Device and method for separating label cores from a film tube

Abstract

Device (1, 21, 31) for separating label tubes (5) from a film tube (3), in particular along transverse tear lines (4), comprising a mandrel (2) for unfolding the film tube (3) from the inside and a conveying means (6) formed in the area of ​​the mandrel (2) for frictionally pulling the film tube (3) over the mandrel (2), characterized in that the conveying means (6) comprises at least one pair of magnetic belts (7, 8) on which an outer working section (7a) running outside the film tube (3) and an inner working section (8a) running inside the film tube (3) are designed to attract each other magnetically in order to carry the film tube (3) between them by means of static friction and / or sliding friction in the longitudinal direction of the mandrel (2).

Description

[0001] The invention relates to a device and a method for separating label tubes from a film tube according to the preambles of claims 1 and 9.

[0002] It is known to supply continuous film tubes for container labeling from a roll as longitudinally folded tubes and to equip them with transverse perforations for singulation in a perforating unit. Label cores can then be torn off during labeling by generating longitudinal tension in the film tube along the transverse perforations. EP 0763498 describes a labeling device in which a transversely perforated film tube is drawn over an internal, floating mandrel and unfolded in the process. For this purpose, transport rollers are provided on the mandrel, which frictionally engage the film tube on its outer surface and thus pull it over the mandrel. By accelerating the film tube in the area of ​​the mandrel, it tears off along the transverse perforations previously created in a perforating unit.For further transport and targeted ejection of the detached label cores from the mandrel, a pair of belts with cam-shaped carriers running in the transport direction is also provided. The latter press the label core into grooves running lengthwise in the mandrel and eject the label core downwards towards a container to be labeled.

[0003] A disadvantage of this method is that the advancement of the film tube and the detached label core is achieved by means of friction wheels and drive lugs, which each act only on a relatively small surface area of ​​the film core and therefore generate comparatively high mechanical loads at specific points. Undesirable consequences of this include longitudinal stretching of the film tube, twisting of the film tube around its longitudinal axis, and tearing of the film tube at vent perforations used for subsequent shrinking and / or at engravings used, for example, for marking with expiration dates or similar information. Perforation and / or marking of labels using a laser beam is known, for example, from US 2003 / 029850, DE 10 2008 030 868, and US 5922422.

[0004] Therefore, especially when separating perforated and / or engraved label tubes from film tubes, there is a need for gentle transport of the film tube over a folding mandrel in order to separate the label tubes from the film tube in a controlled manner along the intended tear lines and to avoid damage to the label tubes in areas of vent perforations, marking engravings or the like.

[0005] The stated problem is solved by a device according to claim 1. This device serves to separate label cores from a film tube, particularly along transverse tear lines. It includes a mandrel for unfolding the film tube from the inside and a conveying element formed in the area of ​​the mandrel for frictionally drawing the film tube over the mandrel. According to the invention, the conveying element comprises at least one pair of magnetic belts, on which an outer working section running outside the film tube and an inner working section running inside the film tube are designed to attract each other magnetically in order to carry the film tube between them in the longitudinal direction of the mandrel by means of static friction and / or sliding friction. The film tube is therefore, by definition, conveyed in the longitudinal direction of the mandrel.

[0006] The magnetic belt pair comprises at least two cooperating magnetic belts according to the invention, each of which is endless and runs around deflection pulleys. Each working strand is thus assigned at least one slack strand. For example, the magnetic belts can run around two deflection pulleys, so that the working strand is assigned one slack strand. Likewise, the magnetic belts can run around three or more deflection pulleys, so that the working strand is then assigned two or more slack strands. The term "magnetic belt pair" is to be understood functionally. That is, outer and / or inner magnetic belts could each consist of several belts or bands running side by side, provided that an outer working strand running outside the film tube, formed by these, interacts with a corresponding working strand running inside.

[0007] The function of the magnetic belt pair according to the invention results from the magnetic attraction between the inner and outer belts, so that the magnetic belts exert a clamping force on the intervening foil tube, which, in the sense of a normal force, generates a frictional force between the foil tube and the inner and outer working sections.

