EP2426058A1

EP2426058A1 - Self-closing can for a food product

Info

Publication number: EP2426058A1
Application number: EP10174888A
Authority: EP
Inventors: Erwin Vanderstraeten; Roland Van Haudenhuyse
Original assignee: E V D S bvba
Current assignee: E V D S bvba
Priority date: 2010-09-01
Filing date: 2010-09-01
Publication date: 2012-03-07
Also published as: UA110625C2; WO2012028338A1

Abstract

A metal beverage can for a food product is described, especially for a carbonated drink, including a body (1,101) and a can end (2,102). The can end includes:
- a cap top (3,103), arranged in connection to a pull tab (4,104) configured to remove the cap top along a pre-defined groove (9,109), to thereby create a drinking or pouring aperture, the cap top including a raised lip-contact portion (7,107) on its upper surface;
- a resiliently operated shut-off valve (6,106) configured to open the drinking or pouring aperture under pressure during drinking or pouring and to seal off the drinking or pouring opening after drinking or pouring.

The cap top is configured to remain located, after the removal, on top of the shut-off valve (6,106), and the shut-off valve includes a relief valve (8,108), actuatable by interaction with the cap top (3,103) and configured to release gas pressure from inside the can, upon the first contact pressure, e.g. exerted by the drinker's lips.

Description

FIELD OF THE INVENTION

The present invention relates to a container such as a can for a food product, especially a beverage as well as a method of manufacturing the container or can. The container or can is especially suitable for carbonated beverages or drinks. The container or can can be provided with means for automatically reclosing after the first opening.

BACKGROUND TO THE INVENTION

Metal beverage cans usually have a pull tab (working as a lever mechanism) to allow for the opening of the can along a pre-determined shallow groove. This design allows venting the excess pressure in the can when it is opened. As the tab is lifted, first a vent score is severed, allowing the gases in the can to be released, and then the aperture score is ruptured, which defines an aperture through which the contents of the beverage can may be dispensed. The groove has the shape of a non-closed loop, so that when pressure is applied by the lever to rip the metal along the groove, the metal tab that is ripped off remains attached to the top of the can, even when the lever is returned to its original position.
With existing cans, a permanent opening is formed by these manipulations, so that the contents of the can may be drunk, but on the other hand carbon dioxide may escape and spills may occur.
Patents US4784283 and US5810189 disclose beverage cans that include a spring-loaded tab inside the can that is configured to reclose the drinking aperture after the can is opened for the first time. However, for a carbonated beverage can, after every sip of the beverage, carbon dioxide within the drink escapes, and thus the pressure of the gas within the container increases. This pressure increase becomes smaller as the amount of liquid in the can decreases, but the pressure can be quite high initially: depending on the temperature of the liquid, this pressure can be between 3 and 4 bar. Such a high pressure on a closing surface of e.g. 2.5 to 3.5cm² results in a large force that needs to be counteracted when opening the can for drinking when the can still contains a large amount of beverage.
Patent application US 2008/0314904 , with inventor Perra, discloses a closing device for a food product container, more particularly a drink container, that includes a wall part provided with an opening and a shield member sealing the opening. The shield member is displaceable between a first, closed position sealing the opening in the wall part and a second, opened position leaving the opening at least partly open. The shield member is provided with a locking member securing the shield member in the first, closed position, and the shield member oriented in the first, closed position can be unlocked by displacing a locking member. The operations of unlocking and opening a (drinking) opening are separated such that both operations can be optimized independently of each other. The food product container can be used for carbonated drinks, such as sparkling water. In this case, pressure is built up in the drink container because of the gases. In an embodiment, a closing device with a gas passage is disclosed that acts as a relief valve to decrease pressure in the drink container when it is opened for the first time. Instead of for carbonated beverages, the food product container can also be used for other food articles, such as for example non-carbonated beverages, instant soup, instant coffee, oil, honey, sauces, dairy products such as milk or yoghurt, et cetera.

SUMMARY OF THE INVENTION

The present invention provides an alternative container, e.g. can for food products, especially beverages such as carbonated drinks. An advantage of embodiments of the container or can is that it is provided with means for automatically reclosing after it is opened for the first time. Thus, spilling food or liquid is avoided. In some embodiments the reclosing is not only liquid tight but also gas tight. In case of a carbonated drink, the carbon dioxide will not escape from the can as is the case with a traditional can, since the can according to the present invention automatically recloses.
The present invention provides a metal can optionally for carbonated drinks, comprising a body and a can end, said can end comprising:

a cap top, arranged in connection to a pull tab configured to remove said cap top along a pre-defined groove, to thereby create a drinking or pouring aperture, the cap top comprising a raised lip-contact portion on its upper surface;
a resiliently operated shut-off valve configured to open the pouring or drinking aperture under pressure during drinking or pouring and to seal off the drinking or pouring opening after drinking or pouring;

