EP0388364B1 - Method of closing a bag - Google Patents

Abstract

The reclosable bag (10) has an opening, from which the contents can be poured out, including a first non-reclosable sewn closure (15) along the opening, which closure closes said opening. The sewn closure (15) comprises a detachable chain stitch and a tear-off strip (17) in order to facilitate the manual opening of the first closure (15). The reclosable bag (10) also comprises a second reclosable closure with a pair of profile strips (22, 25) which engage in one another and are attached on the lower inner wall part to the upper edges of the bag walls outside the sewn closure (15). The second profile closure (22, 25) is hot-sealed (33) at its ends and allows the bag (10) to be closed again when the first non-reclosable closure (15) has been removed. <IMAGE>

Description

The invention is arranged in the field of methods for closing reclosable bags or sacks which are secured against access and has in particular to do with reclosable sacks which have a first non-reclosable closure and a second reclosable closure.

Various ideas of bags secured against access have been received, which were provided with a reclosable closure, including bags with the possibility of preventing access to their contents without leaving any traces of access. Many of these ideas relate to the packaging of relatively small quantities of goods, so that tear-off plastic fiber mats or weak fiber mat zones are sufficient to withstand normal handling, packaging and shipping wear.

However, such closures protected against access are unfavorable for heavy, bulky goods such as dog food, charcoal, cat litter and the like, which usually require a packaging that can withstand more than 7 kg net weight. For this type of goods, the bags typically only had a first non-resealable closure of any kind. A disadvantage of this type of closure on bags with bulky goods is that the bags are not resealable, so that the goods can be spilled through the open packaging when tipped over. In addition, due to the open packaging, the contents can often easily be attacked by bugs or dry out. It is desirable that functional and inexpensive reclosable means for such sacks for bulky goods are produced, because the contents may have to be emptied out of the sacks to an increased extent, given the often large distances between two deliveries.

The device of the Ferrell patent, US-A-4,241,865, is an attempt to overcome many of the disadvantages of these prior inventions of non-resealable packages or sacks. This patent describes a method for closing a reclosable sack with a first non-reclosable, sewn closure and a second reclosable zipper-like closure that sits outside the first closure. While the invention of the Ferrell patent offers a tamper-evident, reclosable sack for the transportation of heavy, bulky goods, it also has a disadvantage: it is generally complicated to create. The production of sacks with a first non-reclosable closure and a zipper requires several spools of material that are stitched together in an uninterrupted process. The zipper needs stoppers at the ends. In addition, the stoppers must be correctly aligned with the bag for the zipper. In other words, the zipper must fit the bag properly. From FR-A-1.529.850 a method for producing plastic sachets with profile closures is known, which are produced by cutting and welding from a plastic band with a profile closure attached to it. The known method also discloses steps which make it possible to manufacture the sachets produced with leg side edges so that they can be filled. This document does not provide any information about connecting the profile fastener to the sachet material.

The main object of the present application is to create a method with which a reclosable closure can be applied in a simple and secure manner to already filled bags which are continuously fed to the closing machine.

• Abb. 1 ist eine perspektivische Ansicht eines wiederverschliessbaren Sackes, der die Erfindung darstellt.
• Abb. 2 ist eine vergrösserte Teilansicht eines Querschnitts entlang Linie 2-2 von Abb. 1 mit Blick in Pfeilrichtung.
• Abb. 3 ist eine ähnliche Ansicht wie Abb. 2, aber der erste, nicht-wiederverschliessbare Verschluss ist geöffnet.
• Abb. 4 ist eine perspektivische Teilansicht mit geöffnetem erstem und zweitem Verschluss für den Zugriff zum Sackinhalt und das Ausschütten desselben.
• Abb. 5 ist eine perspektivische Teilansicht, die zeigt, wie eine Reihe von Säcken mit Verschlüssen versehen wird und dann voneinander getrennt wird.
• Abb. 6 ist eine schematische Abbildung der Schritte bei der Herstellung der wiederverschliessbaren Säcke dieser Erfindung.
• Abb. 7 ist eine Teilansicht eines Querschnitts entlang der Linie 7-7 der Abb. 6 mit Blick in Pfeilrichtung.
• Abb. 8 ist eine vergrösserte Teilansicht eines Querschnitts, ähnlich wie Abb. 2, und zeigt eine zweite Verwirklichung dieser Erfindung.
• Abb. 9 ist eine ähnliche Ansicht wie Abb. 2 und ist eine weitere Verwirklichung der Erfindung nach einem Zwischenschritt der Herstellung.
• Abb. 10 ist eine ähnliche Ansicht wie Abb. 9; sie stellt den fertiggestellten Gegenstand von Abb. 9 dar, nachdem der Herstellungsprozess abgeschlossen ist.