[0008] The generated frictional force can drive the film tube using both static and sliding friction. Sliding friction allows for a smooth start to the driving motion on the film tube. This enables, for example, a controlled increase in the longitudinal tension generated in the film tube with each work cycle until the label core detaches from the trailing film tube along the predetermined tear line. Simultaneously, the large clamping surface between the inner and outer working sections, compared to friction wheels or similar devices, allows for gentle material handling and a more even distribution of the forces acting on the film tube during tearing along the predetermined tear lines. This reduces the risk of the film tube tearing at vent perforations, markings, or similar features.

[0009] Preferably, the outer and inner working sections are deflected at an inlet-side distance from each other and designed to attract magnetically such that they converge freely in a common inlet-side inlet section for the film tube. This means that, at least in the area of ​​inlet-side deflection rollers, a conveying gap for the film tube, narrowing in the transport direction, forms between the inner and outer working sections. Preferably, a corresponding conveying gap, widening in the transport direction, is present at the outlet-side end of both the outer and inner working sections. Between these points, the magnetic attraction ensures that the working sections run essentially parallel to each other. This automatically creates a common central conveying section for the working sections.

[0010] This allows for a comparatively large conveying gap to be formed between the mandrel and the film tube, which closes automatically around the film tube due to the attraction of the magnetic belts in the working area. This facilitates the threading of film tubes of different diameters or with comparatively large dimensional tolerances through the device according to the invention and simultaneously enables reliable conveying and tearing of the label cores.

[0011] Preferably, the device according to the invention further comprises a conveying means formed upstream of the mandrel for the continuous feeding of the film tube at a conveying speed, wherein the feed speed of the outer and / or inner working section can be set to a higher value than the conveying speed. This allows longitudinal tension to be generated in the film tube in the area of ​​the outer and inner working sections in order to tear off the label cores in a controlled manner along the transverse tear lines. Optionally, the detached label cores can be pushed off the mandrel downstream of the magnetic belt pair by means of separate conveying means.The advance speed of the outer and / or inner working section can, for example, be set such that the foil tube gradually entering between the working sections is subjected to an increasingly higher frictional force and thus longitudinal stress by means of sliding friction.

[0012] Preferably, the magnetic belt pair comprises an outer, actively driven belt and an inner, passively running belt, which is supported, in particular, in the mandrel. This enables a structurally simple drive and eliminates the need for actively driven conveying elements in the floating mandrel. The drive is effected, for example, by means of a drive roller or similar located between the outer working run and an idle run. An active drive of the outer belt with a drive roller positioned between two idle runs is particularly advantageous. This especially facilitates a direct drive of drive rollers or similar devices. The term "roller" here refers to any functionally suitable type of wheel, roller, or the like.

[0013] Preferably, the working sections are at least two centimeters long, and in particular at least five centimeters long. This allows for a large contact surface with the foil tube, enabling it to be gently engaged by friction.

[0014] Preferably, the device according to the invention comprises at least two pairs of magnetic belts distributed along the circumference of the mandrel. A configuration with two pairs of magnetic belts running along the mandrel at 180° intervals from each other is particularly advantageous, as is a configuration with three pairs of magnetic belts distributed along the circumference of the mandrel at 120° intervals from each other. This enables particularly gentle conveying and prevents unwanted twisting and / or tearing of the film tube during the singulation of the label cores. In principle, any other number of magnetic belt pairs is also suitable, for example, a single pair of magnetic belts.

[0015] Preferably, the device according to the invention further comprises a perforating unit formed upstream of the mandrel for producing predetermined tear lines in the film tube, in particular by means of laser beam engraving and / or laser beam perforation. Engraving, as defined in the invention, refers to the removal of material on at least one side of the film tube, which runs through the perforating unit in a longitudinally folded state, thereby reducing the thickness of the film tube. In contrast, perforation, as defined in the invention, refers to the formation of through holes and / or slits in the film tube. Engraving and / or perforating with a laser beam is particularly flexible, since different patterns for engraving and / or perforating can be generated by programming and / or input at an operating terminal or the like, in particular without changing tools.Nevertheless, the device according to the invention could also include mechanical perforating works with cutting rollers or the like.

[0016] Preferably, the perforating unit is further configured to create venting perforations and / or marking engravings in the film tube, particularly by means of a laser beam. Venting perforations facilitate the escape of air during the thermal shrinking of the label tubes over tapered container contours.

