EP3041753B1 - Self-opening plastic closure - Google Patents

Description

The present invention relates to a self-opening plastic closure consisting of a spout with a flange for connection to a single or multilayer packaging film of a closed package, with a movably guided inside the spout cylindrical cutting member, and a screw cap with a shell wall with internal thread and a top surface, said the screw cap with the spout with external thread is screw-connected and the screw cap and the cutting member have means that implement the screwing of the screw cap in a purely translational relative movement of the cutting member to the spout.

Self-opening plastic closures are closures that are welded or glued on a completely closed container made of a single or multi-layer packaging film and have a cutting member which cuts open the packaging film when the screw cap is first screwed on and holds it in an open state. The reclosability of the Closure is then effected only by the screw cap.

Plastic closures of this type have been practically on the market for about 20 years. Already in one of the earliest applications of a closure of this type two different types are disclosed. In particular, such self-opening plastic closures are provided either with a rotating cutting member or with a cutting member which performs a purely translational movement. This latter type is already out of the EP 0328652 known, which discloses the features of the preamble of claim 1. The cutting member is axially guided in the spout and has on an upper edge a ramp-like feed device which presses with a corresponding ramp-like end face of a ring wall segment when unscrewing the cap of this cutting member down. Accordingly, the cutting member has a plurality of perforating teeth, which are distributed over the entire circumference, except for a short portion which is without teeth, to avoid that the packaging film is completely separated from the packaging and would fall into the container. The problem with such a solution is the force applied here. The entire force to be applied must be practically applied with only a quarter turn of the screw cap. Because of the high forces that are required, such a Closure to open, these closures have not prevailed in the market.

An early version of a self-opening plastic closure with a rotating cutting member is from the WO 95/05996 known. In this closure, the spout has an internal thread in which the cutting member with an external thread stores. The screw cap, which has a circumferential casing wall and a top surface, has arranged on the inside of the top surface at least one driver which cooperates when screwed with a driver on the inner wall of the cutting member and now the cutting member screwed down while the screw cap is unscrewed upwards , Again, the cutting member has a plurality of perforation teeth, all of which also act simultaneously on the packaging film. Again, a very large force is needed to perform the opening, but here requires less force through a much longer Schraubweg. Nevertheless, it was initially hardly possible to open such a packaging film, especially if this is so-called composite films, which consists of a plurality of layers of plastic, cardboard, aluminum and again plastic. Accordingly, it has been provided here to provide the package with a punched opening and to glue or weld this opening with a thin, easily cut film. Such solutions are Of course, expensive and expensive and have the great disadvantage that the closures must be welded exactly to the exact location, so that only the patch patch must be severed and not the cutting member sometimes even the composite foil of the package must be separated. Although one has then alternatively punched in such composite films, which went down only to the barrier layer, so that the cutting member had to cut through only this barrier layer and the underlying plastic film. It is easy to see that this solution requires a considerably higher precision of the assembly of the plastic closure on the packaging.

Another variant is from the WO 2004/000667 known. Here, the delivery of the cutting element in a first step is purely translational by a drive, as already mentioned EP 0328652 known and in the achievement of its lowest level, the cutting element is now only rotated.

Another variant is from the EP 2 055 640 known. Here, the delivery of the cutting element in a first step is purely translational by a drive, as already mentioned EP 0328652 known and at the end of the first step, the cutting member is now moved not only axially but also rotationally.

While one has worked in the beginning and in particular in connection with so-called cardboard composite packaging with a variety of perforating teeth, one is later largely moved away from it. A major reason for this variety of perforating teeth is the fact that the paperboard layers of such packages require relatively much power to be pierced. The large number of teeth does not actually cause a cutting but a sawing.

However, the structure of such cardboard composite films has changed over the years. On the one hand, the paperboard layer has become thinner and thinner and, on the other hand, several different layers of plastics have been used, which in principle have repeatedly demanded different requirements for the cutting element. Accordingly, a variety of patent applications have been made, which deal with the shape and the arrangement of the perforating teeth and incisors. Typical examples of such designs, for example, from the WO 2004/083055 or EP 1533240 out. An even more complex arrangement shows, for example, the EP 1795456 , One reason for the many embodiments are, as already mentioned, the different types of packaging films, in particular, the recently distributed on the market tubular bags made of pure plastic composite films are one reason. While in many cases the perforation with only one or a few perforating teeth succeed relatively reliably, the subsequent cutting activity is much more problematic. These two different activities require, namely, during perforation a relatively large force at the same time low relative movement during the subsequent cutting process, a much lower force with the greatest possible relative movement of the cutting edge is required relative to the severing film. At the today's Plastic closures available on the market are no different here.

