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(11) | EP 1 155 961 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Multiple format machine for wrapping products |
| (57) The present invention relates to a multiple format machine (1) for sacking individual
or collectively grouped products (2) fed in succession in a tubular wrapping made
of packaging film. The wrapping (3) is obtained by means of progressive folding operations
on a planar, continuous strip of packing film effected in such a way as to obtain
a tubular shape having superposed longitudinal edges (4, 5) and by means of successive
sealing operations (6, 7). One (6) of such seals, effected by transverse sealing (13),
is oriented transversely to the tubular form, and encloses a front end thereof (8);
the other seal (7) being effected longitudinally to the tubular shape by related sealing
means (9) to connect its longitudinal edges (4, 5). The sealing means (9) for the
longitudinal sealing are movable in translation longitudinally to the wrapping (3)
in order to effect the longitudinal sealing (7) of the edges (4, 5) at a selectively
variable distance from the transverse seal (6) of the front end (8) of the wrapping
(3). |
[0001] The present invention relates to a multiple format machine for sacking individual or collectively grouped products, fed in succession in a tubular wrapping of packing film, particularly for packaging products in rolls.
[0002] In the packaging of numerous types of products, such as paper rolls for home or hygienic use, sacking machines are used which sack the rolls, or their sets, in tubular wrappings constructed automatically by the machine itself on the products to be packaged. In practice, the machine provides for forming the wrapping starting from a planar strip of packing material which, by means of particular folder elements, is progressive folded back onto itself in such a way as to generate a tubular shape, sustained from the interior of the wrapping being formed by suitable support elements and having longitudinal edges that are mutually approached and superposed.
[0003] Sealing means positioned anteriorly to the wrapping and oriented transversely to the tubular shape allow to seal the wrapping, transversely, in such a way as to form, in sequence, a closed front end and a rear end thereof. Additional sealing means, oriented longitudinally to the wrapping and opposite to the longitudinal edges, lastly close the tubular wrapping also laterally and longitudinally.
[0004] Simultaneously to the forming of the wrapping, described above, a certain number of products, or of sets thereof, are introduced in serial mode, one after the other until they come to abut - directly or indirectly - against the closed front end of the wrapping. The latter, under the thrust of the products, is then made to advance beyond the transverse sealing means whilst, simultaneously, its formation progresses as the closed front end advances along the machine together with the inserted products.
[0005] An additional operation of the transverse sealing means then closes the wrapping posteriorly to the sacked products; whereupon cutting means separate the sack from the rest of the wrapping, thereby starting a new and successive product sacking cycle.
[0006] Since the wrappings are modestly over-dimensioned, relative to the products to be contained, the serial introduction of the products into the tubular wrapping determines, in the air contained between the lateral walls of the wrapping and the closed end of the wrapping or between the lateral walls and two successive products, a back pressure that opposes the advance of the products that are successively introduced into the wrapping. This air, although it is not contained in air tight chambers, takes a certain amount of time to vent out, blowing by, from the space in which it remains confined: which entails the need not to have an excessively high speed of introduction of the products into the wrapping in order to avoid the risk of separating the already superposed parts of the longitudinal edges of the wrapping which have not yet reached the area of operation of the longitudinal sealing means.
[0007] To solve such problems a known constructive solution provides for the use of air aspirating means comprising a vacuum generating system connected with means for capturing the air associated to the support elements of the wrapping being formed.
[0008] Such a solution has, in practice, yielded poorer than expected results and has been found not to be free of drawbacks, such as that of being constructively costly and not easy to operate functionally.
[0009] In multiple format sacking machines, i.e. those able to package products with different formats, variable for instance in the overall disposition of the product, in their mutual aggregation mode or in the overall dimensions of the package, the problem of air back pressure, discussed above, is further exacerbated by the fact that the means for sealing the longitudinal edges of the wrapping are positioned on the machine in a rigorously fixed and predetermined position.
[0010] Normally, this position is selected in relation to the width of the largest format of the products that can be packaged by the machine. Due to a merely geometric question, connected to the shape of the folding means that allow to wrap the planar strip of packing film onto itself, as the width of the package format decreases, the length of the segment in which the longitudinal edges are superposed grows proportionately starting from the position in which the longitudinal sealing means are located, i.e. in which the longitudinal edges are mutually interconnected.
