WO2009070077A1

WO2009070077A1 - An apparatus and a method for facilitating reforming of a material web

Info

Publication number: WO2009070077A1
Application number: PCT/SE2008/000625
Authority: WO
Inventors: Mats Turesson
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 2007-11-28
Filing date: 2008-11-04
Publication date: 2009-06-04
Also published as: SE0702628L; CN101878156A; CN101878156B; SE531691C2; JP2011504861A

Abstract

The present invention relates to an apparatus (40) for facilitating reforming of a web (10) of flexible packaging material into a tube (19), the web (10) including a crease pattern which has crease lines (11) running substantially transversely of the web, and the web (10) running over a deflector device (18) before the reforming into the tube is initiated. The apparatus (40) is characterised in that it includes a form device (42) which is disposed downstream of the deflector device (18) but upstream of tube forming means (20), the form device (42) at least in one case where a sprain has been formed in the web along one of said transverse crease lines, being disposed to be in contact with one side (17) of the web (10) which is intended to form an inside of the finished tube, so that the web (10) is given an indication to commence the reforming into the tube. The invention also relates to a method for facilitating reforming of a web (10) of flexible packaging material into a tube (19).

Description

AN APPARATUS AND A METHOD FOR FACILITATING REFORMING OF A MATERIAL WEB

TECHNICAL FIELD The present invention relates to an apparatus for facilitating the reforming of a web of flexible packaging material into a tube, the web including a crease pattern which has crease lines running substantially transversely of the web, and the web running over a deflector device before the reforming into the tube is initiated. The present invention also relates to a method for facilitating the reforming of a web of flexible packaging material into a tube.

BACKGROUND ART

In a number of today's packing and filling machines for the manufacture of, for example, parallelepipedic packaging containers for substantially liquid foods, a web-shaped flexible packaging material is progressively reformed into tube form in that both of its longitudinal edges are brought together to overlap and are sealed. Thereafter, the desired contents are fed to the packaging material tube and this tube is transversely sealed at uniform intervals in transverse sealing zones. The sealed off portions of the tube thus containing their contents are thereafter separated from the tube by incisions in the sealing zones and, where applicable, are formed by folding to the desired geometric configuration depending upon how the seals disposed transversely of the longitudinal direction of the tube have been oriented. The packaging container may, for example, be given parallelepipedic configuration.

The reforming of the original planar packaging material into tube form takes place with the aid of a number of tube forming means which force the packaging material progressively to assume a substantially circular cross section so that its longitudinal edges can be sealed to one another. The tube formation is initiated with the aid of a substantially arcuate tube forming means and the forming subsequently takes place through one or more tube forming means in the form of open forming rings. At the last of the tube forming means, which is preferably a closed forming ring, the packaging material tube has attained its final cross section and the longitudinal sealing is carried out. The packaging material is normally of the type which comprises a core layer of paper or paperboard and surrounding layers of thermoplastic, such as for example polyethylene and polypropylene. The material may also include barrier layers which protect the contents against, for example, light and oxygen. Such a barrier layer may consist of, for example, aluminium foil. Further, the packaging material may be of the type which is provided with a crease pattern, comprising crease lines, for facilitating the final forming into, for example, parallelepipedic packaging containers.

In above all thin packaging materials, in certain cases these crease lines may impede the reforming of the planar web into tube form. This is because the web, just before the reforming, among other things runs over a bending roller whose purpose is to quite radically change the direction of the web. This bending roller which, because of lack of space, has a relatively slight diameter, can in certain cases cause one or other of the crease lines running transversely of the web to be sprained and form a fold. This means that the paper layer included in the packaging material is sprained in the crease line, with the result that the packaging material is folded along said crease line. When the web is subsequently to be reformed into a tube, and thereby instead undergo a bending around a geometric axis directed in the same direction as the longitudinal crease lines, i.e. substantially 90° to the transverse fold which occurred, this may in certain cases be difficult. It has proved difficult to form a packaging material web in one direction if it has already been formed, or folded, in another direction. The earlier folding, in this particular case the fold, gives an undesirable rigidity against the bending of the web which is needed in order to realise a tube form. The rigidity can have as a result that, after passage of the bending roller, there will be one or more substantially straight sections along the fold. The packaging material is thus not bent in the desired manner but will instead display edges along certain regions. On passage through the tube forming means, the packaging material web, because of its inherent rigidity, strives to bulge out through the openings which are present in the tube forming means. If the packaging material then displays straight sections, depending upon where the straight sections are located in relation to the openings in the tube forming means and how long the straight sections are in relation to the size of the openings, there is a risk of obtaining a temporary twisting or deformation of the tube since the uneven cross section of the tube configuration strives to adjust itself in each respective tube forming means. This can result in the tube not moving uniformly and there is thereby a risk that the finished packaging containers will not have a correct configuration. In the worst case scenario, the tube will rupture.

