METHOD OF MANUFACTURING BAG-LIKE PACKAGING BLANKS PROVIDED WITH CLOSURE RIBBONS

Abstract: Method of manufacturing preferably bag-like packages of flexible material, in which every package is so arranged as to have a number of closure ribbons (38, 48). A blank belt (1) which is essentially double-folded in its longitudinal direction is divided up into a number of consecutive, bag-like packaging blanks (7). A number of closure ribbons (38a, b and 48a, b) extend through similarly located channels in all the packaging blanks. The ribbons are shortened in their longitudinal direction, for instance by folding. The blank belt is moved over guide devices (6a, b) which open the packaging blanks at the same time as the distance between their openings (32'', 32''') increases. This involves drawing out sections of the closure ribbons (38, 48) from the channels in the aforementioned adjacent packaging blanks. The drawn-out closure ribbons are attached to each other in pairs and are cut off at the areas of attachment so as to form endless closure ribbons for each and every one of the packaging blanks. The packaging blanks are then removed from the blank belt.

Description: Method of manufacturing bag-like packaging blanks provided with closure ribbons The present invention relates to a method of manufacturing from flexible material bag-like packaging blanks provided with closure ribbons, said method consisting of feeding a belt of packaging blanks arranged one after the other and capable of being separated from each other and interacting with guide devices for opening the packaging blanks, whereby each of the opposing side walls of the blank belt is provided in the vicinity of the openings of the packaging blanks with at least one channel extending in the longitu¬ dinal direction of the packaging belt, and at least one closure ribbon, which has been shortened,for instance,by folding, being arranged in the channel. From prior art is known the use of bag-like packages of flexible material, e.g. plastic film, in which every package is provided with a number of endless closure ribbons which run in channels adjacent to the opening of the package. In addition to providing a means of closing the package, the ribbons are often also used as a hanging device. This type of package is used particularly for health products such as cotton wool, paper handkerchieves and bath salts, etc. The use of the packages described in the above paragraph has been limited to a certain extent by their price. The high unit cost of the packages is due to the absence of a simple and expedient method of providing the packages with the endless closure ribbons. Thus the use of packages with closure ribbons results in high packaging costs, which are often almost twice as high as the cost of using packages without closure ribbons. Previously disclosed in Swedish Patent 189 052 is a method for pro¬ viding bags with tunnels for drawstrings, whereby the walls of the Lag are welded together at its opening. The Patent provides no solution for inseting the strings in the tunnels and for attaching the sections of string to each other. A device for manufacturing bags with drawstrings is described in Swedish Patent 789583, in which the blank belt is provided with cut-outs for the subsequent exposure of the strings, although the blank belt has no upper edge areas with suspension devices intended to interact with special guiding devices designed to expose sections of string so that they may be attached to each other and cut off. Instead of cut-outs, Danish Patent 100 014 proposes that holes be produced through the blank belt enabling the strings to be exposed. According to Finnish Patent 51 068 cut-outs are also produced in the belt from which ribbons are drawn out to form loops, said ribbons being joined to¬ gether in pairs at the same time as transverse joints are produced in the belt so as to form bags. British Patent 1 509539 also de¬ scribes a device for the filling of bags made of textile material and arranged in a continous line, although it makes no mention of closure ribbons or of the fact that the packaging blanks are to be provided with channels for such closure ribbons. Also, the line of blanks in accordance with the latter mentioned Patent is not provided with stripe-like edge areas incorporating suspension devices which interact with guide devices for the purpose of exposing the closure ribbons so that they may be attached to each other. The aim of the present invention is to produce packages provided with closure ribbons by a new method, which provides considerably reduced packaging costs compared with previously used techniques, and which is simple and reliable in operation with the closure ribbons between the packages being easily accessible to welding jaws or other fixing devices. The operation of the new method produces no loops in the ribbons and calls for no devices for deflecting the ribbon away from the belt, as is required in the arrangements which have already been disclosed. The invention is characterized principally in that adjacent to its free edges the blank belt is provided with opposing stripe-like areas in the vicinity of the edges, which areas link the packaging blanks together and which provide suspension devices designed to OMPI A, IPO interact with guide devices which control the positions of the areas