CAN LID

Description

[0001] The invention relates to a can lid, particularly for beverage cans, with a metallic lid surface having a first flat side and a second flat side extending away from the first flat side, wherein an opening is formed in the lid surface bounded by a closed edge of the lid surface, which is closed by a closure element of the metallic lid surface, wherein the closure element is separated from the surrounding lid surface by a micro gap extending at least partially along the edge of the lid surface, wherein a base plane of the closure element is defined by the course of the micro gap, wherein a first end region of the closure element is connected to the surrounding lid surface via a pivot bearing, and with a tear-off element arranged on the first flat side, which engages a second end region of the closure element opposite the pivot bearing.so that by pulling on the tear-off element, the closure piece can be swung out of the base plane in the direction of the first flat side, wherein the microgap between the first end region and the second end region is interrupted by at least one retaining rib, via which the closure piece and the surrounding cover surface are bonded together.

[0002] Can lids of this type are widely used in the production of beverage cans, food cans, and similar products. They are simple and inexpensive to manufacture, allow for space-saving stacking of identical cans, and can be easily opened and, if necessary, reclosed by manually moving the locking mechanism. Due to the staggered opening action created by the retaining ridge and the associated venting effect, there is no significant splashing, popping, or overflowing upon initial opening.

[0003] Ideally, opening a can for the first time should require minimal effort. However, this is countered by the need to prevent leaks at the opening or stretching of the sealing film on the second flat side, even if pressure increases inside the can. In practice, it is difficult to simultaneously ensure easy initial opening and sufficient stability under increased pressure. A particular challenge is posed by the pasteurization process required for many canned contents, such as juices, food, and the like. This process involves a pressure of, for example, 6 bar and can lead to considerable material stress.

[0004] US Patent 3,756,449 A discloses a can lid in the lid surface of which an opening is formed which is closed by a closure piece, wherein the closure piece is separated from the surrounding lid surface by a micro gap extending along the edge of the lid surface, wherein a base plane of the closure piece is defined by the course of the micro gap, wherein a tear-off element engages the closure piece, and wherein the micro gap is interrupted by at least one retaining rib, via which the closure piece and the surrounding lid surface are materially bonded to each other.

[0005] Can lids with tear-open closures are also disclosed in WO 02 / 072432 A2, WO 00 / 58161 A1 and US 4 186 678 A.

[0006] It is an object of the invention to provide a can lid that is easy to open and yet has a high resistance to pressure increases in the associated can.

[0007] The problem is solved, firstly, by a can lid having the features of claim 1.

[0008] According to the invention, at least one pressure relief ridge is embossed into the metallic lid surface, extending at least partially around the opening. The pressure relief ridge provides mechanical decoupling of the inner area encompassing the opening from the surrounding outer lid surface. If the can lid bulges due to a pressure increase inside the can, or bulges further from an already bulged state, the pressure relief ridge is pulled apart to a certain extent, effectively dispensing material inwards. In this way, the connection between the closure and the surrounding lid surface, and in particular the retaining ridge, is relieved of stress. It has been shown that a can lid equipped with a pressure relief ridge is easy to open and reliably withstands relatively high pressure values.

[0009] The pressure relief wave can include a wave trough extending transversely to the base plane with a curved cross-section. The curved shape provides a degree of flexible coupling between the inner and outer lid areas, thus contributing to stabilization of the sealed opening in the event of bulging of the can lid.

[0010] The pressure relief shaft may be designed to have a height or depth relative to the base plane that is at least half the thickness of the metallic cover surface and at most four times the thickness of the metallic cover surface. Preferably, the height or depth of the pressure relief shaft is at least as large as the thickness of the metallic cover surface and at most twice the thickness of the metallic cover surface. The thickness of the metallic cover surface is understood here to be a uniform or average thickness. Preferably, the height or depth of the pressure relief shaft is uniform along its longitudinal extent. A height or depth as specified has proven particularly advantageous in practice.