In the manufacture of the reclosable bags of the invention (according to claim 1), the opposing profile elements are formed separately, hooked together and wound on a single spool. In an uninterrupted process, the second closure is released from the spool and the lower assembly points of the profile elements are attached to the walls of a row of sacks. The ends of the profile elements are heat sealed between adjacent bags. Thread or thread is wound on a separate spool. With the thread, the sack opening is sewn along the chain stitch to create the non-reclosable, removable closure, thus closing the sack opening. The stitches are sewn so that they can be separated manually. The sealed bags are separated by cutting the second seal on the heat-sealed part. The invention is explained in more detail using exemplary embodiments. Show it:

• Figure 1 is a perspective view of a reclosable sack embodying the invention.
• Fig. 2 is an enlarged partial view of a cross section along line 2-2 of Fig. 1 looking in the direction of the arrow.
• Figure 3 is a similar view to Figure 2, but the first, non-resealable closure is open.
• Fig. 4 is a partial perspective view with the first and second closures open for accessing and dispensing the contents of the sack.
• Figure 5 is a partial perspective view showing how a row of sacks are sealed and then separated.
• Figure 6 is a schematic illustration of the steps in making the resealable bags of this invention.
• Figure 7 is a partial cross-sectional view taken along line 7-7 of Figure 6 looking in the direction of the arrow.
• Figure 8 is an enlarged partial cross-sectional view similar to Figure 2 and shows a second implementation of this invention.
• Fig. 9 is a view similar to Fig. 2 and is a further implementation of the invention after an intermediate step of manufacture.
• Fig. 10 is a view similar to Fig. 9; it represents the finished item of Fig. 9 after the manufacturing process is complete.

To understand the features of the invention, reference is now made to the embodiments shown in the drawings and they are described in detail.

A reclosable sack (10) consists of a lower part, which can be made of any suitable material and can be single-layer or multi-layer, depending on the material and sack content. In the preferred implementation, the sack (10) is shown with front and rear walls (11) and opposite side walls (12), all of which are made of two-ply strong paper. The sack walls (11) and (12) can also consist of plastic material such as polyethylene or polyvinyl chloride. In the preferred embodiment, the sack (10) also comprises a firm bottom closure (13) made of a permanent chain stitch or, in the case of plastic material, a heat-sealed or adhesive seam.

The reclosable sack includes an upper closure (14) which is shown in more detail in the cross-sectional view of Fig. 2. According to this invention, the upper closure (14) comprises a non-reclosable sewn closure (15) and a second reclosable closure (20) so that the bag is a tamper-evident container after the initial filling and sealing, but after opening through the consumer can be closed again. If access to the sack contents is desired, the first non-reclosable sewn closure is opened and thus offers access to the sack opening, while the second resealable one Closure over the bag opening can be closed again after the first closure has been removed.

The first non-reclosable closure (15) comprises a line of chain stitches made of thread, cord or thread (16), which close together the sack walls (11). The chain stitches made of thread are applied so that the thread ends (16A) are loose. The chain stitches can be torn apart or released by pulling the loose thread ends (16A) by hand. To make it easier to remove the chain stitches (16) of the first fastener, a tear strip or tear tape (17) is attached, see dashed lines in Fig. 2. The tear tape (17) is sewn onto the sack walls (11) if the first one is not - reclosable closure is created.