in the vicinity of the edges relative to each other; in that at least one of the packaging blanks is opened by the guide devices as the blank belt advances by that said areas in the vicinity of the edges being moved apart in order at the same time to increase the distance between the openings of two adjacent packaging blanks so that parts of the closure ribbons are drawn out of the channels in th packaging blanks; and in that the closure ribbons are attached in pairs in the area of said drawn-out parts by a method known per se, and are cut off in the attachment areas so as to form endless closure ribbons in each packaging blank. A preferred embodiment of the invention has slits arranged essen¬ tially at right angles to the longitudinal direction of the belt, said slits separating the packaging blanks from each other, as well as slits arranged essentially in the longitudinal direction of the belt and located at the transition between the packaging blanks and the stripe-like areas in the vicinity of the edges, said slits separating parts of the edges of the openings of the packaging blanks from the stripe-like areas in the vicinity of the edges. These slits are usually joined together in pairs, so that they have the form of a letter T with the blank belt seen from the side. One or more connecting bridges may possibly be present in the slits between adjacent packaging blanks. In the areas in the vicinity of the edges the blank belt is also provided with suspension devices which interact with devices for controlling the distance of the areas in the vicinity of the edges relative to each other as the blank belt advances in the longitudinal direction. Also present at the transition between the packaging blanks and the stripe-like areas in the vicinity of the edges are tear-off notches extending between those slits which are arranged in the longitudinal direction of the belt. Each channnel on the side wall is so positioned as to form similarly positioned channels in the longitudinal direction of the blank belt. The channels are interrupted by the aforementioned slits. Inserted into the similarly positioned channels are the closure ribbons, which OMPI IPO extend through all the packaging blanks. The closure ribbons are shortened, for instance by folding, in the longitudinal direction of the blank belt. When producing packages from blank belts in accordance with the present invention, the suspension devices interact with guide devices along which the blank belt is advanced. As the belt advances, the distance between the areas in the vicinity of the edges is in¬ creased, whereby the packaging blanks are opened at the same time as the distance between them is increased. In conjunction with this, parts of the closure ribbons are drawn out from the channels in the aforementioned adjacent packaging blanks. The closure ribbons drawn out in this way are attached to each other in pairs, for instance by welding, gluing or knotting, etc. and are cut off in the attachment areas so as to form endless clousure ribbons for each and every one of the packaging blanks.The maximum distance between the openings of the fully opened packaging blank and the opening of the iπmediately preceding or immediately following packaging blank and consequently the maximum drawing-out of the closure ribbon and the maximum working space for attaching and cutting the closure ribbons will be achieved if the guide devices are made in such a way that, of the adjacent packaging blanks, at least that side of the opening closest to the fully open packaging blank is extended to the maximum extent permitted by the respective packaging blank. Once the endless closure ribbons have been produced, the packaging blanks are advanced further along the guide devices i order to be separated in one or more consecutive operations from each other and also from the stripe-like areas in the vicinity of the edges. In a preferred embodiment of the invention, elding together of the closure ribbons is achieved by means of welding jaws which hold the closure ribbons between them, at the same time as the closure ribbons for forming separate endless closure ribbons are held apart by devices located on the welding jaws. OMPI In one embodiment of the invention, the closure ribbons which have been attached together in pairs are cut off by an operation in which hooking devices take hold of the ribbons in the area in which the ribbons are attached to each other, after which the ribbons are cut at the attachment areas by a knife-l ke device so as to produce the endless closure ribbons allocated to each and every one of the packaging blanks. In an alternative embodiment of the invention,the slits are replaced either wholly or in part by tear-off notches. In another alternative embodiment of the invention,the slits in the longitudinal direction of the blank belt are replaced by means of cutting devices which cut into the walls of the belt as it advances longitudinally in those areas in which the slits are located in accordance with previously described embodiments of the invention. These cutting devices are preferably located adjacent to the guide devices which control the relative distance between the areas in the vicinity of the edges. The closure ribbons consist, for instance, of cotton or plastic. In the event of plastic ribbons being used, a material