EP2483170A1

EP2483170A1 - Plastic closure comprising a cutting and perforating device

Info

Publication number: EP2483170A1
Application number: EP10752834A
Authority: EP
Inventors: Dan Barron
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-09-29
Filing date: 2010-09-15
Publication date: 2012-08-08
Also published as: WO2011039054A1; US20120241471A1; CN102548852A; DE102009045124A1

Abstract

The invention relates to a closing device (1) consisting of a plastic material for applying to a closed container consisting of a plastic film material. Only two cutting teeth (20, 21) of the same height are to be applied to the cylindrical perforator (5) of said device, said teeth being arranged in an angular region of between 70° and 120° of the circumference. In this way, the section of the subsequent tooth extends into the section of the previous tooth, enabling a secure opening, without the risk of cutting an entire rondelle out of the plastic film of the container. The creation of only two partial sections without producing an opening in the container is also prevented.

Description

PLASTIC LOCK WITH A CUTTING AND PUSHING DEVICE

The present invention relates to a closure device made of plastic for attachment to a closed container made of plastic film material, consisting of a lower part with a cylindrical spout and a flange for attachment to the container and a screw cap which is screwed on the lower part, and a cylindrical piercing with external thread, which is open on both sides in the axial direction and runs in the spout of the lower part in the internal thread, wherein means are provided in the screw cap, the screw at the first screw movement of the screw through the screw down, and that the cylindrical piercer on the cylindrical wall, on End which is directed to the container wall, has cutting teeth.

Closure device of the type mentioned above have been attached to today only made of laminated film material containers. These laminated films have at least three layers of different materials. On the one hand, such a material consists of one Cardboard layer, which gives the container the required rigidity, an aluminum layer which serves as aroma barrier and a plastic layer which guarantees the required tightness. In order to cut through these three layers, the corresponding piercer of a closing device mentioned at the beginning has to fulfill different functions. In order to sever the paperboard layer, a plurality of saw teeth are often suggested, while a raised tooth with a front cutting edge cuts through the aluminum layer while a perforating tooth pierces the plastic layer before the aforesaid cutting edge can further cut the plastic film. In these containers made of laminated film material, in principle, the separation of the cardboard layer is a problem, especially if the serving for supporting partial punching that at least partially cuts through the cardboard layer does not match exactly with the cutting line of the piercer, so either the teeth are too weak or in the case of a large number of teeth, the cardboard material comes between the teeth and these can barely produce a perforated effect thereafter.

However, the present invention is a closure device which is applied to a pure plastic film material. Such

Tubular bags, in the jargon usually called pouches, have not been previously mentioned by means of the aforementioned Closure devices opened, but an opening was already punched out and a closure was welded correct position with his spout or welded between two layers of film. As a result, the stability of the bottled food or beverage is thus dependent only on the tightness of the closure, such closures have been used practically only in unproblematic areas, especially in the field of cosmetics.

When using the closure device of the type mentioned, the container bag remains completely closed until the time of the first opening. This gives an increased shelf life. In addition, in such solutions, the plastic film is much more robust and designed with a higher wall thickness than the very thin plastic film layer in a laminated film. This results in other requirements for the closing device. First attempts at sealing devices of the known type gave no reliable results.

Piercers such as those of US-A-5020690 or US-A-5141133 have a plurality of teeth. These adjacent teeth form virtually the shape of an annular saw blade. Such solutions have either resulted in a rondelle being completely cut out and dropped into the container or that due to the toughness of the foil individual teeth have broken off and fallen into the container. If it is the case here for containers for drinks, so this is completely unacceptable.

So far, it was assumed that a large number of teeth is advantageous, as a result, a variety of perforations. In fact, however, it has been found that a plurality of perforations per se give no advantage. Rather, it has been shown that a large number of teeth automatically means that these teeth must be relatively weak. This leads to the disadvantage already mentioned above.

