DE202020102277U1 - Folding roller with coating - Google Patents

Abstract

Folding roller (1) for folding signatures in a folding device (10), wherein the folding roller (1) comprises a cylindrical folding roller body (3) with a lateral surface, the lateral surface at least partially having an elastic coating (5), characterized in that the elastic coating (5) is compressible.

Description

The invention relates to a folding roller for folding signatures in a folding device, the folding roller comprising a cylindrical folding roller body with a jacket surface, the jacket surface having at least partially an elastic coating.

Furthermore, the invention relates to a folding device for forming a fold on a signature to be folded, wherein in the folding device a signature to be folded is pressed by means of a folding knife into an incoming nip of an oppositely rotating pair of folding rollers to form a fold.

For forming folds on printed or unprinted signatures in, for example, offset, gravure or inkjet printing machines, numerous folding devices such as knife folding devices or knife folding devices are known from the prior art. Such folding devices can either be integrated into a printing machine, or they are used to fold the signatures outside the printing machine.

Here, the folding principle is essentially comparable with many folding units that work with folding rollers arranged in pairs. In pocket folding units, the leading edge of the signature essentially runs against a stop until the signature accumulates and the resulting bulge is captured by a roller gap and conveyed through the pair of folding rollers to form a fold across the transport direction of the signature.

So-called knife folding or knife folding devices usually consist of a folding table with a recess on which the sheet to be folded comes to rest. To form the fold, the sheet is pressed by a folding knife through the recess in the folding table into the inlet gap of two counter-rotating folding rollers. The folding rollers grasp the sheet with their outer surfaces and convey it into a strip line, forming a fold which runs parallel to the axis of rotation of the folding rollers. This ribbon line usually consists of several conveyor belts arranged next to one another at a certain distance, which either loop around at least one folding roller or are designed independently of the folding rollers.

Folding rollers used in folding devices of this type are also known from the prior art. So reveals the DE 38 36 342 A1 a so-called clocked folding roller which, for example, does not have a continuous cylindrical outer surface. In the DE 103 04 534 A1 a folding roller is disclosed which has a friction layer on certain parts of the surface.

The folding rollers known from the prior art have a more or less grippy outer surface in order to capture the signature and transport it through the nip, although the outer surface of the folding rollers is usually relatively hard.

However, such hard outer surfaces of folding rollers have the disadvantage that the roller gap must be adapted both to the thickness of the substrate of the signature and to the number of pages, the thickness of the signature to be folded, etc.

Such setting processes are mostly carried out manually, require appropriate experience on the part of the operating personnel and, in addition to the additional expenditure of time, represent an additional source of errors. If the roller gap is set too narrow, the signature to be folded can either no longer be conveyed by the counter-rotating pair of folding rollers and causes a stop or the folded product is squashed too much and thus damaged. A roller gap that is set too wide between the folding rollers, on the other hand, can also lead to a stopper or an improperly executed fold.

In addition, it should be noted that due to fluctuating substrate thicknesses during continuous printing or during production, the roller gap may also have to be adjusted during ongoing production, which increases the risk of stoppers and / or additional waste.

Furthermore, especially in the case of relatively thick and / or signatures to be folded that already have at least one fold, the folding rollers known from the prior art do not necessarily have to be set parallel to one another; have a suitable angle to each other.

The invention is therefore based on the object of creating a solution with which both different and / or differently thick folded products can be produced without changing the roller gap between the pair of folding rollers with constant folding quality and thus also an adjustment of the roller gap during the production run or the ongoing Production is not required.

This object is achieved by a folding roller according to claim 1. The inventive Device comprises a folding roller in which the elastic coating is compressible.

Furthermore, the device according to the invention comprises a folding device in which at least one roller of the counter-rotating pair of folding rollers is designed as a folding roller with an elastic and compressible coating.

Such designs, based on a folding roller with an elastic and compressible coating, have the advantage that the elastic and simultaneously compressible coating adapts the effective roller gap to the respective printed product regardless of its substrate thickness and / or number of pages, so that the distance between the folding rollers to each other and thus the roller gap does not have to be changed or does not necessarily have to be changed both before a new production and during a production.

However, should a change in the roller gap be necessary due to the production of signatures to be folded of very different thicknesses, for example due to greatly varying page numbers and / or greatly varying substrate thicknesses, the roller gap can be set within a large tolerance range and is therefore much less critical because changes in the signature thickness can be compensated to a large extent by the elastic and compressible coating of at least one folding roller.

Furthermore, due to the compressibility of the coating, fluctuations in thickness within the signature, usually caused by already existing folds of the signature to be re-folded, can be compensated, thereby avoiding, for example, setting a suitable angle between the axes of rotation of the folding rollers.