In a preferred embodiment, the container or can includes a body and a container or can end, the container or can end comprising a cap top, arranged in connection to a pull tab configured to remove the cap top along a pre-defined groove or other form of mechanical weakness, to thereby create a drinking aperture. The cap top preferably comprises a raised lip-contact portion on its upper surface; and a resiliently operated, e.g. spring operated shut-off valve configured to open the drinking aperture under lip pressure during drinking and to seal off the drinking opening after drinking. The sealing off may be liquid and/or gas tight sealing. The cap top is preferably configured to remain located, after the removal, on top of the shut-off valve. The shut-off valve preferably includes a relief valve, optionally actuatable by interaction with the cap top and e.g. configured to release gas pressure from inside the can, upon the first pressure exerted by the drinker's lips.
The container or can according to the present invention is suitable for mass production.
An advantage of a container or can according to the invention is that it can easily be produced. In comparison with a traditional can, only the can end is different. Thus, a traditional production line of cans can be modified to produce the container or can, e.g. by replacing the production steps for the traditional can end by the production steps for the can end according to the invention; e.g. by adaptation of the tooling for the production line. The production steps and tooling for the can body and for attaching the can end to the can body can remain unchanged. Moreover, the can end in accordance with the invention requires only a small number of parts.
The invention also includes a can end, and a method for producing a container or can.
The container of can will be described below especially when used for beverages, particularly carbonated drinks. It will be clear from the description however that the can may also be used for other food products, such as instant soup, instant coffee, oil, honey, sauces, dairy products such as milk or yoghurt, et cetera.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:

Figs. 1 a and 1 b show 3D views of the top portion of a can in accordance with a first embodiment of the invention, seen respectively from the top and from the bottom;
Figs. 2a and 2b show views of an element that comprises a spring portion and a shut-off valve, and that can be applied in a can according to the first embodiment the invention;
Figs. 3a and 3b show respectively a 3D view and a side view of an assembly of a number of parts in a can according to the first embodiment. Fig. 3c shows a side view of the can end of the can, with this assembly, and Fig. 3d shows a 3D view of an assembly of the element shown in Figs. 2a and 2b with two other parts;
Fig. 4a and 4b show respectively a top view and front view of a beverage can according to a second embodiment of the invention;
Fig. 5 shows a can according to the second embodiment when it is being opened for the first time, and also shows an embodiment of a pull tab of a can in accordance with the invention;
Fig. 6 shows the can according the second embodiment after it was opened for the first time, and resealed automatically;
Figs. 7a and 7b show details of a relief valve in accordance with the invention;
Fig. 8 shows details of an assembly of a pull tab and a can end according to an embodiment of the invention;
Figs. 9a and 9b show details of an assembly of the spring and the shut-off valve/cap top arrangement in the second embodiment of the invention;
Fig. 10 shows in detail a connection of the shut-off valve to the spring in the second embodiment of the invention;
Fig. 11 shows in detail a connection of the cap top to the spring in the second embodiment of the invention;
Fig. 12 shows a top view of the can end in the second embodiment of the invention, with a possible arrangement of the spring;
Figs. 13 and 14 illustrate drinking from a beverage can according to the invention;
Fig. 15 illustrates an embodiment with specific features of the shut-off valve and another design of the wire spring;
Fig. 16 shows an alternative can end design and how the spring is attached to the can end according to this design;
Fig. 17 shows an alternative design for the connection of the alternative designed spring to the shut-off valve;
Figs. 18 and 19 show alternative designs for the spring load system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are nonlimiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.
Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.
Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.
It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.
Figure 1 a shows a 3D view of the top portion of a container or can, e.g. a re-sealable beverage can in accordance with an embodiment of the present invention. The can includes a can body 1 and a can end 2 attached to the body. The can body may be a standard can body, typically made out of steel, or out of aluminum. The can end is often produced in aluminum. None of these materials represent a limitation to the invention, e.g. the can end 2 in accordance with the invention may be made from steel. If steel is used, for the can body 1, the can end 2 or for both, it is customarily coated. The invention may be applied to different standard containers such as beverage cans and sizes, as well as to so-called "slim" and "super sized" cans. Hereafter, the design is described for a large opening, e.g. drinking opening, but other designs of openings such as drinking or pouring openings may be used as well. In an embodiment, the edge of the can end 2 is standard, especially the way it has to be assembled on the can body 1 after filling with the food product. The can end shown in Fig. 1 a has a circumferential collar 29, adjacent to a circumferential groove 30.
The central part of the can end 2 has a non-removable tear panel 3, called the cap top in this document, which is very similar to the pull-off part of a standard beverage can end. The cap top 3 has in the embodiment shown in Fig. 1 a a raised portion in the form of a bead 7, preferably formed by embossment, on its top surface. As in a known, traditional beverage can, the cap top 3 can be torn off along the pre-formed shallow groove 9 or a form of mechanical weakness, by pulling at the pull tab 4, which works as a lever. The opening that is thus created serves as a pouring or drinking opening, as in a traditional beverage can. However, in a traditional beverage can the cap top remains attached to the can, whereas in the disclosed embodiment according to the invention the cap top 3 is torn completely from the can end along the groove 9. As opposed to a traditional can, the cap top 3 is not bent inside the can. After tearing off the cap top 3, the cap top 3 remains attached to a shut-off valve 6, which is configured to reseal the pouring or drinking opening after drinking, by the action of a resilient member such as a spring 5 (shown in Fig. 1 b), which is described in detail further below. In the shown embodiment, before it is opened for the first time, the can is closed in the same way as a traditional can. It is opened by making a rupture through metal, as is the case for a traditional can, and it is thus as leak-proof as a traditional can. Many other existing re-sealable cans rely on other opening mechanisms, e.g. on opening by a rotation, and they are often not at all as leak-proof. The bead 7 (see Fig. 1a) has several functions. It stiffens the can end 2, and it serves as a contact point for the consumer's lips: when the consumer wants to drink, and puts the can to his or her mouth as with a traditional can, the consumer's lip touches bead 7, which opens the can, as will be explained further below.
In an embodiment, the shut-off valve 6 is a plate-like element, which is resiliently biased, e.g. spring-biased against the underside of the can end 2, by the resilient force, e.g. spring force exerted by a resilient member such as a spring 5, and further, optionally, by any force resulting from the internal pressure that is built up when the can is filled with a carbonated drink. The shut-off valve 6 is provided with a relief valve 8. Different embodiments of this relief valve are disclosed further below.