[0017] The stated problem is also solved by a method according to claim 9. This method serves to separate label cores from a film tube, particularly along transverse tear lines. The film tube is drawn frictionally over an internal mandrel and unfolded in the process. According to the invention, the film tube is frictionally clamped between mutually magnetically attracting working strands of a pair of magnetic belts and drawn longitudinally along the mandrel. A suitable clamping force can thus be generated without additional pressure rollers for the working strands. In particular, the working strands then do not run under tension but rather so loosely that, especially at the inlet end of the working strands, a gap is formed that tapers towards the film tube, allowing the film tube to be fed in by means of magnetic attraction between the working strands.

[0018] Preferably, the working sections move faster in the conveying direction than the film tube entering the mandrel. This allows a longitudinal tension suitable for cutting along the predetermined tear lines to be generated in the film tube.

[0019] Preferably, the working sections generate a longitudinal tension in the film tube by means of sliding friction and / or static friction. The generated longitudinal tension can then be adjusted, for example, by adjusting the feed rate of the outer and / or inner working section to the tensile strength of the film tube and the tear-away strips, as well as to the coefficients of friction acting between the working sections and the film tube.

[0020] Preferably, the generated longitudinal stress is greater than the tensile strength of the film tube under longitudinal tension along the predetermined tear lines defining the label cores. This allows the label cores to be selectively separated from the film tube in the area of ​​the working sections.

[0021] Preferably, the generated longitudinal stress is less than the tensile strength of the film tube under longitudinal tension in the area of ​​a vent perforation and / or marking engraving present in the film tube. This reliably prevents damage to the film tube or the detached label core due to the longitudinal stress required for separation.

[0022] Preferably, the foil tube is perforated and / or engraved using a laser beam while folded lengthwise, particularly on both sides. This allows suitable perforations and / or engravings to be flexibly created on the label sleeves for labeling different containers and / or products, especially also completely.

[0023] Preferably, the working sections for tearing off the label cores are accelerated intermittently in the conveying direction. This means that the working sections are temporarily accelerated to detach the label cores and then decelerated again afterward. Suitable speed profiles for each work cycle can thus be defined for the targeted detachment of the label cores. However, the working sections could also be driven continuously at a constant speed. Intermittent acceleration is particularly advantageous when the label cores are to be detached by means of static friction. A constant feed rate of the working sections, especially in combination with at least some sliding friction, is suitable for continuously increasing the clamping force acting on the film tube.

[0024] Preferably, the film tube is a shrink tube. In particular, the film tube has vent perforations to facilitate the escape of air when the film tube is shrunk onto inwardly curved container contours.

[0025] Preferred embodiments of the invention are shown in the drawing. They show: Fig. 1 a schematic longitudinal section through a first preferred embodiment; Fig. 2 a schematic cross-section through a second preferred embodiment; Fig. 3 a schematic side view of a third embodiment; and Fig. 4A - 4F schematic representations of exemplary perforations or engravings in a foil tube.

[0026] As the Fig. As can be seen from Figure 1, the device according to the invention, in a first embodiment 1, comprises an inner mandrel 2, which is mounted in a known manner to float, for unfolding a film tube 3, preferably fed continuously from a roll (not shown). The film tube 3 has predetermined tear lines 4 for singulation, i.e., for separating label cores 5 along the predetermined tear lines 4. For this purpose, conveying means 6 are provided on both sides of the mandrel 2. The conveying means 6 serve to frictionally engage the film tube 3 and thereby generate a longitudinal tension 3a in the film tube 3 running over the mandrel 2, so that the leading section of the label tube 3, carried along by the conveying means 6, tears off along the predetermined tear lines 4 and can be provided as a singulated label core 5.

[0027] According to the invention, the conveying means 6 each comprise a pair of magnetic belts 7, 8 with an outer belt 7 running outside the film tube 3 and an inner belt 8 running inside the film tube 3. The outer and inner belts 7, 8 are each designed to attract each other magnetically such that the film tube 3 is frictionally clamped between corresponding outer and inner working sections 7a, 8a. The outer and inner belts 7, 8 are each endless and each comprise at least one slack section 7b, 7c, 8b.

