WO1990008071A1

WO1990008071A1 - A method and a device for manufacturing a bag and a closing ribbon

Info

Publication number: WO1990008071A1
Application number: PCT/BE1990/000003
Authority: WO
Inventors: Bart Gustaaf Heiremans; Wim August Hélène HEIREMANS; Antoine August Victor Heiremans
Original assignee: Sunrock Corporation S.A.
Priority date: 1989-01-20
Filing date: 1990-01-19
Publication date: 1990-07-26
Also published as: AU4835990A; BE1002761A6

Abstract

The invention relates to a method and a device for manufacturing a bag, in particular a garbage bag, and a closing ribbon for closing said bag, wherein said bag is formed starting from a material, in particular a synthetic film, wherein a perforation (2) is applied in said bag (1) material for forming a pullable material strip (3) which forms said closing ribbon.

Description

"A method and a device for manufacturing a bag and a closing ribbon"

The invention relates to a method for manufac¬ turing a bag, in particular a garbage bag, and a closing ribbon for closing said bag, wherein said bag is formed starting from a material, in particular a synthetic film.

Such a method is generally known, and is used for the manufacturing of for example plastic garbage bags, refrigerator bags, breadbags and so on. Generally a cylindrically shaped film is extruded from a synthetic material, such as for example PVC. For forming the individual bags there is breadthwise applied, each time at regular distances from each other, a welded joint for locally welding to each otherto each other two mantle parts obtained from said cylin¬ der mantle. Further, either before said welding or after said welding, folding lines are applied in said cylinder mantle in order to fold the latter according to at least two mantle parts. The individual bags are then obtained by cutting the film in equal length segments or by applying perforations. A collec¬ tion of bags or a roll is thus obtained of which individual bags can be pulled via the perforations. Those bags, respectively rolls are generally available on the market with individual closing clips or closing ribbons which are provided for closing said bags.

The closing clips or closing ribbons are manufac¬ tured separately and are for example furnished in a plastic ribbon shape either of not provided with a metal wire.

A drawback of the known method is that for the manufacturing and the adding of such closing clips or closing ribbons a cumbersome procedure is required since it is necessary to add each time a dedicated amount of closing clips or closing ribbons which have to be manufactured separately from the production of the bag. Thereupon those closing clips or closing ribbons can easily be lost in daily use.

It is an object of the invention to provide a - method for manufacturing a bag, in particular a garbage bag, wherein the above mentioned drawback is mitigated. A method according to the invention is therefore characterized in that a perforation is applied in said bag material for forming a pullable material strip which forms said closing ribbon. Because now the bag and the closing ribbon are made of a same material, the production costs are substantially reduced and the pro- duction process is substantially simplified because it is now no longer necessary to manufacture the separate ribbon from a dedicated material. Thereupon a closing ribbon is obtained which is attached to the bag due to which the possibility that the closing ribbon get lost is substan¬ tially reduced. It has to be mentioned that the application of a perforation in a film from which the individual bags are obtained is known on its own, but that perforation has a completely different function, notably to enable the pulling off of the individual bags.

A first preferred embodiment of a method accor- " ding to the invention is characterized in that said perforation is each time applied at a same side of said welded joint as said further perforation and at a further predetermined distance of said welded joint. This enables to simplify the serial production due to which there is obtained a simple method for manufacturing a bag with a closing ribbon.

A second preferred embodiment of a method according to the invention is characterized in that said pulling strip to be formed is strengthened by applying thereon a further welded joint. According to a particular embodiment of the invention a strengthening is applied at the extremities of said perfo¬ ration. Due to that strengthening there is avoided that during the pulling off of the material strip along the perforation, the bag be damaged when there is for example pulled too hard. According to a further embodiment of the inven¬ tion there is by the application of said perforation applied a first, respectively a second line segment at said further distance, which is smaller than said distance, starting from a first respectively second bag border formed by said first, respectively said second folding line and which line segments extend towards each other. It is thus possible to obtain a better grip on the bag via the material of the closed bag even in the area of the input opening and via the closing ribbon which remains connected to the bag by means of a small mate- rial strip.

The invention also relates to a device for applica¬ tion of the method. A device according to the invention is characte¬ rized in that it comprises at least one perforation element for applying said perforation. Other particularities and advantages of the invention will become clear from the description given hereunder of some embodiments of bags provided with closing ribbons and obtained by application of the method according to the invention. The descrip¬ tion is only given by way of example and thus in no way limits the scope of the requested protection. The reference numbers used here¬ after relate to the annexed figures.