Based on this finding, further developments have been made, in which on the one hand reduces the number of teeth and on the other hand, the shape of the teeth was designed differently. Thus, for example, from EP-A-1415926 a solution with all but the same, but unevenly distributed over the circumference of teeth known. Furthermore, from US-A-6279779 a closure device of the type mentioned above is known with a piercer, which only has a single tooth. This tooth is designed accordingly strong and has different surfaces with different effects. The one-tooth version has clearly not worked. The processes of cutting the film and its perforation, the subsequent cutting and finally the folding away of the cut out part, have not been optimized in a single element. Therefore, the Applicant has made experiments, with a piercer according to WO2007 / 030965 in which three teeth distributed over the circumference and minimally offset from a uniform distribution over the circumference, are present. While piercers of this type have been proven many times, there are always cases in which either the film has been completely cut out and the corresponding roundel in the container much, or in other cases, the films have been cut approximately equidistant only in three places and the film remained hang over the opening. From these findings, the applicant has sought in elaborate experiments an optimization that reliably realizes an opening cut, so that a stuck with the container in connection flap-like rondel gets stuck, which is pushed through the teeth from the open area of the piercer.

This complex object is achieved by a closure device of the type mentioned, which is characterized in that the piercer has exactly two equal teeth, both of which are arranged within an angular range of 70 to 120 ° of the circumference. This causes the plastic film to be cut to be pre-tensioned by the two teeth and at the same time perforate and cut the film at the same time, and after a short distance into the cutting area of the follower tooth Front tooth comes and thus becomes ineffective. If the perforation of the film follows practically immediately at the first contact, the film can nevertheless not be cut out in a completely circular manner and thus no plastic film rondel falls into the container. If the perforation and the subsequent cut are made relatively late, a sufficiently long incision will still be made to ensure that the incision of the trailing tooth will be in the area of the incision of the anterior tooth, and this will still result in a cut exceeding 180 °, so that the film is cut wide enough to achieve a sufficient flow. As already mentioned, the closure device according to the invention is applied to a container of pure plastic film material. This single or multi-ply plastic film is substantially thicker than the plastic film which is used as a sealant layer in the composite film of various materials.

While in the thin film because of their high elasticity, the perforation must first be made to ensure a secure opening, this no longer seems to play the central role in the film now used. Investigations at high magnification have shown that apparently the film is scratched to form chips. It is therefore an additional object of the present invention, this knowledge bill-bearing teeth to provide similar to a steel-cutting insert with Spanleitmittel. In fact, these chips have accumulated at the tooth tip in the previous solutions, and accordingly the previously applied torque performance was much higher than in the present solution according to claim 6.

In the drawing, a preferred embodiment of the subject invention is illustrated and described below. It shows:

Figure 1 shows the closed plastic closure before the first use of a

Side view and

Figure 2 the same m a diametrical

vertical section

FIG. 3 shows a simplified representation of FIG

Piercing from below overlooking the

Edge with the two cutting teeth

Figure 4 shows the piercer and the lower part with flange as a one-piece semi-finished product before assembly, turn in

diametric vertical section and

Figure 5 the same view rotated by 180 °.

Figures 6a-6c show various sectional images.

Figure 7 shows a suitable for harder plastic films piercing with two offset by an angle teeth with others

Cutting characteristics and

Figure 8 the same piercer rotated by 120 °. Figure 9 shows a load-time diagram for the

Piercer according to FIGS. 7 and 8, during

10 shows such a load-time diagram for the

Piercing with the teeth configuration according to Figures 4 and 5 represents.

The plastic closure device is designated overall by 1. This comprises three components, two of which can be produced in one piece in terms of manufacturing technology, as described below and illustrated in FIGS. 4 and 5. The plastic closure device 1 has a screw cap 4, at the lower edge in alignment with the jacket wall of the screw cap, a guarantee strip 7 is formed via predetermined breaking point bridges 8. In the side view according to FIG. 1, only one flange 3, which is part of the lower part 2, of the closure device 1 can be seen.