[0028] For the drive and deflection of the outer and inner belts 7, 8, motor-driven drive rollers 9 and passively rotating deflection rollers 10 are schematically indicated. Preferably, the outer belts 7 are motor-driven and the inner belts 8 are passively rotating. For this purpose, the inner belts 8 run freely around deflection rollers 10 in the floating mandrel 2. The drive rollers 9 can be located between the outer working runs 7a and outer idle runs 7b or, preferably, between two idle runs 7b, 7c. To illustrate this, the following are shown in the Fig. 1 Both variants are shown schematically as examples. A drive roller 9 located between two empty runs 7b, 7c is particularly suitable for direct drive by means of a schematically indicated electric motor 9a, which is, for example, a servo motor.

[0029] As the Fig. As can be further seen in Figure 1, the outer and inner belts 7, 8 are deflected at a distance 11 from each other at the entrance to the respective working sections 7a, 8a. In conjunction with the magnetic attraction between the working sections 7a, 8a, this automatically forms an inlet-side inlet section 12, in which the working sections 7a, 8a run towards each other, defining a tapered conveying gap 13. This is followed by a conveying section 14, in which the working sections 7a, 8a clamp the intervening foil tube 3 directly and over a flat area and consequently run essentially parallel to each other.

[0030] The magnetically generated clamping force causes the working sections 7a, 8a to frictionally engage the film tube 3. The tapered conveying gap 13 facilitates the threading of the film tube 3 and allows for a relatively large clearance between the film tube 3 and the mandrel 2. For this purpose, the working sections 7a, 8a are not under tension between the deflecting rollers 10 and / or drive rollers 9 that define them, but are guided so loosely that the inlet-side inlet section 12 can form. Preferably, but not necessarily, a corresponding discharge section is provided at the outlet-side end of the working sections 7a, 8a, in which the distance between the working sections 7a, 8a increases again in the conveying direction 15.

[0031] The outer and inner belts 7, 8 can be equipped with a suitable coating to drive the film tube in the conveying direction 15 by means of sliding friction and / or static friction. For this purpose, the feed speed 16 of the working sections 7a, 8a is higher than the speed 17 of the film tube 3 upstream of the conveying means 6. The feed speed of the working sections 7a, 8a is essentially determined by the outer belt 7 and the speed of the associated drive roller 9. The electric motor 9a can be used, for example, to set a constant feed speed 16 or to create intermittent fluctuations in the feed speed 16 for each cutting operation. The singulation of the label cores 5 could, for example, be facilitated by selectively accelerating the outer working section 7a. This would then be decelerated again after the intended tear line 4 has been cut.Such pulse-defined speed profiles of the propulsion speed 16 could be variably adjusted by programming and / or input at an operating terminal or the like (not shown).

[0032] According to the invention, the frictional force required for the frictional engagement of the film tube 3 is generated by the normal force resulting from the magnetic attraction between the outer and inner working sections 7a, 8a, acting as a clamping force. In particular, pressure rollers are unnecessary in the area of ​​the working sections 7a, 8a to generate the frictional force. The working sections 7a, 8a thus preferably run freely between the deflecting rollers 10 and / or drive rollers 9 that define them.

[0033] The magnetic attraction is generated, for example, by means of suitably polarized permanent magnets integrated into the outer and inner belts 7, 8. Magnetizable materials could also be used in the outer and inner belts 7, 8. Temporary magnetization of the outer and inner belts 7, 8 on-site using electromagnets (not shown) or similar devices is also conceivable. The belts 7, 8 can have an elastically deformable conveying surface to reliably create the largest possible contact area with the film tube 3.

[0034] The following are schematically indicated in the Fig. 1. Venting perforations 18 and a marking engraving 19, which serves, for example, to indicate an expiration date on a container 20. According to the invention, the magnetic belt pairs consisting of the outer belt 7 and the inner belt 8 enable the targeted separation of label sleeves 5 along the intended tear lines 4 from the film tube 3, avoiding unwanted damage to the label sleeves 5 in areas with a deliberate weakening of the material, such as at venting perforations 18 and / or at marking engravings 19.

