Closing device with a piercing element

Abstract

The invention relates to a closing device (1) which is arranged above a pierceable point of a closed container (B). Said closing device comprises a lower part (2) with a cylindrical discharge nozzle (20), a screw cover (4) and a piercing element (3). Means (44) are used to displace the piercing element (3), which is open on both sides, downwards in an axial direction in a screw-like manner in the screw cover (4) in the lower part (2) of said closing device. Said piercing element (3) has two cutting elements (33) offset at an angle (a) which produce a continuous, interconnected cutting line (2a), and a displacing element (34, 35, 38) which shifts a partially cut-out tab of the container from the region of the discharge nozzle (20).

Description

[0001] The present invention relates to a closure device of plastic which may be attached via a piercable location of a closed receptacle and which consists of a bung-like lower part with a cylindrical pour-out spout which is connected or connectable to the receptacle, and of a screw cap which may be pushed onto the lower part, as well as of a cylindrical piercing element which in the axial direction is open on both sides and which is displaceably mounted in the lower part, wherein in the screw cap there are present means which during the screwing-off movement of the screw cap for the first time move the piercing element helically downwards.

[0002] Closure devices of plastic consisting of three parts, as described above, specifically of a bung-like lower part with a cylindrical pour-out spout, of a cylindrical piercing element movable therein and of screw cap which comprises means in order to move the piercing element are known in the most varied of embodiment forms. Such closure devices are attached to soft-packaging receptacles. The receptacles consist of multi-layered films which usually have one or more paper or cardboard layers, one or more plastic film layers and at least one blocking layer, for example of aluminium. In the region of the closure devices to be attached the packaging comprise suitable pre-punched piercing locations. Usually according to the piercing element of the closure device mostly only the innermost-lying compact plastic film layer and the aluminium layer need to be severed.

[0003] With most known embodiment forms the piercing element is designed such that the piercing element merely exerts a translatory movement towards the inside of the packaging. For example EP-A-0'328'652 (Toppan Printing Co. Ltd) shows a solution in which in the screw cap a guide-path-like helical line is centrically incorporated on an inner wall, whilst the piercing element has a similar counter-running thread and whereas simultaneously the piercing element is provided with cams which prevent a rotation relative to the pour-out bung. A solution acting in a practically equal manner is also known from WO 99/62776 (Crown Cork and Seal Technologies Corp.). Also from GB-2241224 there is known a closure device with a bung-like pour-out in which there runs a piercing element with guide cams, wherein the guide cams engage into axially running grooves whilst simultaneously the piercing element comprises an inner thread which cooperates with a centric annular wall of the screw cap, wherein the centric wall comprises an outer thread. Simultaneously a threaded connection exists between the screw cap and the pour-out bung.

[0004] The last-mentioned solution according to GB-A-2241224 does not function with a piercable location in the packaging but the pour-out bung is already welded from the inside to the inner wall of the packaging and an additional film is attached on the inside on the flange of the pour-out bung. Such a closure film may have any properties which differ from the actual packaging. Accordingly the shaping of the piercing element may be practically infinite as is for example in the solution according to the FIG. 1 of this publication, or there may be provided several perforation teeth on the circumference of the piercing element. Completely analogous to this, in the embodiment form according to EP-A-0'328'652 there is shown a piercing element which comprises a multitude of perforation teeth on the lower edge. The same is also the case with WO 99/62776 which has otherwise already been mentioned.

[0005] In contrast to the previously mentioned protective patent rights WO 95/05996 (International Paper Company) shows a closure device with which the piercing element does not only carry out a purely translatory movement but a screw movement. The piercing element accordingly comprises an outer thread which is meshingly guided into an inner thread in the pour-out bung. The piercing element may be set into a corresponding screw movement by way of lug means in the screw cap. If the screw cap is screwed off, then the piercing element moves simultaneously in a screw movement downwards into the receptacle to be opened. Here too the piercing element along its lower edge has a multitude of perforation teeth in a completely analogous manner to the previous known solutions.

[0006] Practically all closure devices obtainable on the market today of the type of interest here have given rise to great problems. Whilst initial solutions not documented here functioned practically without perforation teeth and with which the receptacle wall was destroyed somewhere, with perforation teeth one believed that one could come to terms with the problem. This however was not the case. One of the main reasons lies in the fact that all solutions demand a large force effort on opening. Practically with all solutions, over the whole circumference many locations of the films are simultaneously perforated. If the teeth were located at exactly those locations which are located vertically above the pre-separated film, then a solution would be possible. This however would demand a fastening of the closure device onto the receptacle which is exactly to practically a tenth of a millimetre. This is simply not possible. Accordingly the teeth also dig into regions of the packaging which are not pre-punched. For this not only is considerably more force required but also at the same time a pure pulling movement to the film is effected. Whilst films mostly react sensitively to perforations, most films are extraordinarily resistant to tension forces.

