The invention relates to a method for producing packs according to the preamble of claim 1. The invention also relates to an apparatus for implementing the method.
In the case of high-performance packaging machines, in particular for producing cigarette packs, the gluing of pack parts, for example of folding flaps which are to be bonded together, poses a particular technical problem. The joint use of two types of glue, namely cold glue, on the one hand, and hot glue (hot melt), on the other hand, for bonding side flaps for forming side walls of a (cigarette) pack of the hinge-lid-box type is known. In the prior art, the different regions or spots of glue are applied to the inside of outer folding flaps or side flaps in a common glue station using glue nozzles assigned to the different types of glue (EP 1 454 829).
The invention deals with the improvement of performance, quality and reliability of the production of packs, in particular (cigarette) packs of the hinge-lid-box type. The object on which the invention is based consists in improving the durability of the packs in the region of glue bonds and of improving the precise dimensional stability and the performance of the packaging machine.
In order to achieve this object, the method according to the invention is characterized in that, in dependence on the operating state of the packaging machine, in particular in dependence on the operating speed and/or cycle speed, alternatively just one type of glue is processed, or both types of glue are processed, for bonding the same folding flaps.
The invention is based on the use of at lest two types of glue with different reaction behaviors, in particular cold glue, on the one hand, and hot glue, on the other hand.
Furthermore, the invention is based on the finding that the glue used or the quickest-curing glue, in the case of a number of types of glue being used for the same glue bond, may result in a solid, stable glue bond only upon completion of an operation which follows the gluing and folding and in which the pack undergoes precise shaping and dimensional stabilization.
It is thus the case according to the invention that, during a phase of relatively low output or cycle speed of the packaging machine, use is made exclusively of glue with a relatively long curing time, in particular cold glue. This prevents the situation where, as a result of premature curing of the glue, the pack is dimensionally stable prior to completion of precise shaping in the region of a shaping subassembly and/or in the region of a shaping turret. It is only when a higher operating speed/cycle speed, which can be derived from the curing behavior of hot glue, is reached that use is made, according to the invention, of both types of glue. The time window which is critical for the types of glue used can be determined from the point in time at which the glue is applied to the pack or blank, on the one hand, and that at which the pack is shaped in the region of the shaping subassembly or shaping turret, on the other hand.
A separate theme addressed by the invention is that of the residence time of the packs in the shaping subassembly, preferably in shaping pockets of a revolving shaping or drying turret. This residence time can be established according to the invention such that, following and/or during shaping, the packs remain in the shaping subassembly at least until at least one of the types of glue processed has cured on a permanent basis.
Another special feature consists in the fact that the packs, which are transported preferably along a rectilinear pack path and are folded at least partially during transportation, are transferred to a shaping and aligning station following the pack path. This station has mechanisms which grip the pack, preferably on all sides, and give it its precise (cuboidal) configuration. The shaping of the packs preferably takes place in the region of a transfer turret which transfers the packs to a drying turret following partial rotation. This drying turret transports the packs along part of its circumference, the precise pack shape being maintained in the process, until the packs are transferred to a removal conveyor. When the packs leave the drying turret, at least one type of glue on the glued-together folding flaps or other pack parts has (fully) set or cured, and therefore the packs are dimensionally stable. In respect of the number of cooperating pockets, the shaping turret may be dimensioned such that, when the packs are pushed out, merely one glue bond or type of glue is fixed, and one or more further glue bonds have not yet fully cured.
It is an innovation of the apparatus that the (cigarette) packs of the hinge-lid-box type can be transported along an in particular rectilinear pack path with a plurality of, in particular two, successive glue stations with glue subassemblies arranged in the region thereof. The first glue subassembly serves for applying cold glue. The following glue subassembly, as seen in the conveying direction, serves for feeding hot glue. Glue nozzles are directed horizontally such that portions of glue, in particular spots of glue, are transferred in an upright plane, in accordance with a particular pattern, onto folding flaps, preferably onto inner side flaps of the side walls of a pack, these side walls comprising inner and outer side flaps.
Further (special) features of the invention will be explained in more detail hereinbelow with reference to the drawings, in which:
The drawings show a preferred application area, namely the production of packs 10 of the hinge-lid-box type for cigarettes. This type of pack comprises a box part 11 and lid 12. A typical blank for this form of pack is shown in
The apparatus illustrated schematically in
The pack 10 contains a cigarette block 27—a cigarette group wrapped in an inner blank—which is wrapped in the blank according to
When the packs 10 enter into the pack path 24, the folding process for the blank has been largely completed, that is to say apart from the outer side flaps 19, 21. These extend in a wing-like manner in an upper, horizontal plane, with the box front wall 13 and lid front wall 16 oriented upward. The inner side flaps 20 and 22 have already been folded into an upright plane, with abutment against the pack contents, that is to say against the cigarette block 27.