[0035] The Fig. Figure 2 schematically shows a second preferred embodiment 21, which differs from the first embodiment 1 essentially only in that three pairs of magnetic belts 7, 8 are distributed along the circumference of the mandrel 2. Fig. 2 is the overall distribution of the magnetic belt pairs 7, 8 evenly spaced at intervals of 120 degrees, in the example of the Fig. 1 with two pairs of magnetic belts 7, 8 evenly spaced at intervals of 180 degrees. Such a uniform distribution of the magnetic belt pairs 7, 8 is advantageous for conveying the film tube 3 while maintaining its rotational orientation, but is not absolutely necessary.

[0036] As in the Fig. As further indicated in Figure 2, individual belts could be segmented longitudinally. This is schematically illustrated for the outer belts 7 with a left belt 7L and a right belt 7R. This is merely intended to clarify that, according to the invention, a pair of magnetic belts refers to the functional interaction of a magnetic belt 7 running outside the foil tube 3 with a magnetic belt 8 running inside the foil tube 3, regardless of how many individual belts or bands the inner and outer belts 7, 8 each consist of.

[0037] The Fig. Figure 3 schematically illustrates a third embodiment 31 with the longitudinally folded film tube 3, transported as a flat film web, which is preferably perforated and / or engraved on both sides upstream of the mandrel 2 by means of a perforating unit 32. For this purpose, at least one laser 33 is provided, for example, which removes the material of the film tube 3 penetratingly in the sense of perforation and / or non-penetratingly in the sense of engraving.

[0038] The conveying speed 17 of the film tube 3 upstream of the mandrel 2 is determined, for example, by conveying means 34, such as drive rollers and / or deflection rollers. Downstream of the conveying means 6 according to the invention, further conveying means 35 can be provided to transfer the detached label sleeves 5 selectively to containers 20 to be labeled, such as beverage bottles or the like. For this purpose, further transfer means, such as grippers or the like, can be used in a known manner.

[0039] The Fig. Figure 3 further indicates that, in addition to the venting perforations 18 and / or the marking engravings 19, tear-off perforations 36 may optionally be present, which, for example, serve as a locking mechanism for a container 20 after the label sleeves 5 have been shrunk on. According to the invention, the frictional engagement of the label tube 3 allows the label sleeves 5 to detach from the label tube 3 in a controlled manner along the intended tear lines 4, but not along the tear-off perforation 36, which is provided for the subsequent use of the labeled container 20.

[0040] Crucially, the film tube 3 must be engaged in frictional engagement within the conveying section 13 of the working sections 7a, 8a, whereby the tensile forces during this frictional engagement are evenly distributed across the contact surfaces between the working sections 7a, 8a and the film tube 3. This allows the label sleeves 5 to be separated precisely along the transverse tear lines 4, preventing damage to the label sleeves 5 in areas with other functional perforations and / or engravings, which are exemplified in the Fig. 4A to 4F are shown.

[0041] This shows the Fig. 4A a predetermined tear line 4 consisting of continuous slots running in the transverse direction. Fig. Figure 4B shows a venting perforation 18 that allows air to escape when the label sleeves 5 are shrunk onto tapered container areas. Fig. Figure 4C shows a slit-like engraving 37, in which material is removed from the surface of at least one side of the foil tube 3, for example, to be used as a variant for a locking mechanism or the like. Fig. Figure 4D illustrates the engraving of an expiration date or similar on one side of the foil tube 3 using a laser beam, in the sense of marking engraving 19. Fig. Figure 4E illustrates a first variant of a tear-off tab 38 produced by means of perforation and / or engraving, which Fig. 4F a second variant of a tear-off tab produced by means of perforation 39.

[0042] For perforating / engraving the foil tube 3, lasers 33 are preferably used on both sides of the foil tube 3. The laser beam patterns for the perforations / engravings to be produced can be generated, for example, by programmed deflection of laser beams 33a and / or by partial blocking (not shown). Alternatively, perforations / engravings could also be produced mechanically using suitable needles, cutters, or the like.

[0043] The film tube 3 is preferably a shrink tube, but could also be designed as a highly elastic film tube which is temporarily stretched for labeling and adheres to containers after being transferred due to its elasticity.

