EP0427010B1 - Strip fastener for closing plastic bags and method for manufacturing the same - Google Patents

Abstract

A strip fastener, preferably made of plastic, is used for closing bags. It consists of a male profile (1) and a female profile (2, 5, 6) which are connected in each case by a film (3, 4) and can be connected to one another detachably. In order that such a strip fastener can be closed easily with simple and cost-effective manufacture, at least two spaced-apart continuous knobs (8) are provided on the side of the film (3) facing away from the male profile (1). <IMAGE>

Description

The invention relates to a closure, preferably made of plastic, for closing bags in accordance with the preamble of claim 1. Furthermore, the invention relates to a bag, preferably made of plastic, and a method for producing a closure or a bag.

From DE-PS 14 86 627 or DE-PS 19 50 724 a closure, preferably made of plastic, for closing prey is known, which consists of a male profile and a female profile, which are each connected to a film and the are releasably connectable. From US-PS 42 63 079 a closure is known which can be extruded from a nozzle onto a prefabricated film. It is also possible to extrude the closure by itself from a nozzle and then to connect it to a film by welding or gluing.

So far, particular attention has been paid to producing the known closures in the smallest dimensions, on the one hand because of the material savings, but on the other hand also to enable easier cross-welding on the so-called bag machines, since each reinforcement of the closure part during the subsequent separation welding, in which the sealing film bags are made, the welding process is slowed down or additional equipment is required.

The disadvantage of the known closures is that male profile, that is the free-standing single hook, dodges too easily to the side, so that the inexperienced user of such closures or bags often has difficulties in closing the closure or bag. It has been shown that such closures or sealing bags, the use of which has the meaning and purpose, to be used several times in order to keep the filling - especially in department stores and retail stores - tightly closed, lying open after a single opening and dusting the goods . Few users can easily lock the known narrow, thin single-groove closures of the type specified above.

In the closures specified at the outset, the female profile of the closure, which is intended to accommodate the male profile, that is to say the single hook, is stiffer in itself due to the necessarily reinforced back, so that when trying, the known closure or pouch does not come from the closure edge or pouch edge from closing, but from the middle, the male profile, i.e. the single hook, dodges too easily, so that the inexperienced user cannot bring the single hook exactly into the female profile.

DE-A 3 032 889 discloses a closure, preferably made of plastic, for closing bags, which consists of a male profile and a female profile, each of which is connected to a film and which can be detachably connected to one another. This closure is provided on a container having flexible first and second side walls. The reclosable end of the first side wall extends beyond the end edge of the second side wall. On the surface of the first side wall, a first and a second web are arranged at a distance from one another essentially parallel to the first closure profile. The first web runs close to the end edge of the first side wall, while the second web lies substantially opposite the end edge of the second side wall when the closure profiles are in engagement with one another. A third web is arranged on the surface of the second side wall substantially parallel to the second closure profile near the end edge of the second side wall. This configuration is intended to make it particularly easy to open the container.

EP-A-241 334 discloses a closure for pipe insulation which has two spaced, continuous knobs on the side of the closure tape facing away from the profiles. These knobs are arranged at a relatively large distance from the profiles. They only serve to stabilize the flags after they have been welded onto the tube in order to avoid subsequent corrugation.

A closure, preferably made of plastic, for closing bags according to the preamble of claim 1 is known from FR-A 2 620 377. With this closure, there are two spaced, continuous knobs on the side of the film facing away from the male profile and lying on different sides of the profile provided that serve the stabilization.

The object of the invention is to further develop a closure of the type specified at the outset such that it can be easily closed with simple and inexpensive production.

According to the invention this object is achieved by the features specified in the characterizing part of claim 1. The continuous knobs are higher than the intervening parts of the profile for a tactile feeling when closing the lock. As a result, a clear guidance through the two noticeable raised knobs is felt when streaking along the closure with the thumb and forefinger, so that the male profile is guided in a straight direction when the closure is gripped (closed).

