WO2005108233A1 - Vacuum-tight lid for containers - Google Patents

Abstract

The invention relates to a sheet metal lid (2) that is to be mounted on an opening of a container (4) whose content is to be maintained in a vacuum until said lid (2) is opened for the first time. The inventive lid (2) comprises a closing part (8) which seals in relation to a peripheral edge (36) of the opening and is provided with a ventilation hole that is closed by means of a film-type seal (18). The lid further comprises an edge part (10) which surrounds the peripheral edge (36) on the outer side thereof and is provided with a continuous or interrupted bead (56, 64) that protrudes towards the inside and is pressed against the peripheral edge (36) from the outside after mounting the lid (2). In order to make it easier for consumers to see whether the lid (2) has been sealing the container (4) in an airtight manner until the film-type seal (18) is removed, the center of the closing part (8) of the lid (2) is provided with a molded-in clicking bubble (22) which pops up when the film-type seal (18) is removed from the ventilation hole (22).

Description

 Vacuum sealing lid for containers

Technical field

The invention relates to a closure lid made of sheet metal for attachment to an opening of a container, in particular a container containing food, the contents of which are to be kept under negative pressure until the lid is opened for the first time, with a closure part which spans the opening and seals against a peripheral edge of the opening, and an integrally connected to the closure part, surrounding the peripheral edge on its outside edge part, the closure part is provided with a ventilation opening closed by a film seal and the edge part is provided with an inwardly projecting circumferential or interrupted bead, which is attached after the lid is attached Container is pressed from the outside against its peripheral edge.

State of the art

Sealing covers made of sheet metal are commercially available, in which the edge part is provided with a circumferential or interrupted bead which projects inwards. These lids are used quite frequently to seal airtight glass containers filled with a foodstuff, such as mustard, mayonnaise or the like, in which the peripheral edge around the container opening is not sufficiently thick for attaching a screw thread and / or in which the container tightens the consumption of the container contents should be suitable for further use as drinking glass. To ensure the quality of the container contents, the contents of these containers are normally kept under a vacuum until they are opened for the first time, which allows control of the maintenance of the seal between the closure lid and the opening edge. However, this means that when you first open such a lid, it does not only the mechanical anchoring of the lid on the container due to the engagement of the bead behind the usually thickened peripheral edge of the container but also the negative pressure in the container has to be overcome. Particularly with closures with a larger diameter, this is only possible with considerable effort or using technical aids, which often leads to damage to the cover.

In order to solve this problem, DE 297 11 363 U1 already proposed a closure cover of the type mentioned at the outset, which has a small ventilation opening in the middle, which is closed by a sealing film. This sealing film can be removed before the container is opened for the first time in order to allow ambient air to enter the container through the ventilation opening. This eliminates the pressure in the container, whereupon the lid can usually be opened effortlessly.

Problems with opening often also occur with preserving or jam jars with metallic screw lids, the contents of which are under a negative pressure. The screw caps of such containers also have a closure part which bears against the circumferential edge of the container opening and an edge part which is connected to the closure part and surrounds the circumferential edge on its outside and which for engagement with protruding threaded ribs on the outside of the circumferential edge at its free lower front end with an inward protruding bead or flare is provided. This beading or flanging is pressed against the threaded ribs on the outside of the peripheral edge when the lid is screwed on and, together with the negative pressure inside the container, ensures that it is securely closed. To open it, the screw cap has to be unscrewed, which is especially difficult for older and weaker people. In order to make opening easier, it is already known, for example from DE 92 00 763 Ul, even with such screw caps, to provide a punched-out ventilation opening on the closure part, which is covered from the outside by means of a foil seal, whereby the negative pressure in the

Container can be relieved before removing the lid by pulling or piercing the foil seal.