Figure 1 shows a film part comprising a number of successive bags with a closing ribbon manufactured by^' application of the method according to the invention. Figure 2 shows such a film part wherein the closing ribbon is applied in the neighbourhood of the welded joint of the bag.

Figure 3 shows such a film part wherein the closing ribbon is strengthened. Figure -. shows such a film part wherein the closing ribbon is strengthened and each time applied at the bottom of an individual bag.

Figure 5 shows a film part divided lengthwise and with a lateral closing ribbon for each bag. Figure 6 shows a bag obtained by application - n* -

of the method according to the invention and provided with a perfora¬ tion which is applied over a part of the bag circumference.

Figure 7 shows a bag closed by means of a closing ribbon according to the invention. Figure 8 shows a bag with a perforation made of two line segments.

Figure 9 shows an analogous bag with a bent line segment provided with a strengthening.

Figure 10 shows a bag according to the invention with a T-shaped perforation.

In the different figures the same references relate to same or analogous elements.

Figure 1 shows a film part, in particular a garbage bag manufactured starting from . said film and obtained by application of a method according to the invention. A film 12 is obtained by means of an extrusion process of a synthetic material such as for example PVC. The extruded film is cyiindrically shaped and after the extrusion process there is breadthwise applied, at regular distances from each other, each time a welded joint 13 due to which the mantle parts obtained from the cylinder mantle are each time locally welded to each other in order to obtain each time the bottom of an individual bag. The two mantle parts are folded towards each other either after the welding or before the welding. For folding the cyiindrically shaped film into two mantle parts, at least two folding lines are applied in a known manner in the film, which folding lines divide the cylinder in two substantially equal mantle parts. Preferably however six folding lines are applied, at each upstanding side three, in order to reduce the width of the folded bag to be obtained without having to reduce the volume thereof. In order to obtain individual bags, a first perfora¬ tion 6 is applied in the film material at a predetermined distance of the welded joint 13, for example at 1 cm of the welded joint, and substantially parallel thereon, along which first perforation 6 the individual bags can be pulled off. The bags are generally sold rolled up on a roll and the user pulls each time a bag off. But it is also possible to sell the bags as individual bags. In the latter case, no first perforation 6 is applied during the manufacturing but the film is mechanically cut, for example by means of a knife, along the line 6.

In a first preferred embodiment of a method according to the invention a second perforation 2 is now applied substantially parallel to the welded joint 13. This second perforation is also applied in the film material, at a small distance of the first perforation 6, for example at 1 to 3 cm of the first perforation, and on the same side as the welded joint. The second perforation serves for forming a pullable material strip 3, notably the strip situa¬ ted between the first and the second perforation. This strip is then, after having been pulled off, used as a closing ribbon to close the filled up carbage bag.

As shown in Figure 1, the second perforation 2 is applied near the input opening of the bag formed by the first perforation 6, where the pullable strip 3, is at the upper side of the bag. It is however also possible to apply the pullable strip 3 in the neighbourhood of the welded joint, such as illustrated in Figure 2. Hereto the sequence of the second perforation 2 and the first perforation 6 is changed. By pulling off or cutting the individual bag along line 6, the strip 3 is now automatically situated at the under side of the bag.

According to a second embodiment of the inven¬ tion, which is illustrated in Figure 3, a further welded joint 14 is applied at a small distance of said welded joint 13 and substantially parallel thereon. Both welded joints 13, 14 are preferably applied immediately after each other. Both welded joints can however also be simultaneously applied. Further the first perforation 6 is now applied in an analogous way as described hereabove, and in such a manner that it is now situated between those both welded joints 13, 14. The second perforation 2 is now applied in such a manner that it is situated at another side of the further welded joint 14 then the one where the first perforation 6 is applied. In this manner, a material strip 16 is obtained which, due to the further welded joint 14, forms a stronger closing ribbon. It is also possible, as illustrated in Figure 4, to apply the second perforation 2 between both welded joints 13, 14 and the first perforation 6 at said other side of the further welded joint 14. Thus the material strip 16 Is situated at the under side, i.e. in the neighbourhood of the bag bottom. This embodiment has the advantage that the strengthened closing ribbon which is situated at the under side of the bag has not to be pulled off before the bag is filled.

Further, it is therewith, also possible when both welded joints are applied contiguous to each other, to apply the second perforation 2 in the welded joint 14 itself.