In the sectional drawing according to FIG. 2, it can be seen that the screw cap 4 has a jacket wall 9, as well as a cover surface 10. The screw cap 4 has an internal thread 11 designed as a fine thread. The lower part 2 with its flange 3, which serves the welding or adhesive bond with the container, has a cylindrical spout 6, which is tubular and open on both sides. This spout 6 has an external thread 12 that is also designed as a fine thread and when screwing and unscrewing the screw cap 4 with the internal thread 11 of the screw cap 4 meshes. The fine thread 11, 12 is preferably designed as a double-threaded thread. The fine thread has the advantage of easy assembly by the internal thread of the screw cap can be pushed ratchet-like over the external thread 12 of the spout 6. This allows mounting without relative rotation of the parts to each other. In the screw cap 4, two diametrically opposed drivers 13 are present, which are integrally formed on the underside of the top surface 10 of the screw cap 4. These drivers 13 act together with driver 14 in Piercing 5. This piercing 5 is described in detail below with reference to Figures 4 and 5.

As already mentioned, the piercer 5 and the lower part 2 are produced in one piece, as shown in FIG. Here, the lower part 2 and the piercer 5 together form a semi-finished product which can be produced by means of a single injection mold. For mounting lower part 2 and 5 Durchstosser can easily be pushed together. Here, the piercer 5 is completely within the cylindrical spout 6 to lie. In this position as a semi-finished product, the piercer 5 is formed over predetermined breaking points 15 at the upper edge of the spout 6. The piercer 5 consists of a cylindrical tube section 16, the outside has a coarse thread 17. This coarse thread 17 with a large pitch, meshes with a suitably adapted trapezoidal thread 18 on the inside of the spout 6. The piercer 5 also has two diametrically opposed driving rib 19, to which the previously mentioned driver 13 of the screw 4 at the corresponding screwing come to the concern. At the bottom of the piercer 5, two cutting teeth are formed, of which both are visible in Figure 2, while in Figure 5, only the trailing tooth is visible, while the leading tooth is cut away. The leading tooth is designated by 20 and the trailing tooth by 21. Both teeth 20, 21 have the same length 1. This length refers to the vertical distance from the lower edge 22 of the cylindrical tube section 16 to the tip 23 of the corresponding cutting tooth. In the assembled state, as shown in FIG 2, the piercer 5 is completely within the cylindrical spout 6. Here, the tip is resp. In a Abschraubbewegung the screw 4, the piercer 5 moves in the opposite direction in the axial direction, the piercer performs a much larger translational vertical path per revolution, as the screw cap 4 in the opposite direction. In fact, the piercer 5 performs at most a rotational movement of about 330 °, while the screw cap performs one or more passages until complete unscrewing.

Depending on the strength, elasticity and other conditions, in particular with respect to the bias of the plastic film of the tubular bag, the plastic film is punctured sooner or later. Practically always the piercing of the cutting teeth 20, 21 takes place simultaneously. This results in the sectional images, as shown in Figures 6a to c. In FIG. 6a, the partial sections of the following tooth have not yet penetrated into the section of the leading tooth. In contrast, in FIG. 6b, this has already happened. This figure shows the worst case cut line, which is practically of the order of 200 to 240 degrees. If this were the end position, then in principle the leading tooth would push down the tab-shaped part L, so that in this case too, the flow is at least more than 50% open. Normally, however, the cutting line will extend around a circle of about 330 °. This situation is shown in FIG. 6c.