[0011] According to one embodiment of the invention, the metallic cover surface is rotationally symmetrical, and the radial extent of the at least one pressure relief shaft, relative to the center of rotation of the metallic cover surface, is at least twice and at most five times the thickness of the metallic cover surface. A pressure relief shaft of a corresponding width fulfills the relief function particularly reliably.

[0012] Preferably, the at least one pressure relief wave within the base plane has a circular or arc-shaped profile. This results in a particularly uniform relief effect, especially with a circular cover surface.

[0013] The opening can have a geometric center point that coincides with the center point of the circular or arc-shaped path of the at least one pressure relief wave. This further promotes a uniform relief effect.

[0014] According to a further embodiment of the invention, at least two, preferably at least three, and particularly preferably exactly three pressure relief ridges are embossed into the metallic cover surface, which extend parallel to each other at least partially around the opening. This increases the pressure relief effect. Furthermore, the presence of several parallel pressure relief ridges allows for a graduated pressure relief in a tailored manner.

[0015] Preferably, the magnitude of the height or depth of the pressure relief waves, relative to the base plane, increases towards the opening. The radially innermost pressure relief wave thus provides the greatest compliance. Such a graduated pressure relief has proven to be particularly advantageous.

[0016] According to a specific design, the arc lengths of the pressure relief waves increase towards the opening. This is because, generally, less expansion potential is required the further the pressure relief wave is from the opening.

[0017] It is preferred that the pressure relief wave closest to the opening has a closed circular path within the base plane, and that at least one pressure relief wave located further away from the opening has an interrupted circular path. For example, an interruption can be arranged in an area where the opening is closest to the edge of the cover surface. In this area, there may not be room for another circumferential pressure relief wave. However, a pressure relief wave with an interrupted path can already be provided. A particularly preferred embodiment provides one closed inner and two interrupted outer pressure relief waves.

[0018] A particular embodiment of the invention provides that the metallic cover surface and the opening each have geometric centers arranged at a distance from one another, wherein the at least one pressure relief shaft located further away from the opening has an interruption in its circular path through which a connecting line between the two geometric centers passes. For example, the metallic cover surface and the opening can be rotationally symmetrical, in particular circular, and the respective centers of rotation can form the geometric centers.

[0019] The invention also relates to a can lid, particularly for beverage cans, especially as specified above, with a metallic lid surface having a first flat side and a second flat side extending away from the first flat side, wherein an opening is formed in the lid surface bounded by a closed edge of the lid surface, which is closed by a closure element of the metallic lid surface, wherein the closure element is separated from the surrounding lid surface by a micro gap extending at least partially along the edge of the lid surface, wherein a base plane of the closure element is defined by the course of the micro gap, wherein a first end region of the closure element is connected to the surrounding lid surface via a pivot bearing, and with a tear-off element arranged on the first flat side, which engages a second end region of the closure element opposite the pivot bearing.so that by pulling on the tear-off element, the closure piece can be swung out of the base plane in the direction of the first flat side, wherein the microgap between the first end region and the second end region is interrupted by at least two retaining ribs, via which the closure piece and the surrounding cover surface are bonded together.

[0020] The more numerous and wider the retaining ridges are, the more securely the locking piece sits in the opening. However, a secure fit of the locking piece makes initial opening more difficult. As mentioned above, it is challenging to simultaneously ensure easy initial opening and sufficient stability under increased pressure.

[0021] To solve this problem, according to one aspect of the invention, an elongated elevation is embossed into the closure piece, which rises in the direction of the first flat side above the base plane and extends transversely to a line that passes through two of the at least two retaining ribs and through the elongated elevation.

[0022] When the can lid bulges due to a pressure increase inside the can, the central area of ​​the closure piece initially moves upwards. The raised section has a stiffening effect and, due to its shape and orientation, acts like a lever, ensuring that the upward movement of the central area is accompanied by a downward movement of the outer edge. This creates a virtual axis of rotation that runs parallel to or coincides with the line connecting the two retaining ribs. This relieves stress on the transition between the closure piece and the surrounding lid surface and prevents unwanted drifting of the metal edges at the micro-gap. It has been shown that, as a result of the action of the elongated raised section, it is possible to position the retaining ribs further back from the point of application of the tear-off element than was previously possible.Such a setback is particularly advantageous because of the improved "venting" effect.

