Package making – Progressively seamed cover web or web folds – With closing of web between package units
Reexamination Certificate
2001-06-04
2003-03-04
Rada, Rinaldi I. (Department: 3721)
Package making
Progressively seamed cover web or web folds
With closing of web between package units
C053S064000, C053S370600, C053S372500, C493S008000, C493S009000, C493S011000, C493S231000, C493S243000, C493S429000
Reexamination Certificate
active
06526733
ABSTRACT:
The invention concerns an apparatus for setting a tube of packaging material in relation to a processing station in a packaging machine in which a tube of round cross-section is formed from a printed web of packaging material provided with embossing lines, closed by longitudinal sealing, filled and shaped in a transverse sealing unit and divided into parallelepipedic packs, wherein the transverse sealing unit is designed for intermittently conveying the tube with an adjustable stroke movement and is provided in relation to the tube on diametrally opposite sides with a respective folding flap pivotable about a pivot axis, and a sensor is arranged to sense a printing mark.
DE 29 46 059 discloses an apparatus which forms a tube of packaging material, in particular paper coated with plastic material, by longitudinal sealing, fills it, shapes it at least in the lower region by means of a transverse sealing unit intermittently conveying the tube, and divides the tube into individual packs, wherein the filled closed parallelepipedic packs, after reaching the end of a first vertical processing path, are subjected to final shaping on a second horizontal processing path and are conveyed away.
It is known that liquid products are packed in such parallelepipedic packs, for example long-life milk, and that a decoration which assists with the advertising is printed on the outside surface of the pack. Besides the decoration, printed on the pack in a fixed position in relation to the decoration there is also a printing mark while approximately at spacings of a good pack height there are also embossing lines in the tube, which facilitate the shaping operation. The transverse sealing unit conveys the tube intermittently by a given stroke movement which, in the case of an in-house state of the art, is equal to the height of the parallelepipedic pack to be produced plus double the sum of half the depth of the parallelepipedic pack and the height of the transverse sealing seam of the pack material, which connects the tube body portion of the parallelepipedic pack to the transverse sealing seam.
It will be appreciated that the transverse sealing unit with its transverse sealing jaws and the separating blade must be in the correct position relative to the embossing lines on the one hand and the decoration and the printing mark on the other hand, if satisfactory operation is to be guaranteed. In a further in-house state of the art, for that purpose there is provided a correction device which increases or reduces the length of the movement of the folding flaps in such a way that, in operation of the transverse sealing unit with which the folding flaps co-operate, the folding flaps convey either more or less packaging material, that is to say tube length, in the respective conveyor stroke movement. Such a correction device operates satisfactorily for the correction of relatively small displacements and in particular in the continuous procedure of filling, closing and separating the tube into packs.
Problems however have frequently arisen in the initial phase when the filling material, that is to say the product to be packed, for example milk, has not yet been supplied and the tube of the web of packaging material is just being formed for the first time and is being conveyed by the transverse sealing unit in the initial phase of the procedure. More specifically, the printing mark is then not at the correct location, for example it is not in front of the sensor, so that the operator knows that the decoration and the embossing lines are not at the correct, intermittently recurring distance from the transverse sealing unit. The tube of the packaging material therefore has to be adjusted or set or oriented, and that was managed by controlling the correction device and therewith the position of the folding flaps to move to a predetermined position in order thereby to move the printing mark to the correct position, for example in front of the sensor, during the intermittent movement.
As in the above-mentioned position of the folding flaps the paper tube is also disposed in the region of engagement of the folding flaps, the folding flaps, by virtue of the undefined shape of the tube of packaging material, implement a proportion, which is not to be estimated, of the length of conveying movement of the tube of paper. That means that the commencement of production of filled, properly decorated packs is linked to the preceding production of an indefinite number of filled waste packs which are not properly decorated. The number of waste packs produced is dependent on the one hand on the time at which a stable product filling height in the paper tube is reached and on the other hand on the above-mentioned factors and circumstances. That procedure involves the disadvantage that a relatively large number of packs had to be conveyed without producing a satisfactorily filled, sealed pack provided with the correct decoration. The amount of waste which is involved in that respect is disproportionately high. Up to the moment at which correct positioning of the printing mark was reached, between 30 and 60 packs were lost as wastage, in which case up to 20 packs were partially filled with liquid product. That therefore also involved the disadvantage that an intolerably long period of time elapsed before the cut in the transverse sealing unit was positioned at the correct location relative to the tube.
In terms of practical use of present machines, in the initial phase thereof, when setting the tube in relation to the transverse sealing unit as the processing station, the further disadvantage was incurred, if the tube of packaging material is of a round cross-section, that the folding flaps contact the tube from the outside and urge it inwardly in an undefined manner, in which case the tube is creased and in part even damaged. The undefined bend lines in the plastic-coated surfaces on the inside and/or outside of the tube give rise to damage and cracks which result in a loss of sealing integrity for liquids or lack of sterility in the case of sterile packs. On the other hand however the movement of the folding flaps is indispensable in order to provide the desired folded configuration at the respective lower end of the tube body portion of the pack. The folding flap control, the movement of the flaps and the technical components for implementing that flap movement are complicated and take up a great deal of space so that it is not possible to switch off the flap movement at just any times when the tube is in the initial phase of being set.
Therefore, the object of the present invention is to provide an apparatus of the kind set forth in the opening part of this specification, which permits faster termination of the initial phase when setting the packaging machine in operation, with a smaller amount of waste material, in order to prevent damage to the paper tube and to considerably reduce the loss of product during the start-up phase.
In accordance with the invention that object is attained in that arranged on the upstream side of each folding flap is a folding element which is driven controlledly by the sensor and by means of which the tube can be folded in to a width approximately equal to the width of the finished pack in such a way that the tube is out of engagement from the folding flaps.
The folding element which is of a very simple design configuration and which can be easily driven and which is arranged upstream of the respective folding flap in the direction of movement of the tube can provide that the tube can be brought out of engagement from the folding flaps in its region downstream of the operative location of the folding elements and in particular through the transverse sealing unit. That mode of folding applies only for the initial phase of operation of the packaging machine, during which the tube of packaging material is being adjusted or suitably oriented. During that initial phase, the result obtained is a pack portion which is folded differently or, to put it better, a tube portion which does not lead to t
Cavazzuti Mauro
Polster Steffen
Schellenberg Frank Mario
Dunn Michael L.
Rada Rinaldi I.
Tetra Laval Holdings & Finance S.A.
Weeks Gloria R
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