[0044] The film tube 3 is preferably fed continuously in the sense of an endless web from a roll or the like, for example via a buffer device with dancer rollers, and unfolded over the mandrel 2 at a predetermined conveying speed 17. The faster-running working strands 7a, 8a of the at least one pair of magnetic belts 7, 8 according to the invention engage the film tube 3 with friction such that it tears along predetermined tear lines 4 and the resulting individual sections of the label tube 3 can be used as label cores 5 for subsequent labeling of a continuously supplied stream from containers 20.

[0045] The embodiments described above can be combined in any technically sensible way.

Claims

[1] Device (1, 21, 31) for separating label tubes (5) from a film tube (3), in particular along transverse tear lines (4), comprising a mandrel (2) for unfolding the film tube (3) from the inside and a conveying means (6) formed in the area of ​​the mandrel (2) for frictionally pulling the film tube (3) over the mandrel (2), characterized by , that the conveying means (6) comprises at least one pair of magnetic belts (7, 8) on which an outer working section (7a) running outside the film tube (3) and an inner working section (8a) running inside the film tube (3) are designed to attract each other magnetically in order to carry the film tube (3) in the longitudinal direction of the mandrel (2) by means of static friction and / or sliding friction. [2] Device according to claim 1, wherein the outer and inner working sections (7a, 8a) are deflected at an inlet-side distance (11) to each other and are designed to be magnetically attractive in such a way that a common inlet-side, tapered inlet section (12) for introducing the foil tube (3) between the working sections (7a, 8a) is formed on the outer and inner working sections (7a, 8a). [3] Device according to claim 1 or 2, further comprising a conveying means (34) formed upstream of the mandrel (2) for the particularly continuous conveying of the film tube (3) at a conveying speed (17), wherein a propulsion speed (16) of the outer and / or inner working section (7a, 8a) can be set to a higher value than the conveying speed (17). [4] Device according to one of the preceding claims, wherein the pair of magnetic belts (7, 8) comprises an outer actively driven belt (7) and an inner passively rotating belt (8) which is in particular mounted in the mandrel (2). [5] Device according to at least one of the preceding claims, wherein the working sections (7a, 8a) are at least 2 cm, in particular at least 5 cm long. [6] Device according to at least one of the preceding claims, comprising at least two pairs of magnetic belts (7, 8) distributed along the circumference of the mandrel (2). [7] Device according to at least one of the preceding claims, further comprising a perforating unit (32) formed upstream of the mandrel (2) for producing predetermined tear lines (4) in the foil tube (3), in particular by means of laser beam engraving and / or laser beam perforation. [8] Device according to claim 7, wherein the perforating unit (32) is further configured to produce venting perforations (18) and / or marking engravings (19) in the foil tube (3), in particular by means of a laser beam (33a). [9] Method for separating label tubes (5), in particular along transverse tear lines (4), from a film tube (3) which is frictionally pulled against an internal mandrel (2) and thereby unfolded, characterized by , that the foil tube (3) is frictionally clamped between the magnetically attracting working strands (7a, 8a) of a pair of magnetic belts (7, 8) and pulled in the longitudinal direction of the mandrel (2). [10] Method according to claim 9, wherein the working sections (7a, 8a) move faster in the conveying direction (15) than the film tube (3) arriving at the mandrel (2) and the working sections (7a, 8a) generate a longitudinal stress (3a) in the film tube (3) by means of static friction and / or sliding friction. [11] Method according to claim 10, wherein the generated longitudinal stress (3a) is greater than the load-bearing capacity of the film tube (3) by longitudinal tension along the tear lines (4) limiting the label sleeves (5). [12] Method according to claim 10 or 11, wherein the generated longitudinal stress (3a) is less than the load-bearing capacity of the film tube (3) by longitudinal tension in the area of ​​a venting perforation (18) and / or marking engraving (19) present in the film tube (3). [13] Method according to at least one of claims 9 to 12, wherein the foil tube (3) is perforated and / or engraved in a longitudinally folded state by means of a laser beam, in particular on both sides. [14] Method according to at least one of claims 9 to 13, wherein the working sections (7a, 8a) for tearing off the label sleeves (5) are accelerated intermittently in the conveying direction (15). [15] Method according to at least one of claims 9 to 14, wherein the film tube (3) is a shrink tube.

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