[0023] The elongated protrusion can extend from the second end region towards the first end region. That is, the elongated protrusion can extend from the point of application of the tearing element towards the pivot bearing. If the can lid bulges, the area of ​​the tearing point is then particularly relieved of stress. This is advantageous because the retaining ribs, due to the "venting" effect, should be as far away from the tearing point as possible, and this area is therefore particularly susceptible to pressure loads.

[0024] Another embodiment of the invention provides that the opening has a geometric center and the elongated projection has a longitudinal axis that passes through the geometric center of the opening. This ensures a particularly favorable pressure relief effect.

[0025] Preferably, the elongated projection, relative to the base plane, has a height that is at least as large as the thickness of the metallic cover surface and at most four times the thickness of the metallic cover surface, wherein the height of the elongated projection is particularly preferably at least one and a half times the thickness of the metallic cover surface and at most three times the thickness of the metallic cover surface. Such a height has proven to be particularly advantageous in common applications.

[0026] It is preferred that the elongated projection has a length that is at least five times the thickness of the metallic cover surface and at most seventy times the thickness of the metallic cover surface, wherein the length of the elongated projection is particularly preferably at least twenty times the thickness of the metallic cover surface and at most fifty times the thickness of the metallic cover surface. Such projection lengths ensure a particularly good adaptation of the stiffening effect to conventional cover designs.

[0027] The opening can be designed with a rounded hexagonal shape, and the elongated projection can extend from one corner of the opening towards the opposite corner. In particular, the elongated projection can extend from a corner that coincides with the second end. Opening at the corner allows for particularly good ventilation. The projection also prevents the closure from prematurely detaching at the corner. The rounded hexagonal shape of the opening is advantageous because it makes it particularly easy to incorporate the retaining tabs on the straight sections.

[0028] The elongated elevation can have a club shape. This allows for a particularly favorable, graduated stiffening effect.

[0029] According to a specific embodiment, the elongated projection has a head section near the edge and a tail section that is narrower than the head section. It has been shown that a particularly pronounced increase in stability is desirable in the area of ​​the edge.

[0030] The tail section can be tapered in a direction away from the head section, preferably continuously. The stiffening effect then decreases from the point of tearing, which has proven to be particularly advantageous.

[0031] The invention further relates to a can lid, particularly for beverage cans, especially as specified above, with a metallic lid surface having a first flat side and a second flat side pointing away from the first flat side, wherein an opening is formed in the lid surface bounded by a closed edge of the lid surface, which is closed by a closure element of the metallic lid surface, wherein the closure element is separated from the surrounding lid surface by a micro gap extending at least partially along the edge of the lid surface, wherein a first end region of the closure element is connected to the surrounding lid surface via a pivot bearing, and with a tear-open element arranged on the first flat side, which engages a second end region of the closure element opposite the pivot bearing.so that by pulling on the tear-off element, the closure piece can be swung out of the base plane defined by the opening in the direction of the first flat side, wherein the microgap between the first end region and the second end region is interrupted by at least one retaining rib, via which the closure piece and the surrounding cover surface are bonded together.

[0032] To solve the problem mentioned at the outset, according to a further aspect of the invention, a closure relief groove is embossed into the closure piece, which extends along the edge of the opening at least past the at least one retaining rib.

[0033] In the event of a pressure increase inside the can, the retaining rib is decoupled from the central area of ​​the closure by the pressure relief groove, thus protecting it from unwanted overloading. Expansion of the lid surface is compensated for by the pressure relief groove, preventing overloading or even breakage of the retaining rib.

[0034] The closure relief groove can be curved away from the edge in the area of ​​the retaining rib. In this design, the closure relief groove shields the retaining rib particularly effectively from the central area of ​​the closure piece.