However, in the known sealing lids, before the sealing film is pulled off, it is not readily apparent to the consumer whether the container contents are still under a vacuum and thus an uninterrupted tightness has been ensured since the filling. To do this, the consumer would have to apply a force to the lid before pulling off the sealing film in order to convince yourself of the tightness of the closure based on the resistance, since when pulling off or piercing the sealing film, a slight hissing can be heard at most if you listen carefully Ambient air is caused to enter the container through the ventilation opening.

Proceeding from this, the object of the invention is to improve a closure lid of the type mentioned in such a way that when the film seal is removed the consumer can clearly see whether the lid has still hermetically sealed the container up to this point.

Presentation of the invention

According to the invention, this object is achieved in that the closure part is provided in the middle with a molded-in click bubble, which blows upward when the film seal is removed from the ventilation opening.

Click bubbles, which are also referred to as flip or button, have long been converted into metallic ones Screw caps of canned glass with preserves, jam or similar glass containers used. These click bubbles are circular bulges that were formed in the middle of their closure parts under special stress conditions during the manufacture of the screw cap and that are pressed down into the interior of the container by the ambient pressure when the pressure difference between the ambient pressure and the negative pressure in the Containers exceeds a predetermined dimension. If the screw cap has been loosened when the container was opened for the first time so that ambient air can enter the latter between a seal formed on the underside of the cover and the peripheral edge of the container, the click bubbles will snap up again to their unloaded position with an audible click , However, the already mentioned considerable effort required to open these screw caps means that many consumers place their palms on the top of the lid when unscrewing the lid, so that the click sound generated when the click bubble pops up is muffled or no audible click sound is generated at all. Because of the effort required, many consumers concentrate so much on the opening process itself when opening the container that the clicking sound is not perceived. This is also due to the noises that occur when the cover is unscrewed, which can overlay or even drown out the click sound. In addition, the snap-up bubble cannot be visually checked by the consumer, since there is hardly any way of gripping the lid so that the click-bubble remains visible.

In contrast to this, the invention is based on the idea that when the film seal is pulled off, the consumer will focus his attention on the closure cover, so that he will snap up those provided in the center of the cover

Click bubble can be perceived both visually and acoustically. This is achieved to a particularly high degree when the ventilation opening with the film seal according to a preferred embodiment of the invention is arranged eccentrically next to the click bladder in the closure part of the lid, so that the process of blowing up the click bladder is neither covered nor hindered by the fingers of the consumer attacking the film seal. This latter arrangement also has the advantage that the click sound generated when the click bubble pops up, unlike a film seal that completely or partially overlaps the click bubble, is not dampened by the seal. However, the eccentric arrangement requires measures to ensure an exact positioning of the film seal on the ventilation opening, for example by introducing the ventilation opening into the sealing cover after painting the sealing cover and immediately before attaching the sealing film, so that twisting between these work steps of the cover lid avoided. This in turn means that the closure lid is not coated with lacquer along the cut edges within the opening, but it has been shown that this does not cause any problems, in particular with aluminum closure lids, for most food products.

A further preferred embodiment of the invention provides that the ventilation opening closed with the film seal is arranged in the radial direction of the cover between an outer edge of the click bladder and an elevated sealing edge of the closure part provided with a sealing material on the underside, preferably within an annular section of the Sealing cover which forms the groove base of a flat annular groove arranged between the outer edge of the click bladder and the sealing edge. In the case of an unloaded click bladder arched upward, this groove base is essentially parallel to the planes which are spanned by the flat upper side of the raised sealing edge of the cover or by the lower edge of the edge part. If there is a negative pressure of around 0.2 to 0.3 bar inside the container, this negative pressure depending on the diameter of the lid and being adjustable within certain limits, for example by changing the thickness of the lid and other parameters, the click bubble will change from the ambient pressure to its own retracted position in which it is under tension. When the vacuum is released when the cover 2 is opened for the first time, the click bubble pops up, producing a clearly audible click sound.

In order to make any manipulation of the container more difficult, a further advantageous embodiment of the invention provides that the film seal no longer adheres to the lid after it has been removed. However, if required, a seal variant can also be used, which can be stuck back over the ventilation opening on the lid.

