OA19020A - Metal can and associated can lid - Google Patents

Abstract

A can lid and in particular a can connected to this can lid that comprises an opening region provided in the material of the lid surface and comprises a two-armed lever member that is intended to open this opening region and that is connected to the lid material, wherein this arrangement is characterized in that the opening region configured as a tongue tab is delineated from the lid surface by a tear line in the form of a material weakening or of an at least partial material perforation extending over the tab periphery and the tongue tab base connected to the lid surface forms a pivot bearing that becomes effective during the opening procedure; in that the lower side of the lid is coated, in particular over the whole surface, with a plastic material, in particular a plastic film, in a firmly adhering manner, and this coating of the tear line that covers the tear line is weakened in an adjacent manner, in particular notched and preferably at least partly notched open between the tongue tab and the lid surface; and in that the container part and the can lid at least substantially comprise the same aluminum alloy.

Description

METALLIC CAN AND ASSOCIATED CAN LIP

The invention relates to a can, in particular to a beverage can, comprising a cylindrical container part and a can lid sealingly connected thereto via a folded joint and having a bounded opening région provided in the lid material of the lid surface, and comprising a two-armed lever member that is intended to open this opening région and that is fixedly connected to the lid material, in particular via a rivet connection or a weld connection.

Metallic cans of this kind are used worldwide to a very great degree, i.e. in volumes of a number of billions per year. They can be manufactured simply and inexpensively and allow a space-saving stacking while ensuring the required leak tightness under ail practically occurring environmental conditions. The opening of the cans by the consumer is made possible by a simple upward pivotîng of the long arm of the lever member.

In view of the extremely high volumes of cans produced and consumed annually, the manufacturing costs of such cans play a very large rôle, with, in addition to the recycling capability, an energy balance being aimed for which is as good as possible in connection with the materials used.

The known cans, in particular beverage cans, comprise aluminum alloys, with it being customary to use the alloy aluminum 3000 for the cylindrical can part and the alloy aluminum 5000 for the lid part since the technical demands on the materials used with the can part and the lid part are different. As part of a réduction in material consumption or in can weight, it has already been possible to reduce the material thickness of the can wall down to approximately 0.09 mm, and indeed while using the alloy aluminum 3000 that is also less expensive than the alloy aluminum 5000 that is typically used as the lid material. The wall thickness of the lid material has to be at least twice as much as the material thickness of the can wall to ensure the required compressive strength of the can despite the notch to be formed in the can material to provide a tear groove. This stamping or notching bounds the opening région and has a depth that typically corresponds to approximately half the material thickness of the can lid. Ail the demande on the can lid with respect to the opening criteria and the leak tightness can be satisfied by the use of the higher-quality alloy aluminum 5000.

It is the object of the invention to design a can, and in particular a can lid to be connected to the cylindrical part of the can, such that the general production costs can be reduced in addition to a targeted further weight réduction. The opening procedure of the can should moreover be facilitated, i.e. should be able to be carried out with reduced force in comparison with conventional cans and otherwise ail the advantages of known cans should be maintained.

This object is substantially satisfied in accordance with the invention in that the opening région of the lid surface formed as a tongue tab is deiineated by a tear line extending over the tab periphery in the form of a material weakening or of an at least partial material perforation and the tongue tab base connected to the lid surface forms a pivot bearing that becomes effective during the opening procedure; in that the lower side of the can is coated, in particular over the full surface, with a plastic material, in particular a plastic film, in a firmly adhering manner, and this coating of the tear line that covers the tear line is weakened in an adjacent manner, in particular notched and preferably at least partly notched open; and in that the container part and the can lid at least substantially comprise the same aluminum alloy.

The opening région ofthe lid surface is preferably separated from the lid surface by a microgap, in particular a stamped gap, extending over the tab periphery and the container part and the can lid preferably likewise comprise the same aluminum alloy, in particular the alloy aluminum 3000, preferably 3104, with the material thickness of the can lid being substantially the same as the material thickness of the container part and preferably not exceeding at least twice the value of the material thickness ofthe container part.

ft is essential for the solution in accordance with the invention that the demands made on the can lid with respect to leak tightness and compressive strength are at least largely satisfied by the layer of plastic material, in particular a firmly adheringly attached plastic film, provided at the lower lid side and that due to the spécifie design of this plastic layer in the région of the tongue tab periphery, an opening ofthe can is possible in a conventional manner, and indeed in particular with smaller force when the notch bounding the opening région is particularly deep or is partly perforated or above ail when a microgap is provided instead of a notch.