In addition, it has been found that in self-opening plastic closures with rotating cutting the foil to be cut due to their high elasticity, as is the case practically for all polyethylenes, causes the material stretched and at the same time dammed at the cutting edge in the direction of rotation and thus practically makes the cutting edge ineffective. This then leads either to an incomplete cutting line or an uncontrolled tearing of the packaging film. This only partially open container only allows poor emptying.

It is therefore an object of the present invention to provide a self-opening plastic closure of the type mentioned, which can be actuated in response to the Zustellweges with different forces, so as to master the problems discussed herein before.

This object is achieved by a self-opening plastic closure according to claim 1, characterized in that the means provided are a first and a second successive engaging feed mechanism, which cause different axial feed paths per revolution.

Further advantageous embodiments of the subject invention will become apparent from the dependent claims and are explained with reference to the accompanying drawings in the following description.

Figur 1

eine perspektivische Ansicht eines zusammengebauten, selbstöffnenden Kunststoffverschlusses, in Ansicht von oben, und

Fig. 2

in Ansicht auf die Unterseite.

Fig. 3

zeigt eine Schraubkappe des selbstöffnenden Kunststoffverschlusses in einem axialen Vertikalschnitt, und

Fig. 4

in einer perspektivischen Ansicht auf die Unterseite.

Fig. 5

stellt einen axialen Vertikalschnitt durch den Ausgussstutzen dar, der in der

Fig. 6

in einer perspektivischen Ansicht dargestellt ist; in

Fig. 7

sieht man das Schneidorgan in perspektivischer Darstellung und

Fig. 8 und 9

zeigen die einstückig gefertigten Schneidorgane und Ausgussstutzen zusammen vor dem Anbringen der Schraubkappe in zwei unterschiedlichen, perspektivischen Darstellungen.

Fig. 10 - 13

zeigen den zusammengebauten, selbstöffnenden Kunststoffverschluss, jeweils in einem Diametralschnitt in verschiedenen Öffnungsstadien.

It shows:

FIG. 1

a perspective view of an assembled, self-opening plastic closure, in top view, and

Fig. 2

in view on the bottom.

Fig. 3

shows a screw cap of the self-opening plastic closure in an axial vertical section, and

Fig. 4

in a perspective view on the bottom.

Fig. 5

represents an axial vertical section through the spout, which in the

Fig. 6

is shown in a perspective view; in

Fig. 7

you can see the cutting element in perspective and

8 and 9

show the integrally manufactured cutting members and spout together before attaching the screw in two different perspective views.

Fig. 10 - 13

show the assembled, self-opening plastic closure, each in a diametrical section in different opening stages.

In FIG. 1 is a possible embodiment of the inventive, self-opening plastic closure, which is generally designated 1, shown in perspective. In this view you can see practically only the screw cap 2 and that part of the spout 3, which is not covered by the screw cap. This uncovered part of the spout is practically only the terminal, circumferential flange 31. From the outside can be seen on the screw cap 2 whose peripheral jacket wall 20, at the lower end of a corresponding not visible here breaking points bridges a guarantee strip 22 is formed. The circumferential jacket wall 20 carries the upper cover surface 21. Outside of the jacket wall 20 are a plurality of Handle ribs 29 attached, which increase the grip for the user in the operation of the screw cap.

In the FIG. 2 is the same, self-opening plastic closure 1 shown in the assembled state obliquely from below. In the position shown here, the self-opening plastic closure 1 is shown in an intermediate position, in which the cutting member 4 with the perforating teeth arranged thereon is already slightly protruding from the spout 3, thus the cutting member 4 is at least partially visible. The spout 3 is now partially visible from the bottom, so that now recognizes a mounted on this bottom power line rib 32. The design of the power fins is shown here as a single, circumferential rib, but other design forms of such power fins 32 are known and their design is adapted according to the welding connection to be formed and the material pairing.

