Parallelepipedic packing container and a method for its manufacture

The presen-t invention relates to a pralleLepipiedic packing container of the type which is manufactured ~rom a tube of packing material, which tube is filled with contents and is divided into individual packing containers by successive flattenings and transverse sealings of the tube along zones situated at a distance from one another within which the packing material is arranged so that it lies inside against inside, the packing containers being separated from the tube by cuts in said ~!

zones.

The invention also relates to a method for the manufacture of ~he packing container.

The invention relates in particular to parallelepipedic packing containers manufactured from flexible packing material, such as plastics film or a laminate of plastics and paper laminate of aluminum, plastics and paper.

It is an object of the invention to provide a packing container of greater rigidity than that used to-day, thereby enabling a thinner packing material, and hence also a cheaper packing material, to be used without any risk of deformation of the package when the same is handled.

The invention provides a parallelepipedic packing container which is formed from a web of packing material and which can be emptied by pouring the contents from one end surface of the packing container, whilst at least two side walls of the packing container,which are substantially at right angles to said end surface of the package, are stiffened or reinforced in a substantial area along the side walls by overlappiny layers of the material from which the package has been made. A container in accordance with the invention can be manufactured by ` forming of a web of packing material into a tube, which is filled with the intended contents, e.g. a liquid formed with the help of suitable devices and dividing the tube into containers by transverse seals, whereupon the packages thus formed axe separated ~rom each other by means of cuts in the transverse sealing ~ones. A method for the manufacture of packages of this kype is disclosed in British patent No. 1,012,867 (Swedish patents ~os. 324,132 and 324,986).

In the practical realization of the abovementioned method for the purpose of manufacturing packages in accordance with the invention, a tube forming device and a package forming device are arranged so that the longitudinal si~es of the packing containers are at right angles to the tube axis, and consequently the transverse sealing zones of the tube extend along the central parts of two opposite side walls of the finished package, whilst the longitudinal, tube-forming seal, which is preferably of the overlap type, extends at least partly around three side walls of the finished package.

It is a characteristic feature of the invention that the longitudinal fins along the side walls of the packing containers formed during the sealing are cut through when adjacent packing containers are separated from one another, whereupon the fins so formed are folded down against and sealed to the side walls of the packing container for the purpose of contributing to the stiffening and reinforcement of the same, at the same time as the adverse effects of projecting sealing fins are eliminated. To ensure that this result is obtained, the folded down fins are given an appreciable width, which is equal to one half of the width of the side wall of the container against which the fin is folded down and fixed.

The flattening zone from which the fins are obtained is formed by a method wherein the tube of packi.ng material, which may have a circular or elongate cross-section, is flattend between sealiny jaws and the packing material pressed together by flattening, which is brought into contact inside to inside, is heat-sealed to itself along two narrow sealing regions close ~- - 2 to the limiting edges or base lines of the flattening zone, whilst the portions of the flattening ~one in between remain unsealed~ When a formed package is to be separated from the adjacent package or from the tube, one layer of material in the double-walled, unsealed flattening zone is cut through quite close to one of the said sealing regions whilst the opposite layer of material is cut through close to the opposite sealing region, the parts of the sealing fin situated between the sealing regions being in principle separated from one another. F~owever, since in oraer to separate the packages the fin must also be cut off between the said cuts which both go through one layer of material, a cut must be made from the one side o~ the fin which goes through the one material layer between the two first cuts in the middle of the sealing region. In this manner fins are formed on each package which fins have a single thickness of material along substantially the full length of the sealing ` regions.

The fins of substantially a single thickness of material are subsequently folded down against and sealed to adjoining side walls of the packing container, where they form stiffening and reinforcing areas comprising a double thickness of material, which areas extend over the whole length of the package.

In the forming of the package from a tube, projecting triangular, double-walled lugs are formed at the corners of the package, and these lugs are folded down and sealed preferably against the side walls and one of the end walls of the package respectively, whilst one of the end walls of the package is left completely free and plane. This free, plane end wall is appropriately provided with a pouring hole through which the contents can be emptied. The pouring hole is sealed with a tearoff strip, which is arranged so that it acts as a seal around the pouriny hole, but which can be torn off when the contents .

.

, . :

i ~ .

are to be made accessible.

The invention is further described below b~ way of example with reference ~o the accompanying drawing5, in which:

Fig. 1 shows a perspective view of a part of a tu~e of packing material which is formed by joining together the edge regions of a web by an overlap joint;

Fig. 2 shows the manner in which the tub~ of Fig~ 1 is formed into a packing container, Fig. 3 shows a perspeckive view of two partly inished packing containers in accordance with the invention, which have been separated from one another after being formed and sealed from a tube of the type which is shown in Fig. l; and Fig. 4 shows a perspective view of a finished packing container in accordance witht~e inventio~.