The second reclosable fastener comprises a pair of opposing profile elements or strips (22) and (25). The first profile strip (22) comprises a number of ribs (23) protruding from the inner surface. Profile strip (25) comprises a number of ribs (26) protruding from the inner surface, which are aligned with the ribs (23) of the opposite profile strip (22) for an interlocking toothing. The interlocking rib profiles (23) and (26) reach high enough to the upper end or the opening of the sack, so that the ribs (23) and (26) can interlock as in Fig. 7. As a fixed rule of the invention, the profile strips (22) and (25) can interlock to close the upper part of the bag when pressure is applied along the outer surfaces of the profile strips so that the ribs interlock. The interlocking ribs (23) and (26) can come loose if the edges (24) and (27) are gripped which protrude beyond the interlocking ribs. If the edges (24) and (27) are separated or pulled apart, the interlocking ribs (23) and (26). The profile strips (22) and (25) are attached at the assembly points (30) and (31) of the strips (22) and (25) to the upper end of the sack walls (11). The chain stitch thread (16) of the first non-reclosable fastener (15) is sewn through the assembly points (30) and (31) of the profile strip. The profile strips (22) and (25) are sealed together at the ends (33), as shown in Fig. 4. The strips are preferably heat-sealed at the ends, but sonic welding, adhesive or similar sealing processes can also be used. The purpose of the seal is to close the ends of the profile strips in order to guarantee an airtight seal when the bag is reclosed and to keep the interlocking ribs in the correct position. Heat sealed profile strip ends (33) of the reclosable sack of this invention overcome a disadvantage of the prior zipper invention in which the zipper cannot fully close the sack opening. Moreover, the prior zipper invention is susceptible to inadvertent opening, while the profile strips (22) and (25) of this invention guarantee an absolute closure that is very resistant to accidental opening.

Figures 3 and 4 show the resealable sack of this invention with the first, non-resealable closure (15) removed. Once the chain stitch thread has been torn loose to release the chain stitches, a number of small holes (18) along the side walls (11) and through the profile strips (22) and (25) are visible, where the stitches were previously. If the non-reclosable closure (15) is removed, the upper end of the sack is open and allows access to its contents. The upper end of the bag can be closed again by the two profile strips (22) and (25) and their corresponding interlocking ribs (23) and (26).

The process for making the reclosable jacket of this invention is shown in Figures 5-7. The resealable sack can be in one continuous Process are produced in which a number of such bags are equipped with the upper closure (14). The row of sacks (10) are filled in an earlier step and the sack openings are left open.
In a separate work step, the second reclosable closure (20) with the profile strips (22) and (25) is formed in a conventional extrusion process. The profile strips are toothed and wound onto a delivery spool (35). The toothed closure (20) is dispensed from the spool and arranged over the openings of the bags (10) as shown in Figs. 6 and 7. The lower assembly points (30) and (31) of the interlocking profile strips (22) and 25) are attached to the sack walls (11) by an adhesive attached to the inner surfaces of the strips. The adhesive can also be applied directly to the sack walls (11) instead of on the inner surfaces of the profile strips. The adhesive applied at the assembly points (30) and (31) must bond the plastic and the bag material sufficiently whether the bag is made of plastic material or paper. The lower ends of the plastic profile strips (22) and (25) can be pressed against the sack walls with a pair of rollers (37) on both sides. Other suitable means for guaranteeing strong adhesion between the bag walls (11) and the reclosable toothed closure (20) can be determined.

When the reclosable closure (14) is glued to the walls (11) of the bag (10), the ends of the reclosable profiles are heat sealed at the points (33). In the continuous sack making of this invention, the heat sealing step occurs between adjacent sacks (10).

The first non-reclosable closure (15) can be attached before or after the heat sealing. In the preferred implementation, the first closure is placed before the heat sealing because the thread (16) and the tear strip (17) are not made of plastic material and are therefore not sensitive to them Are heat seals. If the tear-off strip (17) consists of plastic material, it must be attached after the heat sealing so that it can be removed again.

When attaching the first sewn fastener (15), twine or cord (41) is released from a roll or spool (not shown) and sewn in a conventional manner to form a chain stitch that is tight enough to close the sack, but loose enough to be solved again. During chain stitches application, it is important to leave loose ends (16A) of thread (16) to allow the chain stitch to pull apart when the sack is to be opened. If a tear strip is attached, it is emitted by a spool (42) before the chain stitch is sewn. If the first non-reclosable closure is attached, the individual bags (10) are cut apart, namely between the bags, along a cutting line (36) which leads through the center of the heat-sealed point (33) of the reclosable profile closure (14).