The knobs, which are relatively small in relation to the profile, are attached to the back of the male profile, ie they point in the opposite direction to the male profile. Since the knobs are relatively small, very little material is required for their manufacture, which means that the closure can be produced very inexpensively. The knobs can be easily attached. The closure is easy to close because the knobs provide very good guidance.

From EP-A-114 373 it is known to stiffen the male profile by means of ribs which extend in the same direction as the male profile and which are spaced apart from the male profile. The ribs lie on different sides of the male profile and point in the same direction. This closure described in the cited EP-A-114 373 has the disadvantage that a considerably greater consumption of material takes place, namely due to the relatively large ribs and the additionally existing, reinforced back. The ribs are essentially the same size as the male profile. All of this has a negative impact on manufacturing costs and is also undesirable for environmental reasons (disposal). The manufacture of the tools is also more difficult since the respective nozzles (extrusion nozzles) have to be adjusted in a relatively complex manner.

A solution is known from EP-A-223 125 in which two webs are attached to the left and right of the male profile, which webs point in the same direction as the male profile. However, the back strength of the profile is reduced. However, the webs involve considerably more material than the knobs proposed here. It is also disadvantageous in the embodiment according to EP-A-223 125 that when the two profile parts are pressed together and when they are slid along to close the Profile of the thumb only feels the slight increase that is provided immediately below the male profile and that cannot be avoided for rheological reasons. The guidance of the thumb when closing the profile is therefore poor. In contrast, the knobs proposed here lead the thumb much better when the profile is closed.

The knobs stabilize the male profile sufficiently so that the end user (user) can not only close the closure more easily from the edge of the bag, but can also engage the closure strips anywhere in the middle of the bag or closure, to close the shutter.

Another great advantage of the knobs is that they lie on the back of the profile, ie on the outside of the closure or the bag. The male profile and the knobs point in opposite directions. This arrangement has the advantage that after the first pressing of the profile parts into each other and the subsequent streaking with the thumb and index finger, the thumb feels a very clear guidance through the two noticeable rising knobs and thus unconsciously the male profile when the closure is closed (closed) straight direction. It is achieved by a simple but greatly improved design that the disadvantages known hitherto are avoided and nevertheless an easier and safer closing of the closure parts is ensured, all this with the least possible material expenditure.

Advantageous further developments are described in the subclaims.

Two continuous knobs can be provided. This achieves sufficient stabilization with a minimum of material. In certain applications, it is advantageous if four continuous knobs are provided, since this achieves greater stabilization or stiffening.

It is also possible to provide at least two spaced, continuous knobs on the side of the other film facing away from the female profile.

One, several or all of the knobs are preferably colored. These colored knobs also represent a locking aid purely optically.

The invention further relates to a bag, preferably made of plastic, characterized by a closure of the type specified above. The closure is preferably in one piece with the bag.

The invention further relates to a method for producing a closure of the type specified above or for producing a bag of the type specified above. According to the invention it is provided that the foils and the knobs or the bag and the closure are extruded from a tool in one operation . It is possible to extrude one or more knobs in color. The method for attaching the knobs represents a further advantage over the known closures. Because the knobs are attached to the back of the profile, ie beyond the direction of the profile, the profile nozzle can be produced undisturbed by unpleasant influences. While in the process according to EP-A-114 373 or EP-A-223 125 largely in the nozzles to take into account the flow behavior and the resulting radial forces, caused by the relatively thick parts of the profiles and the relatively thin parts of the film, in the present case the knobs are completely separated from the actual profile either by a side extruder molded separately or a corresponding material flow is introduced into the outer ring of the nozzle, which is independent of the actual closure profile. Accordingly, a tool for producing a closure or a bag of the type specified above consists of a ring and a core, which form an annular gap between them. Radially outside the annular gap, channels for material feed are provided, which are used to produce the knobs. A side extruder is preferably provided for these channels. The material required to produce the knobs is fed into the channels through this auxiliary extruder. The side extruder can supply colored material, so that colored knobs can be produced particularly easily in this way.

