The invention refers to can lids for two-piece aluminum beverage cans.

The invention refers to two-piece aluminum beverage cans with a unitary DWI can body and can lid with a pull tab.

Two-piece beverage cans comprise a can body made from one piece of aluminum sheet metal and a can lid with a pull tab affixed to the can lid. A score line in a panel of the can lid defines a tear panel that can be opened by means of the pull tab. The pull tab can be a stay-on-tab that opens a hinged tear panel. In prior art cans, the pull tab is affixed to the can end by a rivet that is formed from the sheet metal of the can lid. Can lids are also known as can ends.

The can body is a drawn and ironed (DWI: drawn and wall-ironed) can body that is produced by first drawing an aluminum blank into a cup and then ironing the walls of the cup to form the can body. The can body has an open end with a reduced diameter. The reduced diameter of the can body's open end is achieved by way of necking the can body in a necking machine in which the diameter of the open end is reduced in several stages.

Prior art cans often have a body that is cylindrical along the largest portion of its longitudinal extension. A typical diameter of prior art aluminum beverage cans is 66 mm. These cans are named 21 1 cans in the industry.

After filling of a can body e.g. with a carbonated beverage, a respective can lid is at- tached to the can body by way of a folded double seam. The can lid has a smaller diameter than the can body.

To match a respective can lid, the can body diameter at the can body's open end is reduced from 66 mm to the fitting diameter for the can lid, e.g. -57 mm (206), 55 mm (204), 52 mm (202) or 50 mm (200), by way of necking. A typical can body has a base and a cylindrical side wall that extends upwardly from the base and that has a wall thickness in the order of 94 to 97 μητι for a can having a diameter of 66 mm. A can having a diameter of 58 mm typically has a wall thickness in the order of 90 to 94 μιη. The can body further has a tapering neck that extends upwardly from the cylindrical side wall and that defines the reduced diameter open end of the can body prior to seaming. The can body's open end has a smallest internal diameter called plug diameter, which approximately matches the metrical dimension of the can lid, e.g. 52 mm.

The ratio between the can maximum diameter and the plug diameter that is achieved by way of necking is called necking ratio. The base includes a standing ring and a dome arranged within the standing ring. The can lid is made from sheet metal aluminum and has a central panel wherein the rivet and the tear panel are arranged. The central panel is circumferentially surrounded by a countersink that in turn is circumferentially surrounded by an upwardly extending leg, e.g. a chuck wall. At the outer end of the upwardly extending leg, a curl is arranged that eventually is folded to form the seam that connects can body and can lid and that defines the lid outside diameter. The can lid's chuck wall defines a plug diameter of the can lid.

On the central panel, a rivet for connecting a pull tab and a tear panel defined by a score line are arranged. The tear panel can be opened by means of the pull tab that breaks the score line when a handle part of the pull tab is lifted and thus an opening part of the pull tab is pressed on the tear panel next to the score line. Between the handle part and the opening part of the pull tab, a rivet island is arranged that is connected to the central panel by means of the rivet and that serves as a bending hinge for the pull tab. It is an object of the invention to provide a can lid for an improved two-piece aluminum beverage can.

According to the invention, this object is achieved by a can lid for an aluminum beverage can, said can lid comprising a pull tab, said can lid having a chuck wall defining a plug diameter, a countersink and central panel having a panel radius. On the central panel, a score line defining a tear panel and a rivet for connecting a pull-tab to the can lid are arranged. The lid has a lid plug diameter of between 45 to 49 mm, an outside diameter of between 52 to 55 mm, and a weight of less than 1.9 g. The central panel has a thickness of less than 0.19 mm. The rivet is arranged off-center on the central panel. The rivet is tilted so that the rivet provides an axis of rotation of the pull tap that has an angle of between 1 ⁰ and 6° with respect to an axis vertical that is vertical with respect to the central panel or at least one ramp-up bead is arranged on either side of pull tab or on both sides of the pull tab. Thus, the rivet is tilted with respect a normal to a plane defined by countersink and the axis of rotation defined by the rivet is tilted with respect a normal to a plane defined by countersink. The tilt of the rivet facilitates lifting of a handle part of the pull tab if the pull tab is rotated about the rivet.

Alternatively, both, the rivet is tilted and at least one ramp-up bead is arranged on either side of pull tab or on both sides of pull tab.

Preferably, the pull tab can be swiveled between an initial shelf position wherein the opening part of the pull tab faces away from the tear panel and an opening position wherein the opening part of the pull tab is arranged to touch the tear panel, when the handle part is lifted.

When the rivet is arranged off centre with respect to the central panel the finger access space for opening of the easy opening end can get too small. This problem can be solved by a rotation tab. Initially, in factory finished position and when a beverage can is stored in a shelf, the handle part of the tab is positioned in line or partly rotated to the centre line of the tear panel. Rotation of the tab will now be required in either direction to get the tab in the opening position, like for standard ends. Accordingly, the pull tab is initially not in the opening position allowing opening the tear panel and, therefore, first must be rotated from the initial shelf position to the opening position prior to opening the tear panel. Rotation of the pull tab about the tilted rivet not only results in an alignment of the pull tab with the tear panel but also results in a lifted handle part of the pull tab that thus can easier be gripped. In addition to a tilt of the rivet or as an alternative, at least one ramp-up bead can be provided that is arranged on either side or on both sides of the pull tab. Such ramp can also cause or support a lifting of the handle part if the pull tab is rotated about the axis of the rivet. Preferably, the ramp-up bead is arranged on the central panel.

To accommodate this action, and to improve finger access, two different approaches are provided:

Two ramp-up beads are arranged on both sides of the tab to accommodate bridging the tab over the chime and elevating the edge to an easy finger access level. Optionally a tab-positioning bead underneath the tab is incorporated in the central panel or on the tab's side facing the central panel or both, which accommodates finding the accurate opening position at the end of the rotation.