The consumer can drink or pour from the can by tearing open the cap top 3, as explained above, and by then putting his lips to the released cap top, normally to bead 7 or by tipping the can. By exerting a force on the cap top, the consumer pushes the shut-off valve 6 away from the opening, against the resilient force, e.g. spring force. After pouring or drinking, the opening is automatically closed again by the resilient force, e.g. spring force. The relief valve 8 is configured to release pressure built up in the can under the shut-off valve 6, by the first force exerted by the consumer's lips. Thus, because of this pressure release, the shut-off valve 6 opens easily. This is described in detail hereafter.
In the embodiment of figure 1, the resilient member such as spring 5 is a specially designed plate spring element, shown in Fig. 1b, which is a 3D view of can end 2, seen from below. In this view, it can be seen that shut-off valve 6 is integral with the resilient member, e.g. spring 5, in that the spring and shut-off valve are formed from a single resilient element or spring element 10, which is shown separately in figure 2a and 2b. Before being mounted in the can, one portion of the resilient element or spring element 10 is bent backwards so that a bent-back portion 5' is obtained. The end 5" of bent-back portion 5' is biased against the underside of shut-off valve 6. Spring or resilient element 10 may be made of a type of material having good resilient properties, e.g. a metal such as steel. Spring or resilient element 10 has an opening 11 through which it can be attached to the can end, via a fixing device such as a rivet 12 (Fig. 1 a) by which also pull tab 4 is connected to the can end. In the embodiment of Fig. 2a, shut-off valve 6 is connected to resilient portion or spring portion 5' by narrow strips 13. Strips 13 and bent-back portion 5', with their elastic properties, make up the resilient member or spring 5, that biases shut-off valve 6 against the underside of the can end (Fig. 1 b). The bent-back portion 5' preferably comprises a narrow end strip 14, which is positioned underneath rim 30 of can end 2 (see Fig. 1 b). The function of narrow end strip 14 is discussed further below.
As shown in Figs. 3a and 3b (which show respectively a 3D view and a side view of the assembly of cap top 3, shut-off valve 6, resilient member or spring 5 and pull tab), seal 19 is attached to shut-off valve 6, around the circumference of the valve 6. Seal 19 may be made from silicone or another suitable material. Seal 19 closes the pouring or drinking opening of the can when the consumer does not drink or pour. Cap top 3 is optionally connected to shut-off valve 6 via U-shaped wire portions 20, that are attached through holes 21 in the shut-off valve 6 (Fig. 2a and 3d). Bead 7 (see Fig. 2a) comprises a notch 22, while the wire portions 20 comprise a corresponding deformation 23, which may be hooked behind the notch, so as to secure cap top 3 to shut-off valve 6.
Of course cap top 3 may be fastened in other ways to shut-off valve 6.
Release valve 8 functions as follows in this embodiment. As shown in Figs. 3a and 3b, cap top 3 comprises a bulging portion 25, pointing downwards. Shut-off valve 6 has a hole 26, positioned in front of bulge 25. Hole 26 may have a crater-shaped cross-section, in order to receive the bulge 25. Bent-back portion 5' of resilient member or spring 5 is provided near its end with a portion 5" which is substantially parallel to shut-off valve 6 and which is provided with a seal element 27 which effectively closes off opening 26 when the consumer does not drink or pour, since bent-back portion 5' is biased against the underside of shut-off valve 6 when the can is not used by the consumer. At the first contact with the drinker's lips or other body part however, cap top 3 is pushed downward and bulge 25 pushes - through hole 26 - against seal element 27. In this way, bulge 25 pushes bent-back portion 5' away from shut-off valve 6, before the shut-off valve itself opens. This action releases pressure from inside the can through opening 26 and thereafter facilitates opening of the shut-off valve itself, when the drinker exerts further pressure. In this way, the opening 26 together with the bulging portion 25 and seal 27 together act as the pressure relief valve 8 (fig. 1 a).
Fig. 3c is a side view of an embodiment of can end 2. It shows that the extended portion 14, or narrow end strip 14, of bent-back portion 5' extends outward so as to be positioned underneath the rim 30 of the can end. The extended portion 14, together with pressure relief valve 8, acts as a security pressure relief, as will now be explained. When an already opened can that contains a carbonated beverage is resealed by shut-off valve 6, pressure builds up underneath the can end, since, after every sip of the beverage, carbon dioxide within the drink escapes, as discussed already above. As the drinking opening has been created, the strength of the can end has significantly decreased, and the can end may gradually deform under the built up pressure.
Such a deformation causes the can end to bulge outwards. Especially in high temperatures, this effect may become important and there may be a risk of rupture of the can. However, when the can end has deformed to a certain degree, extended portion 14 comes into contact with the rim 30 of the can end (see Fig. 3c). When deformation continues, extended portion 14 will be pushed down and eventually cause seal 27 to be removed from opening 26, thus opening the pressure relief valve 8. Gases are thus released and pressure inside the can decreases, so that the deformation decreases as well. Thus, extended portion14, together with relief valve 8, provides a security pressure relief means: even at very high pressure, a can that contains a carbonated beverage will not be ruptured and will not explode.
Other embodiments having modifications compared to that described above are included within the scope of the invention. For example, instead of forming shut-off valve 6 and resilient member or spring 5 from a single element 10, shut-off valve 6 may be a separate piece connected to a resilient member or spring element comprising a bent-back portion similar to portion 5' in Fig. 1b. Bent-back portion 5' preferably has an opening facing opening 11 in the bent-back position, so that it may easily be riveted to the can end.
Figs. 4a and 4b illustrate a second embodiment of a beverage can in accordance with the invention. Fig. 4a shows a top view with see-through illustration of all the main parts of a self-closing re-sealable beverage can according to this second embodiment, while Fig. 4b shows a front view.