[0007] With the embodiment according to WO 95/05996 is was not recognised that with the solution cited here, essentially a cutting effect is achieved instead of a piercing effect. Accordingly the concept with a multitude of perforation teeth in itself doesn't make sense. Added to this is the fact that already with a small rotational angle the complete inner region is cut out of the packaging and falls into the contents of the receptacle. This is not only undesirable and unhygienic, but it additionally leads to the fact that during the pouring-out the loose part again and again gets into the pour-out region and leads to uncontrollable pour-out characteristics.

[0008] As a result of this it, is the object of the present invention to improve a closure device of the initially cited type in a manner such that a simple opening is possible, with which simultaneously the disadvantages described further above may be avoided.

[0009] A closure device which has the features of patent claim 1 achieves this object.

[0010] With the selection of the offset angle α with a size of less than 180° it is ensured that no complete separation out of the packaging region is possible, whereas with a selection of the offset angle of more than 100° it is ensured that at the moment at which the displacing element becomes effective, more than half the circumference is severed and thus the already severed part may be folded away. The latter would also be given per se, even if the offset angle were to be less than 100°, but on the one hand there is the great danger that the displacing element not only pushes the already separated region to the side, but also simultaneously would cause the region not yet severed to tear. Finally however on the other hand with an offset angle of less than 100° the open pour-out region would be greatly restricted.

[0011] Further advantageous design forms of the subject matter of the invention are to be deduced from the dependent claims and their significance and manner of acting is explained in the subsequent description with reference to the accompanying drawings.

[0012] In the drawing there is shown one preferred embodiment form of the subject-matter of the invention. There are shown in:

[0013] FIG. 1 a vertical section through the closure device in the assembled condition on a receptacle, before opening for the first time and

[0014] FIG. 2 the same closure device after opening for the first time, with a screwed-off screw cap, again in the assembled condition in a diametrical vertical section.

[0015] FIG. 3 shows the piercing element in the position of manufacture connected as one piece to the lower part, again as a diametrical vertical section, whilst

[0016] FIG. 4 shows the closure device in the assembled condition in the position of use, wherein merely the packaging is shown partly sectioned.

[0017] FIG. 5 and FIG. 6 represent schematic cutting and bending plans for two different offset angles α.

[0018] Although the invention is essentially concerned only with the design of the piercing element, for a better understanding of the whole construction the closure device 1 consisting of three parts is shown. These are a lower part 2, which is adheringly attached to the receptacle B, a piercing element 3 which is screwably movably mounted therein and a screw cap 4 engaging over the lower part 2. The lower part 2 has a cylindrical pour-out spout 20, which at the end merges into a lower flange 21 and comprises an inner thread 22 as well as an outer thread 23. The flange 21 serves for the adhering connection to the receptacle B. This receptacle consists of a multi-layered soft packaging manufactured of films, wherein the multi-layered film comprises a so-called pre-punching V which partly passes through one or more layers and thus defines a nominal opening. For opening the receptacle B as a result the multi-layered film has yet to be completely severed in the region of the pre-punching V. The flange 21 of the lower part may be welded or adhered on the multi-layered film of the receptacle B. The pre-punching V defines a circular surface which is to lie within the opening of the cylindrical pour-out spout 20. The diameter of the pre-punching V is a few percent smaller than the diameter of the pour-out spout 20. In contrast the diameter of the pre-punching V corresponds extremely accurately to the diameter of the piercing element 3 or the circular path which the cutting elements of the piercing element define with their movement. The inner thread 22 of the cylindrical pour-out spout 20 is a course thread. This means that on the one hand the thread height is relatively large and the thread as a result has a larger pitch. As a result of this, already with a rotation of the about 360° or less the piercing element 3 is moved from its original assembly position, as represented in FIG. 1, into the lower position of use according to FIG. 2. Accordingly the outer thread 23 is realised as a so-called fine thread. Accordingly the thread 23 only has a slight height of the thread flanks and the pitch of the thread is flat. As a result of this, in order to screw off the screw cap 4 this needs to undergo several rotations.