In accordance with the invention a web of packing ;;

material consisting of e.g~ a layer of paper with a plastics coating on each side is formed into a tube by causing the edges of the web to overlap one another, whereupon the overlapped edge regions are heat-sealed to each other. In the present case the overlapping area 1 is of a substantial width, e.g.

30 mm or more, so as to form an effective gripping area and a reinforcement of the side of the package. It is not necessary, however, for the realization of the invention to make the overlap joint so wide, but it is also possible to work with an overlap joint of only a few mm width.

The tube formed from the packing material web is filled with contents, e.g. milk, and is formed to parallelepipedic packing containers in a known manner, e.g. in the manner which is described in Swedish patents Nos. 324,132 and 324,986. In Fig. 1 is shown a section of a tube 15, which is formed from a packiny material web, the end edges of which have been joined together in a longitudinal overlap joint 1. The packing material - 4 - : ` , s web, from which the -tube 15 is formed, is provide~ before the formation of the tube with A punched-out pouring hole 16, which also before the formation of the use, is covered over with a tear-off cover strip 11, which is fixed to the packing material in a tight sealing joint around the hole 16.

In Fig. 2 is shown how the tube 15 is formed into a parallelepipedic package by a method which e.g. may be of the type described in Swedish patents Nos. 32~,132 and 324,986. As can be seen from Fig. 2 triangular lugs 17 are present at the corners of the formed packaye, which lugs are connected to a flattened part 18, which extends along the whole side wall of the package. At edges of the flattened part 18 the packing material pressed together is sealed inside against inside in narrow sealing regions 19, whilst the portion 18, situated in between, is not sealed. As is evident from Fig. 2, the flattened '~ portion 18 is relatively wide, the width of the flattened portion `''` h~ar'~ f~an 18 ~ff~Y~*~ltbeing equal to~ half the width of the side wall of ;

the packing container to which the flattend portion is connected.

The packages are separated from the sealed off tube in a manner which is characteristic of the invention and which is evident from F~g. 3.

The non-sealed portion 18 is double-walled ;~ and the method of the invention ensures that one wall thickness of the portion 18 is associated with the packing container which is situated above the flattened area and the other wall thickness is associated with the packing container which is situated below the flattened area. This is brought about by cutting through the non-sealed portion 18 with cuts from both sides of the portion, one cut being close to the upper sealing region l9 and being made from one side of the flattened part, whilst another cut is made from the opposite side of the flattened portion and - is close to the lower sealing region 19.

Such cuts do not make it possible to separate the packages from one another, owing , . . . . :

.. , . ,, , . ......... ~ .. - . ..

" to the fact -that the packages also hany -together along the longitudinal edges o~ -the oriyinal tube, khat is to sa~ the side edges of the ~lattened portion 18, and it has been found to be appropriate, as shown in Fig. 3, to provide, in addition to the abovementioned cuts in the flattened region 18, also cuts 5, 7 made from the one side of the flattened part and which allow the packages to be separated from one another. Fig. 3 shows the formed packages 2, 3 separated from one another, the package 2 and the package 3 each presenting a projecting fin 9 at its bottom, the width of the fin being half the width of the package side which is connected to the transverse seal.

As can be seen from Fig. 3, the fin 9 does not extend to the tips of the triangular lugs 17 but, owing to the arrangement of the cuts 5, 7, the fin 9 is shorter than the distance between the tips of opposite triangular lugs 17. The sealing regions 19, on the other hand, e~tend over the entire distance between the tips of the triangular lugs 17 and extend over the entire length of the side of the package. The upper fins 10 of the packing containers 2, 3 are substantially also of single material thickness, but owing to the transverse cuts 5, 7 which extend between the cuts 6, 8 and which are made from opposite sides of the fin 18, the parts of the fin 10 which are situated near the tips of the triangular double-walled panels 17 have double material thickness and define a "notch".

It will readily be understood that the fin 9 fits into the "notch" in fin 10, and wide fins 9, 10 are readily obtained at each of the opposite outside walls of the packing container, which wide fins can be folded down and fixed to the side walls of the packing container in the manner as shown in Fig. 4, substantial reinforcement of the side walls of the packing container being thus obtained, - whilst at the same time the projecting sealing fins, which are ungainly and in some cases would hinder the handling of the packages, are not present, and smooth side walls of the package -- 6 - are obtained.

After the foldiny in and fixing of the fins 9, 10, the triangular lugs 17 are folded down in the manner as shown in Fig. 4 against the sides and bottom respectively of the packing container and fixed in this position, a whollv plane upper end surface 20 being obtained on the package, in which upper end surface is provided the pouring hole 16 and the tear-off cover strip 11.

The stiffening of the side walls of the packing containers is of special value when a package is to be handled in connecti~n with it having to be opened for the contents to be made accessible, since it allows the packing container to be gripped in one hand without any risk of the side wall buckling and thereby rendering difficult the pouring out of the contents.

It is possible to modify the folding in of the triangular, double-walled lugs and also the design of the fins within wide limits without thereby departing from the scope of the invention. ~ ` ~' ` :