The compressibility of the coating is essential here, since it prevents the formation of a bead on the roll gap in comparison to purely elastic and thus incompressible coatings. Such bulges make it difficult or prevent the signature from being captured by the nip and drawn securely into the nip. In addition, with a purely elastic and thus incompressible coating, the formation of a bead results in a non-uniform speed profile within the nip, which causes damage to the signature to be folded or - in the case of multiple-layered signatures to be folded - the individual layers can be shifted relative to one another, which leads to an unsatisfactory result overall Product quality leads.

According to an advantageous embodiment of the invention, the coating consists of foamed polyurethane. Polyurethane has a very high fatigue strength and wear resistance and thus ensures a long service life of the coating.

In a further advantageous embodiment of the invention, the coating consists of microcellular polyurethane, since this has even higher strength and damping properties.

• 1 einen grundsätzlichen Aufbau einer beschichteten Falzwalze
• 2 eine Falzwalze umfassend eine Mehrzahl von schalenförmigen Segmenten
• 3 eine Falzeinrichtung mit Falzmesser und Bandleitung unterhalb der Falzwalzen
• 4 eine Falzeinrichtung mit Falzmesser und eine die Falzwalzen umschlingende Bandleitung

Preferred developments of the invention emerge from the subclaims and the following description. Various exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being restricted thereto. It shows:

• 1 a basic structure of a coated folding roller
• 2 a folding roller comprising a plurality of cup-shaped segments
• 3 a folding device with folding knife and ribbon cable below the folding rollers
• 4th a folding device with folding knife and a tape line wrapping around the folding rollers

The present invention relates to a folding roller for folding signatures in a folding device, the folding roller comprising a cylindrical folding roller body with a jacket surface, the jacket surface having at least partially an elastic coating.

The basic structure of such a folding roller 1 is in 1 pictured. A folding roller 1 rotates around an axis of rotation 2 and comprises a substantially cylindrical folding roller body 3 , which has a lateral surface through which the signature to be folded is detected and also forms the fold to be generated. The folding roller also includes 1 usually a roll neck at both ends 4th on which the in 1 bearings, not shown, are attached. These bearings are usually seated in folding roller levers, not shown, so that each folding roller 1 around its axis of rotation 2 is rotatably mounted, so that the distance between the folding rollers 1 of the pair of folding rollers 14th can be changed. On the outer surface of the folding roller body 3 is at least partially an elastic coating 5 applied, the elastic coating 5 is compressible.

The outer surface of the folding roller body 3 can, as for example in 1 shown, completely a coating 5 exhibit. However, it is also possible that the axis of rotation extends axially in certain areas 2 no Coating 5 is attached to the outer surface, so that, for example, the in 4th shown ribbon line 16 in these uncoated areas directly on the folding roller body 3 be able to walk.

However, it is also possible that the coating 5 only in certain areas in the circumferential direction on the lateral surface of the folding roller body 3 is applied, for example only in the areas in the circumferential direction comparable to clocked folding rollers 1 with which the signature to be folded is captured from the outer surface and folded away.

The elastic, compressible coating 5 the outer surface of the folding roller body 3 consists in an advantageous embodiment of the invention of foamed polyurethane or of microcellular polyurethane. As an elastic polymer, polyurethane is suitable for such areas of application due to its high strength and resistance, thanks to the design of the coating 5 as foamed or microcellular polyurethane is the compressibility of the coating 5 to avoid bulging in the roll gap 15th ensured.

2 shows an alternative embodiment of a folding roller according to the invention 1 . In this configuration, the folding roller body is 3 no rigid and immutable part of the folding roller 1 as in 1 shown, rather includes in the in 2 illustrated folding roller 1 the folding roller body 3 a plurality of cup-shaped segments which can be joined together 6th , wherein on at least part of the through the bowl-shaped segments 6th formed outer surface an elastic and compressible coating 5 is appropriate.

The in 2 The example shown consists of the folding roller body 3 from two half-shell-shaped segments 6th , which extends over the entire length of the folding roller body 3 extend and by means of for example designed as screws duck 8 to each other and to the shaft 7th the folding roller 1 be clamped. Although not in 2 shown, it is also possible in the axial extent of the folding roller body 3 a plurality of bowl-shaped segments 6th to be arranged side by side. It is also basically possible in the circumferential direction of the folding roller body 3 more than two segments 6th to arrange.

Due to the design of the folding roller body 3 as a plurality of segments that can be joined together 6th it is thus possible at least partially with the coating 5 coated segments 6th and thus the coating 5 Replace when worn without the folding roller 1 as a whole and thus the roll neck 4th must be dismantled from the storage, not shown.