Subsequently, the three self-opening plastic forming parts will now be described individually and then explained their interaction. The screw cap 2 is in the FIGS. 3 and 4 shown individually. Like any screw cap, this also consists of the already mentioned shell wall 20 and the top surface closing off the screw cap 21. Escape under the shell wall 20 is likewise already mentioned warranty band 22, on, not specifically shown here, predetermined breaking points bridges formed. Here one recognizes, in particular in the sectional picture according to FIG. 3 , the internal thread 23 on the casing wall 20. This internal thread 23 serves to cooperate with an external thread on the spout 3. In the sectional drawing can be seen a first annular wall 24, which has a different height in this sectional drawing. To the right of the central axis in this figure, the first annular wall 24 is higher than to the left of the central axis. The first annular wall 24 is completely circumferential in this embodiment and extends from a lowest point to the highest point, the lowest point being the starting point at the first opening, and the highest point corresponding to an end point after a rotation of 360 °, this being the end point the delivery route of a first delivery mechanism represents.

The ramp-shaped first annular wall 24 has a sliding surface 25 facing away from the top surface 21. This sliding surface 25 then cooperates with a second sliding surface of a first delivery mechanism, which will be discussed later. Concentrically to the first annular wall 24, offset inwardly, a second annular wall 26 is integrally formed on the underside of the top surface 21. This second annular wall 26 is the same height over its entire circumference. The axial length of the second annular wall 26 is here greater than the axial length of the shell wall 20. This is related to that Screw cap 2 is held in the assembled state with its guarantee strip 22 on the flange 31 of the spout and distanced to this. On the outside of this second annular wall 26, an external thread 27 is formed. This external thread 27 forms part of a second delivery mechanism.

In principle, four concentric annular walls are formed under cover surface 21, the outermost annular wall representing the lateral wall 20 and the innermost annular wall forms the so-called second annular wall 26. Between the second annular wall 26 and the jacket wall 20 follows from the inside to the outside only the first annular wall 24 and then an annular wall which forms a so-called sealing olive 28 which comes to rest in the closed state of the closure after the first opening sealingly on the inside of the spout. In the mounted state before the first opening, the packaging film is still closed and the sealing function of the sealing olive is not yet required.

The spout 3 is in the FIGS. 5 and 6 each represented individually, the FIG. 5 a diametrical section shows and FIG. 6 is a perspective view with a view from above into the spout into it. The spout 3 consists of a cylindrical spout 30 having a lower edge peripheral, circumferential flange 31. This flange 31 has In principle, the flange can be glued to such a package, which is the case in particular in so-called Brikverpackungen consisting of multilayer packaging films, a cardboard layer, a - or multi-layer plastic and at least one barrier layer included. But even on such a packaging film, the spout, and thus the entire, self-opening plastic closure, also be welded, especially if the outermost layer of the packaging film is a plastic layer. If the self-opening plastic closure 1 is mounted on a tubular bag, which usually consists of a complex, multi-layered plastic film with a barrier layer, it goes without saying that in most cases only welding and hardly any sticking is possible here. On the inside of the cylindrical spout 30 can be seen an axially extending guide rib 34. This axial guide rib extends from approximately the upper edge of the cylindrical spout 30 to the lower edge of the spout 30. This axial guide rib 34 serves to secure axial guidance of the cutting member to be described Further, on the inner wall of the cylindrical spout 30 in the lower region relatively close to the plane defining the peripheral flange 31, a plurality of latching cams 35 are arranged. Indeed there are practically two directly superimposed locking cams 35. These serve to hold the cutting member in a defined lowermost position. Furthermore, a plurality of separate predetermined breaking point bridge parts 36 can also be seen on the inner wall of the cylindrical spout 30 in the upper quarter. This will also be returned later. The attached on the outside of the cylindrical spout 30 stop ribs 37 which extend down to the peripheral flange 31, serve to cooperate with the guarantee strip. Finally one recognizes in the FIG. 6 a notch formed in the outer periphery of the flange 31 which forms an orientation notch 38 which serves only to orient the various parts in an assembling plant.

