Method for packaging groups of articles combined to form packaging units

Abstract

A method of combining groups of articles to form packaging units includes wrapping a packaging unit along a running direction thereof on a transporting path with a sheet material, concurrently with the wrapping, forming a sheet-material overlap and folding flaps that each project beyond the packaging unit along transverse peripheries thereof, positioning the folding flaps against the packaging unit as the packaging unit passes through a folding unit, and fixing the folding flaps to each other, thereby forming a sheet-material wrapper that is closed on all sides.

Claims

1. A method comprising using sheet material to envelop containers that have been arranged into a packaging unit, wherein using said sheet material to envelop said containers comprises conveying said packaging unit along a running direction thereof on a horizontal transport path with said sheet material, said horizontal transport path leading to a folding machine, said sheet material having been formed into a sheet-material overlap defined by overlapping ends of said sheet material upon which said containers stand upright with bases thereof in contact with said overlapping ends of said sheet material, and folding flaps that each project beyond said packaging unit along transverse peripheries thereof, receiving said packaging unit at said folding machine, wherein, by the time said folding machine receives said packaging unit, said packaging unit has already been wrapped, wherein, by the time said folding machine receives said packaging unit, said folding flaps are already projecting from said transverse peripheries, then, after said folding machine has received said packaging unit, causing said folding machine to position said folding flaps against said packaging unit as said packaging unit passes through a folding unit, and after having positioned said flaps against said packaging unit, and while said flaps are still positioned against said packaging unit, causing said folding flaps, which are positioned against said packaging unit but not yet fixed to each other, to become fixed to each other as said packaging unit passes through said folding machine, thereby forming a sheet-material wrapper that is closed on all sides, wherein forming folding flaps comprises forming first and second folding-flap pairs, each of which comprises a pair of opposed folding flaps, and positioning said folding flaps one after the other against said packaging unit, and wherein positioning said folding flaps against said packaging unit comprises using pressing rails with angled folding sections to position a leading folding flap of said first folding-flap pair, using a rotating cam to position an upper folding flap of said second folding-flap pair against said packaging unit, then, after having positioned said leading folding flap of said first folding-flap pair and said upper folding flap of said second folding-flap pair against said packaging unit, using a rotating comb for positioning a trailing folding flap of said first folding-flap pair against said packaging unit, said rotating comb interdigitating with said pressing rails, and after having positioned said trailing folding flap of said first folding-flap pair against said packaging unit, positioning a lower folding flap of said second folding-flap pair against said packaging unit.

2. The method of claim 1, further comprising positioning folding flaps of said first folding-flap pair by a predominantly horizontal movement during a folding operation and positioning folding flaps of said second folding-flap pair against said packaging unit by a predominantly vertical movement during a folding operation.

3. The method of claim 1, further comprising folding said folding flaps, wherein folding said folding flaps comprises using a stationary folding element.

4. The method of claim 1, further comprising folding said folding flaps, wherein folding said folding flaps comprises using four moving folding elements.

5. The method of claim 4, further comprising moving said moving folding elements synchronously together with said packaging unit.

6. The method of claim1, further comprising, using a first stationary folding element, positioning said leading folding flap of said first folding-flap pair against said packaging unit, and using a second stationary folding element, positioning said lower folding flap of said second folding-flap pair against said packaging unit.

7. The method of claim 6, further comprising, using a first moving folding element, positioning said upper-folding flap of said second folding-flap pair against said packaging unit, and, using a second moving folding element, positioning said trailing folding flap of said first folding-flap pair against said packaging unit.

8. The method of claim 1, wherein fixing said folding flaps to each other comprises fixing said folding flaps using folding elements.

9. The method of claim 1, wherein fixing said folding flaps to each other comprises fixing said folding flaps using pressing elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained more fully below by reference to drawings that collectively depict just one embodiment.

(2) FIGS. 1 to 5 show steps of a method for the packaging of groups of articles combined to form packaging units in various phases, and the apparatus used for executing such a method.

DETAILED DESCRIPTION

(3) FIGS. 1 to 5 show an apparatus for the packaging of articles 1. In the depicted example, articles 1 are cans that, in this case, have been combined to form a group. In the depicted example, the cans exhibit a matrix-like six-by-four arrangement in which six cans 1 are arranged transversely to a running direction L, while four cans 1 are oriented along the running direction, in longitudinal direction, L. Appropriate sorting and orienting devices may be disposed upstream of the apparatus depicted in the figures in order to combine cans 1 to form the group of articles, to form a packaging unit 2 that is to be wrapped, and to position cans 1 correctly.