[0011] In other words, the more the width of the format to be packaged is reduced, the more the portion of tubular wrapping into which the products are inserted when the longitudinal edges of the film are not mutually sealed is lengthened.
[0012] Consequently, to prevent the longitudinal members from being moved away from the condition of correct mutual superposition, the speed of introduction of the products into the wrapping must be proportionately decreased relative to the maximum operating speed of the machine.
[0013] Such a situation therefore entails the drawback of having, in a multiple format machine, a productive yield that varies according to product format and that, in particular, decreases from large to small formats.
[0014] Since these machines perform terminal functions of the general process of packaging the related products, when they operate in line with machines that carry out other phases of the aforesaid packaging process, the need for a reduction of their operating speed entails a slow-down of the entire line. This appears all the more severe if one considers that in order to have a constant productivity of the line, the packaging speed should progressively increase when shifting from the largest format to formats with smaller product size, and not the opposite as is instead the case with known sacking machines.
[0015] The aim of the present invention is to overcome such drawbacks by means of a multiple format sacking machine wherein productive yield is wholly independent from the dimensions of the packaging format being processed.
[0016] In accordance with the invention this aim is achieved by a multiple format machine according to the preamble to claim 1 wherein the sealing means of the longitudinal edges of the wrapping are movable in translation longitudinally to the wrapping itself in order to effect the longitudinal sealing of the edges at a selectively variable distance from the transverse seal of the wrapping.
[0017] If the displacement run of the sealing means, superiorly to the longitudinal edges of the wrapping, is delimited between extreme points respectively corresponding to a minimum distance from the transverse sealing means and relative to the largest format and respectively corresponding to the maximum distance of such sealing means, corresponding instead to the smallest format of the package, the machine constantly operates under conditions of maximum productivity regardless of the packaging format undergoing work.
[0018] Further features and advantages of the invention shall become more readily apparent from the indicative and non limiting detailed description of an embodiment of the invention made with reference to the accompanying drawings, in which:
- Figures 1, 2, 3 and 4 respectively show some examples of packages of various formats obtainable with a multiple format sacking machine according to the invention;
- Figure 5 is an illustrative schematic representation of the typical conformation of the package wrapping used in the machine according to the invention and in known machines of similar types;
- Figures 6 and 7 are respectively a view of the sacking machine according to the invention, shown in elevation and in lateral view.
[0019] With reference to the accompanying drawings, the reference number 1 globally indicates a multiple format sacking machine for sacking products 2, individual or collectively grouped, fed in succession in a tubular wrapping of packing film; products 2 which in particular are represented by paper roll for home or hygienic use, some indicative and non limiting examples of packaging formats whereof are shown in Figures 1 through 4.
[0020] Whatever the package format, the wrapping 3 is obtained, in wholly known fashion - as partially exemplified in Figure 5, starting from a planar strip of packing film which is subjected, in the machine 1, to a series of folding operations able to allow the achievement of tubular shape, with quadrangular contour having superposed, open longitudinal edges 4, 5; shape which is then closed by means of seals 6, 7 respectively transverse and longitudinal to the wrapping 3.
[0021] More in particular, the seals 6, oriented transversely to the tubular shape, serve the purpose of closing and forming corresponding front and rear ends 8 of the wrapping 3 containing the products 2 or their sets grouped collectively. The longitudinal seal 7 serves the purpose of indissolubly connecting the longitudinal edge 4, 5 of the wrapping 3.
[0022] In regard to the sequence of execution of said seals: the front transverse seal 6 of the wrapping is executed first; then follows the longitudinal seal 7 which is executed progressively as the wrapping 3 advances along the machine 1; and last is executed the transverse rear seal 6 of the wrapping 3.
[0023] The seals 6, 7 are effected by known sealing means 13, 9. The sealing means 13 provided for forming the transverse seals 6 of the wrapping 3 are shown very schematically in Figure 6; they are identified with the reference number 13 and are so designed as to integrate in their structure cutting means, also conventional, able to separate, after the execution of the transverse seals 6, successive segments of wrapping 3 containing the groups of products 2, as these are formed, from the remaining rear part of the wrapping 3 which is formed continuously.