In the FIG. 7 the cutting member is shown by itself in perspective view. It has a cylinder wall 40, whose upper edge is designed as a ramp-shaped end wall 41. The ramp-shaped end wall 41 has a sliding surface 42 which rests in the assembled state of the self-opening plastic closure 1 on the sliding surface 25 of the first ramp-shaped annular wall 24. In the axial direction of the sliding surface 42, a plurality of perforating teeth 43 are integrally formed on this edge. Each perforating tooth 43 becomes bounded by Perforierkanten 44 and together include an acute angle. Cutting edges 45 follow on both sides of these perforating edges 44. Two cutting edges 45 each directed to the same perforating tooth 43 together enclose an obtuse angle. In an axial movement now lead the perforating teeth 43 thanks to the acute angle, which include the perforation 44, only a small cutting function, but practically only a puncture. The subsequent cutting edges 45, which are relatively flat, now lead, in the case of the further, purely translatory, axially acting delivery of the cutting member in the direction of the packaging film, to a significantly greater relative movement, with respect to the circumferential line per delivery path section. After the perforation of the packaging film thus takes place thanks to the second feed mechanism immediately the cutting movement. Experiments have shown that now practically the cutting movement immediately continue the resulting in the perforation in the direction of the perforation cracks tears in a cutting line.

On the outside of the cylinder wall 40 of the cutting member 4 reinforcing ribs 491 are formed, which extend from a peripheral collar 47 to as close as possible to the tip of the respective perforating tooth 43. The circumferential collar 47 extends in a plane perpendicular to the central axis of the cutting member. The upper edge of the circumferential collar 47 is arranged at the height of the lowest point of the ramp-shaped end wall or the sliding surface 42. At least at those points at which the axial guide rib 34 is arranged in the spout, the circumferential collar 47 has a guide recess 49. Further, one recognizes on the outside of the circumferential collar 47 several separate predetermined breaking bridges 48, the cutting member 4 with the spout before mounting 3 connects. Before assembly, these separate predetermined breaking point bridges 48 are connected to the separate predetermined breaking point bridges 36.

The cutting member 4 and the spout 3 together form a one-piece unit 70, which in the FIGS. 8 and 9 each shown in perspective view with different angles.

The aforementioned orientation notch 38 in the flange 31 of the spout part 3 is not least of importance because the spout part 3 and the cutting member 4 are preferably made as a one-piece structural unit 70. This reduces the cost of production and assembly. The one-piece assembly 70 is realized so that the cutting member 4 is completely within the spout 30 of the spout 3. In this position, the highest point of the ramp-shaped end wall 41 of the cutting member 4 is at least approximately in the plane which is spanned by the upper edge 39 of the cylindrical spout 30.

During assembly, the screw cap 2 is now placed on the one-piece assembly 70 with the screw cap is aligned so that the highest point 493 of the ramp-shaped end wall 41 is at that point corresponds to the point corresponding to the point on the first ramp-shaped annular wall 24 of the screw cap. 2 the top surface 21 is closest. During axial pushing together, the predetermined breaking point bridges between the circumferential collar 47 and the inner wall of the spout 30 are now preferably separated at the last moment of pushing together so that only the separate predetermined breaking point bridges 36 and 48 are present.

At the same time, the cutting member 4 is moved slightly axially downward so that the point of the cutting member 4 which is in the axial direction, namely the tips of the perforating teeth 43, is still above the plane defining the underside of the flange 31. This ensures that not already during welding of the assembled self-opening plastic closure 1 this does not rest on the packaging film of the container on which it is to be attached. This position is now in the FIG. 10 shown in a diametrical section. This position shows the inventive self-opening plastic closure 1 in the mounted position before the first opening. The predetermined breaking points between the screw cap 2 and the thereto Molded guarantee strip 22 are still intact, but since the diametrical section does not pass through a predetermined breaking point bridge this is not visible in the figure. In this position, the first feed mechanism 50 is in its home position. This first feed mechanism 50 consists, as mentioned, of the first ramp-shaped annular wall 24 with its sliding surface 25, wherein the sliding surface 25 rests on the sliding surface 42 of the annular end wall 41 of the cutting member 40 over the entire circumference.

In the FIG. 11 now the screw cap 2 is shown rotated 360 °. On the left side you can now see the ramp-shaped end wall 41 which is practically at the highest point, while the highest point of the ramp-shaped annular wall 24 is just exceeded and therefore only shown dotted. The opposite position on the right side thus shows the ramp-shaped annular wall 24, which is only half as high here, since the sliding surface 42 on this side has already moved down by the same amount.

