APPARATUS FOR TRANSPORTING A WEB MATERIAL

Description

[0001] The present invention generally relates to a method and apparatus for transporting material webs. More particularly, the invention relates to transporting a folded paper web in a web-fed rotary printing machine.

[0002] Devices, such as nip roller arrangements, are well known for pulling or drawing material webs through a web-fed rotary printing machine or a paper-production machine. In web-fed rotary printing machines, a nip roller arrangement is usually located in the former and folder section of the printing machine, usually underneath a former board which applies a longitudinal fold to the printed paper-web.

[0003] JP-A-01 192661 discloses a first shaft with a driven wheel which is mounted to the first shaft and a further non-driven wheel which is rotatingly mounted to the first shaft. Moreover, there is disclosed a secorid shaft with a driven wheel which is mounted to the second shaft and a further non-driven wheel which is rotatingly mounted to the second shaft. The wheels mounted to the first and second shaft have a diameter larger than the wheels mounted rotatingly the the first and second shaft. Each one of the wheels mounted to a shaft contacts a wheel mounted rotatingly to the other shaft and a material web is guided by the wheels and deformed in a wavelike manner.

[0004] NL 6506362 discloses a first and a second shaft with respective rotatingly mounted non-driven wheels and respective mounted driven wheels. A paper web is guided by the driven and non-driven wheels of the two shafts and deformed in a wavelike manner. Moreover, the two shafts are connected to eachother for common driving.

[0005] US 3,784,187 discloses a folding apparatus for a web-fed rotary printing machine which comprises groups of nip rollers arranged below first and second triangular former boards. The nip rollers pull the web downstream of the triangular former boards, so as to give tension to the web and to the folds of the web.

[0006] The nip rollers used in conventional nip roller arrangements of web-fed rotary printing machines often include a first driven roller which is made of rigid material, (e.g. steel or other metal) and a second, non-driven roller, which is covered with a resilient material (e.g. polyurethane). For transporting the web, the rigid roller is driven with a slightly higher speed than the web speed, and the tension applied to the web is controlled by the pressure between the driven and the non-driven nip roller. To increase tension in the web, the pressure between the two nip rollers is increased so that frictional force between the driven nip roller and the web is increased too.

[0007] As a result of the constant slip between the driven nip roller and the paper web, the nip rollers wear out very quickly. The wear of the nip rollers is increased when the driven nip roller is coated with a resilient material (for example rubber or polyurethane). Moreover, as a result of the slip between the nip rollers and the paper web, there is the danger of smearing the printed image. Further, there is the danger that changes in the web tension, in the form of small disturbances, are directly passed through the nip of the nip roller arrangement into the cutting sections or further folding sections of the printing machine.

[0008] It is an object of the present invention to provide a method and apparatus for directly controlling web tension. Exemplary embodiments relate to a nip roller arrangement, which is easy to produce and assemble, which prevents the propagation of disturbances in the web tension into subsequent sections of the printing machine, and which reduces wear of the nip rollers.

[0009] According to a first embodiment of the invention, a nip roller arrangement is provided for transporting a folded paper web in a web-fed rotary printing machine. This arrangement comprises a first nip roller having a first set of driven and non-driven wheels arranged side by side along a rotational axis of the first nip roller, and a second nip roller having a second set of driven and non-driven wheels arranged side by side along the rotational axis of the second nip roller, the wheels of the first and second nip rollers being arranged such that the driven wheels of said first roller face the non-driven wheels of the second roller to form a nip for receiving and conveying the web material.

[0010] According to another exemplary embodiment of the invention, the non-driven and/or the driven wheels of the first and second nip rollers are coated with a resilient material, such as any elastomer, including rubber or polyurethane.

[0011] According to still another exemplary embodiment of the invention, the driven wheels and/or non-driven wheels of the first and second nip rollers are formed of a rigid material, such as metal (e.g. steel).