Both welded joints can thereupon have a different thickness, due to which they are more easily distinguishable.

Figure 5 shows a third embodiment of a film from which bags according to the invention are manufactured. Hereby two welded joints 13, 14 are also applied each time at a distance from each other, for example 2 to 3 cm. The first and the second perforations are now applied in an area which is each time situated between both welded joints. Thereafter the film is cut along its central axis 17 situated between two successive welded joints. But it is also possible to cut the film along an oblique line instead of along a horizon¬ tal axis. In such a manner two substantially equal film halves are obtained whereby the first and the second perforations have the same function as described hereabove. The material strip 3, which is provided to form a closing ribbon, is now however situated along a standing up side of the bag, whereby the bag bottom is formed by one of said folding line in the film and the supply input thereof is now on the middle line.

In a third embodiment it is also possible to strengthen the closing ribbon formed by the material strip by welding both mantle part to each other.

Figure 6 shows an individual bag 1, in particular a plastic garbage bag, which is manufactured by the application of the method according to the invention. This bag 1 is also provided with a second perforation 2 which is applied in the bag material. In the bag illustrated in Figure 6 the second perforation 2 extends over at least 3/4 of the width of the mantle part starting from a bag border formed by one of said folding lines, at a distance of substantially 1 cm of the upper bag side where the supply input 5 is provided.

By a bag obtained according to said first preferred embodiment it is now so that, when the bag is filled, the strip 3 is pulled off along perforation 2 and serves as a closing ribbon for closing the filled up bag as illustrated in Figure 7. With such a bag it is thus no longer necessary to manufacture a closing clip or closing ribbon from a separate material since the closing ribbon is now manu¬ factured of the same material as the bag. Due to this, the production costs are substantially reduced because it is no longer necessary to manufacture such a separate closing clip or closing ribbon and to join this to the packing of the bags. A further advantage of such a bag is that the closing ribbon is now originally fixed to the bag and can now be pulled off just before closing the bag. This enables to avoid that the closing ribbon get lost.

The perforation 2 can of course also be applied over the whole width of the bag. In this case there is obtained, after pulling off the material strip 3, a lose strip which serves as closing ribbon for the bag.

When use is made of a bag provided with a second welded joint 14, such as illustrated in figure 3, the strengthened strip 16 is at least partially pulled off along the second perforation

2 before the bag is filled up and eventually after pulling off along the first perforation 6 when the bag to be used is rolled up on a roll, in order to obtain an access to the inner volume of the bag.

When however the strengthened strip 16 is applied at the under bag side (Figure 4) then this strip can remain attached to the bag until the bag is being closed. The advantage of a strengthened closing ribbon is that it is more easy to manipulate by closing the bag, because both mantle parts remain of course welded to each other and can thus not move with respect to each other. Thereupon by application of the strengthening the closing ribbon is less vulnerable and the probability of being teared up is reduced. Figure 8 shows a further embodiment of a garbage bag obtained by application of a method according to the invention. By this further embodiment the second perforation is formed by a first and a second line segments 8, 9 which each starts from a bag border formed by the folding lines and extend parallel with the welded joints towards each other until a certain distance from each other. This enables to pick up the filled bag via the material of the closing ribbon itself and which remains fixed to the bag by means of a small material piece 11. Figure 9 shows an analogous embodiment wherein respectively the extremities of those line segments show a somewhat downward bent profile 10. Thus two projections are obtained by pulling off the strip 3. In such a manner, it is possible to take with both hands the closed bag, which is particularly useful when the fulled up bag is heavy. The bent profile can of course be upwardly oriented, i.e. towards the supply input 5 of the bag.

In an alternative embodiment of a bag according to the invention, each extremity of the perforation is provided with a strengthening 7. Therewith there is avoided that when pulling off the bag the strip could be damaged. Indeed the strengthening takes care that the pulling off stops at the correct place.

It is also possible to give a substantially T-shaped profile to the perforation, as illustrated in Figure 10. For- this purpose, the downgoing part 15 of the T-shape connects the supply input of the bag with said perforation 2 which extends substantially parallel to the supply input 5 thereof.

Also the second perforation can be applied thicker than the first one, whereby for example the perforation holes of the respective perforations shows a larger diameter and/or follows each other more closely in such a manner that the pulling off strength of the second perforation is smaller than the one of the first perforation.

This avoids that the user for example by inadvertance will first pull off along the second perforation provided for pulling off the material strip before pulling along the first perforation line which is provided for pulling off the individual bag. For increasing of the distinction possibility of the material strip, it can be useful to provide a colour mark at the height of the strip itself or of the second perforation.