with a higher melting point than that of the film material of the blank belt must be selected in order to prevent the welding together of the film material and the closure ribbons during manufacture of the packaging blanks. Examples of suitable materials for the closure ribbons are plastic materials of the polyester or polya ide types. As indicated above,the packaging blanks are opened in conjunction with the completion of the closure ribbons. It is appropriate in many applications to place the contents in the packaging blanks at this point. In accordance with the Patents considered above, which relate to the manufacture of packaging blanks provided with closure ribbons and the blanks arranged as a belt, the closure ribbons must be drawn out _OMPI from the supply of ribbon in order to form loops, which calls for special arrangements. No such loops are formed by the method in accordance with the present invention, instead of which sections of ribbons are exposed between two adjacent packaging blanks by causing these to be separated from each other by opening at least one of the packaging blanks in a unique manner. This in turn is based on the idea of providing the blank belt with special areas in the vicinity of the edges and of causing these areas to interact with special guide devices which move the areas in the vicinity of the edges away from each other, thereby forcing the openings of two adjacent packaging blanks to be separated from each other into a suitable distance. The present invention is described in greater detail in relation to the drawings, in which Fig. 1 shows a blank belt viewed from the side; Fig. 2 shows a section through the blank belt in accordance with Fig. 1; Fig. 3 shows a perspective view of a blank belt passing over the device for controlling the distance of the areas in the vicinity of the edges from each other; Fig. 4a and show respectively a side view and a front view of the Fig. 4b welding device; and Fig. 5a and show respectively a side view and a front view of the Fig. 5b cutting device. Figures 1 and 2 illustrate an essentially double-folded blank belt 1 of a flexible material, preferably a plastic film. The blank belt consists of a number of consecutive bag-like packaging blanks 7', 7", 7'''. Each packaging blank consists of two walls 2 a, b which are welded or glued together along two of the areas in the vicinity of OMPI their edges so as to form joints 15, 16. A third edge of the packaging blanks, i.e. the bottom 8 of each of the packaging blanks shown in the figures, consists of the fold produced by the double- folding of the blank belt. Between the joints 15, 16 are produced slits 11, shown running vertically in the Figure, which separate adjacent packaging blanks from each other. Each slit is bridged by one or more bridges 18, which are shown in the Figure to be located adjacent to the bottom 8 of each packaging blank. Located adjacent to both free edges of the double-folded blank belt are stripe-like areas 33 a, b in the vicinity of the edges. Each of the areas in the vicinity of the edges is joined to one of the walls 2 a, b of the packaging blank,with tear-off notches 17 a, b being located at the transition between the areas in the vicinity of the edges and the walls. The tear-off notches are interrupted in the areas between two adjacent packaging blanks by slits 12 shown running horizontally in the Figure, which are united with the slits 11. Each and every one of the horizontal slits delimit parts of the openings 32 (cf. Fig. 3) of adjacent packaging blanks. Furthermore, the stripe- like areas in the vicinity of the edges are so arranged as to have tunnel-like suspension devices 4 a, b. In each of the areas adjacent to the stripe-like areas in the vicinity of the edges the side walls of the packaging blanks are provided with at least one channel 30, 31 running longitudinally in the direction of the blank belt. Each of the channels on the side walls is situated in such a way that similarly situated channels are present in the longitudinal direction of the blank belt, said channels being interrupted by the aforementioned vertical slits 11. Into each channel are introduced a number of continuous closure ribbons 38, 48 which extend through all the channels in the packaging blanks. The closure ribbons are shortened, for instance by folding,in the longitudinal direction of the blank belt. Fig. 3 shows a blank-belt as described in conjunction with Figures 1 and 2 introduced by means of its suspension devices 4 a,b onto the guides 6 a, b attached to a frame 34. The guides consist of rela¬ tively narrow rods which in the vicinity of their ends are located relatively close to each other and have central and essentially parallel parts 6"a, 6"b located at a greater distance from each other than the end sections. One of the end sections of each guide is attached to the frame 34. The cutting device 24 is located at the point of transition between the guides and the frame. Figs. 4a and 4b illustrate a device for welding together the closure ribbons 38, 48. The device consists of a holder 53 at the lower end of which are arranged two welding jaws 50 a, b capable of be ng moved towards and away from each other. One of the welding jaws is fitted with a ribbon-separating device 51, which operates in conjunction with a receiving opening 52 in the other