EP0925911B1 - Device for embossing a foil, use of the device, and method for the operation of the device. - Google Patents

Abstract

A foil web is fed between a pair of rolls, each having the same truncated, square pyramidal toothed surface pattern. Either one or both of the rolls may be driven, and the free relative axial play between the rolls should be at least 0.5-0.75 times the engaging tooth width. The truncation of the teeth should be 5-25% of the theoretical pyramid height.

Description

The present invention relates to a device for Satinizing a film according to the preamble of claim 1 and a method for operating the device according to the preamble of claim 10. Such a device is disclosed in US-A-5 598 774, the movable suspension being a the roller axes allow synchronization of both rollers. The arrangement and design of the teeth is described in nothing is disclosed in this document.

From US-A-5 007 271 a device for satinizing is known a film in which the pyramidal teeth have a square floor plan, with the sides aligned parallel or perpendicular to the roller axes are and in the circumferential direction the teeth of a roller by one half the tooth width compared to the teeth of the other roller are offset. This known satinizing device was Underlying problem, despite the relatively fine Interlocking of the satin rollers both high quality Satination as well as mutual synchronization in particular of the satin rollers in the sense that only one of the rollers is driven and the other roller takes along. It had been shown that the required Conditions are not readily met if both Rollers were similarly provided with hardened teeth to achieve an attractive service life for the rollers.

To meet the requirement of mutual synchronization of the To meet satinizing rollers, the rollers were aligned that the circumferential rows of teeth of the both rollers are in the same plane, which means the teeth in the area of engagement of the rollers against each other, flank to flank lie, which is an inevitable take, so to speak the freely rotating roller by the driven roller is achieved.

The arrangement or mutual alignment mentioned Satinizing rollers have proven their worth as long as satin foils, especially packaging foils, consisted mainly of aluminum. However, recently increasingly films in use or even prescribed, which are mainly made of paper. These slides are much stiffer than aluminum foils, and it has shown that the known satinizing rollers meet the requirements no longer suffice, because the higher proportion of paper leads to that the tendency of the film to settle after satinizing deform, e.g. to curl up, increases rapidly.

GB-A-2 311 949 discloses flexible packaging material to satinize, the rollers arranged in this way are that one tooth of a roller is between four teeth each the other waltz comes to rest, but with the teeth are arranged obliquely to the roller axis and thus by this Helical gear locking of the rollers is necessary.

In addition, a satinizing roller is known from US-A-5 036 758 known, on which the teeth flattened, their edges broken and arranged obliquely to the axis.

It is based on this known prior art Object of the present invention to provide a device that meets the new requirements, d. H. the it allowed to optimally satin any kind of foils, whereby the foil should deform so little after satinizing, that smooth further processing is possible. This The object is solved by the independent claim 1.

The dependent claims describe special features of an embodiment.

The invention also relates to a use of the inventive Apparatus according to claim 9 and a method for operating the device according to claim 10.

The solution according to claim 1 is a combination of partly known measures, which together form a very precise machining without significant deformation per se very problematic foils allowed and not just one stable mutual entrainment and synchronization of the Roll rotation, but also an optimal satin finish guaranteed regardless of the material to be satinized.

Figur 1

ist eine schematische Darstellung der Abwicklung der Verzahnung einer Satinierwalze,

Figuren 2 und 3

zeigen eine Eingriffsstellung der Verzahnungen der Satinierwalzen bei Inbetriebnahme der Vorrichtung,

Figuren 4 und 5

zeigen die stabile Eingriffsstellung der Verzahnungen der Satinierwalzen,

Figur 6

veranschaulicht den Einfluss einer durchgeführten Folie auf die Selbststabilisierung der gegenseitigen Walzenstellung,

Figur 7

zeigt schematisch die erfindungsgemässe stabilisierte gegenseitige Stellung der Walzenverzahnungen, und

Figur 8

ist eine entsprechende Darstellung für eine stabile gegenseitige Walzenstellung.

The invention will now be explained in more detail using a preferred exemplary embodiment.

Figure 1

is a schematic representation of the development of the teeth of a satinizing roller,

Figures 2 and 3

show an engagement position of the teeth of the satinizing rollers when starting the device,

Figures 4 and 5

show the stable engagement position of the teeth of the satinizing rollers,

Figure 6

illustrates the influence of a performed film on the self-stabilization of the mutual roller position,

Figure 7

shows schematically the inventive stabilized mutual position of the roller teeth, and

Figure 8

is a corresponding representation for a stable mutual roller position.

The basic structure of the satin finish is based on referred to above-mentioned U.S. Patent No. 5,007,271. A foil tape is placed between two toothed satin rollers carried out, one of which is permanently stored and is driven while the other rotates freely on one Is mounted and by spring force, pneumatic or otherwise resilient with adjustable pressure against the driven roller can be pressed.