Fig. 1

einen Verschluß der vorbekannten Art,

Fig. 2

einen Verschluß mit Zwei Noppen,

Fig. 3

einen Verschluß mit vier Noppen,

Fig. 4

einen Verschluß mit zwei weiteren Noppen beim weiblichen Teil,

Fig. 5

einen Verschluß während des Schließvorganges,

Fig. 6

einen Beutel mit einem Verschluß während des Schließvorganges,

Fig. 7

ein Werkzeug zum Herstellen eines Folienschlauches mit integrierten Verschlußprofilen und zur Anspritzung der Noppen mittels Beistellextruder und

Fig. 8

ein weiteres Werkzeug, bei dem die Noppen ohne Beistellextruder durch Zuspeisungskanäle angespritzt werden.

Embodiments of the invention are described below with reference to the accompanying drawings. In the drawing shows

Fig. 1

a closure of the known type,

Fig. 2

a closure with two knobs,

Fig. 3

a closure with four knobs,

Fig. 4

a closure with two further knobs on the female part,

Fig. 5

a closure during the closing process,

Fig. 6

a bag with a closure during the closing process,

Fig. 7

a tool for producing a film tube with integrated closure profiles and for injection molding the knobs by means of a side extruder and

Fig. 8

Another tool in which the knobs are injected through feed channels without the need for an extruder.

In the closure of the known type shown in FIG. 1, the male profile 1 is connected or hooked to the female profile 2. The female profile 2 consists of a hook profile 5 and a profile part 6 without a hook. The hook of the male profile 1 is complementary to that of the profile part 5 of the female part. The male profile 1 is connected in one piece with a film 3, the female profile 2 is connected in one piece with the other film 4. The male profile 1 has a reinforced back 7 on the side of the film 3 opposite the profile.

Fig. 2 shows a closure made of plastic for closing bags, consisting of a male profile 1 and a female profile 2, which consists of the hook part 5 and the profile part 6, both the male profile 1 and the female profile 2 with are each connected to a film 3, 4. By hooking are the male profile and the female Profile releasably connectable. On the side of the film 3 facing away from the male profile 1, two spaced, continuous knobs 8 are provided. The knobs 8 are integrally connected to the film 3. As can be seen from FIG. 2, only the knobs 8 of the previously known reinforced back (FIG. 1) are left, while the remaining profile back 7 is thinned out and is essentially no thicker than the film itself. The contour of FIG 2 is represented in FIG. 1 by the dashed line 9.

In the embodiment of FIG. 3, four knobs 8 are provided instead of two knobs in order to obtain greater stabilization of the film.

As can be seen from FIG. 4, on the side of the other film 4 facing away from the female profile 2, that is to say the film 4 belonging to the female profile 2, several, in the illustrated case two, spaced, continuous knobs 9 can be provided. The knobs 8, 9 are essentially semicircular in cross section. However, other cross-sectional shapes are also possible.

From Fig. 5 it can be seen how the two knobs are touched by the thumb 21 when closing and the thumb thereby feels a very clear guidance through these two elevations (knobs) and so unconsciously leads the male profile in a straight direction when the closure is engaged . Another finger 22 of the same hand lies opposite the thumb 21, generally the index finger.

Fig. 6 shows a closure bag 10 of the type described, which by stiffening the knobs 8 in the closure part at the upper end of the bag 10 with thumb 21 and index finger 22 of the middle can be closed by simply pressing it in without the locking parts evading laterally. The knobs 8 have a stiffening effect here, in a manner similar to that in the case of thin sheet metal, short corrugations or applied strips can bring about an enormous stiffening. If the male profile consists of only a single hook, this inevitably moves to the side when a bag is pressed in from the center (as shown in FIG. 6) and does not hit the female part if there are no knobs. The knobs 8 make it possible to reliably close the closure also from the center, as shown in FIG. 6.