In this position, in which now the first delivery mechanism has reached its maximum delivery, now the second delivery mechanism 60 takes over its function. As can be seen both left and right of the central axis, this second feed mechanism 60, consisting of the external thread 27 at the second annular wall 26 with the internal thread 492 on the cylinder wall 40 of the cutting member 4 in engagement. In this position now has the first delivery mechanism 50 as in the FIG. 10 described the cutting member 4 already moved as far down in the direction of the flange 31 that the perforating teeth 43 are below the plane spanned by the flange. In the event that the self-opening plastic closure is welded onto a packaging film, the perforating teeth 43 have already perforated this sealing film.

If the screw cap 2 is moved by a further complete revolution, then the cutting member 4 is moved further in the direction of the flange 31 and not only the perforating tooth with its Perforierkanten 44, but also the adjacent cutting edges 45 as well as the Umfaltkante 46 are now below the of circumferential flange spanned plane and the packaging on which the self-opening plastic closure 1 according to the invention is mounted, is now completely cut and only in the region of Umfaltkante 46 still connected to the package. The cut-open packaging film is folded over outside the region of the spout 30. In the position shown, both the internal thread 23 with the external thread 33 of the spout in combination, as well as the external thread 27 on the second annular wall 26 with the internal thread 492 of the cutting member 4 is still engaged.

If you now screw the screw cap 2 again by half a turn, you reach the position as in FIG. 13 shown. Now, the internal thread 492 with the external thread 27 on the second annular wall 26 is no longer engaged. At the same time, however, it can be seen in this figure on the left side, that the circumferential collar 47 is engaged on the cutting member 4 with the latching cam 35 on the inside of the spout 30. This now leaves the cutting member 4 in this position even if the screw cap 2 is still completely unscrewed from the spout 3. After having taken a portion of the contents of the package and the screw cap 2 has screwed again, now moves at each opening and closing only the screw cap 2 while the cutting member 4 remains in the same position.

As already mentioned, only a preferred embodiment is shown in the drawing. Other embodiments not described here are, of course, possible without departing from the spirit of the invention. Thus, of course, all 3 components of the self-opening plastic closure 1, namely the screw cap 2, the spout 3 and the cutting member 4 can all be made separately. Of course, the sequence of the first and second feed mechanisms 50, 60 described here can of course also be changed. In other words, the first Annular wall may be designed as a normal cylindrical annular wall and be provided with corresponding threads, while then the second annular wall is designed as a ramp-shaped annular wall. This second annular wall would then have to interact with the ramp-shaped end wall of the cutting member. Although this solution is of course also conceivable has been omitted here on the presentation of this solution, this variant is less preferred over the illustrated embodiment, since such a variant reduces the diameter of the cutting member and, accordingly, to achieve a same opening, the entire self-opening plastic closure would have to be designed larger, which would be associated with a higher material consumption.

In addition to the solution described in detail and the above variants, it is also possible to implement both the first and the second feed mechanism both threaded or both with Zustellrampen. These need only be arranged in height so that both Zustellmechanismen can not be engaged simultaneously.

Furthermore, the first feed mechanism 50 may be configured, instead of as shown, over 360 °, also only of two ramp-shaped sections extending over 180 °. This leads to a symmetrical power transmission, but then the ratio of delivery path per Rotation increases, as well as the required effort in the Erstöffnung.

Instead of the variant with three perforating teeth shown here, only one or two perforating teeth or even more than three perforating teeth may be present. This will be made dependent on the diameter of the self-opening plastic closure 1. If only one perforation tooth 43 is provided, the adjoining cutting edges 45 extend without gaps by at least two thirds of the circumference. The perforating tooth 43 diametrically opposite then the Umfaltkante 46th

LIST OF REFERENCE NUMBERS

1

Self-opening plastic closure

2

screw cap

3

pouring spout

4

cutting member

20

shell wall

21

cover surface

22

guarantee strip

23

Internal thread in the shell wall

24

first ring wall ramped

25

Sliding surface of the ramp

26

second ring wall

27

External thread on the second ring wall

28

sealing olive

29

grip ribs

30

cylindrical spout

31

flange

32

Energieleitrippe

33

external thread

34

axial guide rib

35

arresting pin

36

separate breakpoint bridge

37

Stop ribs for guarantee band

38

orientation notch

39

upper edge of the spout 30

40

Cylinder wall of the cutting element

41

ramp-shaped end wall

42

Sliding surface of 41

43

perforating

44

Perforierkanten

45

cutting edges

46

Folding edge (see Fig. 13 )