The above-outlined problem risks becoming particularly severe in those cases when the packaging containers are provided with opening devices of the type which are injection moulded direct on the material web before the formation of the tube and which then project out a distance from the material web, for example an opening device with a pouring opening formed as a neck. This technology is described, for example, in international Patent Publication WO 98/18609 and in US Patent 6,386,851. In the case with such opening devices, the tube forming means are provided with an extra opening through which the opening device may pass. Thus, an additional opportunity is provided for the material web to bulge outwards, and thereby become twisted.

BRIEF SUMMARY OF THE INVENTION

One object of the present invention is thus to realise an apparatus for facilitating reforming of a web of flexible packaging material into a tube, the apparatus counteracting the effect of any possibly formed transversely directed folds in the packaging material web and working towards causing the web to strive to be formed into a tube with uniform curvature.

This object is solved by means of an apparatus and a corresponding method as defined in the appended Claims and discussed hereinbelow. An apparatus according to the present invention is disposed to be employed in connection with a web which is provided with a crease pattern which at least comprises crease lines running substantially transversely of the web. The web runs over a deflector device before the reforming into the tube is initiated. The apparatus is characterised in that it includes a form device which is disposed downstream of the deflector device but upstream of tube forming means. The form device is disposed, at least in a case where a sprain has been formed in the web along one of said transverse crease lines, to be in contact with a side of the web which is intended to form an inside of the finished tube so that the web is given an indication to commence the reforming into the tube.

In that the packaging material web, on fold formation, will come into abutment against said form device, the fold is forced to assume arcuate form which is subsequently the beginning of the formation of the tube. As a result of the abutment of the form device against the packaging material web, the rigidity is manipulated along the sprained crease line and the web becomes more pliable.

The form device may be disposed so as to abut against the web in at least an area between a longitudinal centreline and a longitudinal edge of the web. Alternatively, the form device may be disposed to abut against the web at least in an area on either side of a longitudinal centreline of the web, between the centreline and a respective longitudinal edge of the web.

The apparatus may be designed so that said area is located more proximal said longitudinal edge of the web than the longitudinal centreline of the web. It has proved that this embodiment gives the greatest effect on the sprained crease line.

In accordance with one embodiment of the present invention, said form device includes at least one freely rotatably disposed forming roller. In the case with the above-mentioned first abutment of the form device, this forming roller is disposed to extend over said area of the web. In the case with the above-mentioned alternative abutment of the form device, this forming roller may be disposed to extend over both of said areas of the web. In that the forming roller is freely rotary, the friction between the forming roller and the packaging material web is reduced, which effectively reduces the risk of damage to the packaging material.

In accordance with a further embodiment of the present invention, said form device includes at least two freely rotatably disposed forming rollers with coincidental axes of rotation. In the case with the above-mentioned alternative abutment of the form device, these forming rollers are disposed to extend over a respective one of said areas of the web. In accordance with that previously disclosed, it is an advantage if the forming rollers are freely rotary, since the friction between the forming rollers and the packaging material web is then minimised, which effectively reduces the risk of damage to the packaging material. A method according to the present invention for facilitating reforming of a web of flexible packaging material into a tube, the web including a crease pattern which has crease lines running substantially transversely of the web, and the web running over a deflector device before the reforming into the tube is initiated, is characterised by the step of bringing, at least in a case where a sprain has been formed in the web along one of said transverse crease lines, a form device into contact with a side of the web which is intended to form an inside of the finished tube. By such means, the web is given an indication to commence the reforming into the tube. The form device is disposed downstream of the deflector device but upstream of tube forming means.