According to a further advantageous embodiment of the invention, the film seal has a sealing part which is sealed on the top of the lid to the edge of the ventilation opening and a grip tab which is integrally connected to the sealing part and which projects on one side beyond the preferably essentially circular sealing part, its central axis expediently essentially is aligned perpendicular to a cover radius running through the ventilation opening. In this way, the film seal can be peeled off in a direction that runs past the click bladder so that it is not covered by the fingers of the consumer engaged with the grip tab when the blister is peeled off.

The foil seal itself preferably consists of a gas-tight foil, such as an aluminum or composite foil, which is connected to the lid around the circular ventilation opening, on an area whose radius is a multiple of the radius of the ventilation opening. In order to connect the film seal to the cover, it is preferably coated on its underside facing the cover with a plastic-containing lacquer which melts with a corresponding plastic-containing lacquer applied to the outside of the cover when the film seal placed on the cover in the region of its sealing part briefly heated to a temperature exceeding the melting temperature of the lacquer and pressed against the lid. The sealing film or the outside of the cover can be coated with the lacquer either over the entire surface or only partially in the areas to be sealed, although in the former case only the sealing part may be heated and pressed against the cover. Alternatively, a hot glue can also be used.

The diameter of the ventilation opening, the amount of lacquer or hot glue applied to the underside of the film seal, its viscosity in the heated state and the contact pressure are preferably matched to one another in such a way that a small amount of lacquer flows into the opening during pressing in order to create a space inside the eccentric ventilation opening to achieve so-called cut edge sealing, but this amount remains so small that the opening is prevented by the lacquer or hot glue.

In order to make it easier to grasp the grip tab of the film seal, the grip tab can be provided with an embossing, which causes its rear edge facing away from the sealing part to protrude slightly above the lid surface. Alternatively or additionally, the closure part of the lid can also be provided with a small impressed bulge in the vicinity of the ventilation opening for the same purpose.

Brief description of the drawings The invention is explained in more detail below with reference to two exemplary embodiments shown in the drawing. Show it:

1: a top view of a closure cover according to the invention;

Fig. 2 is a sectional view through the entire cover along the line A-A of Fig. 1;

Fig. 3 is a sectional view through part of the

Cap along the line B-B of Fig. 1;

4: a partially broken sectional view through a container closed with the closure lid;

5: a view corresponding to FIG. 4, but with the closure cover partially open;

6 shows a partially sectioned side view of a modified closure cover;

7: a partially sectioned side view of another modified closure cover;

8 shows a partially sectioned side view of a further modified closure cover;

9 shows a sectional view through a closure cover according to the invention designed as a screw cover;

Fig. 10: a partially broken sectional view through a container closed with the screw cap.

Detailed description of the embodiments

The cover 2 shown in the drawing for one

Mai nna ϊ ceπl a c / TT ϊ mn-on 1 bis 8) oder ein Konservenglas (Figuren 9 und 10) , bestehen im Wesentlichen aus einem einstückig aus Aluminiumblech hergestellten Deckelkörper 6 mit einem Verschlussspiegel 8 und einem einseitig über den Verschlussspiegel 8 überstehenden Randteil 10, einem angrenzend an einen Übergang 12 zwischen dem Verschlussspiegel 8 und dem Randteil 10 auf der Unterseite eines erhöhten Dichtungsrandes 14 des Verschlussspiegels 8 ringförmig angeformten Dichtungsmaterial 16, sowie einem auf der Oberseite des Verschlussspiegels 8 angebrachten Foliensiegel 18, das eine den Verschlussspiegel 8 durchsetzende Belüftungsöffnung 20 verschließt.Rehabilitation A

Mai nna ϊ ceπl ac / TT ϊ mn-on 1 to 8) or a preserving jar (FIGS. 9 and 10) essentially consist of a cover body 6 made in one piece from aluminum sheet with a locking mirror 8 and an edge part 10 projecting over the locking mirror 8 on one side, one adjacent to a transition 12 between the locking mirror 8 and the edge part 10 on the underside of a raised sealing edge 14 of the closure mirror 8, ring-shaped sealing material 16, and a film seal 18 attached to the top of the closure mirror 8, which seals a ventilation opening 20 passing through the closure mirror 8.