[0024] The sealing means 9 provided for effecting the longitudinal seals 7 of the edges have known structure and functionality and are movable in translation longitudinally to the wrapping 3 in order to effect the longitudinal seal 7 of the edges 4, 5, positioning themselves at a selectively variable distance from the transverse seal 6 of the wrapping 3, distance which is a function of the various packaging formats desired for the products 2 and which more specifically is selected in relation to the width of the formats, indicated as A in Figures 3 and 5.
[0025] More in particular, the sealing means 9 can be positioned superiorly to the longitudinal edges 4, 5 of the wrapping 3 in an adjustment range delimited by two limit positions. One limit position, corresponding to the minimum distance (dmin) from the sealing means 13 that effect the transverse seals 6, is determined by the maximum width of the largest package format of the products 2 (dimension A) that can be sacked on the machine 1. The other limit position, corresponding instead to the maximum distance (dmax) from the sealing means 13 of the transverse seal 6, is determined instead by the smallest width format of the products to be packaged.
[0026] For both these limit positions the positioning of the sealing means 9 coincides with the extreme area of superposition of the longitudinal edges 4, 5 lying farthest away from the front transverse seal 6 of the wrapping 3 (Figures 5 and 6).
[0027] The possibility of adjusting the sealing means 9 derives from the fact that they are mounted in sliding condition on guides 10 sustained by a support structure 12 and opposing the longitudinal edges 4, 5 of the wrapping 3.
[0028] On the machine 1 are also provided setting means able to allow selectively to vary the position of the sealing means 9 along the longitudinal edges 4 and 5 of the wrapping 3, according to the current package format. The setting means can be embodied in numerous different ways and can, for instance, simply comprise a manually operated screw 15 for locking and unlocking the sealing means 9, integrated by a graduated line for measuring the displacements of the sealing means 9 along the guides 10; or they may assume different, more complex forms, motorised and possibly also controlled by a programme for the automatic setting of the sacking machine 1 as the production format varies.
[0029] In regard to the structure 12 for supporting the guides 10, Figures 6 and 7 show that it can be translated vertically, transversely to the guides 10, away or towards the longitudinal edges 4, 5 of the wrapping 3 to allow to adjust the distance of the sealing means 9 from the edges 4, 5 of the wrapping 3 containing the products 2.
1. A multiple format machine for sacking individual or collectively grouped products
(2) fed in succession in a tubular wrapping (3) of packing film, which wrapping (3)
is obtained by means of progressive folding operations on a planar, continuous strip
of packing film effected in such a way as to obtain a tubular form having superposed
longitudinal edges (4, 5) and by means of successive sealing operations (6, 7), one
(6) of which, oriented transversely to the tubular shape, and effected by transverse
sealing means (13) closes a front end (8) thereof, another seal (7) being effected
longitudinally to the tubular shape by related sealing means (9) to connect said longitudinal
edges (4, 5) thereof, characterised in that said sealing means (9) for the longitudinal seal are movable in translation longitudinally
to the wrapping (3) in order to effect the longitudinal seal (7) of the edges (4,
5) at a selectively variable distance from the transverse seal (6) of the front end
(8) of the wrapping (3).
2. A machine as claimed in claim 1, characterised in that the sealing means (9) can be positioned superiorly to the longitudinal edges (4,
5) of the wrapping (3) and are movable between two limit positions, whereof a first
position, corresponding to the minimum distance (dmin) from the transverse sealing
means (13), is correlated to the largest format in terms of width of the products
(2) that can be sacked on the machine (1), the second of such positions, corresponding
instead to the maximum distance (dmax) from the transverse sealing means (13), being
instead correlated to the smallest format in terms of width of the products (2) to
be packaged.
3. A machine as claimed in any of the previous claims, characterised in that the sealing means (9) are mounted on at least a guide (10) opposite to the longitudinal
edges (4, 5) of the wrapping (3), and in that it comprises setting means for setting the position of the sealing means (9) according
to the current packaging format.
4. A machine as claimed in claim 3, characterised in that the setting means comprise a graduated line (11) for measuring the displacements
of the sealing means (9) along said at least one guide (10).
5. A machine as claimed in claim 3, characterised in that it comprises a structure (12) for supporting said at least one guide (10), which
can be translated transversely to said guide (10) away or towards the longitudinal
edges (4, 5) of the wrapping (3).