Those characterising features which were discussed in connection with the apparatus according to the present invention for facilitating the reforming of a web of flexible packaging material into a tube are naturally transferrable to the corresponding method according to the present invention for facilitating reforming of a web of flexible packaging material into a tube. These characterising features may further naturally be combined in the same embodiment.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will now be described in greater detail hereinbelow, with reference to one currently preferred embodiment and with further reference to the accompanying Drawings, in which:

Fig. 1 schematically illustrates a packing and filling machine including an apparatus according to the present invention;

Fig. 2 schematically illustrates, in a view from above, a first tube forming means which initially forms the packaging material web;

Fig. 3 schematically illustrates in perspective view the first tube forming means of Fig. 2, as well as the packaging material web, the deflector device and the apparatus according to the present invention;

Fig. 4 schematically illustrates, in a view from above, the first tube forming means of Fig. 2, and also, by means of broken lines, forms of incorrectly formed packaging material webs; Fig. 5 schematically illustrates in side elevation the parts included in Fig. 3; and

Fig. 6 schematically illustrates the apparatus according to the present invention in a view from above, as well as the material web. It should be observed that the figures are not mutually to scale.

DESCRIPTION OF ONE EMBODIMENT

The apparatus according to the present invention may advantageously be employed in a packing and filling machine of the type which was described by way of introduction and which is employed in the manufacture of, for example, parallelepipedic packaging containers. One example of such a packing and filling machine is illustrated in Fig. 1.

This machine is supplied with a web 10 of flexible packaging material. The packaging material is, as was mentioned previously, normally of the type which at least comprises a core layer of paper or paperboard and surrounding layers of thermoplastic, for example polyethylene and polypropylene. Further, the material web 10 is of the type which is provided with a crease pattern, comprising transverse crease lines 11 (only one is schematically illustrated in Fig. 1) and longitudinal crease lines (not shown) for facilitating the final forming into parallelepipedic packaging containers.

The web-shaped packaging material is supplied to the machine on a magazine reel 12 from which the packaging material web 10 is unwound and led substantially upwards through the packing and filling machine with the aid of guide rollers 14. In some packing and filling machines, there is provided at this position a sterilization chamber where the packaging material web 10 undergoes suitable sterilization treatment in order to extend the shelf-life of the contents. No sterilization chamber is shown in the figure.

At the uppermost region of the machine, the packaging material web 10 passes int. al. a movable web tensioning roller 16 and a deflector device 18 in the form of a bending roller. The packaging material web 10 runs over the bending roller 18 with its decorative artwork side 15 facing towards the bending roller 18 and its inside 17, i.e. that side which will constitute the inside in the packaging material tube 19 formed lower down, turned to face away from the bending roller 18.

After turning about the bending roller 18, the packaging material web 10 is guided substantially vertically downwards through the packing and filling machine with the aid of tube forming means 20. At the last, lowermost tube forming means, the two longitudinal web edges 21 overlap one another and they can be sealed to one another with the aid of a longitudinal sealing device 22 for forming the material tube 19. Concentrically down through the material tube 19 extends a filler pipe 24 which extends in through the upper open end of the tube and discharges in the tube immediately above that position where the tube is reformed into sealed-off sections which will subsequently become individual packaging containers 26. The sealing takes place by means of forming and sealing jaws 28 which cooperate in pairs in order to clamp together and transversely seal the packaging material tube 19. Said jaws 28 also provide for the cutting of the sealed-off sections in the sealing zones so that individual packaging containers 26 are formed.