Figure 8 shows a second implementation of the reclosable sack of this invention. A reclosable sack (10) comprises outer walls (11) and (12) and a first non-reclosable closure (50) with a chain stitch thread or thread (51) with pulling or tear strips (52). The second reclosable fastener (60) comprises a pair of profile strips (61) and (62) which are glued to a second pair of strips. The strips (63) in this embodiment are made of the same material as the tear-off strip, such as crepe paper. The profile strips (61) and (62), which are made of plastic, are attached on their outer surfaces to the inner surfaces of the strips (63) at the point (64). The second pair of strips (63) is attached to the sack walls (11) on the inner surfaces thereof at point 65. An advantage of this design is that the similar materials of the sack walls (11) and the strips (63) can be easily and quickly produced in an uninterrupted manner Bags can be joined together, in contrast to the dissimilar materials that come together in the design of Fig. 7. The profile strips (61) and (62) can be attached to the strip (63) before the sack production and wound onto a supply roll, as shown with roll (35) in Fig. 6.

Figures 9 and 10 show another embodiment of the method and bag of this invention. The embodiment shown in Figs. 9 and 10 is identical to that of Fig. 2, except that the stitches are carried out on the sack before the resealable plastic fastener is attached to the sack. Therefore, Fig. 9 shows the sewn closure (15˝), which is fastened by the sack walls (11˝), without the profile strips (22˝) and (25˝). In a later step, see Fig. 10, the profile strips made of plastic (22˝) and (25˝) are attached to the bag outer wall of the sewn closure (15˝).

Claims (5)

1. Method of closing the filler openings of bags (10; 10′), which are filled with a filling material, by utilising a reclosable fastener (20) and a non-reclosable, stitched fastener (60), which fasteners (20; 60) include interlocking profile strips (22, 25; 61, 62), comprising the following method steps:

   - the filled bags (10; 10′) pass from a filling apparatus to a closing device adjacent one another,

   - the interlocked profile strips (22, 25; 61, 62), which have been rolled-up on a single supply reel (35), are released from the reel (35), and their mounting portions (30, 31) or strips (63), lying beneath the profiles (23, 26), are supplied to the bag walls (11; 11′) along the openings and are connected thereto,

   - the non-reclosable, separable fastener (20; 60) is stitched along the bag openings,

   - the two profile strips (22, 25; 61, 62) are non-detachably interconnected, by means of a heat-sealing process, in the region of the bag ends and between the adjacent bags (10) at the portions (33), and

   - are subsequently separated along a cut line (36) through the heat-sealed portion (33) of the reclosable profile fastener (20; 60).
2. Method according to claim 1, characterised in that, prior to the profile strips (61, 62) being connected to the side walls (11′) of the bags (10′), the profile strips (61, 62) are connected to strips (63), which are intended to be adhered to the side walls (11′) of the bag (10′).
3. Method according to claim 2, characterised in that, prior to the profile strips (61, 62) being wound onto the supply reel (35), the strips (63) are connected to the profile strips (61, 62) and are unwound from the supply reel (35) together with the profile strips (61, 62) when being applied to the bags (10′).
4. Method according to claim 1, characterised in that the mounting portions (30, 31) or the strips (63) of the profile fastener (20, 60) are pressed towards the bag walls (11; 11′) by a pair of rollers (37), and they are connected to said bag walls by an adhesive, which is applied to the inner surfaces of the mounting portions (30, 31) or to the side walls (11; 11′) of the bags (10; 10′).
5. Method according to one of claims 1 to 4, characterised in that, simultaneously with or subsequently to the profile fastener (10; 60) being connected to the bag (10; 10′), a tear strip (17; 52) is mounted upon one of the mounting portions (30, 31) or upon a strip (63) and is connected to the profile fastener (20; 60) and the bag (10; 10′) by a seam which is stitched with cord or string (41; 51).

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