[0035] It can be provided that the microgap between the first end region and the second end region is interrupted by several retaining ribs, via which the closure piece and the surrounding cover surface are bonded together, with the closure relief rib extending past all retaining ribs and curved away from the edge in the area of ​​each retaining rib. Thus, all retaining ribs are protected against overload.

[0036] Preferably, the closure relief groove is curved towards the edge in the area between two successive retaining ribs. This allows the formation of a continuous closure relief groove despite the curvatures pointing away from the edge in the area of ​​the retaining ribs.

[0037] Another embodiment of the invention provides that the closure relief groove, relative to the base plane, has a height or depth that is at most one and a half times the thickness of the metallic cover surface, wherein the height or depth of the closure relief groove is preferably at most as large as the thickness of the metallic cover surface. This has proven to be particularly advantageous in common cover designs.

[0038] Preferably, the closure relief groove has a first flank facing the edge of the cover surface and a second flank facing away from the edge of the cover surface, the second flank being steeper than the first flank. This results in a particularly favorable relief effect.

[0039] A combination of a pressure relief shaft as described above with an elongated projection and / or the closure relief groove as described above has proven particularly advantageous. In particular, the aforementioned relief features can operate in stages. For example, with a moderate pressure increase, initially only the pressure relief shaft can be activated, and the retaining bridge can be protected by the closure relief groove only when a higher threshold is exceeded.

[0040] Further developments of the invention can also be found in the dependent claims, the description and the accompanying drawings.

[0041] The invention is described below by way of example with reference to the drawings. Fig. 1 is a top view of a can lid according to the invention in a closed state. Fig. 2 shows the can lid according to Fig. 1 without locking components. Fig. 3 shows a locking piece of the can lid according to Fig. 2 in detail. Fig. 4 shows a cross-section through the closure piece of the Fig. 3 along line AA. Fig. 5 shows an arrangement of pressure relief shafts of the can lid according to Fig. 1 in a cross-sectional view.

[0042] Fig. 1 and 2 Figure 1 shows a can lid 11 designed according to the invention for a beverage can or the like, with a metallic lid surface 13. The metallic lid surface 13 has a first, here upper, flat side 16 and a second, here lower, flat side 17 pointing away from the first flat side 16 ( Fig. 4 The lid 11 is formed from a sheet of aluminum or tinplate. Preferably, the metallic lid surface 13 has a uniform thickness of 0.1 mm to 0.3 mm, more preferably about 0.2 mm. A coating of plastic material can be applied to the second flat side 17 of the metallic lid surface 13. In the illustrated embodiment, the metallic lid surface 13 is circular in plan view and has a circular center 20. The can lid 11 can be connected to a beverage container via a crimped edge 18 of the metallic lid surface 13.

[0043] The metallic lid surface 13 has an opening which, in the illustrated delivery state of the can lid 11, is closed by a section of the metallic lid surface 13 in the form of a closure piece 19. As shown in Fig. 2 As can be seen, the closure piece 19 is separated from the surrounding cover surface by a border in the form of a microgap 21. The microgap 21 runs within a plane and defines the Fig. 4 recognizable base plane 23 of the can lid 11. As shown, the opening is arranged off-center in the metallic lid surface 13, that is, the geometric center of the opening is spaced away from the center of the circle 20.

[0044] The can lid 11 comprises a sealing frame made of plastic material, which surrounds the opening and is not visible in the figures. This frame is firmly connected to the metallic lid surface 13. Furthermore, a closing unit 29, also made of plastic material, is provided and carries the closure piece 19. This closing unit is pivotally connected to the sealing frame via a pivot bearing 30. A detachable, fluid-tight connection between the sealing frame and the closing unit 29 is enabled by means of a locking device (not shown), formed by sealing and locking ribs and associated receiving grooves. Accordingly, the can lid 11 is resealable.

[0045] A ring-shaped tear-off element 37, preferably also made of plastic, is connected to the closure unit 29. By pulling on the tear-off element 37, a user can pivot the closure piece 19 upwards out of the base plane 23 and thus release the opening.