In addition to the saving in production costs achieved by material sélection and weight réduction with a simultaneous improvement of the handling properties in practice use, it is furthermore of essential importance that it is no longer necessary to use a spécial material for the lid material, for example an aluminum alloy of the 5000 sériés, in particular the alloy 5182, since now an inexpensive recycling material or the same recycling material can also be used for the lid material on which no spécial demands hâve to be made with respect to strength and the possibility of introducing an always safely functioning tear groove. The unity of the aluminum material used for the can part and the lid part also represents an advantage in recycling procedures.

Although the invention can also be implemented using a notch for fixing and bounding the tongue tab in the aluminum material used for the lid, it is of advantage if, instead of a notch, a microgap is used, and indeed preferably in a manner such that the tongue tab of the metallic can lid is separated from the cover surface surrounding it by a cutting procedure, in particular by a stamping procedure, while forming mutually engaging projections and recesses, and such that the tongue tab and the lid surface adjacent thereto are connected via the projections and recesses in a shape-matched and force-transmitting manner while forming the microgap, with the leak tightness of the filled and opened can being ensured by the inwardly disposed plastic coating or film having a thickness preferably in the range of approximately 1/10 mm to 2/10 mm.

The projections and recesses are in particular coupled via undercuts and the lid surface is concavely formed in the région of the tongue tab, which has the conséquence that the pressing in the microgap is increased by the internai container pressure.

The plastic layer provided at the lower side of the lid is preferably formed by a plastic film that forms a separate molded blister part before its seaiing with the lower side and the notch or partial notch opening décisive for the can opening procedure is already provided in said molded blister part.

On a design of a can lid in which the opening région is pivoted into the interior of the can during the opening procedure, the notch in the plastic film is arranged radially outside the microgap and slightly spaced apart from the microgap.

With a can lid in which the opening région is outwardly pivoted during the opening procedure, the notch in the plastic material or in the plastic film is provided radially within the microgap and slightiy spaced apart from the microgap.

The invention is also explicitly directed to a can lid of the above-described design possibiiities that can be handled separateiy from the can part and that is only connected to the can part after filling the can.

The invention will be described in more detail in the following with reference to an embodiment and to the drawing; there are shown in the drawing

Fig. 1 an only sectionally and schematically shown can with a can lid configured in accordance with the invention; and

Fig. 2 a sectional représentation along a diameter of the can lid in accordance with Fig. 1.

The représentation in accordance with Fig. 1 shows an only sectionally shown container part 15 that is connected to a can lid 1 via a flange rim orfolding rim 2. The can lid 1 is provided with a tear closure that can generally be of any desired known design, but preferably has one of the aspects described within the framework of this application. They can in this respect be both non-reclosable embodiments and reclosable embodiments such as are described, for example in EP2 354 022 B1, in PCT/EP2016/057225 or in DE 10 2016 103 801.6.

Unlîke known cans comprising aluminum alloys, in particular beverage cans, no aluminum alloy is used that substantially differs from the material of the container part 15 for the can lid 1 in accordance with the invention, but the same aluminum alloy is preferably used.

This is made possible by the spécial design of the can lid 1 and of the associated tear closure.

With conventional beverage cans of aluminum alloys, an alloy of the aluminum 3000 sériés is used for the container part 15, with wall thicknesses of 0.09 mm already being able to be achieved with this material as part of the always targeted weight saving. As a rule, an alloy of the aluminum 5000 sériés is used as the material for the can lid, with a much higher wall thickness being required in comparison with the container part to be able to reaîize the material notch along the tear line required for the tear closure and in this respect simultaneously to ensure the demands on the compressive strength at internai pressures of at least 6.3 bar.

It becomes possible by the design in accordance with the invention of the can lid and of the tear closure to use substantially the same aluminum alloy for the container part 15 and the can lid 1, and preferably the same aluminum alloy, namely the aluminum alloy used for the container part, in particular from the aluminum 3000 sériés, and preferably 3104.

This is achieved, on the one hand, by the use of a plastic coating at the inner can side ensuring the compressive strength and the leak tightness of the can and, on the other hand, by the spécial design of this plastic coating and its interaction with the design of the tear line in the can lid. Although this tear line is preferably configured as a microgap, it forms part of the invention to use, instead of a microgap, a tear line, that is perforated for example, or a pronounced notch that could alone not produce the required compressive strength.

Fig. 1 shows a preferred embodiment of a can 15 in accordance with the invention with a can lid 1 in a schematic plan view. The can lid is provided at its peripheral région with a bead rim 2 in a conventional manner, wherein the région disposed within the bead rim 2 is formed by a lid surface 3 that has an opening région 4 formed as a tongue tab offset with respect to the center. This can lid preferably comprising an aluminum alloy of the 3000 sériés is provided, surrounding the opening région 4, with a stiffening région 14 formed by materiai deformation. The same aluminum alloy is preferably also used for the container part 15.