In the region of the pack path 24, the packs 10 are transported by an endless conveyor at a distance apart from one another. This endless conveyor is designed as a belt conveyor 28, to be precise as a toothed belt. Drivers 29 are arranged on the free side, and these drivers grip, and transport, a respective pack 10 in the region of the base wall 15 at the rear. The packs 10 rest on the belt conveyor 28 and/or on a carrying profile 30 which runs in the longitudinal direction of the pack path 24, with their longitudinal extent oriented in the conveying direction. This carrying profile 30 here comprises a rail-like shaping component with a central depression 31 into which a conveying strand of the belt conveyor 28 enters. Supporting surfaces 32 are formed laterally alongside the same as a lateral support for corresponding peripheral regions of the pack 10.
It is also the case that guiding and supporting mechanisms are provided on the upper side of the pack 10, in the region of the pack path 24. The sideways directed folding flaps, namely box side flaps 19 and lid side flaps 21, are located on carrying mechanisms, namely lateral guide profiles 33 with peripheral edging. Also arranged on the upper side of the packs 10 is a rail-like holding-down means 34 which runs in the conveying direction and retains the packs 10 in the precise position on or in the pack path 24.
The packs 10 are transported preferably continuously along the pack path 24. In the process, folding flaps, in the present case the upright inner box side flaps 20 and lid side flaps 22, are provided with glue. These flaps are then folded, to be precise into the end position, with abutment against the associated side flaps 20, 22. The (outer) folding flaps 19, 21 are preferably moved, in the region of the pack path 24, into an intermediate folding position, namely into an oblique position at an acute angle to the side flaps 20, 22.
Glue stations are set up in the region of the pack path 24. The apparatus is set up to transfer two different types of glue, namely, in particular, cold glue, on the one hand, and hot glue (hot melt), on the other hand, onto the pack 10. A first glue station 35 serves for transferring preferably cold glue. A second glue station 36, which follows downstream in the conveying direction, is set up, in particular, for transferring hot glue.
Each glue station 35, 36 has at least one glue subassembly, the first glue station 35, in the case of the present exemplary embodiment, having two glue subassemblies 37, 38, one on either side of the pack path 24. The glue subassemblies 37, 38 have glue nozzles for transferring spots 39 of glue onto the pack 10. It is a special feature that the portions of glue are discharged in the horizontal direction and are transferred onto an upright folding flap 20, 22. Furthermore, the glue subassemblies 37, 38 of the first glue station 35 are designed, or arranged, so as to produce two rows 41, 42 of spots of the glue located one above the other. The first, lower row 42 of spots is applied by a first glue subassembly 37 and the second, upper row 41 of spots is applied by a second glue subassembly 38, which follows downstream in the conveying direction. The glue subassemblies 37, 38 are offset vertically in relation to one another at least in respect of the arrangement of the nozzles.
The downstream glue station 36, in the present case, comprises just one glue subassembly 33 (on either side of the pack path 24) for transferring an individual row 44 of spots 45 of a different type of glue, in particular of hot melt. This row 44 of spots is applied in a lower plane—in relation to the pack path 24. In particular, the spots 45 of hot melt are applied approximately centrally between the spots 39 of the row 42 of spots, that is to say adjacent to a free periphery of the outer side flaps 19, 21, which are intended for bonding to the side flaps 20, 22. The spots 39, 45 of glue can be transferred by appropriately designed glue subassemblies while the packs 10 are at a standstill. In the present case, the spots 39, 45 of glue are transferred onto the side flaps 20, 22 by individual nozzles as the packs 10 are moving.
Following the glue station 36, the packs 10 pass into the region of a folding station with folding mechanisms which are designed here as folding diverters 46 on either side of the pack path 24. The shaped, rail-like folding diverters 46 cause the side flaps 19, 21 to be folded over downward during transportation, in the present case into an intermediate folding position (
The packs 10 are transported on the pack path 24 into the region of a shaping station 48. In this region, the packs 10 are folded to completion—in respect of the folding flaps 19, 21—and made into a geometrically precise shape by mechanisms which butt against a number of opposite sides or surfaces and transmit aligning forces thereto. Thereafter, the pack 10, which has been completed to this extent, but has not yet cured fully in respect of the glue bonds, is transferred to the drying turret 25. When the packs 10 leave the latter, the glue bonds have set to the extent that the packs 10 are dimensionally stable.
