EP0663344A1 - Device for opening a container for liquids - Google Patents

Abstract

The opener has a cylindrical support ring (7) attached to the pack's top wall (1) by a flange (5) gripping over an opening disc (21). The support ring's inner surface (12) has a threaded ridge (13). The support ring includes the outer thread (16) of the plastics screw-cap (41). A cutter blade (18) is moulded in one piece on the free edge (17) of the screw-cap and has a front cutting edge (19) at an angle through the free edge. The pitch of the threaded ridge on the support ring, and the axial height of the cutter blade match so that the front cutting edge is moved through the entire plane of the top wall when the screw cap is turned by approximately 270 degrees.

Description

The invention relates to a device for opening a plasticizer pack, which is fastened to the top wall of the pack, with a screw cap and a cylinder-shaped support ring.

Devices are known for opening packs which consist of a support ring and a screw cap screwed thereon, the support ring being fastened around a hole previously made in the top wall of the pack. The hole in the top wall generally causes tightness problems, which must be compensated for by appropriate seals between the support ring and screw cap. The opening device must inevitably be provided with reliable sealing devices, as a result of which a more complex production and possibly also a more difficult opening have to be accepted.

It has already been planned within the company to use clamping caps with internal cutting knives. However, one was dependent on a certain design of the top wall, in order to offer the knives surfaces through this design that could be cut through. In addition to the fact that the cutting knives had to be suitably concealed in the push-on cap so that the dealer and also the end user were not exposed to cutting injuries when touching the pack, the special design of the pack top wall was limited to packs made of plastic, because deep-drawn cylindrical parts of these were deep-drawn could manufacture.

The invention has for its object to provide a device of the type mentioned that is easy to manufacture and easy to open and does not affect the tightness of the package in any way.

This object is achieved in that the cylindrical jacket-shaped support ring is fastened to the upper wall of the pack by means of a fastening flange encompassing an opening disk, has a threaded bead on its inner surface and comprises the external thread of the plastic-made screw cap, and that a screw is attached to the free edge of the screw cap Cutting knife is integrally formed, which has a front cutting edge running at an angle through the free edge. With the new opening device it is possible to completely close the top wall of the package before opening it for the first time, i.e. after filling, during transport and during storage hold so that the tightness of the package is not affected in any way, regardless of the design of the opening device. The great advantage of the new device is also its versatility. Not only the large number of plastic packs but also the packs made of composite material with paper can be provided and opened with this new opening device. It is only necessary that the opening device is reliably attached to the top floor at the point where the pouring opening is later desired. However, packaging materials for flow agents usually have plastic on at least one surface, be it that the entire top wall is made of plastic or that composite material has a thin plastic coating. But even with non-coated cardboard materials, the cylindrical jacket-shaped support ring of the new opening device could be attached by gluing. The mounting flange of the support ring, which surrounds the opening disc, is used for this. The opening disk is the part that is at least partially cut out of the upper wall to be opened and thus releases the pouring opening. For the sake of clarity, that part of the top wall which is at least partially separated by the cutting knife of the new opening device to create the pouring opening is referred to in the description.

The support ring of the new invention does not have an external thread, as in the prior art, onto which a screw cap with an internal thread is screwed, but rather has a thread bead on its inner surface. This can be a single-stage or a multi-stage thread with one or more threads arranged in the form of a thread. In the preferred embodiments described in the following, it is sufficient to form only a thread bead which rotates about 360 ° on the inner surface of the support ring. The support ring is preferably made of plastic. But it can also be made of other materials, provided that they are glued to the top wall or attached in some other way. In the structure according to the invention, the inside of the threaded ring of the support ring comprises the external thread of the screw cap, the screw cap preferably being formed from plastic. Roughly speaking, without particularly critical sealants, the opening device only consists of the outer support ring, which holds the screw cap on the inside. The screw cap has a free edge directed downwards towards the still closed top wall, on which the cutting knife mentioned is formed in one piece in a particularly expedient manner. The manufacture of such a cutting knife is technically simple and extremely economical. The packaging manufacturer can produce such screw caps in large numbers at a low price and in a short amount of time. The cutting knife is out of engagement after manufacture, during transport and also during storage of the package under consideration here, ie before the package is opened by the end user for the first time with the topsoil. The screw cap is thus only screwed into the support ring to such an extent that the screw cap is held and the cutting knife remains above the undamaged top surface. It is advantageous if, according to the above description, the cutting knife has a front cutting edge which runs through the free edge at an angle. This front cutting edge can be straight or curved and has this inclination to the free edge of the screw cap, so that a cutting operation can easily be carried out by the end user as with a knife blade. If the user wants to open the package, all he has to do is screw the screw cap further into the support ring in a direction indicated, for example, by an arrow or other instruction, and the cutting knife with its leading cutting edge already engages with the top surface. This intervention takes place at a point on the circumference of the opening disk described above in the top floor. By turning the screw cap, the front cutting edge, which is at an angle to the central longitudinal axis of the screw cap and the support ring, moves at least a little along the circumference of this opening disk and separates it from the top surface in the area within the support ring. This opens the top of the pack and the end user can empty the contents.