The in 1 and 2 illustrated folding rollers 1 exhibits the coating 5 a thickness in radial extension of 3 millimeters to about 30 millimeters. In a particularly preferred embodiment, the coating 5 a thickness in radial extension of about 10 millimeters to about 20 millimeters.

The coating 5 furthermore consists of an elastic, compressible material with a Shore hardness of approximately 20 Shore D to approximately 80 Shore D, the hardness of the coating in a particularly advantageous embodiment 5 is preferably in a range from about 40 Shore D to about 70 Shore D.

3 shows a folder 10 , in which, for example, the folding roller according to the invention 1 is used, and with which a fold can be formed on a signature to be folded, not shown.

The signature to be folded is usually placed on the folding table 13 in the direction perpendicular to the plane of the drawing in the folding device 10 transported and is braked at least by a sheet stop, not shown, and thus in a defined position on the folding table 13 positioned.

The folding device 10 further comprises a pair of folding rollers 14th of counter-rotating rollers, with at least one roller of the counter-rotating pair of folding rollers 14th as a folding roller according to the invention 1 is trained. In an advantageous embodiment, both rollers are the pair of folding rollers 14th as a folding roller according to the invention 1 with an elastic and compressible coating 5 executed. If only one roller of the pair of folding rollers 14th as a folding roller according to the invention 1 is executed, the other roller is with a hard folding roller body 3 executed.

The two counter-rotating rollers of the pair of folding rollers 14th form a nip 15th in which the signature to be folded is drawn in due to the direction of rotation.

The folding device 10 further comprises a folding knife 11 which at least at the time when the folding knife 11 the signature to be folded into the nip 15th pushes, a direction of movement 12 essentially perpendicular to the through the folding table 13 the spanned plane. The folding knife 11 can either be designed as a rocker, arranged in a rotating folding drum, or driven by other mechanisms such as a crank drive.

By pressing the signature to be folded into the nip 15th becomes the signature of the pair of folding rollers 14th recorded and for training or with the formation of a fold through the nip 15th drawn.

The one through the pair of folding rollers 14th The folded signature is determined by the direction of rotation of the pair of folding rollers 14th transported on and into a ribbon line 16 routed so that the signature by means of the tape line 16 in transport direction 17th from the folder 10 to be led.

3 shows a folding device 10 , in which the tape line used to hold the folded signature 16 below the counter-rotating pair of folding rollers 14th is arranged.

4th shows a folder 10 which is essentially identical to the one in 3 folding device shown 10 is. The difference between the in 3 and the in 4th shown folding device 10 is that the in 4th shown folding device 10 a band line 16 includes, in which the ribbon line 16 both rollers of the pair of folding rollers 14th partially wrapped around it, so that the signature to be folded is captured through the nip 15th directly into the band line 16 to be led.

At the points where the tape line 16 the folding rollers 1 wraps around the compressible coating 5 either have a groove, or there is no coating on these areas 5 on the outer surface of the folding roller body 3 upset.

Although not shown in the figures, a combination of those shown in FIGS 3 and 4th Variants shown are possible, so that a first roller of the pair of folding rollers 14th at least partially from a ribbon line 16 is wrapped around while the other part of the ribbon line 16 below the second roller of the pair of folding rollers 14th is arranged. It is irrelevant here whether the first roller and / or the second roller of the pair of folding rollers 14th as a folding roller according to the invention 1 with elastic, compressible coating 5 is executed.

5 shows a detailed view of a pair of folding rollers 14th out 3 or 4th . The in 5 illustrated pair of folding rollers 14th can either only one of the two rollers or both rollers of the pair of folding rollers 14th as a folding roller according to the invention 1 with elastic and compressible coating 5 be executed. In a preferred embodiment, both rollers are the pair of folding rollers 14th as a folding roller according to the invention 1 with elastic and compressible coating 5 executed.

How out 3 and 4th As can be seen, the two rollers of the pair of folding rollers rotate during operation 14th opposite to each other, for the sake of clarity, however, the arrows of the rotary movements are not in 5 shown.

The first roller of the pair of folding rollers 14th has a first roller radius r1 in the normal state not under compressive stress. The second roller of the pair of folding rollers also has 14th in the normal state not under compressive stress, a second roller radius r2. The first roller diameter d1 of the first roller is twice the first roller radius r1, the second roller diameter d2 of the second roller is twice the second roller radius r2.

With folding roller pairs known from the prior art 14th with a relatively hard outer surface of the folding roller body 3 With a setting that is suitable for production in order to avoid stoppers or product damage such as pinch folds etc., a gap remains between the first and the second roller of the pair of folding rollers 14th so that with folding roller pairs known from the prior art 14th the distance between the two axes of rotation 2 is greater than the sum of the first roller radius r1 and the second roller radius r2.