[0012] Pursuant to a further embodiment of the invention, the diameter of the non-driven wheels of the first and second nip rollers is larger than the diameter of the driven wheels.

[0013] Further, each nip roller comprises a central drive shaft extending through the center of the driven and non-driven wheels, to which the driven wheels are drivingly connected by means of a clamp mechanism. The non-driven wheels of the nip rollers can be supported on the central drive shaft by bearings. Additionally, the driven and/or non driven wheels of the first and second nip rollers can be mounted axially immovable on the central drive shaft, in accordance with exemplary embodiments of the invention.

[0014] According to another exemplary embodiment of the invention, the central drive shafts of the nip rollers are drivingly connected to each other by meshing gears, such that the rollers have essentially the same rotational speed.

[0015] Furthermore, according to a further exemplary embodiment, at least one of the nip rollers can be movably supported by bearings such that a width of the nip for receiving and conveying the material web can be adjusted. Such a feature can be used to render the circumferential speed of the driven wheels of the first and second nip rollers essentially equal to the speed of the web material.

[0016] The present invention, together with additional objects and advantages thereof, will be best understood from the following description of exemplary embodiments when read in connection with the accompanying drawings, in which:

Fig. 1

is a schematic side view of a web-fed rotary printing machine with a nip roller arrangement according to an exemplary embodiment of the present invention;

Fig. 2

shows a schematic front view of a former board used in a web-fed rotary printing machine for longitudinally folding a printed web, with a nip roller arrangement according to an exemplary embodiment of the present invention located underneath the former board;

Fig. 3

shows a schematic three-dimensional side view of a nip roller arrangement according to an exemplary of the present invention, wherein the pressure between the nip rollers is adjustable by means of air-cylinders;

Fig. 4

shows a schematic side view of a driven wheel used in an exemplary nip roller arrangement of the present invention;

Fig. 5

shows a schematic side view of a non-driven wheel of a nip roller arrangement according to an exemplary embodiment of the present invention; and

Fig. 6

shows a schematic cross-sectional view of a nip roller arrangement according to an exemplary embodiment of the present invention.

[0017] As shown in Fig. 1, an exemplary nip roller arrangement 1 for pulling a printed web 4 in an exemplary web-fed rotary printing machine 2 is located downstream of a dryer section 6, a chill section 8 and/or a former board 10. The former board 10 is provided for longitudinally folding the printed web 4 before it is supplied to a downstream cutting section 12 for further processing.

[0018] Although the present invention is described herein with respect to a web-fed rotary printing machine, it is also usable in other kinds of apparatuses for processing web material. For example, as those skilled in the art will appreciate, the present invention is equally applicable to paper processing machines, such as paper production machines and so forth.

[0019] As shown in Fig. 2, the nip roller arrangement 1 includes at least a first nip roller 14 and a second nip roller 16, which are arranged on opposite sides of the web 4 (e.g., a printed and folded web), thereby forming a nip 18 for transporting the web 4.

[0020] As shown in Fig. 3, each of the nip rollers 14 and 16 comprise a first set of driven wheels 20 and a second set of non-driven, free-wheeling wheels 22, the driven wheels and the non-driven wheels being arranged side by side along the rotational axes 24 and 26 of the first and second nip rollers 14, 16, respectively. Thereby, a driven wheel 20 of one nip roller is facing a non-driven wheel 22 of the other nip roller. That is, for each driven wheel 20 on one roller, there is a corresponding non-driven wheel 22 on the other nip roller, and vice versa.

[0021] As shown in the exemplary Fig. 3 embodiment, the central drive shafts 34 and 36 of the first and second nip rollers 14, 16 are drivingly connected to each other by means of meshing gears 54 and 56, mounted to the central drive shafts 34 and 36. Only one of the drive shafts 34, 36 is driven by a motor 48, and the speed of the motor 48 is controlled in dependence on the press speed such that the circumferential speed of the driven wheels 20 of each of the nip rollers 14, 16 equals the surface speed of the material web 4. To control the speed of the nip rollers 14, 16, any known and readily available harmonic drive 50 can, if desired, be provided between the motor 48 and the respective central drive shaft which is driven by the motor 48. As an alternative embodiment either or both of the drive shafts can be driven.