In an advantageous further embodiment of the invention, the pitch of the threaded bead on the support ring and the axial height of the cutting knife from the free edge in the direction of the pack are coordinated so that the front cutting edge on a rotation of the screw cap of about 270 ° through the plane of Upper wall is moved through. The front cutting edge has a certain length, which is generally greater than the axial height mentioned. The outermost and bottom end of the front cutting edge understandably enters the top wall first and, as the screw cap rotates further, penetrates the top panel so that the next parts of the front cutting edge behind it come into cutting engagement until the front cutting edge completely during the further rotation of the screw cap has been pushed through the plane of the top wall. Then the cutting effect stops, even if you turn the screw cap further, because the front cutting edge is then completely inside the packaging, i.e. under the top wall, and no longer performs a cutting function. The same also applies to a rotation of the screw cap of approximately 270 ° and more, but not much more than 350 °, so that the opening disk gets stuck and does not fall into the filling material.

The axial height of the cutting knife from the free edge in the direction of the pack or its top base lies in the direction of the central axis or is measured in this direction, which is why it is called the "axial" height. If you look at the screw cap in longitudinal section or in a side view perpendicular to the central axis of the screw cap, the top wall then appearing as a preferably straight line because one looks along the surface of the top wall, then the free edge of the screw cap also shows up as a line. If the front end of the front cutting edge facing the top wall is just not yet in engagement with the top wall, then the free edge of the screw cap is at a distance which, seen in the direction perpendicular to the central axis, has the aforementioned height of the cutting knife. It can also be said that the front cutting edge of the cutting knife has a component in the direction of the central axis, and from the point where the front cutting edge cuts the free edge to the upper surface of the top wall, this axial component of the front cutting edge has exactly the amount of the mentioned axial Height.

It is preferred that the pitch of the thread bead or the pitch of the external thread of the screw cap is greater than the axial height of the cutting knife. The cutting knife thus needs less than a rotation angle of 360 ° from the point of penetration into the top wall at the beginning of the rotation until the moment when the inner end of the front cutting edge has just penetrated through the top wall, which is called the end point of the pitch circle cut. The advantageous consequence of this measure is that the opening disk cut or cut from the top wall is not completely cut out of the top bottom and thus cannot fall into the inside of the package into the contents; Instead, there remains an uncut connection between the opening pane and the upper floor surrounding it, like a kind of bridge, which is guaranteed to hold the opening pane securely in place.

Because the cutting knife now only extends over a fraction of the circumference or the free edge of the screw cap, the invention ensures that the remaining predominant part of the circumference bears the thread on the free edge of the screw cap. The result of this is the advantage that when the screw cap is turned further while the front cutting edge is disengaged from the top panel, namely inside the packaging, the adjacent thread now grips the opening disk and folds over like a flap so that the area of the opening disk is free and so that the pouring opening is opened properly.

The opening device according to the invention thus provides a perfectly closed upper base and thus a tight packing before the cutting knife is cut, and the pouring opening is created in a favorable manner simply by rotating the screw cap simply because the opening disk is cut sufficiently far, for example via a Angle of rotation of about 270 °, is folded over and the emptying of the filling material Pouring out is not in the way.