The mechanisms for shaping and aligning the packs 10 are, at the same time, mechanisms belonging to a conveyor for the packs 10 for transferring the same from the pack path 24 to the drying turret 25. This conveyor, in the present case, is a transfer turret 49. The latter is mounted in a rotatable manner in an (upright) plane such that it is offset in relation to the plane of the drying turret 25. The transfer turret 49 is located above the pack path 24, and it is therefore possible for a respective pack 10, by virtue of being raised up from the pack path 24, to be introduced into a downwardly oriented holder or shaping pocket 50 of the transfer turret 49. The transfer turret 49 is located, as seen in the transporting direction of the packs 10, on that side of the drying turret 25 which is opposite to the glue stations 35, 36.
The transfer turret 49 is designed in a particular manner in respect of multifunctioning. The shaping pocket 50 contains a shaping component 51 which has a U-shaped cross section, to be precise which has the precise dimensions of a pack 10. The latter is moved upward out of the region of the folding diverter 46. The cross-sectional contour of the folding diverter 46 means that the latter acts like a mouthpiece and, when the pack is moved upward, folds the side flaps 19, 21 into abutment against the inner side flaps 20, 22. This completes the pack 10, and the latter thus passes into the shaping pocket 50 or the shaping component 51. The latter has lateral limbs 52 butting against the side surfaces of the pack 10, namely against the previously folded side flaps 19, 21.
The packs 10 are fixed in the shaping pocket 50, of the transfer turret 49, to be precise in the shaping component 51, by movable retaining mechanisms. For this purpose, each shaping pocket 50 is assigned retaining fingers 53 which are located opposite one another. These retaining fingers are of angled design with a transversely directed retaining limb 54 which, in a closed position of the shaping pocket 50, butts peripherally against the free outer side of the pack 10. In the open position of the shaping pocket 50, the pivotable retaining fingers 53 have been moved into a position in which free ends of the retaining limbs 54 are located in extension of the plane bounded by the folding diverters 46 or the folding surfaces 47, and they thus form a functional part of a guide well for the pack 10 en route into the shaping pocket 50. The retaining fingers 53 are mounted by means of pivot bearings 55 on an annular pocket carrier 56 of the transfer turret 49.
The limbs 52 of the shaping components 51 are active to provide precise shaping in the region of elongate side surfaces or side walls of the packs 10, namely in the region of the side flaps 19 . . . 22. To provide for shaping and dimensional stability, further mechanisms are active in the region of the shaping station 48. Directly in the region where the packs 10 are transferred to the transfer turret 49, namely once a pack 10 has entered into a shaping pocket 50, aligning means 57 are active on mutually opposite sides of the pack 10, namely at the base wall 15 and end wall 18. The aligning means 57 preferably come into abutment against the pack before the retaining fingers 53 have moved into the closed position. The aligning means 57 are mounted in a fixed position such that they can be pivoted (
A transfer mechanism, namely a lifting means 59, serves for transferring the packs 10 from the pack path 24 to the transfer turret 49. This lifting means is mounted in a fixed position in the region of the pack path 24. Two spaced-apart lifting walls 60 are used for the purpose of raising a pack 10. These lifting walls grip a pack 10, in the region of the shaping station 48, on the underside, to be precise around the periphery (
The packs 10 are each introduced into a downwardly oriented shaping pocket 50 of the transfer turret 49. Thereafter, the transfer turret 49 is rotated (in the counterclockwise direction) into a transfer position, immediately upstream of the charging station. Accordingly, the packs 10 are retained in the transfer turret 49 over a maximum transporting distance and are thus stabilized in respect of precise shaping.
The packs 10 are transferred to the drying turret 25 by a pusher 62 which can be moved in an axis-parallel manner and pushes the pack 10—with the retaining fingers 53 open—axially out of the shaping pocket 50 and directly into a precisely positioned drying pocket 63 of the drying turret 25. These drying pockets 63, which are arranged in large numbers along the circumference of the drying turret 25, form a cross-sectionally rectangular channel which is open on either side in the axial direction and in which a respective pack 10 fits in a play-free manner. The glue bonds are thus set as the precise pack shape is being maintained. Moreover, the drying turret 25 is positioned in a conventional manner.
