or stretched to a predetermined width of the fabric.

Fig. 2 shows a longitudinal section along the line AA through the device 1 according to FIG. 1a , For processing the web W, the web W of the roller 2 is supplied for example from above via a guide roller 5 at a predetermined inlet angle to the longitudinal axis L and leaves the device 1 again via a further guide roller 5 ', in a predetermined outlet angle to the longitudinal axis L of Roller 2.

By choosing the entry and exit angles of the wrap angle w of the roller 2 is determined by the web 4, i. that cross-sectional or circumferential region of the roller 2, which is wrapped by the moving web W during the machining process and thus subjected to a processing by means of the roller 2. In the present embodiment, the wrap angle w is preferably 120 °, i. one third of the roll surface.

Fig. 3 shows a schematic side view of an inventively designed roller 2 with a moving web W without that in the FIGS. 1a, b shown housing and possibly received therein drive units, which for driving the roller. 2 are provided via the drive mechanism 4, 4 '. Fig. 4 shows a section along the line AA through the roller 2 and the end drive mechanism 4, 4 '. In the Figures 5 and 6 is a partial view of the left and right drive mechanism 4, 4 'is shown. Fig. 7 shows a perspective view of a section through the roller 2 with guided material web W, for example along the line BB in FIG. 3 ,

As can be seen from the figures mentioned, the roller 2 consists of the drive mechanism 4, 4 'and associated drive units (not shown in the figures) driven drive shaft 3, which is preferably designed arcuate, and the drive axle 3 surrounding elastic pad 6, the preferably closed and integrally formed and rotated about the drive shaft 3. The elastic covering 6 also has a circular or annular cross-section and is inherently dimensionally stable. The elastic covering 6 is arranged, for example, by means of several, objectionable and preferably ring-shaped support elements (not shown in the figures) to the drive axle 3 spaced apart.

In the roller surface, in the elastic covering 2 a plurality of guide grooves 7 are introduced, which run parallel to each other along the longitudinal axis L of the roller 2, wherein the guide grooves 7 are preferably arranged concentrically about the longitudinal axis L of the roller 2 and uniformly over the roller surface or the surface of the elastic covering 2 are distributed.

According to the invention in the guide grooves 7 axially to the longitudinal axis L of the roller 2 movably arranged and guided over the guide grooves 7 elastic connecting bands, in particular expander bands 8 are taken, which preferably extend over the entire length of the roller 2 and with their free ends 8 ', 8 " with the respective end-face drive mechanism 4, 4 ', in particular a curved path mechanism 10, 10' provided therein, are in operative connection.

The guide grooves 7 have a T-shaped cross-section which extends from the surface of the elastic lining 2 in the direction of the drive axle 3 accommodated in the elastic covering 2. This forms two of an elongated Guide channel 7.1 in the elastic covering 2 each laterally aligned guide recesses 7.2, 7.2 'from.

The elastic connecting bands, in particular expander bands 8 are formed mushroom-shaped in cross-section, and indeed they have a rounded, preferably flat cap portion 8.1, to which a reverse in cross-section T-shaped holding and guiding section 8.2 connects, which is used to guide the expander bands 8 in the guide grooves 7 is adapted to the cross-sectional shape.

In FIG. 8a is an example of a section through the elastic pad 7 with inserted expander bands 8, in FIG. 8b the elastic covering 7 without expander bands 8 and in FIG. 8c a cross section through an expander belt 8 exemplified. It is understood that elastic connecting bands, in particular expander bands 8 and associated guide grooves 7 with deviating cross-sectional shapes can be used, which realize a similar holding and guiding function.

The free ends 3 ', 3 "of the elastic connecting bands, in particular expander bands 8 cooperate with a cam mechanism 10, 10' provided in the drive mechanism 4, 4 ', which images a cam track 9 whose mode of operation is shown by way of example in a diagram in FIG FIG. 9 is shown.

The cam track 9 has, for example, three approximately equally large curved path sections or sectors I, II, III, which in each case rest depending on the set rotational angle position between the curved path mechanism 10, 10 'and the roller 2. As from the in FIG. 9 shown diagram, the curved path 9 in sector I to the direction of movement of the web W or axially to the roller 2 a neutral course, whereas in sector II a preferably linearly increasing course and in sector III a preferably linearly falling course are present, in each case on the longitudinal axis L of the roller. 2

FIG. 10 also shows the image of the sector II with preferably linearly increasing course and the sector III with preferably linearly decreasing course in the curved path mechanism 10, 10 '.