welding jaw. Figs. 5a and 5b illustrate a device for cutting the closure ribbons 38, 48. The device consists of a holder 55 for a knife device 58 which moves in the longitudinal direction of the holder. The holder is also provided with hooking devices 56, 57. The holders in accordance with Fig. 4 and Fig. 5 are arranged in a device for operating the method in accordance with the present invention in conjuntion with the guides 6.a, b in Fig. 3 in such a way that they are in a fixed position relative to the frame 34. In order not to obstruct the clarity of Fig. 3, both holders have been omitted from Fig. 3 although a person skilled in the art will easily appreciate that the holders can be arranged in such a way that they assume positions in those spaces formed between the packaging blanks 7' 1 ' - 7" and 7" - 7' respectively. They are thus arranged in such a way that the holders are moved by drive units in a vertical direc¬ tion so that when in the lower position they will adopt operating positions in which the welding operation and the cutting operation respectively on the closure ribbons can be executed. In the application of the present nvention, the tunnel-like suspensio devices 4 a, b on the blank belt are introduced onto rod-like guides OMPI A WIPO . 6 a, b and are moved by drive units (not shown in the Figures) along the guides. As they pass along the guides, the strip-like areas 33 a, b in the vicinity of the edges of the blank belt are initially moved away from each other, thereby causing the packaging blank 7" connected to the area in the vicinity of the edge to open, after which they are brought together again, thereby causing the edges of the opening of the packaging blanks to come together once more. As they pass ^ver the central areas 6"a, 6"b of the rod-like guides, the openings of the packaging blanks assume their maximum dimensions. The insertion of any contents is therefore appropriate in this position. As the blanks continue to advance, the tunnel-like suspension devices 4 a, b are cut by the cutting device 24 a, b, causing the blank belt to be released from the guides 6 a, b. The cutting operation may possibly have been preceded by the welding together of the packaging blanks in the area of their openings, for example in accordance with the principle illustrated in Swedish Patent Applications 8004829-1 or 8006976-8. As the stripe-like areas 33 a, b in the vicinity of the edges are moved away from each other, the size of the openings of the packaging blanks in the longitudinal direction of the blank belt is reduced, which in turn means that the distance between the openings of two adjacent packaging blanks is increased. At the same time the closure ribbons are drawn out from the channels 30, 31 of the packaging blanks (cf. the ribbons 38, 48 between .the packaing blanks 7" and 7''' in Fig. 3). The holder 53 for the welding jaws 50 a, b will assume a position in the space formed between the packaging blanks 7" and 7"' such that, when the welding jaws are moved towards each other, the closure ribbons 38, 48 will be pressed between the welding jaws at the same time as the upper ribbons 38 are held apart from the lower ribbons 48. Once welding has taken place, the welding jaws are moved apart and the holder 53 returns them to a position in which the movement of the blank belt along the guides 6.a, b may continue. At the same time as the welding jaws 50 a, b join the closure ribbons 38 a, b and 48 a, b to each other, the holder 55 is moved into the OMPI V ' I? ° space between the packaging blanks 7' - 7" to a position in which the hooking devices -56, 57 will take hold of the closure ribbons 38, 48 in the areas in which they have been welded together and will lift them upwards slightly in the figure, whereupon the knife 58 is move towards the hooking devices 56, 57 and cuts off the closure ribbons 38, 48 and preserving the welded areas of the ribbons on both sides of the cut. The cutting operation completes the formation of the endless closure ribbons in the packaging blank 7', at the same time as the initial stage in the formation of the end- less closure ribbons in the following packaging blank 7" is begun. In Fig. 3 the central and parallel parts 6"a, 6"b of the rod-like guides are shown to have a length which largely corresponds to the length of the opening in an opened packaging blank. By extending the central and parallel parts of the guides so tha* not only the opened packaging blank 7" is fully extended, but also at least the closest sides of the preceding packaging blank 7' and of the follow¬ ing packaging blank 7'", the maximum available space will be pro¬ vided between the packages 7' - 7" and 7" - 7' 1 ' respectively. In this way, sufficient working space will usually be available for the welding devices and cutting devices. If necessary, the horizontal slits 12 may be extended in order to further increase the space between the packaging blanks. The bridges 18 between the packaging blanks are cut off at an appro¬ priate stage, for example in conjunction with the cutting off of the closure ribbons 38, 48. The above specification describes the present invention in relation to a double-folded flexible material, in which the fold formed by the double-folding operation produces the bottom of each packaging blank. It is assumed that the invention as such is also suitable for other types of blank belts, for instance those formed by the welding to¬ gether of two separate belts, of material-. OMPI IPO