The container e.g. beverage can comprise a can body 101 which may be a standard can body, and a can end 102 attached to body 101. The can body may be made of steel, for example but also aluminium. The can end can be produced out of aluminum for example. For example, both the can body and the can end may be made out of other materials. This second embodiment may be applied to different containers such as standard beverage cans and sizes, as well as to so-called "slim" and "super sized" cans. In an embodiment, the edge of the can end 102 is standard, especially the way it has to be assembled on the can body 101 after filling with the beverage or, in general, with the food product.
As in the first embodiment, disclosed above, the central part has a cap top 103, which is provided with a raised portion in the form of a bead 107, preferably formed by embossment, on its top surface. As in a known, traditional beverage can, the cap top 103 can be torn off along the pre-formed shallow groove 109 or other mechanical weakness, by pulling at the pull tab 104, which works as a lever. The opening that is thus created serves as pouring or drinking opening, as in a traditional beverage can. However, in a traditional beverage can the cap top remains attached to the can, whereas in the disclosed embodiment according to the invention the cap top 103 is torn completely from the can end along the groove 109. The bead 107 has several functions. It stiffens the can end, and it serves as a contact point for the consumer's lips: when the consumer wants to drink, and puts the can to his or her mouth as with a traditional can, the consumer's lip touches bead 107, which opens the can, as is explained further below.
The main parts that will be described hereafter in more detail are: cap top 103, pull tab 104, both made e.g. of a metal such as aluminum or of steel, resilient member such as a wire spring 105, made e.g. of spring steel, and shut-off valve 106 with relief valve 108, made e.g. of HSS (High Strength Steel).
Shut-off valve 106 is a preferably rounded, such as a round or ellipse shaped plate-like element, which is resiliently biased, e.g. spring-biased against the underside of the can end 102, by the force exerted by resilient member e.g. spring 105, and further optionally through the internal pressure built up if the can is filled with a carbonated drink. In the embodiment shown, resilient member or spring 105 is a pre-formed wire with a specific shape (described in more detail further below), to which shut-off valve 106 and cap top 103 are attached. The consumer can drink or pour from the can by tearing open cap top 103, and manipulating the released cap top, e.g. by putting his lips to the released cap top 103. By exerting pressure on the cap top, the consumer pushes shut-off valve 106 away from the pouring or drinking opening against the resilient, e.g. spring force. In this way, the pouring or drinking opening is automatically shut off again by the resilient, e.g. spring force, after drinking or pouring. Relief valve 108 is arranged to release pressure built up underneath the shut-off valve, by the first pressure exerted by the drinker's lips, so that the shut-off valve can be opened easily. This is described in detail further below.
Fig. 5 shows a cross section of an embodiment of a can that has just been opened. Pull tab 104, with a specially designed penetrating nose 201, is in a lifted position, pushing down resilient member or spring 105 and cap top 103, which is torn from the can end along groove 109 or other mechanical weakness. In this position, it is possible to pour the liquid out of the can. For drinking, however, pull tab 104 is pushed back down, as for traditional cans. The opening that is thus created serves as the drinking opening, as in traditional beverage cans. However, in a traditional beverage can the cap top remains attached to the can, whereas in the disclosed embodiment according to the invention the cap top 103 is torn completely from the can end along the groove 109. As opposed to a traditional can, the cap top 103 is not bent inside the can. After tearing off the cap top 103, the cap top 103 remains attached to shut-off valve 106.
Keeping cap top 103 attached to shut-off valve 106 may be realized, as shown in Fig. 5, by fixing cap top 103 to shut-off valve 106 via resilient member or spring 105, by means of two hook-like ends 202, arranged at the ends of the wire spring 105 (which is described in detail further below).
As shown in Fig. 6, pull tab 104 is pushed back by the consumer after opening the can, just as for a traditional can. Spring or resilient member 105 then automatically closes the can, as shut-off valve 106 closes in this embodiment along a half ring torus 203 against a corresponding half-ring torus 204 on the underside of the can end. Fig. 6 thus shows the can in the state wherein it is closed automatically by resilient member or spring system 105, the pull tab 104 being pushed back in a flat position. The can is resealed, preventing spillage of the contents and optionally loss of any gas such as carbon dioxide.
Spring or resilient member 105 is designed and shut-off valve 106 is mounted to resilient member or spring 105 in such a way that shut-off valve106 has enough clearance in order to let the two ring torus surfaces 203 and 204 match perfectly, taking account of the manufacturing tolerances of the parts and the displacement of the parts due to pressure changes in the can. In this way, a very good sealing is obtained. The seal can be liquid and/or gas tight. A thin layer of coating applied to both torus surfaces 203 and 204 can still further improve the sealing. A suitable coating material is a water-based varnish as customarily used to cover the inside surface of beverage cans.
Spring or resilient 105 is preferably pre-stressed so that the closing force suffices to prevent leakage of liquid or optionally gas, thus allowing the internal pressure to build up again after drinking. The gas filling, e.g. carbon dioxide of the beverage cannot escape and builds up pressure in the can: the so called "maintained carbonation" of the liquid.
Since after every sip of the beverage carbon dioxide within the drink escapes, the pressure of the gas within the can increases, and thus shut-off valve 106 will close even better, as a result of the consumer drinking of the liquid.