A two-armed lever 5, 6 is connected, in particular riveted or welded, to the opening région 4 or to the tongue tab of the can lid such that a fixed connection point 7 results. This connection point 7 is disposed in the marginal région of the opening région 4, i.e. opposite the tongue base connected to the lid surface 3 and the twoarmed lever comprises a shorter région and a longer région, wherein the longer région is preferably formed by an easily grippable ring tab 5 and the shorter région is formed by a supporting limb 6 that is supported on a part of the stiffening région 14 of the can lid on the upward pivoting of the longer lever. The two-armed lever 5, 6 lies substantially in parallel with the lid surface 3 in the starting state.

The tongue tab forming the opening région 4 is connected in a shape-matched and force-transmitting manner to the lid surface 3 via projections 12 and recesses 13 while forming a microgap 8 and preferably via suitable undercuts of these parts, and indeed with the exception of the région of the tongue base 7 where the opening région 4 and the lid surface 3 are connected in a metallic manner such that an upward pivoting of the tongue tab 4 is made possible by means of the lever practically via a kind of folding joint 9 on the opening of the can and the tongue tab and the lever can then move into a position of rest outside the inner can space while releasing the opening.

The required leak tightness or compressive strength of the can lid is ensured despite the lack of a continuous metallic connection between the lid surface 3 and the opening région 4 in the région of the toothed arrangement by a plastic material, in particular a plastic film, that is applied in particular over the whole surface, to the lower side of the metallic lid and that is attached or sealed to the lower lid side in a fîrmly adhering manner. The coating has a pronounced weakening 14, in particular a notch or partial opening notch, directly adjacent to and disposed within the opening line or the microgap such that on the opening of the can lid and on the pulling up of the tongue tab 4, the narrow région of the plastic film covering the microgap is practically peeled off from the material and thus an opening of the can is made possible that takes place with a small exertion of force.

To achieve this design that precludes any formation of métal splinters on the opening of the can lid, the opening région or the tongue tab is separated from the surrounding lid surface by a cutting procedure or preferably by a punching procedure on the production of the can lid, wherein the splinters or microparticles that are thereby produced can be eliminated completely and free of problems as part of the production process. The tongue tab, that is still connected via its base to the lid surface 3 is pressed back into the lid surface plane directly after its punching out such that the original appearance practically again results for the lid surface, but now with a microgap produced by the punching procedure.

Mutually engaging projections 12 and recesses 13 are preferably produced in the stamping procedure instead of a linear microgap, such as can be seen from Fig. 1.

In this case, the two initially partly separated components are again joined to one another in a shape-matched manner directly after the punching procedure such that the can lid can be handled in further production steps in the same way as conventional can lids that only hâve a weakening groove.

The processes of separating and joining together take place directly after one another, i.e. after the punching stroke the shape-matched joining together of both parts to form a total part takes place in the return stroke. The shape-matched and force-transmitting connection between the two régions is achieved by a suitable shaping or by using undercuts that ensures a sufficient mutual mechanical connection such that the required coating procedures or the process of the application of the film to the lower side can also be carried out as with a uniform part.

Instead of the toothed arrangement shown in the drawing, different, optionally simpler, gap line extents can be provided in accordance with the invention in the punching procedure, wherein, however, the opening région or the tongue tab in every case remains connected to the lid surface 3 via the pivot bearing région 9 and the microgap is covered by the plastic film disposed at the inner side and provided with a notch. The plastic film, which can be an PP film and which reacts to the sealing wax provided at the métal during sealing, is in particular manufactured as a separate molded blister part in which the notch is already provided. If the film has a thickness e.g. of approximately 2/10 mm, a weakening to 1/100 mm takes place in the notch.

The somewhat enlarged part représentation in accordance with Fig. 2 above ail shows, in addition to the embodiment of the connection point 7 in the manner of a rivet connection, the application of the plastic film 10 over the full surface to the lower side of the can lid and in particular the formation of the weakening line 11 in the plastic film 10 preferably achieved by a notching and/or regionally by a notching open, said plastic film extending within or outside the microgap about the opening région 4 depending on the embodiment, with the spacing between the weakening line and the microgap being dimensioned such that, on the one hand, the demands on the compressive strength of the can are satisfied and, on the other hand, the already mentioned peeling effect results during the opening procedure.