It is also expedient according to the invention if the support ring is divided by a predetermined breaking line running parallel to the fastening flange into a lower seat part with the fastening flange and a spacer ring which has a support flange holding the rotating part of the screw cap. With these measures, it is possible in a simple manner to screw in and hold the screw cap in a defined position before the first opening of the superplasticizer, namely a position in which the cutting knife just barely comes into engagement with the top wall. This is achieved in that the rotating part of the screw cap is held by the support flange and can no longer be turned towards the top wall. The end user must first remove the spacer ring with the mentioned support flange by breaking the predetermined breaking line and can then screw the screw cap further into the remaining seat part with the result that the cutting knife penetrates into the upper wall.

Operation is further facilitated by the measure according to the invention that the support ring consists of plastic that can be welded to the top wall and that a tab is formed on the spacer ring for removing the spacer ring from the seat part. Plastic is the easiest to mold, and one can also produce more complicated designs inexpensively by injection molding. The shaping of a gripping tab or pull tab is not a problem. Lines of weakness can also be conveniently and reliably attached between the seat part and the spacer ring, and attachment to an upper wall that has plastic at least on the surface is known technology. As a result, the opening device according to the invention can be easily, simply and reliably attached to the package in such a way that the package can be opened after the spacer ring has been torn off with the aid of the tab.

In a preferred first embodiment, the cutting knife has a tip which projects downward beyond the free edge and is directed toward the pack. The axial height explained above is then the distance of the tip of the cutting knife from the free edge of the screw cap measured in the direction of the central axis. It is expedient to inject such a cutting knife from the same plastic material onto the screw cap, as does the material of the turned part of the screw cap. It then becomes one piece.

It is advantageous if the screw cap has a radially larger turned part and attached to it a radially smaller, preferably hollow cylindrical thread with a trapezoidal external thread and if the free edge of the screw cap is sharpened on at least part of its circumference to the outside in such a way that the the sharpened outline lies in the area forming the base of the external thread. Plastic material and paper, including coated paper and other composite materials, can be cut with such a cutting knife in the manner described here, thus creating an opening device. The hollow cylindrical thread approach can be manufactured up to its final design by injection molding. However, it is also possible to either make the external thread trapezoidal by turning off the rotationally symmetrical workpiece parts or to sharpen the free edge of the hollow cylindrical thread attachment in the manner described. In the embodiment of the cutting knife for plastic, the cutting knife itself can advantageously be produced by such turning work.

For example, while the cutting knife for composite or paper materials has the above-mentioned tip and is expediently shaped by injection molding, the cutting knife for use with plastic materials can be produced in such a way that, according to the invention, the leading cutting edge of the cutting knife is arranged in the outer bead of the external thread of the screw cap . The front cutting edge is preferably straight. If you cut a conical surface, for example that of a turning tool, with the hollow cylindrical thread attachment made of plastic in such a way that the cutting line passes through and intersects with the raised parts of the external thread, then you form a straight front cutting edge of the cutting knife in the outer bead of the External thread of the screw cap, without further injection molding measures being necessary for the formation of the cutting knife.

The person skilled in the art thus recognizes that the described embodiments create an opening device for a packaging which in no way impairs the tightness of the packaging until it is opened for the first time, but nevertheless ensures easy opening and even reclosing.

Figur 1

eine teilweise abgebrochene und teilweise im Langsschnitt genommene Seitenansicht einer ersten Ausführungsform von Öffnungsvorrichtung vor dem Benutzen zum Öffnen,

Figur 2

einen abgebrochenen Teilschnitt durch die Schraubkappe,

Figur 3

eine Draufsicht auf die Schraubkappe der Figur 2 von rechts nach links,

Figur 4

eine gleiche Ansicht wie Figur 1, wobei jedoch die Schraubkappe nach Abnehmen des Abstandsringes so weit in Richtung auf das Innere der Packung eingedreht ist, daß nicht nur der Schnitt längs eines Umfanges über etwa 270° an der Öffnungsscheibe fertiggestellt sondern diese laschenartig umgeklappt ist,

Figur 5

eine Draufsicht auf den eingeschnittenen aber nicht umgeklappten oder abgebogenen Oberboden mit Sitzteil,

Figur 6

eine ähnliche Ansicht wie Figur 1, jedoch bei einer zweiten anderen Ausführungsform und

Figur 7

eine Längsschnittansicht durch die Schraubkappe der zweiten Ausführungsform der Figur 6 mit analoger Darstellung wie Figur 2.