[0022] As shown in Fig. 3, there can further be provided means for moving the two nip rollers 14 and 16 with respect to each other, to adjust the width of the nip 18 between the two nip rollers 14, 16 for transporting and conveying the web material 4. The movement or adjustment of the nip 18 can be performed by a moving means which includes, for example, levers 58a and 58b and respective air cylinders 60a, 60b. Of course, any other kind of actuating device, such as electric motors or manual levers can alternately be used.

[0023] Referring to the exemplary Fig. 4 embodiment of the invention, the driven wheels 20 are formed of a body or core 44 of rigid material, such as metal (e.g. steel or any kind of metal). Further, as illustrated in Fig. 6, the exemplary driven wheels have a slightly smaller diameter than the non-driven wheels 22. As shown in Fig. 5, the non-driven wheels 22 include a rigid core 30 covered with a resilient material (e.g., a bonded material) or coating 28, such as rubber or polyurethane. As shown in the exemplary Fig. 6 embodiment, the coating 28 can be applied to the rigid core or body 30 of the non-driven wheels 22, and although the overall diameter of the non-driven wheels can be the same as or larger than that of the driven wheels in the Fig. 6 embodiment, the core 30 of each non-driven wheel is of a smaller diameter than the diameter of the body 44 of each driven wheel 20. In an alternative embodiment, the non-driven wheels 22 can be entirely formed of a resilient material.

[0024] In another embodiment of the invention, both the driven wheels 20 and the non-driven wheels 22 can be formed of a rigid material. Alternatively, as indicated by dashed lines in Fig. 4, a resilient coating 28A can be provided on the body 44 of the driven wheels 20 of the first and second nip rollers 14, 16. In such an embodiment, the non driven wheels 22 can be formed as shown in Fig. 5, or can be formed of a rigid material, such as metal.

[0025] In an exemplary embodiment of the invention as illustrated in Figs. 3-6, each of the nip rollers 14, 16 comprise a central drive shaft 34, 36, respectively extending through the center of the driven and non-driven wheels 20, 22, and being rotatably supported by bearings. As shown in Fig. 4, means are provided for drivingly connecting the driven wheels 20 of each nip roller 14, 16 to a respective one of the drive shafts 34, 36 by, for example, a key 38 and a groove 40 in the drive shaft. The non-driven, free wheeling wheels 22 are, for example, supported on the central drive shafts 34 and 36 by bearings 42, as indicated in Figs. 5 and 6. To prevent axial movement of the non-driven wheels 22 on the shafts 34, 36, the fitting of the bearings 42 on the shafts can be established with a reasonably tight tolerance, and sleeves can be provided between the driven and the non-driven wheels 20 and 22 for maintaining a defined axial position of the wheels along the length of the shafts 34, 36.

[0026] In an exemplary embodiment of the invention, the core or body 44 of the driven wheels 20 and the core or body 30 of the non-driven wheels 22 can be formed in two parts, which can be clamped together by any clamping means, such as screws 46 of Figs. 4 and 5. This exemplary configuration of the bodies 44 and 30 of the driven and non-driven wheels 20 and 22 provides easy assembling of the nip rollers 14, 16 and provides for quick replacement of the wheels in the event one or more of the wheels becomes defective.

[0027] In an exemplary embodiment of the invention, the pressure between the first and the second nip rollers 14 and 16 is adjusted such that there is no slip between the nip rollers and the surface of the web material 4. As a result of the resilient coating on the driven end/or non-driven wheels 22, the web material 4 comprises a corrugated shape such as shown in Fig. 6, by which the web 4 is stabilized and the web handling in subsequent processing units is improved. The corrugating effect, which is applied to the web 4, depends on the radial thickness of the resilient coating 28 and on the space between a driven wheel 20 and a non-driven wheel 22.