Fig. 2 shows a first, arcuate tube forming means 30 seen from above from the bending roller 18. It comprises four freely rotary forming rollers 32 which are intended to abut against the decorative artwork side 15 of the packaging material web 10 and form the web. In the opening 34 between the intermediate forming rollers 32, a projecting opening device (not shown) may, where applicable, be permitted to pass. The, broken line W in the figure illustrates that form which it is desirable that the packaging material web 10 shall have when it passes this first tube forming means 30. The longitudinal edges 21 of the packaging material web are far from establishing contact with one another, and the configuration here is somewhat reminiscent of the upper portion of a heart.

As was described by way of introduction, in certain cases it may be difficult to achieve the desired configuration of the packaging material web 10, in particular in that case when a fold 36 has occurred along a transverse crease line 11 in connection with the passage of the web over the bending roller 18. Such a fold 36 is illustrated at the bending roller in Fig. 3, and it can be seen that the fold points outwards from the inside 17 of the packaging material web 10. If such a fold 36 occurs, there is instead a risk that the packaging material web 10 will display, at the fold 36, residual straight portions 38 at the first arcuate tube forming means 30. The broken line W₁ and the ghosted line W₂ in Fig. 4 illustrate examples of forms with partially straight portions 38. As was described by way of introduction, such forms are not desirable.

With reference to Fig. 3, 5 and 6, the apparatus 40 according to the present invention will be described which effectively remedies this form problem.

The apparatus 40 includes a form device 42 disposed immediately downstream of the bending roller 18 but upstream of the first arcuate tube forming means 30. .

In general terms, the function of this form device 42 is to counteract the rigidity in the sprained crease line, i.e. the fold 36, and give the packaging material web 10 an indication to commence reforming into the tube, i.e. to begin being bent in the same direction as the bending direction on reforming into the tube. In order for this to be put into effect, said form device 42 is placed so that the inside 17 of the web 10, i.e. that side which will constitute the inside of the tube 19, can come into contact with the form device 42. At least, the form device 42 should come into contact with the web 10 where there is a fold 36 along a transverse crease line 11, and on such contact, the form device 42 will come into abutment with and urge lightly against the packaging material web 10 in at least one of the two areas 44 illustrated in Fig. 3. The areas 44 (encircled with broken lines) are disposed on either side of a longitudinal centreline M of the web (shown schematically in Fig. 1), between the centreline M and each respective longitudinal edge 21 of the web 10. As is apparent from the figures, the areas 44 are located more proximal the respective longitudinal edge 21 of the web 10 than the centreline M for optimum function of the form device 42. The form device 42 may thus abut against both areas 44 of the web 10 simultaneously. In actual fact however, the form device 42 often abuts against one of the areas 44 at a time, and alternates between the areas depending upon where the straight portions are to be found. In the figures, one embodiment of said form device 42 is shown. In Fig..3, it may be seen that the form device 42 includes two forming rollers 46. These are freely rotatably journalled on a shaft 48 which in its turn is fixedly secured in a frame 50. The frame 50 is fixed in the upper, arcuate tube forming means 30 and is designed so that it provides a distance between the form device 42 and said tube forming means 30, as well as between the form device 42 and the bending roller 18. Both of these distances are approximately equal in size. Fig. 6 shows how the two forming rollers 46 in the form device 42 are placed in relation to the packaging material web 10. The broken line W constitutes substantially that form which the packaging material web 10 has when it passes the two forming rollers 46, and it may be seen that the forming rollers in the example have come into abutment on either side of the centreline M of the web, a good distance out towards the longitudinal edges 21. The abutment entails that the fold 36 will^' strive to form an arc in a direction away from the forming rollers 46. When the packaging material web 10 subsequently arrives at the first tube forming means 30, it allows itself to be formed in the desired manner by the four forming rollers 32 according to that illustrated in Fig. 2. Fig. 5 shows the form device 42, the bending roller 18 and the first tube forming means (drawn in simplified presentation) 30 in a view from the side. It can be seen that the outer periphery of the rollers 46 of the form device lies on an imaginary line A which is located a distance further out (i.e. in a direction to the right in the figure) than a line B which lies in the direction of the tangent from the point where the packaging material web 10 releases its contact with the bending roller 18. The forming rollers 46 may also lie on a line which corresponds to the line B which lies in the direction of the tangent.