Due to the elastic and compressible coating according to the invention 5 at least one folding roller 1 of the pair of folding rollers 14th however, it is also possible to use the two rollers of the pair of folding rollers 14th to adjust to each other in the form that the center distance a , that is, the distance between the two axes of rotation 2 of the two rollers of the pair of folding rollers 14th , is equal to or smaller than the sum of the first roller radius r1 and the second roller radius r2 and is thus equal to or smaller than the sum of the roller radii r1, r2.

In 5 a setting is shown in which the center distance a is smaller than the sum of the roller radii r1, r2, so that the surface lines overlap in the drawing. Of course, this overlap does not occur in reality; rather, the lateral surface of the at least one elastic and compressible coating is flattened 5 in the contact zone. Rather, this representation is intended to make clear that the center distance a can also be smaller than the sum of the roll radii r1, r2.

With such an adjustment, a nip is thus created 15th in which a signature to be folded is always drawn in, which means a high level of operational reliability. Signatures of different thicknesses to be folded can be caused by the compressibility of the coating 5 be balanced.

The center distance a of the pair of folding rollers 14th can be set in a particularly preferred embodiment in such a way that the center distance a by about 0.1 millimeter to about 5 millimeters smaller than the sum of the roller radii r1, r2. With this setting there is a constant pressure between the rollers of the folding roller pair 14th ensured, without driving too high a pressure and thus to be able to capture and fold signatures to be folded with a smaller or larger thickness.

Regardless of whether the center distance a is equal to or smaller than the sum of the roll radii r1, r2, due to the compressibility of the coating 5 a folding roller according to the invention 1 the center distance a be kept constant with a changing signature thickness. This applies, on the one hand, to setup processes that are no longer required when there is a change in production and, on the other hand, to changes to the folding roller setting that are no longer required during production.

List of reference symbols

1

Folding roller

2

Axis of rotation

3

Folding roller body

4th

Roll neck

5

Coating

6th

segment

7th

wave

8th

Connecting element

10

Folding device

11

Folding knife

12

Direction of movement

13

Folding table

14th

Pair of folding rollers

15th

Nip

16

Band management

17th

Transport direction

a

Center distance

d

Roll diameter

r

Roll radius

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 3836342 A1 [0006]
• DE 10304534 A1 [0006]

Claims (13)

Folding roller (1) for folding signatures in a folding device (10), wherein the folding roller (1) comprises a cylindrical folding roller body (3) with a lateral surface, the lateral surface at least partially having an elastic coating (5), characterized in that the elastic coating (5) is compressible. Folding roller (1) Claim 1 , characterized in that the coating (5) consists of foamed polyurethane. Folding roller (1) Claim 1 , characterized in that the coating (5) consists of microcellular polyurethane. Folding roller (1) one of the Claims 1 to 3 , characterized in that the folding roller body (3) comprises a plurality of cup-shaped segments (6) which can be joined to one another. Folding roller (1) after one of the Claims 1 to 4th , characterized in that the coating (5) has a thickness of 3 mm to 30 mm. Folding roller (1) Claim 5 , characterized in that the coating (5) has a thickness of 10 mm to 20 mm. Folding roller (1) after one of the Claims 1 to 6th , characterized in that the coating (5) has a hardness of 20 to 80 Shore D, in a particularly advantageous embodiment of 40 to 70 Shore D. Folding device (10) for forming a fold on a signature to be folded, with the folding device (10) pressing a signature to be folded by means of a folding knife (11) into an incoming roller gap (15) of an oppositely rotating pair of folding rollers (14) to form a fold is, characterized in that at least one roller of the counter-rotating pair of folding rollers (14) as a folding roller (1) according to one of the Claims 1 to 7th is executed. Folding device (10) Claim 8 , characterized in that at least one tape line (16) serving to receive the folded signature is arranged below the counter-rotating pair of folding rollers (14). Folding device (10) Claim 8 , characterized in that at least one tape line (16) serving to receive the folded signature wraps around at least one folding roller (1) of the pair of folding rollers (14). Folding device (10) according to one of the Claims 8 to 10 , characterized in that the center distance a between the two rollers of the pair of folding rollers (14) is equal to or smaller than the sum of the roller radii r1, r2. Folding device (10) Claim 11 , characterized in that the center distance a is 0.1 to 5 mm smaller than the sum of the roller radii r1, r2. Folding device (10) according to one of the Claims 10 to 12 , characterized in that the center distance a is constant with changing signature thicknesses.

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