The packs 10 are moved along a maximum circular transporting distance by the drying turret 25 and, in the region of a pushing-out station, are pushed out of the respective drying pockets 63 by a pushing-out means 64 and transferred onto the removal conveyor 26. The pack 10 exiting from the drying turret 25 is transferred to an intermediate mechanism, namely to a pivotable platform 65, which pivots the pack 10 into the relative position which is necessary for removal, and in which a longitudinal side of the pack 10 is directed downward.
The arrangement is suitable for packs 10 of different dimensions.
The positioning of regions of glue with different curing behaviors constitutes a special feature. In the case of a standard pack (
For the application of glue bonds made of two (or possibly more) types of glue, in the case of the present example (
In the case of the blank according to
The glue subassemblies 37, 38 and the glue subassembly 43 can be controlled correspondingly, and therefore the abovedescribed pattern of glue is transferred during the transporting movement. It is provided that in a first instance spots of cold glue and then, in a precisely positioned manner, spots of hot glue are transferred. If, according to
During the production of the packs, in particular during the gluing of folding flaps or other parts of the pack, the selection of the currently usable types of glue is controlled in dependence on the operating state of the packaging machine. The selection of the type of glue and the additional processing of a second type of glue are selected in accordance with the known material data for the glue and the known performance of the machine. Selection is based on the following considerations: for a certain period of time extending, for example, from the point in time at which the glue is applied, via the folding of the glued folding flaps, that is to say in particular the operation of folding over the side flaps 19, 21, until the pack, which has been folded to completion, is accommodated in a shaping subassembly, with a shaping and shape-maintaining action, the glue must not cure, in order that it is possible, in the shaping subassembly, to align the glued folding flaps in order to form a precise pack shape. In the case of a concrete exemplary embodiment with an assumed machine output of 600 cycles/min, exclusively cold glue is processed while the machine is operating at a reduced cycle speed, for example up to 120 cycles/min. When the machine reaches an output above, for example, 120 cycles/min, hot glue is processed in addition.
A separate theme addressed is that of the dimensioning of the shaping subassembly, in particular of the drying turret 25, in respect of the number of drying pockets 63. It is an aim to keep the drying turret 25 as small as possible, with the proviso that the packs 10 remain in the drying turret 25 during a rotation, in particular (only) during a partial rotation, of the same. It has to be ensured that at least one of the types of glue in the glue bonds has fully set/cured when the pack 10 leaves the drying turret 25 in the region of the pushing-out station. While the machine is operating at maximum output, the residence time is geared to the curing time of hot glue. In the case of the exemplary embodiment shown, the drying turret 25 is provided with at least 20, and not more than 30, active drying pockets 63.
The drying turret 25 can be dimensioned and/or the cycle speed for switching over the gluing system can be determined as follows:
These given values make it possible to determine, for a preferred embodiment, the number of operating cycles until the dimensionally stable packs 10 are released, as follows:
Specified value: hot-glue-curing time, which can be selected within limits, is, for example, tH=0.5 sec.
The cycle duration tT can be established from
This makes it possible to calculate the rotational speed nZ at which hot glue is activated, that is to say the cycle speed of the machine for the additional processing of hot glue:
The predetermined parameters can be used to determine the number zK of drying pockets 63 necessary until cold glue has cured:
On the basis of the given values and with (a maximum of) 120 operating cycles/min for exclusive processing of cold glue, accordingly, the drying turret 25 should be provided with thirty drying pockets 63.
The number zH of drying pockets 63 which is necessary for the curing of hot glue on the basis of the given values can be determined as follows:
It is therefore the case that (merely) five pockets or operating cycles are required for curing the areas of hot glue. In the case of this particular embodiment, it is possible, using the same basic design of the packaging machine, to provide a higher machine output without changing the drying turret 25.
In the case of the present method with “hybrid gluing”, the curing time tH of the hot glue, to be precise the shortest possible curing time tH of a hot glue, constitutes the critical feature. Series of tests using commercially available hot glues which can be used for cigarette packs have determined the shortest curing time as tH=0.5 s. This means that the operations of joining together and shaping the pack 10 have to be completed after tH=0.5 s. This means that:
The highest curing time which is admissible for hot glue, for a drying wheel with 30 drying pockets, is:
Number | Date | Country | Kind |
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10 2008 029 929.4 | Jun 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/004547 | 6/24/2009 | WO | 00 | 12/14/2010 |