The invention also relates to a (not shown in the drawing) device for execution of the method according to the invention. Hereby for example two perforation elements are provided, which are situated substantially parallel and at a short distance of each other. By this device in substantially the same operation the desired perforations, notably said first and second perforations, desti- nated for each time pulling off the bags respectively the strip in the film. In case the bags are cut from a film, it is sufficient that the device according to the embodiment described hereabove comprises only one perforation element which applies said perforation.

When a further welded joint has to be applied for strengthening the closing ribbon, as illustrated in Figures 3 and

4, the device according to the invention comprises also a welding element for applying said further welded joint. This welding element can be the same as the one with which the welded joints for forming the bottom of the bag is applied. In the latter case, the control of the device has to be modified in such a manner that the welding element applies two welded joint situated beside each other.

In a further embodiment of the device according to the invention a welding element is applied that applies two welded joints. The method for manufacturing the bags can also be applied for manufacturing paper bags.

Further the invention is not limited to garbage bags but can also be applied to bags which are destined for packing deepfries products or breadbags, a.s.o. Also the perforation lines can be punched.

Claims

1. A method for manufacturing a bag, in particular a garbage bag, and a closing ribbon for closing said bag, wherein said bag is formed starting from a material, in particular a synthetic film, characterized in that a perforation (2) is applied in said bag (1) material for forming a pullable material strip (3) which forms said closing ribbon.

2. A method as claimed in claim 1, wherein a cyiindrically shapped film (12) is extruded from a synthetic material, and whereafter a welded joint (13) is breadthwise applied each time at regular distances for locally welding mantle parts obtained from said cylinder shape to each other, which mantle parts are folded according to at least a first and a second folding line and wherein each time a further perforation (6) for pulling off an individual bag is applied over the whole breadth of both mantle parts at a predetermined distance of said welded joint, characterized in that said perforation (2) is each time applied at a same side of said welded joint (13) as said further perforation (6) and at a further predetermined distance of said welded joint.

3. A method as claimed in claim 2, characterized in that said pulling strip (16) to be formed is strengthened by applying thereon a further welded joint (14).

4. A method as claimed in claim 3, characterized in that said welded joint (13) and said further welded joint are applied contiguous to each other and that one of the perforations is applied at the heigth of the connection between said welded joint and said further welded joint.

5. A method as claimed in claim 2, characterized in that a strengthening (7) is applied at the extremities of said perfora¬ tion.

6. A method as claimed in anyone of claims 2 to 5, characterized in that said perforation is applied at a distance of at least 1 cm from said further perforation and starting from a bag border (4) formed by a folding line over at least 3/4 of the breadth of said mantle parts.

7. A method as claimed in anyone of claims 2 to 5, characterized in that, by the application of said perforation (2), a first, respectively a second line segment (8, resp. 9) is applied at said further distance, which is smaller than said distance, starting from a first, respectively a second bag border formed by said first, respectively said second folding line and which line segments extend towards each other.

8. A method as claimed in anyone of claims 2 to 5, characterized in that said perforation line (2) formed by a first, respectively a second line segment (8, resp. 9) is punched in such a manner in said bag that said first respectively said second line segment extends until a first respectively a second bag border formed by said first respectively said second folding line.

9. A method as claimed in anyone of claims

2 to 8, characterized in that said perforation (2) is applied substantially parellel to said welded joint of said bag.

10. A method as claimed in anyone of claims 7 or 9, characterized in that said first and said second line segments are applied in said bag with a bent profile at a zone of their extremities.

11. A method as claimed in anyone of claims 1 to 5, characterized in that said perforation i s applied according to a T-shaped profile, the down going part (10) of which leads to the input opening (5) of the bag.

12. A method as claimed in anyone of claims 2, 3, 4, 6, 9 or 11, characterized in that said perforation is applied over the whole breadth of the mantle parts.

13. A method as claimed in anyone of claims

3 or 4, wherein the film is cut along a line extending at least between two successive corresponding welded joints, characterized in that said perforations are applied at a bag border formed by one of said welded joints in an area delimited by said further welded joint.

14. A device for executing said method according to anyone of claims 1 to 13, characterized in that said device comprises at least one perforation element for applying said perforation.

15. A device as claimed in claim 14, characterized in that said device comprises a welding element for applying a further welded joint for strengthening said pulling strip.