Claims: n PATENT CLAIMS 1. A method of manufacturing bag-like packaging blanks (7) of flexible material provided with closure ribbons (38, 48), said method consisting of feeding a belt (1) of packaging blanks arranged one after the other and capable of being separated from each other and interacting with guide devices (6a, 6b) for opening the packaging blanks, whereby each of the opposing side walls of the blank belt is provided in the vicinity of the openings (32) of the packaging blanks with at least one channel (30a, 30b; 31a, 31b) extending in the longitudinal direction of the blank belt, in which channel is arranged at least one closure ribbon (38a, 38b; 48a, 48b) which has been shortened, for instance by folding, c h a r a c t e r i z e d in that adjacent to its free edges the blank belt is provided with opposing stripe-like areas (33 a, b) in the. vicinity of the edges, which areas link the packaging blanks together and which areas provide suspension devices (4a, 4b) designed to interact with guides (6a, 6b) for guiding the positions of the areas (33a, 33b) in the vicinity of the edges relative to each other; in that at least one of the packaging blanks is opened by the guide devices (6a, 6b) as the blank belt advances by that said areas (33a, 33b) in the vicinity of the edges being caused to move apart in order at the same time to increase the distance between the openings (32", 32'-') of two adjacent packaging blanks so that parts of the closure ribbons (38, 48) are drawn out of the channels in the packaging blanks; and in that the closure ribbons are attached in pairs in the area of said drawn- out parts by a method known per se and are cut off in the attachment region so as to form endless closure ribbons in each packaging blank. 2. A method in accordance with Patent Claim 1, c h a r a c t e r ¬ i z e d in that the closure ribbons (38, 48) are shortened to between about 30 - 80% of their original length, and preferably to 50 - 70%, before being inserted in the channels (30, 31). OMPI WIPO 3. A method in accordance with Patent Claims 1 or.2, c h a r a c t e r i z e d in that the attachment of the closure ribbons to each other in pa rs is achieved by a welding operation. 4. A method in accordance with Patent Claims 1 or.2, c h a ra c t e r i z e d in that the attachment of the closure ribbons to each other in pairs is achieved by a gluing operation. 5. A method in accordance with Patent Claims 1 or 2, c h a r a c t e i z e d in that the attachment of the closure ribbons to each other in pairs is achieved by a knotting operation, whereby two knots located adjacent to each other are formed and the closure ribbons are separated between the knots. 6. i A method in accordance with Patent Claims 3 or 4, c h a r a c t e r i z e d in that the area for the attachment of the closure ribbons to each other is given sufficient length in each area of attachment so that, when the closure ribbons in the area of attachment are cut, it will be possible to obtain connections between closure ribbons belonging to two separate packaging blanks located adjacent to each other. 7. A method in accordance with any of the Patent Claims 1 - 6, c h a r a c t e r i z e d in that a material is selected for the closure ribbons which material is not capable of being welded to the material of the blank belt. 8. A method in accordance with any of the Patent Claims 1 - 7, c h a r a c t e r i z e d in that, when guiding the areas (33a, 33b) in the vicinity of the edges to move away from each other, one packaging blank (7") is opened fully at the same time as those opening sides of the preceding and/or following packaging blank (7', 7' 1 ') which are closest to the said • ^J £ ^ OMPI packaging blank (7") is extended to the maximum permissible length for the packaging blank in question. 9. A method in accordance with Patent Claim 8, c h a r a c t e r i z e d in that the blank belt (1) is provided with slits (12) at the point of transition between the packaging blanks (7) and the stripe-like areas (33a, 33b) in the vicinity of the edges, with every slit separating parts of the openings (32) of two adjacent packaging blanks from each other, in that the length of every slit and the distance between the central and parallel parts (6"a, 6"b) of the guide devices (6a, 6b) are matched to each other so that, as the packaging blanks pass over these parts (6"a, 6"b), the distance between the openings of adjacent packaging blanks (7', 7", 7' * * ) will permit the introduction of devices (53, 55) for joining the closure ribbons (38, 48) to each other and for cutting them off in the area of the attach¬ ment. 10. A method in accordance with Patent Claim 9, c h a r a c t e r ¬ i z e d in that the blank belt is provided with transverse slits (11) which separate the packaging blanks from each other, said slits being connected, possibly by means of breakable bridges, to the aforementioned slits (12), which are located at the point of transition between the packaging blanks (7) and the stripe-like areas (33a, 33b) in the vicinity of the edges. OMPI IPO

Inventors: JOSTLER JAN
Applicants: JOKER SYSTEM AB, JOSTLER JAN
Application year: 1982
Main classification: B31B27
IPC codes: B26D7, B31B19