[0046] The locking piece 19 is in Fig. 3 shown individually. In the illustrated embodiment, the locking piece 19 has a rounded hexagonal shape. A first end region 61 of the locking piece 19 is connected via the pivot bearing 30 ( Fig. 1 ) and the sealing frame is connected to the surrounding cover surface, while the annular tearing element 37 engages a second end region 62 of the closure piece 19 opposite the pivot bearing 30 via the closing unit 29. The two end regions 61, 62 are located at opposite rounded corners of the closure piece 19. As shown, the corner of the closure piece 19 associated with the second end region 62 is more pronounced than the other corners.

[0047] Between the first end region 61 and the second end region 62, the microgap 21 is interrupted by a total of six retaining ribs 65, via which the closure piece 19 and the surrounding cover surface are bonded together. A connecting line 67 runs through the two front retaining ribs 65, that is, the retaining ribs 65 closest to the second end region 62.

[0048] When the can is opened for the first time, the user pulls on the tear-off device 37, thereby pivoting the closing unit 29 with the closure piece 19 upwards. This releases the snap connection between the closing unit 29 and the sealing frame.

[0049] Due to the retaining ribs 65, only a relatively small opening is created in the lid surface 13 at the beginning of the pivoting process. This opening extends from the second end region 62 to the area of ​​the two front retaining ribs 65, i.e., approximately to the connecting line 67. The retaining ribs 65 prevent any further opening, at least temporarily. The relatively small opening in the vicinity of the second end region 62 ventilates the can. As the initial opening process progresses, the retaining ribs 65 break one after the other. The closure piece 19 can then be pivoted fully upwards to release the entire opening. Due to the staggered opening caused by the retaining ribs 65 and the associated "venting" effect, no significant splashing, popping, or overflowing occurs.

[0050] The locking piece 19 has a mounting stud 31 with a flat mounting section 33 embossed into it. The mounting stud 31 of the locking piece 19 is designed similarly to three further mounting studs 34, 35, 39 ( Fig. 1 ), which are embossed in the area surrounding the opening of the metallic cover surface 13. All support studs 34, 35, 39 have the same height 50 ( Fig. 4 ) on.

[0051] To prevent excessive material stress during a pressure increase in the can, three embossed pressure relief ridges 77, 78, 79 ( Fig. 2 The pressure relief wave 77 is provided with a continuous, circular path with the geometric center of the opening at least partially surrounding the opening. Specifically, the radially innermost pressure relief wave 77 has a closed circular path with the geometric center of the opening as its center point. The middle pressure relief wave 78 and the radially outermost pressure relief wave 79 each have arc-shaped paths with the geometric center of the opening as their center point, but are not continuous. Rather, the middle pressure relief wave 78 and the radially outermost pressure relief wave 79 are interrupted, with the respective interruptions 80 being arranged such that they occupy a position closest to the flanged edge 18. Preferably, the interruption 80 of the radially outermost pressure relief wave 79 is longer than the interruption 80 of the middle pressure relief wave 78, as shown.For example, the central pressure relief shaft 78 can extend over an angle of approximately 300° and the radially outermost pressure relief shaft 79 over an angle of approximately 250°.

[0052] In Fig. 5 The pressure relief waves 77, 78, 79 are shown in cross-section. Each pressure relief wave 77, 78, 79 comprises a wave trough 81 extending transversely to the base plane 23, with a curved cross-section. Between the wave troughs 81 are wave crests 82, which also have a curved cross-section. It is preferred that the depth of the wave troughs 81, relative to the base plane 23, is at least as large as the thickness of the metallic cover surface 13 and at most twice the thickness of the metallic cover surface 13. As shown in Fig. 5 The values ​​85, 86, 87 of the depth of the wave troughs 81, relative to the base plane 23, noticeably increase towards the opening, i.e. from the outside in.

[0053] If the can lid 11 bulges due to a pressure increase inside the can, the pressure relief shafts 77, 78, 79, starting with the radially innermost pressure relief shaft 77, are pulled apart to a certain extent. The three pressure relief shafts 77, 78, 79 surrounding the opening thus provide a graduated mechanical decoupling of the opening area from the surrounding outer lid surface. In this way, the connection between the closure piece 19 and the surrounding lid surface is relieved of stress.