The pre-stress of resilient member or spring 105 is limited so that the consumer can easily reopen the can by exerting a small pressure with his lips, presuming that the internal pressure has been released before, by the pressure relief valve 108.
Relief valve 108 functions as follows (see especially Figs. 7a and 7b). As stated already above, cap top 103 is located on top of and in contact with shut-off valve 106. In the embodiment shown in Figs. 7a and 7b, cap top 103 is provided with a protruding pin 301 which can be a bulging portion of the cap top, pointing downwards in the direction of shut-off valve 106. Relief valve 108 is so arranged in co-operation with pin 301 that pin 301, when pushed downwards, is capable of opening relief valve 108. Fig. 7a shows a cross section of cap top 103 and shut-off valve 106, and a detailed cross section of pressure relieve valve 108 and pin 301 that shows that in this embodiment relief valve 108 is formed of a portion of shut-off valve 106, said portion being provided with incisions 601. Pressure relief valve 108 is a self-closing, resiliently operated, e.g. spring operated valve. It may optionally be made from HSS (High Strength Steel), which has fairly good resilience, combined with good mechanical properties for stamping and distortion. In this embodiment, relief valve 108 is formed by a portion of shut-off valve 106, said portion being provided with one or more incisions 601. As illustrated by Fig. 7b, which shows a top view and a side view of shut-off valve 106, relief valve 108 may be a dome-shaped spring with one or more very small incisions 601 (two incisions are shown in Fig. 7b), made along a radial direction of the dome, and dividing the dome in a number of dome flanks 602. Fig. 7b shows an embodiment with two radial incisions 601, so that there are four dome flanks 602 (according to another embodiment, three incisions are made, so that there are six dome flanks). By pushing down flanks 602 with pin 301, the incisions 601 are opened, relieving the internal pressure. A small pressure by the consumer's lips on bead 107 on cap top 103 (see Fig. 4b) is sufficient to open relief valve 108 (see also Fig. 13), and thus to decrease the pressure in the can, so that immediately afterwards shut-off valve 106 is easily opened by further, low pressure from the consumer's lips on bead 107.
Fig. 8, which represents a cross section of a still unopened can end 102, shows an embodiment of pull tab 104. In this embodiment, pull tab 104 has a special bent design 403 that allows to tear off the low lying cap top 103. Pull tab 104 has a specially designed penetrating nose 201. As shown in Fig. 8, the end portion of the penetrating nose 201 is tilted upwards with respect to the portion of the nose that is attached by the rivet 401. This ensures than when pull tab 104 has been pushed back after opening the can, and may have been deformed in doing so, nose 201 does not prevent the shut-off valve from fully closing the drinking opening. Groove 109 can be as for traditional cans, as can be rivet 401 which serves to attach pull tab 104 to the beverage can end 102. A deepening 402 allows to easily put a finger behind pull tab 104. The design of deepening 402 helps to strengthen can end 102 against elastic and plastic deformation due to internal pressure in the can.
The design of bead 107 on cap top 103 permits a good contact with the lips as well as good drinking properties, including good air inflow into the can while drinking.
Fig. 9a shows a cross section of can end 102, after the first opening of the can. The ripped-off cap top 103 is now leaning on shut-off valve 106. The valve, pushed by the resilient member or spring 105 against the underside 204 of the can end, blocks the inside can pressure from escaping. In this position the cap top is "loose" from the can end in such a way that mechanical clenching is avoided (see region 501, which indicates the region between the cap top and the can end)
Figs. 9a and 9b also illustrate details of resilient member or spring 105 according to the second embodiment. According to this embodiment, resilient member or spring 105 is formed of a pre-formed wire, comprising a rounded portion 150, attached along a part of the circumference of the can end 102, and comprising first straight portions 151 extending from the circumference of the can end towards the center of the can end, and preferably inclined downwards as shown in Fig. 9a, and second straight portions 152 extending from said first ends and pointing substantially upward, and wherein shut-off valve 106 and cap top 103 are attached to the ends of the second straight portions 152. In the embodiment shown, the ends of the rounded portion 150, and thus the starting points of the first straight portions 151, are in contact at position 505. This contact may be a point contact between the two sides of the wire that constitute the wire spring, when the wire itself has a circular cross-section. However, instead of having a circular cross section, the wire may have any other suitable cross-section. For example, it may have a section having straight vertical portions, so that the contact at position 505 may be along a line instead of in a point. The two embodiments described above (circular section and section with vertical portions) are illustrated in the two detailed wire cross sections in Fig. 9b.
Spring or resilient member1 05 may be fixed at the underside of the can end 102 (at position 502). The resilient member or spring is simply pressed into the can end border during the assembly of the complete system. For this purpose, can end border 504 is provided with a groove 901 along the circumference of the can end, in which groove the rounded portion 150 of the wire spring 105 can be fitted (as shown in Fig. 9a). Because of the drinking opening at the drinking side, the groove 901 turns into a narrow notch 503 at that position (see Fig. 9a). The resilient member or spring is secured in groove 901 by the resilient, e.g. spring force itself (the two halves of the rounded portion 150 push against the side wall of groove 901). According to one embodiment, a welded or glued joint may be provided between the contacting portions of the resilient member or spring in point 505 (other alternatives are described later).