In the present embodiment, the three sectors I, II, III of the cam track 9 have an approximately the wrap angle w of preferably 120 ° corresponding circumferential length, i. the sectors II, III cause the expander bands 8 to be acted upon with a force F in the axial direction, inwards or outwards, whereby no change in the current position of the expander bands 8 is made in sector I. This results, for example, in a displacement of the free ends 8 ', 8 "of the expander bands 8 in the axial direction of between 50 and 100 mm, preferably 75 mm free ends 8 ', 8 "of the expander bands 8 are made, which generates either a spreading and / or a displacement of the web W in the wrap.

The course of in FIG. 9 shown cam track 9 is shown on the curved path mechanism 10, which is part of the drive mechanism 4, 4 '. The curved path mechanism 10 comprises at least one guide sleeve 10.1, which is arranged between two annular side parts 10.2, 10.2 ', and that is a free edge of the guide sleeve 10.1 connected to the side facing the roller 2 side part 10.2, wherein the opposite free edge of the guide sleeve 10.1 the course of the curved path 9 is shown. The settlement of the free edge of the guide sleeve 10.1 relative to a reference point corresponds to the course of the curved path 9.

At the cam track 9 forming the free edge of the guide sleeve 10.1 are several cam rollers 10.3, which are axially rotatably mounted on a carriage 10.4 a linear guide of the cam mechanism 10. The expander bands 8 are guided via openings in the side part 10.2 directed towards the roller 2 to the carriages 10.4 of the linear guide and mechanically connected thereto, for example by clamping, gluing or screwing. The cam rollers 10.3 are thus on the Linear guide guided axially to the roller 2 and coupled with the rotational movement of the roller 2, so that they rotate with the approximately same rotational speed.

For this purpose, the side parts 10.2, 10.2 'are connected to one another, for example via a holding sleeve 10.5, which is mounted rotatably about the drive axis 3 by means of bearing elements, in particular rolling bearings 11, 11'. On the outer surface of the holding sleeve 10.5 a plurality of elongated guide rails 10.6 are arranged, which are provided concentrically around the longitudinal axis of the holding sleeve 10.5 and extend parallel to this. The guide rails 10.2 are formed for linear guidance of the carriages 10.4.

The cam track mechanism 10, 10 'is - as in FIG. 3 represented - preferably surrounded by a jacket-shaped housing, which is supported by the side parts 10.2, 10.2 '.

The curved path mechanism 10, 10 'is connected via a universal joint 12 with a sprocket 13 for rotating the curved path mechanism 10, 10' relative to the roller 2, wherein the universal joint 12 to compensate for the angular offset of the respective outer stub 3.1 of the drive axle 3 and the remaining, preferably curved axle section 3.2 of the drive axle 3 is provided.

The cam track 9 is held on the cam track mechanism 10, 10 'in position and is silent with respect to the roller rotation. Via a separate drive unit, preferably an electric motor, however, the cam track mechanism 10, 10 'and thus the cam track 9 relative to the roller 2 can be rotated separately, namely the opposite cam track mechanisms 10, 10' are adjusted independently.

In a further embodiment, a further sprocket 14 may be provided, which allows a pivoting of the arcuate portion 3.2 of the roller 2 about the outer stub 3.1 of the drive axle 3.

The cam track mechanism 10, 10 'provided on both free ends 3', 3 "of the drive axle 3 or of the roller 2 for controlling the movement and / or the expansion of the expander belts 8 has a symmetrical construction A control unit (not shown in the figures) is provided for this purpose, which is connected to the drive units and at least two optical sensor units 15, 15. The control of the cam mechanism 10, 10 'takes place thus preferably by means of separate optical sensor units 15, 15 'for the left and right edges K of the web W.

By means of the optical sensor units 15, 15 ', which are preferably formed by line sensors, in each case the current position of an edge K of the moving material web W is detected, preferably independently of one another. The position data are evaluated via an evaluation and control routine executed in the control unit. For this purpose, the optical sensor units 15, 15 'are positioned manually or automatically in predetermined nominal positions and the actual positions of the edges of the material web W are determined via the optical sensor units 15, 15'. By evaluating the deviation of the actual position from the target position, at least two independent control signals are generated via the evaluation and control routine, via which the control of the different drive units of the cam track mechanism 10, 10 'takes place. About the drive units, the cam track 9 is adjusted accordingly to counteract the deviations of the edge position of the target position.