[0054] Further stress relief is achieved by an elongated projection 36 embossed into the closure piece 19, which extends upwards in the direction of the first flat side 16 above the base plane 23, i.e., upwards in the illustrated embodiment. The elongated projection 36 has a longitudinal axis 70 oriented transversely to the connecting line 67. Furthermore, the elongated projection 36 has a club-like shape with a head section 89 near the edge and a tail section 90 that is narrower than the head section 89 near the edge. The tail section 90 tapers continuously in a direction away from the head section 89. The head section 89 is located in the second end region 62, so that the elongated projection 36 extends from the second end region 62 towards the first end region 61.

[0055] When the can lid 11 bulges due to a pressure increase inside the can, the central area of ​​the closure piece 19 initially moves upwards. Due to the stiffening effect of the protrusion 36, this movement of the central area is accompanied by a downward movement of the second end area 62. That is, the part of the closure piece 19 facing the second end area 62 pivots about the connecting line 67, thereby relieving stress on the transition between the closure piece 19 and the surrounding lid surface in the vicinity of the second end area 62.

[0056] Furthermore, a closure relief groove 38 is embossed into the closure piece 19, extending along the microgap 21 and forming a depression with respect to the first flat side 16. That is, the closure relief groove 38 is embossed in the opposite direction to the elongated projection 36. In the illustrated embodiment, the closure relief groove 38 is closed all around and alternately curved away from and towards the microgap 21. The sections 95 curved away from the microgap 21 are located next to the retaining webs 65 and transition between the retaining webs 65 into sections 96 curved towards the microgap 21. This results in a flower-like pattern of the closure relief groove 38 in the top view. At the second end region 62, the closure relief groove 38 transitions into the head section 89 of the elongated projection 36.

[0057] It is preferred that the closure relief groove 38, with respect to the base plane 23, has a depth that is at most as large as the thickness of the metallic cover surface 13. The outer flank facing the edge of the closure piece 19 is preferably less steep than the opposite inner flank.

[0058] In the event of a pressure increase in the can, the retaining webs 65 are decoupled from the central area of ​​the closure piece 19 by the closure relief groove 38 and thus protected from an unwanted overload.

[0059] The invention provides a resealable can lid 11 which is easy to open even on first opening and which nevertheless meets all stability requirements for pasteurization and storage of the can. Bezugszeichenliste:

[0060] 11 Can lid 13 Metallic lid surface 16 First flat side 17 Second flat side 18 Rolled edge 19 Closure piece 20 Center of circle 21 Microgap 23 Base plane 29 Closure unit 30 Swivel bearing 31 Support stud 33 Flat support section 34 Support stud 35 Support stud 36 Elongated protrusion 37 Tear-opening element 38 Closure relief groove 39 Support stud 50 Height of support studs 61 First end area 62 Second end area 65 Retaining rib 67 Connecting line 70 Longitudinal axis 77 Inner pressure relief shaft 78 Middle pressure relief shaft 79 Outer pressure relief shaft 80 Interruption 81 Trough 82 Crest 85 Depth of outer trough 86 Depth of middle trough 87 Depth of the inner wave trough 89 Head section 90 Tail section 95 Section curved away from the microgap 96 Section curved towards the microgap