Figs. 10 to 12 show assembly details of the resilient member or spring 105, cap top 103 and shut-off valve 106. As shown in Fig. 10, shut-off valve 106 is fixed on resilient member or spring 105 at position 701, where the upper portions 152 of the resilient member or spring protrude through the shut-off valve. Shut-off valve 106 can pivot over a small angle on the second straight portions 152, which are part of resilient member or spring 105. Fig. 11 shows how a tail end of resilient member or spring 105 and cap top 103 are "clicked" together with two specially designed hook-like ends 202, which may be formed as barbs or flukes, and which may be obtained by folding back the ends of the resilient member or spring. In this embodiment, bead 107 is formed as a hollow embossed portion (hereafter referred to as 'embossment'). While assembling shut-off valve 106 to the cap top, by pushing these hooks 202 into the cavity of the embossment 107, the two parts click together and stay connected. The interior of the embossment 107 is provided with notches 801 (see Fig. 11), located so that the hooks 202 on the tail end of the resilient member or spring lock themselves behind these notches 801, so that the cap is prevented from loosening before or after first opening or during drinking or pouring. In this way, when the can is collected as waste, the parts made of one material e.g. in steel can easily be recovered and recycled. Fig. 12 shows another embodiment for wire spring 105, where the ends of the rounded portion 150 do not touch. In this embodiment, the spring is kept in the groove by the spring force only (i.e. the spring force of the rounded portion 150, pushing outward against the groove 901).
Fig. 13 shows a consumer putting his lips to the can. As explained above, he thus automatically opens the relief valve 108, resulting in a fast decrease of the carbon dioxide pressure inside the can, so that the shut-off valve is easily opened again.
Fig. 14 shows the consumer drinking from the can by simply pushing back the shut-off valve by a small pressure of his lips to bead 107. When the consumer withdraws his lips to stop drinking, the spring will automatically reclose the shut-off valve.
Figs. 15 to 19 show a number of variations of some of the components of the second embodiment described above.
As shown in Fig. 15, in assembled position, mounted in the notch of can end 102, wire spring 105 is leaning against a small strip 160 which is connected to the (adapted) shut-off valve 106 via a connection strip 161. This prevents the spring from becoming separated from notch 901. The strip 160, connection strip 161 and shut-off valve 106 are preferably formed as a single part. To mount the resilient member or spring, the two straight legs 151 may be pushed together to make the diameter of the resilient member or spring smaller, so that the resilient member or spring may pass the outside of the groove 901 of the can end. While pushing the wire spring legs together, the small strip 160 on the shut-off valve is pushed down by the 2 spring legs 151. The small strip 160 is made of the same material as the shut-off valve 106, and thus also has resilient properties. Therefore it will jump back and will arrive between the two curves of the resilient member or spring 151 at the moment the resilient member or spring is mounted in the notch. From that moment on, the wire spring is fixed onto the can end.
Instead of using one circular groove 901 as shown in Fig. 12, or one circular groove 503 as shown in Fig. 9, in the embodiment of Fig. 16 several smaller notches 165 or scores are used to keep the wire spring 105 in its place.
In the embodiment of Fig. 17 shut-off valve 106 has two protrusions, which may have the form of pointed jags 170, which fit into the cavity of the cap top embossment 107. Two small narrowings 171 in this cavity prevent the pushed-in jags 170 from becoming detached, but still allow a small movement of the cap top. Shut-off valve 106 itself is not fixed on the wire spring 105, which has no hooks as in the previous embodiments, but straight ends 172. The shut-off valve simply lies on the spring, balancing on the two wire ends 172 at the inside of the pointed jags 170. Also, different designs of the pointed jags with corresponding narrowings in the cavity are possible (see e.g. Fig. 18 for another possible design of the jags). When making can end 102 according to this embodiment, after stamping the end itself and fixing the pull tab 104, the shut-off valve 106 is pushed and thus fixed in the cap top, by pushing the jags 170 into the cavity of the embossment 107. At the same time wire spring 105 is pushed and fixed in the can end.
In the embodiment of Fig. 18, the wire spring and the shut-off valve are replaced by one part 180. This is a plate spring. The plate spring comprises a round portion which may be in the form of a torus shaped ring 181 arranged around the bottom of the notch 182 in the can end, so as to fix the spring to the can. The spring comprises two plate spring elements 183 extending from the round portion 181. Shut-off valve 106 is now an integral part of the spring 180. The elasticity of the material of part 180 (preferably HSS steel) allows the plate spring elements 183 to be pushed down, when the cap top is pushed down by the consumer's lips. The same resilience brings the shut-off valve 106, part of the plate spring 180 back, closing the drinking opening. In the embodiment shown, cap top 103 is fixed to the shut-off valve (and thus to the spring 180) with two pointed jags 185. This connection is similar to the one described with reference to Fig. 17, though the form of the jags is different: the jags are formed as arrowheads that fit into the similarly formed interior of the embossment 107.
In the embodiment illustrated by Fig. 19, the wire spring is replaced by a plate spring 190 with the same functions. The plate spring has a round portion 191 fixed around the notch of the can end, as described in Fig. 18. The spring further comprises plate elements 192 protruding from the round portion, and carrying upstanding portions 193 at the end. Shut-off valve 106 leans on the upstanding portions 193, as in the embodiment of Fig. 14. Shut-off valve 106 further comprises jags which fit into the cavity of the embossment 107, as in the embodiments of Figs. 17 and 18.
The present invention is not limited to the embodiments described above. The scope of the present invention is defined by the appended claims.