Further advantages, features and possible uses of the present invention result from the following description of preferred embodiments with reference to the accompanying drawings. Show it:

Figure 1

a partially broken and partially in longitudinal section side view of a first embodiment of opening device before use for opening,

Figure 2

a broken partial cut through the screw cap,

Figure 3

2 shows a top view of the screw cap from FIG. 2 from right to left,

Figure 4

1 is the same view as FIG. 1, but the screw cap is screwed in so far towards the inside of the package after removal of the spacer ring that not only the cut along a circumference of about 270 ° is completed on the opening disk, but the latter is folded down like a flap,

Figure 5

a plan view of the cut but not folded or bent top floor with seat part,

Figure 6

a view similar to Figure 1, but in a second different embodiment and

Figure 7

6 shows a longitudinal sectional view through the screw cap of the second embodiment in FIG. 6 with an illustration similar to that in FIG. 2.

The plastic support ring 4, which is circularly symmetrical with respect to the central axis 3, is welded to the upper floor 1 of a liquid pack 2, which is only shown schematically and broken off, via the fastening flange 5 at 6. The support ring 4 consists of the seat part 7 and the spacer ring 8, both of which are separated from one another by the predetermined breaking line 9 running parallel to the top wall 1. The spacer ring 8 has in its upper part the radially outwardly extended support flange 10 and a tear-off tab 11 formed on the ring 8 on the right.

The support ring 4 and in particular the seat part 7 has on its circular inner surface 12 a threaded bead 13 which extends over a good 360 °.

The screw cap 41 consists of a radially larger rotating part 14 and a threaded projection 15 which is radially smaller with respect to this (14), which is of hollow cylindrical design and evidently has a smaller radius with respect to the rotating part 14. The external thread 16 of the threaded shoulder 15 and thus also the screw cap 41 fits into the rotational engagement in the annular bead 13, as does the outer circumference of the rotating part 14 in the support flange 10 and comes into contact with its flat, horizontal ring.

On the free edge 17 of the screw cap 41 there is a cutting knife 18 with a straight front cutting edge 19, the component of which in the direction of the central axis 3 from the free edge 17 to the lowest end 20 facing the top wall 1 is called the axial height H of the cutting knife 18.

In the first embodiment according to FIGS. 1 to 5, the foremost end 20 of the front cutting edge 19 is designed in the form of a tip 20, and this cutting knife 18 is used to cut paper-containing material. In the embodiment according to FIGS. 6 and 7, the front end 20 of the cutting knife 18 is made flatter and is used to cut through an upper base 1 made of plastic.

The cutting takes place on the outer circumference of the opening disk 21 visible in FIG. 5, which is circular and is cut along the cutting line 22 at an angle of 270 °. In FIG. 5, one looks at the cut-off but not bent or folded-away opening disk 21 with the seat part 7 comprising the opening disk 21 with the fastening flange 5. The innermost surface of the threaded bead 13 is shown as a circle 23, and this is also the circle in FIG. 5 Cutting knife not visible because the screw cap 41 is unscrewed in the illustration of FIG. 5.

FIGS. 1 and 6 show the opening device before the first opening, in which state the front end 20 or the tip of the cutting knife 18 has just not yet come into engagement with the top panel 1. This is achieved by the axial length of the hollow cylindrical threaded shoulder 15 which is adjusted to the height of the support ring 4. A stronger indentation of the front end 20 of the cutting knife 18 is not possible because the radially larger rotating part 14 is held in the support flange 10 of the support ring 4.