Claims

1. A can end (11), in particular for beverage cans, comprising a metallic end surface (13) that has a first flat side (16) and a second flat side (17) facing away from the first flat side (16), wherein an opening is formed in the end surface (13), which opening is bounded by a closed margin of the end surface (13) and closed by a closure piece (19) of the metallic end surface (13), wherein the closure piece (19) is separated from the surrounding end surface by a microgap (21) extending at least sectionally along the margin of the end surface (13), wherein a base plane (23) of the closure piece (19) is defined by the course of the microgap (21), wherein a first end region (61) of the closure piece (19) is connected to the surrounding end surface via a pivot bearing (30); and a tear-open member (37) that is arranged at the first flat side (16) and that engages at a second end region (62) of the closure piece (19), said second end region (62) being opposite the pivot bearing (30), so that a pivoting of the closure piece (19) out of the base plane (23) in the direction of the first flat side (16) is made possible by pulling at the tear-open member (37), wherein the microgap (21) is interrupted between the first end region (61) and the second end region (62) by at least one holding web (65) via which the closure piece (19) and the surrounding end surface are connected to one another in a materially bonded manner, wherein at least one pressure relief wave (77, 78, 79) is embossed into the metallic end surface (13) and extends at least partly around the opening.

2. A can end according to claim 1, characterized in that the pressure relief wave (77, 78, 79) comprises a wave trough (81) having a curved cross-section and extending transversely to the base plane (23).

3. A can end according to claim 1 or 2, characterized in that the pressure relief wave (77, 78, 79) has, with respect to the base plane (23), a height or depth (85, 86, 87) that is at least half the thickness of the metallic end surface (13) and at most four times the thickness of the metallic end surface (13), with the height or depth (85, 86, 87) of the pressure relief wave (77, 78, 79) preferably being at least as great as the thickness of the metallic end surface (13) and at most twice the thickness of the metallic end surface (13).

4. A can end according to any one of the preceding claims, characterized in that the metallic end surface (13) is rotationally symmetrical and the radial extent of the at least one pressure relief wave (77, 78, 79), with respect to the center of rotation (20) of the metallic end surface, is at least twice and at most five times the thickness of the metallic end surface (13).

5. A can end according to any one of the preceding claims, characterized in that the at least one pressure relief wave (77, 78, 79) has a circular or arcuate course within the base plane (23), in particular wherein the opening has a geometric center that coincides with the circle center of the circular or arcuate course of the at least one pressure relief wave (77, 78, 79).

6. A can end according to any one of the preceding claims, characterized in that at least two, preferably at least three and particularly preferably exactly three pressure relief waves (77, 78, 79) are embossed into the metallic end surface (13) and extend parallel to one another at least partly around the opening, in particular wherein the magnitudes (85, 86, 87) of the height or depth of the pressure relief waves (77, 78, 79) related to the base plane (23) increase toward the opening, wherein preferably the arc lengths of the pressure relief waves (77, 78, 79) increase toward the opening.

7. A can end according to claim 6, characterized in that the pressure relief wave (77) disposed closest to the opening has a closed circular course within the base plane (23) and at least one pressure relief wave (78, 79) disposed further away from the opening has an interrupted circular course, in particular wherein the metallic end surface (13) and the opening have respective geometric centers that are arranged at a distance from one another, with the at least one pressure relief wave (78, 79) disposed further away from the opening having an interruption (80) of the circular course, through which interruption a connection line of the two geometric centers extends.

8. A can end (11), in particular for beverage cans, in particular according to any one of the preceding claims, comprising a metallic end surface (13) having a first flat side (16) and a second flat side (17) facing away from the first flat side (16), wherein an opening is formed in the end surface (13), which opening is bounded by a closed margin of the end surface and closed by a closure piece (19) of the metallic end surface (13), wherein the closure piece (19) is separated from the surrounding end surface by a microgap (21) extending at least sectionally along the margin of the end surface, wherein a base plane (23) of the closure piece (19) is defined by the course of the microgap (21), wherein a first end region (61) of the closure piece (19) is connected to the surrounding end surface via a pivot bearing (30); and a tear-open member (37) that is arranged at the first flat side (16) and that engages at a second end region (62) of the closure piece (19), said second end region (62) being opposite the pivot bearing (30), so that a pivoting of the closure piece (19) out of the base plane (23) in the direction of the first flat side (16) is made possible by pulling at the tear-open member (37), wherein the microgap (21) is interrupted between the first end region (61) and the second end region (62) by at least two holding webs (65) via which the closure piece (19) and the surrounding end surface are connected to one another in a materially bonded manner, wherein an elongate elevated portion (36) is embossed into the closure piece (19), said elongate elevated portion (36) extending transversely to a line (67) that extends through two of the at least two holding webs (65) and through the elongate elevated portion (36) and rising above the base plane (23) in the direction of the first flat side (16).