47

circumferential collar

48

separate breakpoint bridge

49

Guide recess for 34

50

first delivery mechanism from 24, 25 and 41, 42

60

second delivery mechanism from 27 and 492

70

one-piece assembly from 3, 4

491

reinforcing rib

492

inner thread

493

highest point of the ramp-shaped end wall

Claims (14)

1. A self-opening plastic closure (1) consisting of a pour-out spout (3) with a flange (31) for connection to a single-layer or multi-layer packaging foil of a closed packaging, with a cylindrical cutting element (4) which is movably guided within the pour-out spout (3), and with screw cap (2) with a lateral wall (20) with an inner thread (23) and with a cover surface (21), wherein the screw cap (2) is screw-connected to the pour-out spout (3) with an outer thread (33), and the screw cap (2) and the cutting element (4) comprise means which convert the screw movement of the screw cap (2) into a purely translatory relative movement of the cutting element (4) to the pour-out spout (3), characterised in that the means are a first (50) and a second (60) advance mechanism (50, 60) which engage one after the other and which effect different axial advance paths per revolution.
2. A self-opening plastic closure according to claim 1, characterised in that the first advance mechanism (50) consists of a first, ramp-like annular wall (24) integrally formed on the inner side of the cover surface (21) of the screw cap (2), and of a mutually opposite face wall (41) running in a ramp-like manner, on the cylindrical cutting element (4).
3. A self-opening plastic closure according to claim 1, characterised in that the second advance mechanism (60) consists of an inner thread (492) on the cylindrical cutting element (4) and of an outer thread (27) on a second angular wall (26) arranged on the inner side of the cover surface (21), in the screw cap (2).
4. A self-opening plastic closure according to the claims 2 and 3, characterised in that the second annular wall (26) is arranged concentrically within the first annular wall (24).
5. A self-opening plastic closure according to claim 1, characterised in that the gradient of the first advance mechanism (50) is less than the gradient of the second advance mechanism (60).
6. A self-opening plastic closure according to claim 2, characterised in that the cutting element (4) on its end which lies opposite the ramp-like face wall (41) is provided with at least one perforating tooth (43), to which a cutting edge (45) connects in the peripheral direction at both sides, and a fold-over edge (46) is present outside the region of the cutting edges and of the at least one perforating tooth (43).
7. A self-opening plastic closure according to claim 6, characterised in that only one perforating tooth (43) with connecting cutting edges (45) is present, and the cutting edges (45) extend in a gapless manner about at least two thirds of the periphery, and the fold-over edge (46) is arranged diametrically opposite the perforating tooth (43).
8. A self-opening plastic closure according to claim 6, characterised in that at least two perforating teeth (43) are present and the cutting edges extend a gapless manner on at least two thirds of the periphery, and the fold-over edge (46) is arranged in the remaining cutting-edge free region.
9. A self-opening plastic closure according to claim 6, characterised in that the cutting edges (46) which are adjacent the same perforating tooth (43) enclose an obtuse angle.
10. A self-opening plastic closure according to claim 6, characterised in that the axial advance path of the first advance mechanism (50) is capable of advancing the cutting element (4) so far until the transition of the at least one cutting tooth (43) to the adjacent cutting edges (46) at least approximately lies in the plane of the flange (31) of the pour-out spout (3).
11. A self-opening plastic closure according to claim 10, characterised in that the advance path of the second advance mechanism (60) is capable of advancing the cutting element (4) so far until the fold-over edge (46) at least approximately lies in the plane of the flange (31) of the pour-out spout (3).
12. A self-opening plastic closure according to claim 1, characterised in that the purely translatory movement of the cutting element (4) relative to the pour-out spout (3) is realised by way of at least one axially running guide rib (34) on the inner side of a cylindrical pour-out (30) of the pour-out spout (3), and a guide recess (49) is realised in a peripheral collar (47) which is arranged at the outside on the cutting element (4).
13. A self-opening plastic closure according to claim 12, characterised in that detent lobes (35) are present on the inner surface of the pour-out (30), at the height close to the flange (31), into which lobes, in the lowermost advance position of the cutting element (4), its peripheral collar snaps in, wherein this position is equal to the end of the advance path of the second advance mechanism (60).
14. A self-opening plastic closure according to claim 1, characterised in that the pour-out spout (3) and the cutting element (4) are manufactured in a separable manner as a single piece, as one component (70).

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