LIST OF REFERENCE NUMERALS

[0028] 

1

nip roller arrangement

2

web-fed rotary printing machine

4

printed web

6

dryer section

8

chill section

10

former board

12

cutting section

14

first nip roller

16

second nip roller

18

nip

20

driven wheel of the nip roller 14

22

non-driven, free-wheeling wheel of the nip roller 16

24

rotational axis

26

rotational axis

28

resilient material on the core 30 of the wheel 22

28A

resilient material of the core 44 of the driven wheel 20

30

core of the non-driven wheel 22

34

drive shaft of the first nip roller 14

36

drive shaft of the second nip roller 16

38

key

40

groove

42

bearings

44

core of the driven wheel 20

46

screws

48

motor

50

harmonic drive

54

gear

56

gear

58a

lever

58b

lever

60a

air cylinder

60b

air cylinder

Claims

1. Apparatus for transporting a material web with
a fast nip roller (14) having a first set of driven and non-driven wheels (20, 22) arranged side by side along a rotational axis (24) of the first nip roller (14);
and a second nip roller (16) having a second set of driven and non-driven wheels (20, 22) arranged side by side along a rotational axis (26) of the second nip roller (16), the wheels (20, 22) of the first and second nip rollers (14, 16) being arranged such that the driven wheels (20) of said first nip roller (14) face the non-driven wheels (22) of the second nip roller (16) to form a nip (18) for receiving and conveying the material web (4),
characterized in that the diameter of the non-driven wheels (22) of the nip rollers (14, 16) is larger than the diameter of the driven wheels (20), and that the nondrive wheels (22) of the nip rollers (14, 16) are coated with a resilient material, or are entirely formed of a resilient material.

2. Apparatus according to Claim 1,
wherein the non-driven wheels (22) of the nip rollers (14, 16) are formed in part of a rigid material.

3. Apparatus according to anyone of the Claims 1 or 2,
wherein the driven wheels (20) of the nip rollers (14, 16) are coated with a resilient material.

4. Apparatus according to Claim 3,
wherein the driven wheels (20) of the nip rollers (14, 16) are formed of a rigid material.

5. Apparatus according to anyone of the Claims 1 to 4,
wherein the resilient material is an elastomer.

6. Apparatus according to anyone of the Claims 2 to 5,
wherein the rigid material is metal.

7. Apparatus according to any one of the preceding claims,
wherein each nip roller (14, 16) further comprises a central drive shaft (34, 36) extending through the center of the driven and non-driven wheels (20, 22) and means for clamping the driven wheels (20) to said central drive shaft (34, 36).

8. Apparatus according to Claim 7,
wherein the non-driven wheels (22) of the nip rollers (14, 16) are supported on the central drive shaft (34, 36) of each nip roller (14, 16) by bearings.

9. Apparatus according to Claim 7 or 8,
wherein at least one of the driven and non-driven wheels of the nip rollers (14, 16) are mounted axially immovable on the respective central drive shaft (34, 36).

10. Apparatus according to any one of the Claim 7 to 9,
wherein the central drive shafts (34, 36) of the nip rollers (14, 16) are drivingly connected to each other by meshing gears (54, 56), such that the driven wheels (20) of the nip rollers (14, 16) are driven at essentially the same rotational speed.

11. Apparatus according to any one of the preceding claims,
wherein at least one of the nip rollers (14, 16) is movably supported with respect to the other of the nip rollers (14, 16), such that a width of the nip (18) for receiving and conveying the material web (4) is adjustable.

12. Apparatus according to any one of the preceding claims,
wherein the driven wheels (20) of at least one of the nip rollers (14, 16) are configured to be driven with a circumferential speed essentially equal to a speed with which the material web (4) is conveyed through the nip (8).