[0019] The actuation of the piercing element 3 is effected by way of the screw cap 4. The screw cap 4 has a cover surface 40 on which a circumferential outer wall 41 borders. The outer wall 41 has an inner thread 42 which is designed as a fine thread, matching the outer thread 23 of the cylindrical pour-out spout. An annular wall 43 running concentrically to the outer wall 41 is integrally formed on the lower side of the cover surface 40. Means in the form of lugs 44 are integrally formed on this concentric annular wall 43 which has a diameter which is smaller than the inner diameter of the piercing element. With a rotation of the screw cap 4 the lugs 44 drive the piercing element 3 in a counter-running direction. Whilst the screw cap 4 moves upwards, the piercing element is moved downwards since the threads between the screw cap 4 and lower part 2 are oriented running counter to the rotational direction of the thread between the piercing element 3 and the lower part 2. A guarantee strip 45 is integrally formed at the bottom on the outer wall 41 via break-off bridge locations 46. This is held in the secured position by retaining cams 24 and the guarantee strip 45 remains here even after opening for the first time, as this is evident in FIG. 2.

[0020] The piercing element 3 which as shown in FIG. 3 is advantageously manufactured with the lower part as one piece consists essentially of an annular wall part 31 with an outer thread 32 which again is designed as a coarse thread, matching the inner thread 22 of the lower part 2. At least two cutting elements 33 and at least one displacing element 34, 35 are integrally formed on this annular wall part 31. The displacing element 34 may be combined with the cutting element 33 or, as is evident from FIGS. 1 to 3 may be designed as a separate element 35. In the section drawings according to FIGS. 1 to 3 in each case only one cutting element 33 may be recognised. Only in the lateral view according to FIG. 4 are both cutting elements 33 visible. The cutting elements 33 which roughly have a triangular shape open into an terminal perforating tooth 36. An arrow D in each case shows the rotational direction of the piercing element. A cutting edge 37 connecting directly to the perforation tooth is integrally formed on the edge at the front in the rotational direction. The cutting edge 37 with the preferred embodiment form here merges into a displacing edge 38 which thus here forms the displacing element 34 and is thus a part of the cutting element 33. On the inner surface of the cutting element 33 above the cutting edge 37 there is integrally formed a lug thickening 39 on which a lug 44 bears during the screwing-off movement of the screw cap for the first time and thus sets the piercing element 3 into a screw movement. The solution with the displacing edge 38 is merely optional. As already mentioned, and likewise realised here, an additional, separate displacing element 35 may be provided. The displacing element 35 is designed shorter in the axial direction of the piercing element 3 than the cutting element 33. Accordingly the displacing element 35 only comes into contact with the film of the receptacle B when the two cutting elements 33 have at least approximately formed a continuous cutting line. The separate displacing element 35 otherwise has roughly the shape of the cutting elements 33, but is however formed bluntly cornered and has no perforation tooth but runs in a rounded arc.

[0021] The manner of acting of the closure device according to the invention is subsequently explained with reference to the FIGS. 5 and 6. The two cutting elements 33 are arranged following one another by an offset angle α. In the initial position before opening the closure device for the first time the two perforation teeth 36 of the two cutting elements 33 are located at the positions a′ and b′. After a certain advance angle β the two perforation teeth 36 contact the film of the receptacle to be severed at the points A and B. With reference to the rotational direction D the perforation tooth of the one cutting element runs ahead of the second cutting element by an offset angle α. With a further rotation in the direction D the perforation teeth 36 pierce the film and in the further course sever the film, wherein the one cutting element runs through the cutting path from point A to point B, whilst the other cutting element defines a cutting line from point B to point C. Thus as soon as the piercing element has been rotated by the offset angle α there results a continuous cutting line of 2α which extends from point A to point C. In this position the cutting edge 37 has inwardly penetrated the film of the receptacle at least approximately completely, and the displacing edge 38 and/or the displacing element 35 now act from point C. The displacing edge now acts from point C whilst the displacing element 35 in the region VB which lies relatively close to the pre-punching V in the not yet severed region. Then the region cut free is pressed down into the receptacle in the manner of a flap. At the same time the pre-punching V practically serves as a bending line. This situation is for example evident in FIG. 2. The remaining, non-severed region of the pre-punching V is larger or smaller, according to the choice of the offset angle α. The offset angle α must theoretically be at least 90°, however this is not sufficient in practice and the actual minimum size of the offset angle α must be larger than 100°. The offset angle α must of course be smaller than 180° in order to ensure that the cutting line is not circumferential and as a result a complete round part is cut out of the film which could fall into the receptacle. Realistically the maximal offset angle α may be about 170°. The solutions shown in FIGS. 5 and 6 relate to realistic details. If one operates with a separate displacing element 35 then the offset angle α may tend to be smaller since in this case the displacing element may already press onto the film before the cutting element at the front in the rotational direction has reached the point C, by which means the film is pressed slightly downwards and thus a somewhat longer continuous cutting line arises than the theoretical cutting line.