Due to the separate detection of both fabric edges K and by the separate control of the opposite cam track mechanisms 10, 10 ', it is possible to perform the functions "spreading" and "centering" of the web in one operation. If the opposing optical sensor units 15, 15 'are set to the predetermined production width of the material web, the predetermined production width is regulated by means of the evaluation and control routine by appropriately adjusting the fabric edges.

The spreading and centering of the web W is thus achieved by the adjustment of the curved path, in relation to the Umschlingposition the web W on the roller 2. The guidance of the web W is carried out with the wrap angle w of preferably 120 °, wherein the wrap angle w in the neutral region of the cam track 9 is congruent with the sector I of the cam track 4. As a result, seen axially to the roller, the casserole and drainage position of the web W unchanged. By twisting the individual cam track mechanisms 10, 10 ', the looped edge K of the material web W can now be axially displaced from the inlet point to the outlet point or stretched or compressed. By a separate control of left and right curved path mechanism 10, 10 ', both the positioning of the web W and its defined width can be controlled. By this width control possible wrinkling is avoided.

In particular, the cam track mechanisms 10, 10 'are rotated relative to the roller 2 in such a way that in each case the desired sector I, II, III of the cam track 9 at least partially overlaps or approximately coincides with the looping region of the material web W. For example, if the product edge K is exactly at the target position, the sector I is set to neutral, i. the neutral portion of the curved path is pivoted in the region of the 120 ° loop. By combining a neutral region with a falling or rising region of the end curved tracks 9, the intensity of the countermovement can be regulated.

In a further embodiment of the device 1, the entire drive mechanism 4, 4 'together with curved path mechanism 10, 10' can be mounted in a preferably O-shaped swing frame 16, and via a corresponding pivot mechanism approximately parallel to the running direction LR of the web W for Schräggrichten the web adjustable. Thus, the entire roller assembly can be pivoted about the swing frame 16, so that at least the roller 2 is slightly oblique to the direction LR of the web W. As a result, a Schrägrichteffekt is achieved.

An exemplary application field is in the field of textile printing by means of so-called inkjet printing machines. On said application, it is necessary that the web W before application of the printed image as possible distortion-free, accurately positioned and stretched out on the printing table. Straightening, spreading and centering devices known from the prior art are designed in several parts and therefore have a high space requirement in addition to high investment costs. The inventive integration of the three processing functions in a device 1, a space-saving structure can be realized immediately adjacent to the printing table.

LIST OF REFERENCE NUMBERS

1

contraption

2

roller

3

drive axle

3.1

outer stub

3.2

intercept

3 ', 3 "

free ends

4, 4 '

drive mechanism

5, 5 '

deflection rollers

6

elastic covering

7

guide

7.1

guide channel

7.2, 7.2 '

guide recesses

8th

elastic connecting means or expander bands

8 ', 8 "

free ends

8.1

cap section

8.2

Holding and guiding section

9

cam track

10, 10 '

Cam mechanism

10.1

guide sleeve

10.2, 10.2 '

side panels

10.3

follower

10.4

carriage

10.5

holding sleeve

10.6

guide rail

11.11 '

bearing elements

12

universal joint

13

Sprocket

14

Sprocket

15, 15 '

sensor elements

16

Swivel frame

I, II, III

first to third curved path section or sector

W

web

L

longitudinal axis

ω

Umschlingwinkel

LR

direction

F

force

Claims (15)