Both satin rollers have the same type Surface serration on, in Figure 1 in development is shown schematically. It is a matter of pyramid-shaped teeth in the circumferential direction or through the direction of rotation indicated in the arrow and in the axial direction are arranged at right angles to it in rows. As mentioned Figure 1 is a schematic representation, d. H. the pyramidal teeth are shown as if they were the precise geometric shape of a pyramid with a sharp tip would have. The teeth were the same with the known one Execution trained.

What is new is that the tooth tips according to FIGS. 2 to 5 are flattened, d. H. the teeth are shortened by one Amount ΔA (Figure 3), in practice this reduction at least 2%, preferably up to 25% of the theoretical geometric tooth height. In addition, the edges the pyramid-shaped or truncated pyramid-shaped teeth broken, which can happen, for example, that after machining the gearing post-processing through general material removal, for example by etching or galvanic removal, such there is an abrasion mainly on the tooth edges he follows.

Another difference from the known version, where the mutual axial position of the satin rollers predetermined was that the rollers with a relative axial play of at least half a tooth pitch, preferably 0.75 times the tooth pitch, mutually are movable so that they are mutually into one can move stable position, as explained becomes.

If the satinizing rollers are first brought together and pressed and driven against each other when the foil tape is put into operation, there is a high probability that the mutual tooth position of the rollers will occur in their engagement area according to FIGS. 2 and 3. Figure 2 shows the mutual tooth position seen in the circumferential direction, Figure 3 shows the mutual tooth position seen in the axial direction. The teeth according to FIG. 3 lie on one another with their flanks, which results in a mutual engagement height E _H1 .

Since the calendering rollers are set in rotation, there is a tendency for mutual axial displacement, and if the mutual support of the teeth of the two rollers on tooth flanks is omitted, the rollers or their teeth penetrate deeper into one another, which results in a lower engagement height E _H2 . This mutual tooth position is shown in FIGS. 4 and 5, FIG. 4 again showing the mutual tooth position in the circumferential direction and FIG. 5 the mutual tooth position in the axial direction. It can be seen that the teeth now mesh with each other so that each tooth lies symmetrically between four teeth of the other roller, i.e. the teeth touch along the tooth edges, and because the tooth edges are broken and the tooth tips are flattened, there is a settling or engagement of the teeth Gears in a deeper, stable engagement position, from which experience has shown that they no longer emerge. The gears are therefore dynamically self-stabilizing in a very specific position. This self-stabilizing effect is supported by the film carried out between the satinizing rollers, as shown in FIG.

When the two embossing rollers mesh into each other Position becomes the medium to be embossed around the structural edges K1, K2 pressed. This creates a paper tension which the forces F1 and F2 on the free-running embossing roller generated. The displacement of this embossing roller is thus eliminated the astable position according to Figure 6 in the stable Position with maximum penetration depth according to Figures 4 and 5 favored. As mentioned, is a significant force required to remove the rollers from their mutual stabilized position of maximum engagement in the axial direction or to shift the circumferential direction of each other. It is with it safe, stable transport of the free-running roller constant mutual tooth position in the respective Area of engagement guaranteed. At the same time it is one optimal satin finish, especially of paper foils guaranteed. At the initial engagement position the teeth could also contact each other in the axial direction Flanks, in which case a relative movement in Circumferential direction for snapping into the stable Intervention position would take place.

Figures 7 and 3 schematically show a comparison of the Embossing process in the position according to the invention (FIG. 7) or conventional tooth position (Figure 8). In the two figures are the tooth tips of a roller with triangles that Tooth tips of the other roller indicated with circles. The dashed lines are the relevant refraction lines, and it turns out that the embossing length at tooth position according to the invention is substantially longer than with conventional tooth position, and the film nerves not only neutral, but also in broken symmetrical diagonal direction.

T1 =

radiale Zahnteilung der ersten Walze

T2 =

radiale Zahnteilung der zweiten Walze

ΔT =

Teilungsdifferenz

T_HT =

theoretische radiale Zahnteilung (Sollteilung)

S_ZF =

Selbstzentrierungsfaktor

E_F =

empirisch ermittelter Faktor = 98, 75

SZF = THT EF    ΔT = T1 - T2   SZF ≥ |ΔT| However, certain minimum conditions must also be met for reliable operation. Thus, the elasticity of the metallized paper in the case of the embossing according to the invention as shown in FIG. 7 can also dynamically compensate for a certain pitch error ΔT of the two embossing rollers by means of its elasticity. This can be expressed in such a way that if the division difference ΔT becomes greater than a certain self-centering factor S _ZF , an embossing according to the invention is no longer possible. In any case, the embossed image changes disadvantageously because self-centering or synchronization is not guaranteed. In the relationships below, mean:

T1 =

radial tooth pitch of the first roller

T2 =

radial tooth pitch of the second roller

ΔT =

Division difference

T _HT =

theoretical radial tooth pitch (target pitch)

S _ZF =

Self centering factor

E _F =

empirically determined factor = 98, 75

S ZF = T HT E F ΔT = T1 - T2 S ZF ≥ | ΔT |

Using a numerical example, this means: T1 = 0.402 T2 = 0.399 T HT = 0.400 ΔT = 0.402 - 0.399 = 0.003 S ZF = 0.400 98.75 = 0.00405 0.00405 ≥ 0.003 which means self-centering is guaranteed. The dimensions above are all given in mm.

The preferred embodiment described above stands out through simplicity, operational safety, long service life the rollers, good satin finish regardless of the film material and simple operation. In this version, the described tooth shape, which the dynamic engagement of the Roll teeth in the stable, preferred mutual Tooth position is beneficial. However, there are also Design variants possible.

The rollers can be of different or the same height Teeth are formed, d. that is, the tooth pitch must naturally match within the limits given above, but the flattening can vary. Preferably at a different tooth height the non-driven, free-running roller with lower teeth, it will worn out a little faster, but can be lighter be replaced as the driven roller.

The rollers can also be used with pre-or Rough orientation, z. B. with a Coarse toothing on the edge of the roller or on the side of the rollers when merging the rollers when starting up intermesh and roughly pre-orient the rollers and so that the correct interlocking and subsequent final transfer of the rollers to the stable position support. The means of orientation must be sufficient Show the free mutual movement of the game Allow rolling to the stable position.

It is also possible to adjust the mutual roller position Locking and reaching the stable engagement position so there is no danger of the rollers jumping over from one to eliminate stable position in another. So could the axial position of the freely rotating roller after the Reaching the stable position by clamping the previously axially movable roller axis, and a backlash-free gear between the two rollers that was previously uncoupled. It would be accordingly finally conceivable that the rollers through from the start backlash-free gears or arrangement are aligned that mutual interference in the sense of the invention is predetermined.

Claims (11)

1. Device for embossing a foil, comprising a pair of rollers having toothings of the same kind and which are connected to a drive and capable of being driven individually or in common, the rollers being capable of being pressed against each other in a resilient manner, characterised in that the pyramidal teeth of the toothing comprise flattened points and a rectangular ground plan disposed in such a manner that the sides are parallel resp. perpendicular to the longitudinal axis of the rollers in order to obtain a self-stabilising operating condition in which the rollers are movable relative to each other and capable of being displaced into mutual positions in which the roller toothings engage in a determined position such that each tooth of each roller is symmetrically enclosed between four teeth of the opposite roller in a stable mutual position.
2. Device according to claim 1, where one roller is capable of being driven while the other one is freely rotatable and capable of being driven by the first one through engagement of the roller toothings, characterised in that the rollers are axially movable relative to each other, the freely rotatable roller being preferably arranged with axial play.
3. Device according to claim 1 or 2, characterised in that in the stable mutual positions, the rollers interpenetrate with maximum penetration depth.
4. Device according to claim 1, characterised in that the edges of the teeth are cut off.
5. Device according to claim 1, characterised in that the amount of flattening is at least 2%, preferably 5 to 25% of the tooth height.
6. Device according to one of claims 1 to 5, characterised in that the rollers comprise teeth of different heights, the freely rotatable roller preferably comprising the lower teeth.
7. Device according to one of claims 1 to 6, characterised in that means for a preliminary mutual orientation of the rollers are provided which engage in each other when the rollers are joined or which act as a gear allowing a certain play between the two rollers.
8. Device according to one of claims 1 to 7, characterised by means allowing to cancel the mutual mobility of said rollers when the determined mutual position of engagement is attained, e.g. by cancelling the mutual axial play or by engaging a gear connected between the rollers.
9. Application of the device according to one of claims 1 to 3 for the embossing of foils which are mainly composed of paper.
10. Method for the operation of the device according to claim 1, whereby in permanent stationary operation, the rollers are operated in a relative position in which each tooth in the contact area of each roller is enclosed at least approximately symmetrically between four teeth of the other roller, and in that at least during start-up, the rollers are set into rotation and brought together in order to obtain a determined, stable mutual position of engagement of the rollers in which they remain in permanent operation.
11. The method of claim 10, characterised in that after having attained the stable position of engagement, the rollers are locked in this mutual position by cancelling their mutual play in the axial and/or in the circumferential direction.

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