Since, unlike with known can lids, no spécial demands hâve to be made on the aiuminum alloy material ofthe can lid 1 in connection with notches producing material weakening and with compressive strength, the same aiuminum alloy can practically be used with preferably the same material thickness both for the container part and for the can lîd. No spécial, in particular high-quality, alloy material such as an alloy of the aluminum 5000 sériés thus also has to be used in the can production, which produces simplifications and above ail cost savings since the same recycling material can thus be used for the entire can.

Reference numéral list can lid bead rim lid surface opening région, longue tab lever arm lever arm fastening point, longue base microgap pivot bearing région plastic film weakening line, notch projection recess stiffening région container part

Claims (20)

1. Claims

   1. Acan comprising a cylindrical container part (15) and a can lid (1) sealingly connected thereto via a folding joint and having a bounding opening région (4) provided in the lid material of the lid surface, and comprising a two-armed lever member (5, 6) intended for opening this opening région, said lever member being fixedly connected to the lid material, characterized in that the opening région (4) configured as a tongue tab is delineated from the lid surface (3) by a tear line (8) in the form of a material weakening or of an at least partial material perforation extending over the tab periphery and the tongue tab base connected to the lid surface forms a pivot bearing (9) that becomes effective during the opening procedure;

   in that the lower side of the lid (1) is coated with a plastic material coating (10) in an adhering manner, and this coating (10) of the tear line that covers the tear line (8) is weakened adjacent to the tear line (8) between the tongue tab and the lid surface; and in that the container part (15) and the can lid (1) at least substantially comprise the same aluminum alloy.
2. 2. A can in accordance with claim 1, characterized in that the plastic material coating (10) is a plastic film (10).
3. 3. A can in accordance with claim 2, characterized in that the opening région (4) is separated from the lid surface (3) by a microgap (8) extending over the tab periphery.
4. 4. A can in accordance with claim 3, characterized in that the tongue tab (4) of the can lid (1) is separated from the lid surface (3) surrounding it while forming mutually engaging projections (12) and recesses (13) by a cutting procedure; and in that the tongue tab (4) and the lid surface (3) adjoining it are connected via the projections (12) and the recesses (13) in a shape-matched and force-transmitting manner while forming the microgap (8), with the leak-tightness of the filled and unopened can being ensured by the inwardly disposed plastic coating or film (10).
5. 5. A can in accordance with claim 4, characterized in that the projections (12) and the recesses (13) are coupled via undercuts.
6. 6. A can in accordance with claim 3, characterized in that the lid surface (3) is formed concavely in the région of the tongue tab (4) and the pressing in the microgap (8) is increased by the internai container pressure.
7. 7. A can in accordance with claim 2, characterized in that the plastic film (10) provided at the lower side of the can lid (1) forms a separate molded blister part prior to its sealing to the lower side and the notch (11) or the partial notching open is already provided in said molded blister part.
8. 8. A can in accordance with any one of the preceding claims, characterized in that the container part (15) and the can lid (1) comprise the same aluminum alloy and the material thickness of the can lid does not exceed at least twice the value of the material thickness of the container part.
9. 9. A can in accordance with claim 8, characterized in that the material thickness of the container part is disposed in the range of approximately 0,1 mm and less.
10. 10. A can in accordance with any one of the preceding daims, characterized in that an alloy of the aluminum 3000 sériés is used as the aluminum alloy.
11. 11. A can in accordance with any one of the preceding daims, characterized in that the can is a beverage can.
12. 12. A can in accordance with any one of the preceding daims, characterized in that said lever member is fixedly connected via a rivet connection or weld connection to the lid material.
13. 13. A can in accordance with any one of the preceding daims, characterized in that the lower side of the lid (1) is coated over its full surface with said plastic material coating (10).
14. 14. A can in accordance with any one of daims 1 to 6, characterized in that the coating (10) of the tear line that covers the tear line (8) is notched.
15. 15. A can in accordance with daim 14, characterized in that the coating (10) of the tear line that covers the tear line (8) is at least partly notched open.
16. 16. A can in accordance with daim 3, characterized in that the microgap (8) is a stamped gap.
17. 17. A can in accordance with daim 4, characterized in that the cutting procedure is a punching procedure.
18. 18. A can in accordance with daim 4, characterized in that the inwardly disposed plastic coating or film (10) has a thickness in the range from approximately 1/10 mm to 2/10 mm.

    5
19. 19. A can in accordance with any one of the preceding daims, characterized in that the alloy 3104 is used as the aluminum alloy.
20. 20. A can lid having the features in accordance with one or more of the preceding daims as a separate component for the subséquent leak tight connection to a can

    10 comprising the same material.