Stiffeners in the form of ribs are already known from EP-A-114 373 and from EP-A-223 125. There, however, the ribs always point in the same direction as the profile. The fact that the knobs 8 and 9 point in the opposite direction to the associated profile increases the overall cross section or the entire length of the cross section, which also increases the overall rigidity.

7 shows a tool for producing a film tube with integrated closure profiles and for molding on the knobs by means of a side extruder, only the part of the tool which is used for spraying the knobs being shown in detail. The tool consists of a ring 11 which encloses a core 12. Plastic material flows from the extruder into the tool from below through the ring channel 13 between the ring 11 and the core 12. It finally flows out of an annular nozzle 15 through the narrow gap 14 and thus forms a plastic tube. From a side extruder mouthpiece 16 is the knob on the through a bore 17 and a narrower channel 18 directly on the upper edge of the ring 11 sprayed plastic hose. The channel 18 opens into the gap 14 in such a way that the hump is formed. As can be seen from view "A", the bore 17 divides into two channels 18 in order to produce both hops. If more knobs are to be produced, more channels can be arranged accordingly.

8 shows another tool without a side extruder. This tool also consists of an outer ring 11 and a core 12 arranged therein, which delimit between them the ring channel 13 through which the plastic material flows to the ring nozzle 15. Through a channel 19 on the cylindrical part of the ring 11 more material is supplied to the exiting hose at this point, so that the desired hop is created. One channel 19 is provided per hop. Depending on the depth and length of the channel 19, the knob is larger or smaller; it can be determined in the desired way.

It is also possible to provide, in addition to the knobs 8 and 9, further knobs which point inwards, that is to say in the same direction as the associated profile part. This embodiment is not shown in the drawings. The inward-facing knobs can lie at the same point as the associated outward-pointing knobs 8 or 9. However, it is also possible to arrange the inward-pointing knobs at a distance from the outward-facing knobs 8 and 9. These additional, inwardly facing knobs serve for further stabilization.

The embodiment shown in FIG. 4 with four knobs 8 on the film 3 of the male profile 1 and two knobs 9 on the film 4 of the female profile 2 is particularly recommended for the profile shown in Fig. 4, which is known from EP-A-223 125. There the back of both the male profile and the female profile is so thin that there is no stabilization. This stabilization is brought about by the knobs 8, 9.

Claims (10)

1. Fastener, preferably of plastic, for closing bags, comprising a male profile (1) and a female profile (2, 5, 6), which are connected in each case to a strip (3, 4) and are detachably connectable to each other, there being provided on the side of the strip (3) facing away from the male profile at least two spaced-apart continuous protrusions (8), lying on different sides of the profile, characterized in that the protrusions are higher than the parts of the profile lying in between, in order to provide sensitive guidance during closing of the fastener.
2. Fastener according to Claim 1, characterized in that two continuous protrusions (8) are provided.
3. Fastener according to Claim 1, characterized in that four continuous protrusions (8) are provided.
4. Fastener according to one of the preceding claims, characterized in that at least two spaced-apart, continuous protrusions (9) are also provided on the side of the other strip (4), facing away from the female profile (2).
5. Fastener according to one of the preceding claims, characterized in that one, more than one or all the protrusions (8, 9) are coloured.
6. Fastener according to one of the preceding claims, characterized in that additional protrusions are provided on the same side as the male and/or female profile (1, 2).
7. Bag, preferably of plastic, characterized by a fastener according to one of Claims 1 to 6, the fastener preferably being in one piece with the bag.
8. Method of manufacturing a fastener according to one of Claims 1 to 6, characterized in that the strips (3, 4), the profiles (1, 2) and the protrusions (8, 9) are extruded from a die in one operation.
9. Method of manufacturing a bag according to Claim 7, characterized in that the bag and the fastener are extruded from a die in one operation.
10. Method according to Claim 8 or 9, characterized in that one or more protrusions (8, 9) are extruded in coloured form.

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