(4) This can be effected, for example, with the aid of stops and/or support bars that are not shown in detail. Nor do the figures show a storage drum for plastic sheet material 3 that has been wrapped around packaging unit 2 as shown in FIG. 1.

(5) Plastic sheet material 3 may be produced from PE, PET, PP etc., as has already been described above. The wrapping of respective packaging unit 2 is effected in the running direction L during the transport of the group of articles or of cans 1 over or on a transporting path T. A sheet-material coil may be cut off and guided through a slit onto transporting path T for this purpose. Packaging unit 2 travels over the leading end of the sheet material coil.

(6) As packaging unit 2 proceeds along transporting path T, a sheet material carrier bar moves from below, under the sheet-material coil, and describes, in the running direction L, a circular path or a generally circular path over the packaging unit 2. The sheet material carrier bar, together with the trailing end of the sheet material coil, subsequently descends into a further slit. As the packaging unit 2 that is wrapped is transported in this way, it travels over the slot and, as it does so, pulls the leading end of the sheet-material coil beneath itself. As a result, packaging unit 2 stands on the overlapping ends of the sheet material coil, and a sheet-material overlap 4 of both ends of the sheet-material coil is defined at the same time. Details of the described wrapping of packaging unit 2 with sheet material 3 are described in DE 42 07 725 A1, column 6, lines 30 to 54, the contents of which are herein incorporated by reference. Express reference is made to this and to the associated figures therein contained. In the case of the example, the width of the sheet-material overlap or sheet-material overhang 4 may be approximately 30 mm in the running direction L. This is, of course, only meant as an example.

(7) As respective packaging unit 2 is wrapped in its running direction L on transporting path T with sheet material 3 and sheet-material overlap 4 is formed, folding flaps 5, 6, 7, 8, which each project beyond packaging unit 2 along the transverse peripheries, are defined at the same time.

(8) The two folding flaps 5, 6 lie opposite each other and form an associated first folding-flap pair 5, 6. As the packaging unit 2, wrapped with the aid of sheet material 3, enters a folding unit 9, first folding-flap pair 5, 6, or associated folding flaps 5, 6, which lie opposite one another, are positioned by a predominantly horizontal folding operation against the packaging unit 2. The horizontal folding operation comes about because the folding flaps 5, 6, which lie opposite one another, are folded along an only suggested horizontal folding plane and positioned against the packaging unit 2.

(9) Two further folding flaps 7, 8, which also lie opposite one, another are realized in addition to the two folding flaps 5, 6 or first folding-flap pair. The two further folding flaps 7, 8 define a second folding-flap pair 7, 8. The two folding flaps 7, 8 of the second folding-flap pair, which lie opposite one another, are positioned against the packaging unit 2 by a predominantly vertical folding operation. This is suggested by a vertical line that marks the vertical folding plane associated with this vertical folding operation.

(10) Folding unit 9, which is for positioning folding flaps 5, 6, 7, 8 against packaging unit 2, is composed of stationary folding elements 10, 11 and of moving folding elements 12, 13 that are moved by the packaging unit 2. The moving folding elements 12, 13 are displaced predominantly synchronously together with packaging unit 2, which is moved in running direction L along transporting path T.

(11) It can be seen in the figure how the two stationary folding elements 10, 11 and the two moving folding elements 12, 13 are realized. The stationary folding elements 10, 11 include a pressing rail 10 and an angled guide 11. The moving folding elements 12, 13 include a rotating folding cam 12 and a folding driver 13, which is moved with the packaging unit 2.

(12) When seen in the running direction L, pressing elements 14 also follow folding unit 9 and folding elements 10, 11, 12, 13, which are realized inside folding unit 9. In fact, two elongated pressing elements 14 in the running direction L are realized. The pressing elements 14 are associated in pairs with the transverse peripheries of the packaging unit 2 or with its lateral regions. The folding elements 10, 11, 12, 13 are also provided in pairs and are each associated with the related transverse periphery or lateral region of the packaging unit 2.

(13) Fixing units 15 are integrated in folding elements 14. In the embodiment shown, the fixing units 15 are charging electrodes that ensure that the folding flaps 5, 6, 7, 8 positioned against packaging unit 2 inside the folding unit 9 receive a temporary fixing. A permanent fixing may be provided by a shrink tunnel or a shrinking unit into which the packaging unit 2, which will have been wrapped in the sheet material 3, enters subsequent to the positioning of folding flaps 5, 6, 7, 8 and following the pressing elements 14. The shrink tunnel/shrinking unit in question is not depicted.