The closure mirror 8 has in its center a so-called click bubble 22, which consists of three successive concentric sections 24, 26, 28 of the closure mirror 8, a circular inner section 24, an annular middle section 26 and an annular outer section 28. Of these sections 24, 26, 28, when the cover 2 is not loaded, the inner section 24 is essentially aligned with one of the flat upper side of the

Sealing edge 14 spanned plane E, while the middle of the two sections 26 is inclined at a flat angle of inclination away from this plane E towards the outer section 28, which in turn is inclined at a somewhat larger angle of inclination away from plane E to the base 32 of a flat annular groove 30 which is concentric with the three sections 24, 26, 28, its inner flank being formed by the two sections 26, 28. As best shown in FIGS. 1, 2, 5 and 9, the annular groove 30 extends radially outward to the sealing edge 14, its groove base 32 when the cover is not loaded

2 (FIGS. 2 and 9) is approximately parallel to the plane E of the top of the sealing edge 14.

If the closure cover 2 has been attached to a previously filled container 4 such that the closure mirror 8 spans the flat mouth opening 34 of the container 4 and the sealing material 16 on the underside of the sealing edge 14 around the container opening 34 rests on its thickened peripheral edge 36, and when the pressure in the container 4 drops as a result of condensation of steam in a cavity 38 below the lid 2 until the pressure difference from the ambient pressure is approximately 0.8 bar, the click bubble becomes 22 pressed from the ambient pressure towards the inside of the container into a retracted position, as shown in FIGS. 4 and 10. In this position, the circular inner section 24 is essentially aligned with the container opening 34, while the two annular sections 26, 28 are each inclined towards one another at a slight angle of inclination in the direction of the plane E. The groove base 32 of the annular groove 30 is then also inclined toward the center of the cover at a slight angle of inclination away from the plane E. As a result of the deformation of the cover 2, the click bladder 22 is pretensioned in this state, which has the consequence that when the cover 2 is opened for the first time it pops up, producing a clearly audible click sound. However, since the pressure in the container 4 can increase not only when the cover 2 is opened for the first time, but also as a result of a leak when small amounts of ambient air enter between the sealing edge 14 of the cover 2 and the peripheral edge 36 of the container 4, the click bladder 22 in their retracted position is a visible sign of the integrity of the seal of the container 4.

The ventilation opening 20 closed with the film seal 18 has a diameter in the millimeter range and is arranged eccentrically with respect to the click bladder 22 approximately centrally in the base 32 of the annular groove 30, that is to say approximately in the middle between an outer edge 40 of the click bladder 22 and one Sealing edge 14 towards the groove flank 42, so that the film seal 18 is essentially completely within the annular groove 30, but the click bubble 22 does not overlap.

The foil seal 18 made of aluminum foil essentially consists of a seal part 44. Rlpr et a circular is formed, covers the edge of the ventilation opening 20 on all sides and is fastened over the entire surface to the top of the closure mirror 8, and a square or rectangular grip tab 46 which is connected in one piece to the sealing part 44 and projects beyond it on one side. In order to avoid that the grip tab 46 held between two fingers to pull off the foil seal 18 has to be moved over the click bladder 22, which is covered by the fingers, the central axis 50 of the foil seal 18 running through the sealing part 44 and the grip tab 46 is im Aligned essentially perpendicular to a radius R through the ventilation opening 20.

For gas and liquid-tight fastening of the foil seal 18, this is coated on its underside facing the cover 2 with a lacquer (not shown), the finely dispersed plastic, e.g. Polypropylene. The outside of the lid body 6 is coated with the same paint. In this way, the two layers of lacquer can be fused together before the lid 2 is attached to the container 4 if the film seal 18 positioned with the sealing part 44 above the ventilation opening 20 in the area of the sealing part 44 over a period of 200 to 300 ms to a temperature heated from 200 to 250 ° C and pressed against the lid 2.