In the figure 3 is simplified, the piercer 5 with a view of the teeth in the direction of the axis of rotation of the cylindrical pipe section 16 is shown. If one draws radii from the two tooth tips to the center of the longitudinal axis, an angle CC forms between them. This angle CC must be within an angular range between 70 ° and 120 °. In addition, it is advantageous if one chooses the external thread of the penetrator 5 and the internal thread 18 of the spout 6 so steep that during the unscrewing movement of the screw cap 4, the cutting teeth 20, 21 in the cutting direction from the point of contact on the plastic film to be cut through the container until complete completed Abschraubbewegung the screw cap 4, a maximum cutting path of 210 ° passes. If one now adds to these 210 ° the maximum angle, the leading tooth 20 and the trailing cutting tooth 21 include each other, namely an angle of 120 ° thereto, this results in one maximum cutting line extending over 330 °. This leaves a sufficient connection between the plastic film of the container and the mentioned tab L. However, if one proceeds from the worst case that only after a quarter turn, ie after 90 °, the perforation of the film takes place and the angle between the two cutting teeth only 70 ° is, so the front tooth still performs a minimum cutting line of 120 °, while the trailing tooth 21 through the additional 70 °, so even in the worst case, a cutting line of more than 180 ° is formed.

Since in this version of the closures the forces occurring on the cutting teeth is substantially greater than with a plurality of small teeth, it is advantageous if one chooses the wall thickness of the cutting teeth 20, 21 greater than the wall thickness of the cylindrical pipe section 16 of the piercer. This can be seen most clearly in FIG. This does not seem to be the case in FIG. 4, but this is simply because the cut line runs through the driver ribs 19 here.

As is known, plastic films are available in many different qualities. They differ not only in the choice of the plastics used, but also in the thickness, the toughness, in the hardness and so on. For the production of tubular bags the one comparable To have strength such as those of multilayer laminates with cardboard Hessen not open reliably with the previously known plastic thinning devices such plastic films. The tighter the film used was the greater the wall thickness of the teeth had to be and thus Hessen then hardly open the slides without too high a torque was required, which is not reasonable for the users. Accordingly, although the tubular bag as a whole made of these relatively thick and hard material, but punched therein an opening and closed this opening with a film section, which was much softer and for cutting with the usual plastic shuttering devices was possible, which was then welded onto the film section is.

One would like to move away from this technique and it has been found that this is possible when designing both the leading and the trailing tooth as shown in Figs. 7 and 8. While emphasis was placed on a perforation of the film in the previous teeth, now the weight is placed on the cutting of the film. In the softer plastic films, a much greater elongation occurs and, accordingly, it was relatively essential that the two teeth impact approximately simultaneously and the film is stretched, so that then a perforation takes place, whereupon the film itself practically along the cutting edge of the corresponding teeth cut without resistance. This is apparent, for example, from the time-load diagram according to FIG. FIG. 9, on the other hand, shows the load-time diagram of the puncture according to FIGS. 7 and 8 with the new teeth configuration. The two curves are not directly comparable insofar as in the case of Figure 10, a thin, much more elastic film is cut, while in the diagram of Figure 9, a thicker film which is much harder but less elastic, has been cut.

It can be seen in FIG. 10 that the torque increases more slowly until the time of perforation of a first of the two teeth, whereupon the torque drops immediately until the second tooth begins to act and then drops off very steeply.

In contrast, when the thicker film is severed by the piercer with the newly designed tooth form, the load to be applied increases faster until the maximum pressure is applied to the film and the cutting action begins. The load drop now decreases continuously until the first trailing tooth begins to act, and in the sloping region, one then recognizes the additional effect of the further trailing teeth. Despite the much harder foil of the required force is practically constant. This amazing result, is related to the fact that in the thicker foil this hardly ruptures, but accordingly Much more must be cut, the cutting characteristic similar to a cutting plate in a turning tool. Microscopically, it can be seen that the plastic is cut under chip formation and this chips must be able to be conducted into a room to prevent them from reaching the actual cutting point of the teeth and thus significantly increase the torque.