(14) In the illustrated embodiment, the pressing elements 14 are designed to be interchangeable and can be adapted, for example in their length, to the dimensions of the packaging unit 2 that is to be wrapped in the sheet material 3. The pressing elements 14 and their associated fixing units 15 together form a pressing-and-charging unit 14, 15 that, when seen in the running direction L, immediately follows the folding unit 9.

(15) It can be seen that the pressing rail 10 and the folding driver 13 are comb-like in configuration. As a result, the folding driver 13 can partly engage the pressing rail 10 through inter-digitation of the comb teeth, as is made clear by the functional representation in FIG. 4. In the illustrated embodiment, the folding driver 13 is connected to a belt 16 circulating around two rollers 17, at least one of which is driven and provides a way to adjust the speed of the speed of the folding driver 13.

(16) The speed of transporting path T in the running direction L of the folding driver 13 and the speed of the packaging unit 2 wrapped with sheet material 3 are adapted to one another or are synchronized with one another, as will be described in more detail. It goes without saying here that both speeds can be controlled or regulated, and that this also applies to their associated speed ratio, so as to guarantee the synchronous movement of the folding driver 13 with the packaging unit 2 as it runs in and through the folding unit 9 and which is wrapped with sheet material 3. The driving of the packaging unit 2 may be served by a not expressly depicted conveyor belt, but may also be provided, for example, by rails or comparable moving elements lying on the trailing edge of the packaging unit 2. The packaging unit 2 is propelled along transporting path T predominantly horizontally and first enters the folding unit 9. Folding flaps 5, 6, 7, 8 are positioned against packaging unit 2 inside the folding unit 9. The folding flaps 5, 6, 7, 8 are mutually fixed inside and/or subsequent to the folding unit 9.

(17) Within the scope of the embodiment there is effected, subsequent to the folding unit 9, a temporary fixing of the folding flaps 5, 6, 7, 8 to one another. This is ensured by charging the electrodes 15 in the pressing-and-charging unit 14, 15 that comes immediately after the folding unit 9. In any event, a fully enclosed sheet-material wrapper as depicted in FIG. 5 emerges from folding unit 9 or the pressing-and-charging unit 14, 15 respectively.

(18) This fully enclosed sheet-material wrapper has two fold pockets 18 in the lateral region of the packaging unit 2 or on its respective transverse periphery. In the region of fold pockets 18, the sheet material 3 exhibits a two-layer or even a three-layer structure such that the fold pockets 18 are characterized by particular stability and/or such that the corner regions of the packaging unit 2 exhibit increased stability.

(19) The procedure when packaging respective packaging unit 2 is explained hereinbelow by reference to FIGS. 1 to 5, which together represent the individual packaging steps. FIG. 1 shows the situation in which packaging unit 2, equipped with the aid of sheet material 3, enters the stationary folding unit 9. The folding flaps 5, 6, 7, 8 are positioned against the packaging unit 2 as it traverses the folding unit 9. Of the first folding-flap pair 5, 6, folding flap 5, which leads in the running direction L, is positioned first. This happens automatically as the packaging unit 2 runs up against the pressing rail 10 as it is transported along the transporting path T in the running direction L. Because the pressing rail 10 is equipped with angled entry sections 10a, the described folding operation of the respectively leading folding flap 5 of the first folding flap pair 5, 6 takes place gradually.

(20) Immediately subsequent to this, the upper folding flap 7 of the second folding-flap pair 7, 8 is positioned against the packaging unit 2. The two folding operations of the leading folding flap 5 on the one hand and the upper folding flap 7 on the other hand take place with a temporal overlap, quasi simultaneously. This applies generally. This means that the folding operations for the individual flaps 5, 6, 7, 8 can be optionally performed with a temporal overlap in order to produce fold pockets 18 or to tension or stretch the sheet material 3 during the folding operation.

(21) The rotating folding cam 12 is responsible for the folding operation of the upper folding flap 7. Two folding cams 12, which are connected to each other for co-rotation by a common shaft 19 and moved together by a motor which drives the common shaft 19, are in fact realized. The motor is triggered such that the rotation of the folding cams 12 about their common shaft 19 is synchronized with the transport movement of the packaging unit 2 in the running direction L.

(22) The corresponding folding operation is visible in FIG. 2. This depiction clearly shows how the stationary pressing rail 10 has increasingly positioned the leading folding flap 5 of the first folding-flap pair 5, 6 against the packaging unit 2. At the same time, the folding cam 12 ensures that the upper folding flap 7 is positioned fully against the packaging unit 2 first, so that the folding operation for the leading folding flap 5 can then be completed and the latter can be positioned from the outside up against the upper folding flap 7. During this operation, the folding cam 12 moves through between the packaging unit 2 and the stationary pressing rail 10.