Ansprüche

1. Vorrichtung zum Transport einer Materialbahn mit
einer ersten Presswalze (14) mit einer ersten Anordnung nebeneinander entlang
einer Drehachse (24) der ersten Presswalze (14) angeordneter angetriebener und unangetriebener Räder (20, 22)
und einer zweiten Presswalze (16) mit einer zweiten Anordnung nebeneinander entlang einer Drehachse (26) der zweiten Presswalze (16) angeordneter angetriebener und unangetriebener Räder (20, 22), wobei die Räder (20, 22) der ersten und zweiten Presswalze (14, 16) in der Weise angeordnet sind, dass die angetriebenen Räder (20) der ersten Presswalze (14) den unangetriebenen Rädern (22) der zweiten Presswalze (16) gegenüber liegen und einen Spalt (18) zur Aufnahme und zum Transport der Materialbahn (4) bilden,
dadurch gekennzeichnet, dass der Durchmesser der unangetriebenen Räder (22) der Presswalzen (14, 16) größer ist als der Durchmesser der angetriebenen Räder (20) und dass die unangetriebenen Räder (22) der Presswalzen (14, 16) mit einem elastischen Material beschichtet sind oder insgesamt aus einem elastischen Material gebildet sind.

2. Vorrichtung nach Anspruch 1,
bei der die unangetriebenen Räder (22) der Presswalzen (14, 16) teilweise aus einem steifen Material gebildet sind.

3. Vorrichtung nach einem der Ansprüche 1 oder 2,
bei der die angetriebenen Räder (20) der Presswalzen (14, 16) mit einem elastischen Material beschichtet sind.

4. Vorrichtung nach Anspruch 3,
bei der die angetriebenen Räder (20) der Presswalzen (14, 16) aus einem steifen Material gebildet sind.

5. Vorrichtung nach einem der Ansprüche 1 bis 4,
bei der das elastische Material ein Elastomer ist.

6. Vorrichtung nach einem der Ansprüche 2 bis 5,
bei der das steife Material ein Metall ist.

7. Vorrichtung nach einem der vorhergehenden Ansprüche,
bei der jede Presswalze (14, 16) weiterhin eine durch die Mitte der angetriebenen und unangetriebenen Räder (20, 22) verlaufende zentrale Antriebswelle (34, 36) und Mittel zum Festklemmen der angetriebenen Räder (20) an der zentralen Antriebswelle (34, 36) umfasst.

8. Vorrichtung nach Anspruch 7,
bei der die unangetriebenen Räder (22) der Presswalzen (14, 16) über Lagerungen auf der zentralen Antriebswelle (34, 36) der jeweiligen Presswalze (14, 16) gelagert sind.

9. Vorrichtung nach Anspruch 7 oder 8,
bei der die angetriebenen und/oder die unangetriebenen Räder der Presswalzen (14, 16) axial unbeweglich auf der jeweiligen zentralen Antriebwelle (34, 36) befestigt sind.

10. Vorrichtung nach einem der Ansprüche 7 bis 9,
bei der die zentralen Antriebswellen (34, 36) der Presswalzen (14, 16) über einander kämmende Zahnräder (54, 56) in der Weise miteinander in Antriebsverbindung stehen, dass die angetriebenen Räder (20) der Presswalzen (14, 16) mit im Wesentlichen derselben Drehgeschwindigkeit angetrieben werden.

11. Vorrichtung nach einem der vorhergehenden Ansprüche,
bei der mindestens eine der Presswalzen (14, 16) bezüglich der anderen Presswalze (14, 16) bewegbar ist, so dass eine Breite des Spalts (18) zur Aufnahme und zum Transport der Materialbahn (4) einstellbar ist.

12. Vorrichtung nach einem der vorhergehenden Ansprüche,
bei der die angetriebenen Räder (20) mindestens einer der Presswalzen (14, 16) derart ausgebildet sind, dass sie mit einer Umfangsgeschwindigkeit angetrieben werden, die im Wesentlichen der Geschwindigkeit entspricht, mit der die Materialbahn (4) durch den Spalt (8) bewegt wird.