Hereinafter, a preferred embodiment of this newly configured teeth of a puncture with reference to Figures 7 and 8 will be explained. The piercer itself is denoted overall by 5. This also has a cylindrical tube section 16 on the outside of a coarse thread 17 is formed. In this coarse thread then engages the trapezoidal thread 18 in the cylindrical spout 6 a. The cylindrical portion 16 is provided on the inside with driving ribs 19. The cylindrical portion 16 is reduced in diameter in this variant in the lower, cutting region 26 in diameter by approximately the depth of the coarse thread 17. At the lower edge of this tapered cutting region 26, in turn, a leading cutting tooth 20 and a trailing cutting tooth 21 is provided. While in the previously described variant of this cutting tooth in the cutting direction leading a straight, relatively steep cutting surface is present, here this leading cutting edge is stepped and there are staggered several consecutive teeth 24 present graded on different Heights are. Depending on the depth of penetration, one after the other of these follower teeth will come into use. Between each of the foremost, leading and trailing cutting tooth 20, 21 and the leading edge arranged in the cutting direction cutting tooth 24 is a chip receiving space 25 which extends approximately arcuately. Also, between each two adjacent trailing teeth 24 is in each case such a chip receiving space 25. This can be seen most clearly in the figure 7.

In contrast to the first solution shown, in which the teeth have practically only a perforating effect by means of a perforating tip 23 and then the leading cutting edge 28 acts, here work both the two main teeth, namely the leading cutting tooth 20 and the trailing cutting tooth 21 as well as the staggered trailing teeth 24 all the same and all together have a cutting action. Therefore, after the leading tooth and trailing tooth 20, 21 have passed through the foil, a follower tooth 24 must take over its function. Therefore, these follower teeth are staggered in height, since the piercing 5 penetrates deeper and deeper into the container to be cut in the screw action. The follower teeth also have a metal-removing action, and accordingly the follower teeth are each provided with one chip receiving space 25 each. It makes sense to have the first effective chip receiving chambers 25 larger than the subsequent effective chip receiving spaces.

Claims

claims

Closure device (1) made of plastic for attachment to a closed container made of plastic film material, consisting of a lower part

(2) with cylindrical spout (6) and a flange (3) for attachment to the container and a screw cap (4) which is screwed on the lower part (2), and a cylindrical piercing

(5) with external thread, which is open on both sides in the axial direction and in the spout (6) of the lower part

(2) running in an internal thread, wherein in the screw cap (4) means (44) are provided which move the piercer (5) helically downwards during the first unscrewing movement of the screw cap (4), and in that the cylindrical piercer (5) on the cylindrical wall, at the end which is directed in the assembled state to the container wall, characterized in that the piercer has exactly two same high incisors, both of which are arranged within an angular range of 70 ° to 120 ° of the circumference.

Closure device according to claim 1, characterized in that the wall thickness of the two cutting teeth is thicker than the wall thickness of the cylindrical jacket wall of the piercer.

3. Closure device according to claim 1, characterized in that the external thread (12) of the piercer (5) and the internal thread (18) of the spout (6) are chosen so steeply that during the unscrewing of the screw cap (4) extending in the cutting direction Tooth passes from the contact point on the plastic film of the container to the fully completed Abraubbewegung the cap a maximum cutting path of 210 °.

4. Closure device according to claim 1, characterized in that the external thread of the spout is a double-course fine thread.

5. Closure device according to claim 1, characterized in that the external thread of the piercer and the internal thread of the spout has a trapezoidal thread profile.

6. Closure device according to claim 1, characterized in that at least one of the two cutting teeth (20, 21) each have a number of staggered follower teeth (24) which are arranged in descending order at different heights, so that depending on the penetration depth of the piercer in the cutting foil one after tooth after the other is effective, and wherein between the respective foremost cutting tooth (20, 21) and the next effective follower tooth, as well as between two adjacent teeth each a chip receiving space (25) is present.

Closure device according to claim 6, characterized in that the first effective

Chip receiving spaces (25) are greater than the subsequent effective chip receiving spaces.