(23) With reference to FIG. 3, the folding flap 6 of the first folding-flap pair 5, 6, and which is trailing in the running direction L, is now positioned against the packaging unit 2. Because the upper folding flap 7 is already positioned against packaging unit 2, this means that the trailing folding flap 6 is guided to upper folding flap 7 in contact against packaging unit 2. This is ensured by the folding driver 13.

(24) In the transition from FIG. 1 to FIG. 2, and finally to FIG. 3, the folding driver 13 has actually run up against the folding flap 6. As it continues moving, the folding driver 13 ensures that the trailing folding flap 6 is positioned against the packaging unit 2. During this operation, the folding cam 12 is located unchanged in its position against the upper folding flap 7 and is kept in its position pressed against the packaging unit 2.

(25) The shaft 19, to which the two folding cams 12 are connected, is stationary. One or both folding cams 12 move synchronously with the packaging unit 2 conveyed on the transporting path T in the running direction L. During this operation, the respective folding cam 12 executes an approximately 180 rotation, as is made clear by a comparison of FIGS. 1 and 4. The design here is selected so that the folding cam 12 stands almost vertically, as shown in FIG. 3.

(26) Because the folding cam 12 is configured like a segment of a circle, the vertical position of a respective cam 12, as shown in FIG. 3, corresponds to the folding cam 12 maximizes an area of an overlap with the packaging unit 2. This is intentional and in this context particularly advantageous because, through this maximum overlap in area, the upper folding flap 7, which is designed to be particularly large in area, is pressed fully up against the packaging unit 2, and in fact almost until, as well as leading folding flap 5, trailing folding flap 6 of the first folding-flap pair 5, 6 additionally provides for and also can provide for the fixing of the upper folding flap 7 to the packaging unit 2. This is the case when the folding driver 13 has fully positioned the trailing folding flap 6 against the packaging unit 2 subsequent to the transition from FIG. 3 to FIG. 4.

(27) It is in fact possible to see, from FIG. 4, that in the functional position according to FIG. 4, the folding driver 13, which is moved by the belt 16, overlaps comb-like with the equally comb-like pressing rail 10 or the latter's entry section 10a.

(28) The folding driver 13 thereby ensures that the trailing folding flap 6 is positioned fully against the packaging unit 2 after passing the entry section 10a. The folding cam 12 can now increasingly leave the upper folding flap 7 because, in addition to the leading folding flap 5, upper folding flap 7 is held by the trailing folding flap 6 and fixed in contact against the packaging unit 2.

(29) In the depiction according to FIG. 4, the leading folding flap 5, the upper folding flap 7 and the trailing folding flap 6 are held in contact against the packaging unit 2 by the pressing rail 10. As the packaging unit 2 proceeds along its path, the lower folding flap 8 now increasingly runs up against the stationary angled guide 11. During this operation, the lower folding flap 8 is raised and gradually positioned against the packaging unit 2. Having passed the folding unit 9 subsequent to the depiction according to FIG. 4, all folding flaps 5, 6, 7, 8 are located in position against the packaging unit 2, namely while the two fold pockets 18 are being defined at the same time, as shown in FIG. 5.

(30) After the folding unit 9, the packaging unit 2, now equipped in such a way with the totally enclosed sheet-material wrapper, traverses the already described pressing-and-charging unit 15 in which the pressing elements 14 ensure that the folding flaps 5, 6, 7, 8 are held unchanged in position against the packaging unit 2. At the same time, the fixing units or charging electrodes 15 ensure that the folding flaps 5, 6, 7, 8 receive a temporary mutual fixing achieved by an electrostatic charge. For this purpose the fixing unit or charging electrode 15 is arranged in the region of an overlap of the respective folding flaps 5, 6, 7, 8 such that all the folding flaps 5, 6, 7, 8 can be engaged with the aid of the charging electrode 15 and electrostatically charged as desired.

(31) As a result, the folding flaps 5, 6, 7, 8 after leaving the pressing-and-charging unit 14, 15, remain in position against the packaging unit 2, as shown at the right of FIG. 5. Subsequent to this, the packaging unit 2, equipped in such a way with the totally enclosed sheet-material wrapper, can enter the previously mentioned shrink tunnel in which the sheet material 3 is heated and then shrunk. Because the sheet material 3 is totally sealed, a particularly stable packaging unit 2 is available at the exit end of the shrink tunnel. Because it has been closed completely on all sides with the aid of the sheet material 3, the packaging unit 2 not only holds articles 1 therein stored in their relative mutual orientation but also protects them from, for example, dirt.