Revendications

1. Appareil permettant de transporter une bande continue de matériau comportant :

un premier rouleau de pressage (14) composé d'un premier ensemble de roues entrainées et de roues libres (20, 22) montées côte à côte suivant un axe de rotation (24) du premier rouleau de pressage (14);

et un second rouleau de pressage (16) composé d'un second ensemble de roues entraînées et de roues libres (20, 22) montées côte à côte suivant un axe de rotation (26) du second rouleau de pressage (16), les roues (20, 22) des premier et second rouleaux de pressage (14, 16) étant disposées de façon à ce que les roues entraînées (20) du premier rouleau de pressage (14) soient en face des roues libres (22) du second rouleau de pressage (16) et forment une zone de pincement (18) destinée à recevoir et à convoyer la bande de matériau (4),

caractérisé en ce que le diamètre des roues libres (22) des rouleaux (14,16) est supérieur au diamètre des roues entraînées (20) et en ce que les roues libres (22) des rouleaux de pressage (14,16) sont revêtues d'un matériau souple ou entièrement constituées d'un matériau souple.

2. Appareil selon la revendication 1, dans lequel les roues libres (22) des rouleaux de pressage (14,16) sont partiellement constitués d'un matériau rigide.

3. Appareil suivant l'une quelconque des revendications 1 et 2, dans lequel les roues entraînées (20) des rouleaux de pressage (14,16) sont garnies d'un matériau souple.

4. Appareil suivant la revendication 3, dans lequel les roues entraînées (20) des rouleaux de pressage (14,16) sont constituées d'un matériau rigide.

5. Appareil suivant l'une quelconque des revendications 1 à 4, dans lequel le matériau souple est un élastomère.

6. Appareil suivant l'une quelconque des revendications 2 à 5, dans lequel le matériau rigide est un métal.

7. Appareil suivant l'une quelconque des revendications 1 à 6, dans lequel chacun des rouleaux de pressage (14, 16) comporte en outre un axe d'entraînement (34, 36) passant par les centres des roues entraînées et des roues libres (20, 22) et des moyens de blocage des roues entraînées (20) de façon à les rendre solidaires dudit axe d'entraînement (34, 36).

8. Appareil selon la revendication 7, dans lequel les roues libres (22) des rouleaux de pressage (14, 16) sont montées sur les axes d'entraînement (34, 36) de chaque rouleau de pressage (14, 16) au moyen de paliers.

9. Appareil selon les revendications 7 ou 8, dans lequel au moins une des roues entraînées et une des roues libres des rouleaux de pressage (14, 16) sont positionnées sur les axes d'entraînement respectifs (34, 36) sans possibilité de translation suivant lesdits axes.

10. Appareil suivant l'une quelconque des revendications 7 à 9, dans lequel les axes d'entraînement (34, 36) des rouleaux de pressage (14, 16) sont couplés l'un à l'autre en rotation au moyen d'engrenages (54, 56) de façon à ce que les roues entraînées (20) des rouleaux de pressage (14, 16) tournent à la même vitesse de rotation.

11. Appareil suivant l'une quelconque des revendications 1 à 10, dans lequel l'un au moins des rouleaux de pressage (14, 16) est monté sur un support réglable en position par rapport au support de l'autre rouleau de pressage (14, 16) de façon à ce que l'ouverture de la zone de pincement (18) par où passe le matériau en bande (4) à convoyer soit ajustable.

12. Appareil selon l'une quelconque des revendications précédentes, dans lequel les roues entraînées (20) d'au moins l'un des rouleaux de pressage (14, 16) sont agencées de façon à présenter une vitesse tangentielle sensiblement égale à la vitesse linéaire de transit de la bande de matériau (4) dans la zone de pincement (18).

Drawing