Claims

A metal beverage can optionally for carbonated drinks, comprising a body (1,101) and a can end (2,102), said can end comprising:
- a cap top (3,103), arranged in connection to a pull tab (4,104) configured to remove said cap top along a pre-defined groove (9,109), to thereby create a drinking or pouring aperture, the cap top comprising a raised lip-contact portion (7,107) on its upper surface;

- a resiliently operated shut-off valve (6,106) configured to open the drinking or pouring aperture under pressure during drinking or pouring and to seal off the drinking or pouring opening after drinking or pouring;
wherein said cap top is configured to remain located, after said removal, on top of said shut-off valve (6,106), and in that said shut-off valve comprises a relief valve (8,108), actuatable by interaction with the cap top (3,103) and configured to release gas pressure from inside the can, upon the first pressure exerted.
The can according to claim 1, wherein the shut-off valve (6) is a part of or is connected to an elastic resilient element (10) attached to the can end, said elastic resilient element (10) comprising a bent-back portion (5'), said elastic resilient element (10) being configured for biasing the shut-off valve (6) against the underside of the can end (2), and wherein the end (5") of said bent-back portion (5') is itself biased against the underside of the shut-off valve (6), and wherein said relief valve (8) comprises :
- a relief opening (26) in the shut-off valve (6);

- a seal element (27) attached to said end (5") of the bent-back portion (5') and arranged to close off said relief opening (26) when the can is not in use; and

- a bulging portion (25) of the cap top (3), configured to be positioned above said relief opening (26), in such a manner that upon first contact pressure, the bulging portion (25) pushes the seal element away from the relief opening (26), thereby decreasing an inner pressure from an inside of the can.
The can according to claim 2, wherein said bent back portion (5') has an extended portion (14), extending underneath a rim (30) of the can end, in such a manner that a contact occurs between said extended portion (14) and the rim (30) when internal pressure deforms said can end, said contact actuating opening of the relief opening (26).
The can according to any one of the preceding claims, wherein said relief valve (108) is formed in a portion of the shut-off valve (106), with at least one incision (601) provided in said portion, and wherein the cap top (103) is provided with a protrusion (301), aligned to said portion, so as to push against said at least one incision (601) to thereby open the relief opening, when a first contact pressure is exerted on said protrusion (301).
The can according to claim 4, wherein said portion of the shut-off valve (106) in which the relief valve (108) is formed is a circular portion, formed into a dome, said incision(s) (601) being provided in a radial direction of said dome.
The can according to claim 4, wherein said incision is a U-shaped incision, and wherein the relief valve is a plate spring element (255).
The can according to claim 6, wherein said plate spring element (255) has a surface larger than the opening created by said U-shaped incision.
The can according to any one of claims 1, 4, 5, 6 or 7, wherein said shut-off valve (106) and said cap top (103) are attached to or supported by a resilient member (105) comprising a pre-formed wire, comprising a rounded portion (150) attached along a part of the circumference of the can end (102), and comprising first straight portions (151) extending from the circumference of said can end to the centre of the can end, and second straight portions (152) extending from said first ends and pointing substantially upward, and wherein said shut-off valve (106) and cap top (103) are attached to or supported by the ends of said second straight portions (152).
The can according to any one of claims 4 to 7, wherein said shut-off valve (106) and said cap top (103) are attached to or supported by a plate spring (180,190,249).
The can according to claim 9, wherein said plate spring (180) comprises at least one plate spring element (183,250), and wherein said shut-off valve (106,255) is integral with said at least one plate spring element.
The can according to claim 10, wherein said raised lip-contact portion (107) on the cap top is at least partially hollow, and wherein the shut-off valve (106) comprises protrusions (170,185) configured to fit into the interior of said raised portion (107), to thereby fix the shut-off valve (106) to the cap top (103).
The can according to claim 11, wherein said plate spring (190) comprises two plate spring elements (192), each comprising at the end an upstanding portion (193), and wherein said shut-off valve (106) and/or said cap top (103) are attached to or supported by said upstanding portions (193).
The can according to claim 12, wherein said raised lip-contact portion (107) on the cap top is at least partially hollow, and wherein the shut-off valve (106) comprises protrusions (170,185) configured to fit into the interior of said raised portion (107), to thereby fix the shut-off valve (106) to the cap top (103) and wherein the shut-off valve and cap top lean onto the ends of the upstanding portions (193).
A can end (2, 102) as described in any one of the preceding claims.
A method for producing a can, the method comprising the steps of:
- producing a can end (2, 102) according to claim 14;

- producing a can body (1, 101);

- attaching said can end to said can body.