9. A can end according to claim 8, characterized in that the elongate elevated portion (36) extends, starting from the second end region (62), in the direction of the first end region (61) and / or in that the opening has a geometric center and the elongate elevated portion (36) has a longitudinal axis (70) that extends through the geometric center of the opening.

10. A can end according to any one of the claims 8 or 9, characterized in that the elongate elevated portion (36) has, with respect to the base plane (23), a height that is at least as great as the thickness of the metallic end surface (13) and at most four times the thickness of the metallic end surface (13), with the height of the elongate elevated portion (36) preferably being at least one and a half times the thickness of the metallic end surface (13) and at most three times the thickness of the metallic end surface (13).

11. A can end according to any one of the claims 8 to 10, characterized in that the elongate elevated portion (36) has a length that is at least five times the thickness of the metallic end surface (13) and at most seventy times the thickness of the metallic end surface (13), with the length of the elongate elevated portion (36) preferably being at least twenty times the thickness of the metallic end surface (13) and at most fifty times the thickness of the metallic end surface (13) and / or in that the opening has a rounded hexagonal shape and the elongate elevated portion (36) extends, starting from a corner region of the opening, in the direction of an opposite corner region of the opening and / or in that the elongate elevated portion (36) has a club shape.

12. A can end according to any one of the claims 8 to 11, characterized in that the elongate elevated portion (36) has a head section (89) close to the margin and a tail section (90) that is narrowed with respect to the head section (89), in particular wherein the tail section (90) is tapered, preferably continuously, in a direction facing away from the head section (89).

13. A can end (11), in particular for beverage cans, in particular according to any one of the preceding claims, comprising a metallic end surface (13) that has a first flat side (16) and a second flat side (17) facing away from the first flat side (16), wherein an opening is formed in the end surface (13), which opening is bounded by a closed margin of the end surface (13) and closed by a closure piece (19) of the metallic end surface (13), wherein the closure piece (19) is separated from the surrounding end surface by a microgap (21) extending at least sectionally along the margin of the end surface (13), wherein a first end region (61) of the closure piece (19) is connected to the surrounding end surface via a pivot bearing (30); and a tear-open member (37) that is arranged at the first flat side (16) and that engages at a second end region (62) of the closure piece (19), said second end region (62) being opposite the pivot bearing (30), so that a pivoting of the closure piece (19) out of the base plane (23) defined by the opening in the direction of the first flat side (16) is made possible by pulling at the tear-open member (37), wherein the microgap (21) is interrupted between the first end region (61) and the second end region (62) by at least one holding web (65) via which the closure piece (19) and the surrounding end surface are connected to one another in a materially bonded manner, wherein a closure relief bead (38) is embossed into the closure piece (19) and extends along the margin of the opening at least past the at least one holding web (65).

14. A can end according to claim 13, characterized in that the closure relief bead (38) is curved away from the margin in the region of the holding web (65), in particular wherein the microgap (21) is interrupted between the first end region (61) and the second end region (62) by a plurality of holding webs (65) via which the closure piece (19) and the surrounding end surface are connected to one another in a materially bonded manner, with the closure relief bead (38) extending past all the holding webs (65) and being curved away from the margin in the region of each holding web (65), wherein preferably the closure relief bead (38) is curved toward the margin in the region between two consecutive holding webs (65).

15. A can end according to any one of the claims 13 or 14, characterized in that the closure relief bead (38) has, with respect to the base plane (23), a height or depth that is at most one and a half times the thickness of the metallic end surface (13), with the height or depth of the closure relief bead (38) preferably being at most as great as the thickness of the metallic end surface (13) and / or in that the closure relief bead (38) has a first flank facing the margin of the end surface and a second flank facing away from the margin of the end surface, with the second flank being steeper than the first flank.