The forming rollers 46, see Fig. 6, have a form which is reminiscent of a mushroom or a champagne cork, i.e. a first end has a portion 51 with a diameter which is greater than the diameter of a portion 52 at the other end. Between the two portions 51, 52 there is a gentle radius transition. Similarly, both of the outer edges of each forming roller 46 are gently rounded.

The forming rollers 46 are positioned on the shaft 48 in such a manner that the smaller portions 52 are turned to face towards one another. While the present invention has only been described with respect to. one currently preferred embodiment, it should be obvious to the skilled reader of this specification that the invention is not restricted thereto, but that a plurality of variations and modifications are conceivable without departing from the scope of the appended Claims.

As was described above, the form device 42 may include two forming rollers

46. However, it should be understood that the form device may alternatively comprise one or a plurality of forming rollers. In addition, the forming rollers may have another form than that described. They may, for example, display one and the same diameter throughout.

Similarly, it should be understood that the form device may be secured in another manner than that illustrated. Naturally, a multiplicity of mechanically viable solutions are available.

In the illustrated embodiment, the packaging material web 10 runs with its decorative artwork side 15, i.e. that side which is to constitute the outside of the tube, and thereby the packaging container, facing towards the bending roller 18. Thus, the reforming into tube form takes place in that the longitudinal edges 21 of the packaging material web 10 are initially led in a direction away from the bending roller 18 in accordance with that which is illustrated in, for example, Fig. 3. However, there are packing and filling machines where the packaging material web 10 runs in such a manner that the inside 17 of the web is instead turned to face in towards the bending roller. In such instance, the reforming into tube form instead takes place in that the longitudinal edges of the packaging material web are initially led in a direction towards the bending roller. However, spraining of any possible transverse crease lines still takes place so that the fold points outwards from the bending roller, which in this case would be outwards on the decorative artwork side. It is of no consequence in which direction the fold points. The important factor is still that the form device is disposed to act against the inside of the packaging material web.

Claims

WHAT IS CLAIMED IS:

1. An apparatus (40) for facilitating reforming of a web (10) of flexible packaging material into a tube (19), the web (10) including a crease pattern which has crease lines (11) running substantially transversely of the web, and the web (10) running over a deflector device (18) before the reforming into the tube is initiated, characterised in that it includes a form device (42) which is disposed downstream of the deflector device (18) but upstream of tube forming means (20), the form device (42), at least in a case where a sprain has been formed in the web along one of said transverse crease lines, being disposed to be in contact with a side (17) of the web (10) which is intended to form an inside of the finished tube, so that the web

(10) is given an indication to commence the reforming into the tube.

2. The apparatus (40) as claimed in Claim 1, wherein the form device (42) is disposed to abut against the web (10) in at least an area (44) between a longitudinal centreline (M) and a longitudinal edge (21) of the web (10).

3. The apparatus (40) as claimed in Claim 1, wherein the form device (42) is disposed to abut against the web (10) at least in an area (44) on either side of a longitudinal centreline (M) of the web, between the centreline and a respective longitudinal edge (21) of the web (10).

4. The apparatus (40) as claimed in any of Claims 2 or 3, wherein said area (44) is located more proximal said longitudinal edge (21) of the web (10) than the longitudinal centreline (M) of the web.

5. The apparatus (40) as claimed in any of the preceding Claims, wherein said form device (42) includes at least one freely rotatably disposed forming roller (46).

6. The apparatus (40) as claimed in any of the preceding Claims, wherein said form device (42) includes at least two freely rotatably disposed forming rollers (46) with coincidental axes of rotation.

7. A method of facilitating reforming of a web (10) of flexible packaging material into a tube (19), the web (10) including a crease pattern which has crease lines (11) running substantially transversely of the web, and said web (10) running over a deflector device (18) before the reforming into the tube is initiated, characterised by bringing, at least in one case where a sprain has been formed in the web along one of said transverse crease lines, a form device (42) into contact with a side (17) of the web (10) which is intended to form an inside of the finished tube in order to give the web an indication to commence the reforming into the tube, the form device being disposed downstream of the deflector device (18) but upstream of tube forming means (20).