To open it, the end user grips the tab 11 and tears off the spacer ring 8 along the circular predetermined breaking line 9. Thus, the screw cap 41 can be turned clockwise further so that the threaded attachment 15 with the cutting knife 18 moves downward in the direction of the central axis 3 in the direction of the top floor 1. In this case, the tip or the front end 20 of the cutting knife 18 penetrates into the top floor 1, for example, at the point designated by 24 in FIG. When the screw cap 41 is turned further in the direction of the curved arrow 25 (clockwise), the front cutting edge 19 runs on the circumference of the opening disk 21 along the three-quarter circle 22 according to FIG. 5 up to the point designated by 26. During this circular path between points 24 and 26, the front cutting edge 19 penetrates ever deeper into the top soil 1, so that the innermost, rearmost end 27 of the front cutting edge 19 stops cutting at the point 26. If the user then turns the screw cap 41 a little further in the direction of arrow 25, then the front cutting edge 19 does not make any further cuts, since it is dipped inward under the plane of the top wall 1 into the pack. Rather, the adjacent thread, as shown in FIG. 4, ensures that the opening disk 21, which is only partially shown in broken form in FIG. 4, is bent and at least partially folded away to an acute angle. If afterwards, i.e. after the pouring opening has been made, would unscrew the screw cap 41, then the pouring opening would be open and the user could empty the contents.

Reference list

1

Topsoil

2nd

Liquid pack

3rd

Central axis

4th

Support ring

5

Mounting flange welded on at 6

7

Seat part

8th

Spacer ring

9

Breaking line

10th

Support flange

11

Tear-off tab

12th

Inner surface

13

Thread bead

14

Turned part

15

Thread approach

16

External thread

17th

edge

18th

Cutting knife

19th

Front cutting edge

20th

End, tip

21

Opening washer

22

Section line, three-quarter circle

23

circle

24th

Job

25th

arrow

26

Job

27

The End

41

Screw cap

H

height

Claims (8)

Device for opening a plasticizer pack, which is fastened to the top wall (1) of the pack, with a screw cap (41) and a cylindrical jacket-shaped support ring (4), characterized in that the cylindrical jacket-shaped support ring (4) has an opening disk (21) on the outside encompassing fastening flange (5) is fastened to the top wall (1) of the pack, has a threaded bead (13) on its inner surface (12) and comprises the external thread (16) of the plastic screw cap (41) and that on the free edge ( 17) of the screw cap (41), a cutting knife (18) is integrally formed, which has a front cutting edge (19) running through the free edge (17) at an angle. Apparatus according to claim 1, characterized in that the pitch of the threaded bead (13) on the support ring (4) and the axial height (H) of the cutting knife (18) from the free edge (17) in the direction of the packing are so coordinated with one another that the front cutting edge (19) on a rotation of the screw cap (41) of approximately 270 ° is moved completely through the plane of the top wall (1). Device according to claim 1 or 2, characterized in that the support ring (4) is divided by a predetermined breaking line (9) running parallel to the fastening flange (5) into a lower seat part (7) with the fastening flange (5) and a spacer ring (8) which has a support flange (10) holding the rotating part (14) of the screw cap (41). Device according to one of claims 1 to 3, characterized in that the support ring (4) consists of plastic which can be welded to the top wall (1) and a tab (11) on the spacer ring (8) for removing the spacer ring (8) from the seat part ( 7) is molded. Device according to one of claims 1 to 4, characterized in that the cutting knife (18) has a tip (20) which projects downward beyond the free edge (17) and is directed towards the pack. Device according to one of claims 1 to 5, characterized. that the screw cap (41) is a radially larger rotating part (14) and attached a radial has a smaller, preferably hollow cylindrical thread attachment (15) with an external thread (16) that is trapezoidal in cross section and that the free edge (17) of the screw cap (41) is designed to be sharpened on at least part of its circumference in such a way that the sharpened outer line (19 ) lies in the area forming the base of the external thread (16). Device according to one of claims 1 to 4 and 6, characterized in that the front cutting edge (19) of the cutting knife (18) is arranged in the outer bead of the external thread (16) of the screw cap (41). Apparatus according to claim 1, characterized in that the pitch of the threaded bead (13) on the support ring (4) and the axial height (H) of the cutting knife (18) from the free edge (17) in the direction of the packing are so coordinated with one another that the front cutting edge (19) on a rotation of the screw cap (41) by about 270 ° to 350 ° is moved completely through the plane of the top wall (1).

Images