This type of sealing is suitable for hot and cold filling of the container contents, with or without thermal aftertreatment, pasteurization up to 100 ° C and / or sterilization up to 125 ° C. In the case of products without thermal aftertreatment, the film seal 18 could also be fastened in another way, for example by means of an adhesive, preferably a hot glue.

If an eccentrically arranged ventilation opening 20 is introduced after painting the cover 2 and immediately before the application of the film seal, in order to twist the To avoid cover 2, the cut edge inside the ventilation opening 20 is not covered with lacquer. However, such a coating, referred to as cut edge sealing, can be formed by the lacquer or hot glue used to fasten the film seal 18, by the contact pressure when applying the film seal 18 a small amount of the heated lacquer or adhesive between the underside of the film seal 18 and the top of the Lid 2 is squeezed out in the direction of the opening 20, the viscosity of which is sufficient to form a protective closed coating on the cutting edge.

In order to make it easier to grip the grip tab 46, it has an indentation 52 which projects beyond its underside and keeps the free rear end 54 of the grip tab 46 at a distance from the groove base 32 (FIG. 3).

In order to facilitate the first-time opening of the gas-tight container 4 (FIGS. 4 and 10), the film seal 18 is first removed before the lid 2 is lifted off the container 4 (FIG. 5) or unscrewed. To the

Pulling off the foil seal 18, the grip tab 46 is gripped with two fingers and pulled off in the direction of the arrow P in FIG. 1 until ambient air enters the cavity 38 in the container 4 and the negative pressure in the interior of the container is eliminated. The click bladder 22 located in the middle of the consumer's field of vision soars upward that it is clearly audible and audible with a clear click, so that the maintenance of the tightness of the closure up to this point in time is clearly recognizable both acoustically and visually for the consumer.

Then the lid 2 can be easily removed from the container 4.

Where the cover 2, as shown in FIGS. 1 to 7, closes a container 4 that can be used, for example, as drinking glass, with a thickened upper opening edge 36, it is placed on the container 4 from one towards the inside via the edge part 10 protruding bead or embossment 56 is held, which engages behind the thickened edge 36 and is pressed from the outside against its underside, as best shown in Fig. 4.

The bead 56 can be designed there as a continuous peripheral bead running around the edge part 10, as in FIGS.

5 and 7, or in the form of a plurality of individual beads 56, for example, depending on the lid diameter, five to seven, distributed at equal intervals around the circumference, as in the figures

6 and 8, the latter facilitating the lifting of the cover 2.

In order to minimize the risk of cut injuries at the free lower end of the edge part 10, this end is rolled up either inwards or outwards, as shown for example in FIGS. 2 and 4 or 6 and 7 at 58.

Where the cover 2, as shown in FIGS. 8 and 9, is designed as a screw cover and engages with a plurality of threaded ribs 60, which protrude beyond the outer peripheral surface of the opening edge 36 of the container 2 and are inclined at a flat angle to the plane E, it is provided in a known manner at the free lower end of its edge part 10 with a circumferential flange 62 which projects radially inwards. In order to hold the lid 2 on the container 4, the flange 62 is also provided in a known manner in its upper side with a number of beads or embossments 64 arranged at an angular distance from one another, corresponding to the number of threaded ribs 60 of the container 2, as a result of which the flange 62 on these Make a little flatter and protrude further inside. When the screw cap 2 is placed on the opening edge 36 of the container 2, these beads 64 each pass between two adjacent threaded ribs 60 and, when the cover 2 is subsequently screwed on, are pressed from the outside against the underside of a threaded rib 60 located above it.