[0022] In comparison to the previously known piercing elements with a multitude of perforation teeth, the perforation here is effected only at two points. This has the advantage that the required force is smaller. Simultaneously, here a real cutting movement is effected. The cutting edge 37 specifically carries out a movement component perpendicular to the cutting line as well as a component in the direction of the cutting line. However, because the pre-punching V also runs relatively close to the relatively rigid connection of the film to the flange 21 of the lower part 2 a certain shear force is effected.

[0023] Of course the gradient of the coarse thread between the piercing element 3 and the lower part 2 needs to be directed to the geometry of the cutting elements. The purely vertical length of the cutting edge 37 must be equal to the thread pitch which corresponds to the angle α. The latter is particularly the case if the displacing element is combined with the cutting elements

LIST OF REFERENCE NUMERALS

[0024] 1 closure device

[0025] 2 lower part

[0026] 3 piercing element

[0027] 4 screw cap

[0028] 20 pour-out spout, cylindrical

[0029] 21 flange

[0030] 22 inner thread

[0031] 23 outer thread

[0032] 24 retaining cam

[0033] 31 annular wall part cylindrical

[0034] 32 outer thread

[0035] 33 cutting elements

[0036] 34 displacing elements

[0037] 35 separate displacing element

[0038] 36 perforation tooth

[0039] 37 cutting edge

[0040] 38 displacing edge

[0041] 39 lug thickening

[0042] 40 cover surface

[0043] 41 outer wall

[0044] 42 inner thread

[0045] 43 concentric annular wall

[0046] 44 lug

[0047] 45 guarantee strip

[0048] 46 break-off bridge locations

[0049] B receptacle

[0050] V pre-punching

Claims

1. A closure device of plastic which may be attached via a piercable location of a closed receptacle (B) and which consists of a bung-like lower part (2) with a cylindrical pour-out spout (20) which is connected or connectable to the receptacle, and of a screw cap (4) which may be screwed onto the lower part (2), as well as of a cylindrical piercing element (3) which in the axial direction is open on both sides and which is displaceably mounted in the lower part, wherein in the screw cap (4) there are present means (44) which during the screwing-off movement of the screw cap for the first time move the piercing element (3) helically downwards, characterized in that the piercing element (3) is equipped with at least two cutting elements (33) which are arranged running after one another by an offset angle (α) of less than 180° and more than 100° so that after a rotation of the piercing element by the offset angle a continuous cutting line of 2α has arisen, and that now a displacing element (34, 35, 38) acts in the non-separated region, which pushes the partly cut-out lobe [tab] of the receptacle out of the region of the pout-out spout (20).

2. A closure device according to claim 1, characterised in that the displacing element is combined with the front-running [leading] cutting element (33), into an element (34, 38).

3. A closure device according to claim 2, characterised in that the front-running [leading] cutting element (33) has a cutting edge (37) which merges into a displacing edge (38) acting as a displacing element, wherein the cutting element (37) is so long that with the screwing movement after one rotation (D) of the piercing element (3) by at least approximately the offset angle α the displacing edge (38) pushes the non-separated region of the receptacle (B) out of the region of the pour-out spout (20).

4. A closure device according to claim 1, characterised in that in the rotational direction of the piercing element (3) there is present a displacing element (35) which is separated from the cutting element and which runs ahead of the front cutting element (33).

5. A closure device according to claim 4, characterised in that in the two cutting elements (33) and the displacing element (35) are integrally connected with the piercing element (3).

6. A closure device according to claim 1, characterised in that the two cutting elements (33) and the displacing element (34) are offset concentrically to the outer wall of the cylindrical piercing element (3) towards the centre approximately by the wall thickness of the annular wall part (31).

7. A closure device according to claim 1, characterised in that the piercing element (3) with the cutting elements (33) has an axial length which corresponds maximally to the axial length of the cylindrical pour-out spout (20).

8. A closure element according to claim 4, characterised in that the displacing element (35) is shorter than the two cutting elements (33) by the axial distance which corresponds to the axial movement path which the two cutting elements (33) have travelled with a rotation of the piercing element (3) by the offset angle α.