1. Device for centring, adjusting the width of and/or straightening a moving, more particularly textile, web of material (W), with at least one preferably curved roller (2) which conveys the moving web (W), characterised in that the at least one roller (2) has several elastic connecting bands, more particularly expanding bands (8), which are formed axially movable along the longitudinal axis (L) of the roller (2) wherein the free ends (8', 8") of the elastic connecting bands (8) are in active connection with two opposing cam track mechanisms (10, 10') for axially displacing the elastic connecting bands (8) along the longitudinal axis (L) of the roller (2).
2. Device according to claim 1 characterised in that the elastic connecting bands (8) are spread out uniformly over the surface of the roller and/or are arranged concentric with the longitudinal axis (L) of the roller and/or are movable independently of one another.
3. Device according to claim 1 or 2 characterised in that the roller (2) has an elastic covering (6) which forms the surface of the roller and which comprises guide grooves (7) which are designed for guiding the elastic connecting bands (8) along the longitudinal axis (L) of the roller (2).
4. Device according to claim 3 characterised in that the roller (2) has a preferably arcuate drive axis (3) which is surrounded by the elastic covering (6).
5. Device according to claim 4 characterised in that at least one drive mechanism (4, 4') is provided at each free end (3', 3") of the drive axis (3) for the purpose of driving the roller (2) around the longitudinal axis (L).
6. Device according to one of claims 1 to 5 characterised in that the cam track mechanisms (10, 10') are part of the drive mechanism (4, 4').
7. Device according to claim 6 characterised in that the cam track mechanism (10, 10') represents at least approximately one cam track (9) comprising at least three cam track sections or sectors I, II, III, wherein the cam track (9) has in sector I a neutral path, in sector II a preferably linearly rising path and in sector III a preferably linearly falling path, namely each in relation to the longitudinal axis (L) of the roller (2).
8. Device according to claim 7 characterised in that the cam track mechanism (10, 10') has at least one guide sleeve (10.1) with at least one free edge copying the path of the cam track (9) and adjoined by several cam rollers (10,3) wherein the cam rollers (10.3) are arranged axially displaceable relative to the longitudinal axis of the guide sleeve (10.1) and are in active connection with the free ends (8', 8") of the elastic connecting bands, more particularly expanding bands (8).
9. Device according to one of claims 6 to 8 characterised in that the opposing cam track mechanisms (10, 10') are adjustable independently of one another, namely in relation to the rotary angle position between the cam track mechanism (10, 10') and the roller (2).
10. Device according to claim 9 characterised in that the cam track mechanisms (10, 10') are rotatable relative to the roller (2) about its longitudinal axis (L) so that the relevant desired sector I, II, III of the cam track (9) overlaps at least partially with the arc of contact (ω) of the material web (W) or coincides at least approximately with same wherein the arc of contact (ω) amounts to preferably 120°.
11. Method for centring, adjusting the width of and/or straightening a moving more particularly textile material web (W) wherein the moving material web (W) is guided over a driven preferably curved roller (2) characterised in that the material web (4) is at least centred and/or stretched widthwise over several elastic connecting bands, more particularly expanding bands (8), provided on the surface of the roller, namely through axial movement of the elastic connecting bands, more particularly expanding bands (8) along the longitudinal axis (L) of the roller (2) wherein the axial displacement of the elastic connecting bands (8) along the longitudinal axis (L) is controlled by way of two cam track mechanisms (10, 10') arranged at the side ends.
12. Method according to claim 11 characterised in that the elastic connecting bands, more particularly expanding bands (8) are movable independently of one another and/or that the movement of the elastic connecting bands, more particularly expanding bands (8) takes place dependent on that cam track section or sector (I, II, III) of a predetermined cam track (9) which is assigned to the relevant arc of contact (ω) of the material web (W) with the roller (2).
13. Method according to claim 11 or 12 characterised in that the elastic connecting bands, more particularly expanding bands (8) are moved dependent on at least a predetermined cam track (9) with at least three cam track sections or sectors (I,. II, III) wherein the at least one cam track (9) has in the first sector (1) a neutral path, in the second sector (II) a preferably linearly rising path and in the third sector (III) a preferably linearly falling path.
14. Method according to one of claims 11 to 13 characterised in that the actual position of the edges (K) of the moving material web (W) is detected by means of optical sensor units (15,15'), namely preferably independently of one another, and dependent thereon the elastic connecting bands, more particularly expanding bands (8) are moved axially by way of the two cam track mechanisms (10,10') on the side ends, namely preferably according to one of the at least three cam track sections or sectors (I, II, III) of the cam tracks (9) provided by the cam track mechanisms (10, 10').
15. Method according to one of claims 11 to 14 characterised in that the degree of strength of the movement of the elastic connecting bands, more particularly expanding bands (8) can be adjusted by a combination of the first cam track section or sector (I) with neutral path with the second or third cam track section or sector (II, III) with falling or rising path.

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