Claims

claims 1.Sealing lid made of sheet metal for attachment to an opening of a container, in particular for foodstuffs, the container contents of which are to be kept under a negative pressure until the lid is opened for the first time, with a closing part which spans the opening and seals against a peripheral edge of the opening, and an integral part with connected to the closure part, the peripheral edge on it Edge part surrounding the outside, the closure part being provided with a ventilation opening closed by a film seal and the edge part being provided with an inwardly projecting circumferential or interrupted bead which is pressed against the circumferential edge of the container from the outside after the cover has been attached, thereby characterized in that the closure part (8) is provided in the middle with a molded-in click bubble (22) which pops up when the film seal (18) is removed from the ventilation opening (22). 2. Closure cap according to claim 1, characterized in that the ventilation opening (20) is arranged eccentrically in the closure part (8). 3. Cap according to claim 1 or 2, characterized in that the ventilation opening (20) is arranged outside of the click bladder (22). 4. Cover according to one of the preceding claims, characterized in that the ventilation opening (20) and the film seal (18) between an outer peripheral edge of the click bladder (22) and a circumferential sealing edge (14) provided on its underside with a sealing material (12). of the closure part (8) is arranged. 5. Closure cap according to one of the preceding claims, characterized in that the ventilation opening (20) and the film seal (18) is arranged in an annular portion of the closure part (8) which the groove base (32) of an annular groove (30) between the outer Forms edge (40) of the click bladder (22) and the sealing edge (14). 6. Closure cover according to claim 5, characterized in that the groove base (32) is substantially parallel to a plane (E) of the top of the raised sealing edge (14) when the click bubble (22) is curved upward. 7. Cover according to one of the preceding claims, characterized in that the film seal (18) no longer adheres to the cover (2) after removal. 8. Cover according to one of the preceding claims, characterized in that the gas-tight film seal (18) consists of aluminum foil or a composite film. 9. Closure lid according to one of the preceding claims, characterized in that the film seal (18) around the ventilation opening (20) with the lid (2) connected to the sealing part (44) and a handle tab (46) integrally connected to the sealing part (44) ) having. 10. Closure cap according to claim 9, characterized in that the grip tab (46) projects on one side over the essentially circular sealing part (44), its central axis (50) being aligned essentially perpendicular to a radius (R) through the ventilation opening (20) is. 11. Closure cover according to claim 9 or 10, characterized in that the grip tab (46) and / or the closure part (8) of the cover (2) is locally raised, so that an edge (54) of the grip tab facing away from the sealing part (44) (46) is kept at a distance from the top of the cover (2). 12. Closure lid according to one of claims 9 to 11, characterized in that the closure part (8) is coated on its upper side at least in regions with a plastic-containing lacquer, that the sealing part (44) of the film seal (18) on its underside with a plastic-containing lacquer is coated, and that the two paints are fused together in the area of the sealing part (44). 13. Closure cover according to one of the preceding claims, characterized in that it consists of aluminum or an aluminum alloy. 14. Closure cover according to one of the preceding claims, characterized in that the free end of the edge part (10) is rolled inwards or outwards. 15. Closure cover according to one of the preceding claims, characterized in that the free end of the edge part (10) is flanged inwards and that the interrupted bead (64) projects inwards over the flanged free end. 16. Container, in particular containing a foodstuff, with an opening delimited by a circumferential peripheral edge, characterized by a closure cover (2) attached to the peripheral edge (36) according to one of the preceding claims, the click bladder (22) of which is caused by a negative pressure inside the container ( 4) is held in a retracted position and pops up by pulling off the film seal (18) from the ventilation opening (20). 17. A container according to claim 16, characterized in that the closure lid (2) is designed as a snap lid, in which the bead (56) from the outside against the underside of a bead-like thickened peripheral edge (36) of the opening of the container (2) is pressed. 18. A container according to claim 16, characterized in that the closure lid (2) is designed as a screw cap, in which the bead (64) from the outside against the underside of a threaded rib (60) on the outside of the peripheral edge (36) of the opening of the container (2) is pressed.