Alternatively or additionally, a tilted rivet island is provided, which from nature provides an tab elevation during rotation to accommodate bridging the chime and to improve finger access. Again, optionally a tab positioning bead can be provided, which accommodates finding the accurate opening position at the end of the rotation. One or more orientation beads can be provided that are configured and arranged to support aligning of the initially rotated pull tab into the opening position suitable for opening the tear panel. For instance, such orientation bead can be configured to provide a click-in effect when the pull is rotated about the rivet and eventually reaches its aligned orientation. The click-in effect providing the tactile feedback can be achieved by means of a gap or a recess in the orientation bead that receives a part of the pull tab, for instance a protrusion of the pull tab facing the central panel, when the pull tab is aligned with the tear panel.

Additionally or alternatively, the pull tab may have a gap or a recess on the side facing the central panel. This gap or recess may engage with the double seam that connects the can lid with the can body when the pull tab is aligned in its opening position, thus providing tactile feedback to the user indicating that the pull tab is positioned for opening the can.

Accordingly, in a preferred embodiment, the central panel comprises at least one tab positioning notch or recess that is arranged to provide a tactile feedback if the tab is swiveled in its opening position suitable for opening the tear panel. The tab positioning recess is provided on the tab's side facing the central panel, the recess being arranged to engage with the seam connecting the can lid to the can body when the can lid is applied to a can body.

The off-set of the axis of rotation of the rivet and the center of the central panel is preferably between 3 and 15 mm and even more preferably between 4 and 8 mm, e.g. 4.5 mm. This allows for large enough an opening even in a central panel having a smaller diameter than previous central panels.

Preferably, the axis of rotation of the pull tap that has an angle of between 2° and 4° with respect to the axis vertical to the central panel. This provides for enough of a lift of the handle part of the pull tab when to pull tab is rotated in its opening position to pass the chime.

Preferably, two ramp-up beads are arranged on the central panel, one ramp-up bead on each side of the pull tab. Thus, a user can rotate the pull tab in both directions from the initial shelf position to the opening position, while either ramp-up bead will help to lift the handle part of the pull tab to pass the chime that is provided by the seam connecting the can lid to the can body after the can lid is applied to the can body.

Preferably, the central panel has a diameter of between 36 mm and 40 mm and is thus smaller than previous central panels. This allows for a smaller overall size of the can lid that in turn allows for lighter can lids an can bodies compared to previous cans having the same contents volume.

Preferably, the can end is made from aluminum or steel sheet metal, that may be pre- coated or plain.

Preferably, an absorption bead is arranged next to the tear panel.

The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof presented in conjunction with the following drawings, wherein:

Figure 1 is a side-elevated perspective view of a seamed two-piece beverage can according to the invention; Figure 2 is a cross-sectional view of a seamed two-piece beverage can along the can's longitudinal axis;

Figure 3 is a cross-sectional view of a can body prior to seaming;

Figure 4 is a cross-sectional view of a can lid prior to seaming;

Figure 5 is a top-level view of a first embodiment of a can lid according to the invention with the tab in its opening position;

Figure 6 is a cross-sectional view of an alternative can lid prior to seaming;

Figure 7 is a top-level view of a second alternative embodiment of a can lid according to the invention with the tab in its shelf position;

Figure 8 is a top-level view of the second embodiment of a can lid according to figure

7 with the tab in its opening position;

Figure 9 is a top-level view of a third alternative embodiment of a can lid according to the invention with the tab in its shelf position;

Figure 10 is a top-level view of the third embodiment of a can lid according to figure 9 with the tab in its opening position;

Figure 1 1 shows details of an orientation notch on the lower side of the handle part of the pull tab that helps aligning the pull tab in its opening position;

Figure 12 shows details of a first variant of the score line; and

Figure 13 shows details of a second variant of the score line.

The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. Figure 1 shows a two-piece aluminum beverage can 10 according to the invention. The can comprises a can body 12 and a can lid 14 seamed to the can body. Can body 12 is a unitary DWI (drawn wall-ironed) can body and can lid 14 has a pull tab 38.

The can body 12 is formed from a single piece of sheet metal aluminum (blank) and has a base 16, a cylindrical sidewall 18 and a neck 20. The base 16 has a standing ring 22 and a dome 24. Can body 12 is preferably made from aluminum, in particular from series 3000 aluminum.

The can lid 14 has a chuck wall 26, a countersink 28 and a central panel 30. In the central panel, a tear panel 32 is provided, which is defined by a score line 34. Next to the tear panel, a material absorption bead 36 is arranged. Pull tab 38 is affixed to the central panel 30 by means of a rivet 40. A central section of pull tab 38 is a rivet island 50 that is fixated to central panel 30 by means of rivet 40. Typically, pull tab 38 can be rotated about rivet 40 if a certain force is applied. The axis of rotation is perpendicular with respect to a plane defined by rivet island 50. Pull tab 38 has a handle part 42 to be gripped by a user's finger and an opening part 44 that is pressed against the tear panel 32 if the handle part 42 is lifted by a user. Thus, the pull tab 38 serves to rupture the score line 34 in order to open the beverage can 10 in a manner known per se. The tear panel 32 thus defines the dimensions of the opening created by lifting the handle part of the pull-tab 38. The tear panel defines an opening - for instance a drinking opening - having an area of between 300 mm ² to 350 mm ² after opening the beverage can.

Can lid 14 is fixed to can body 12 by means of a folded double seam 41 . Seam 41 has a diameter of between 46 mm and 49 mm.

The diameter L of the seam 41 is approximately 48 mm. The diameter J of the stand ring 22 is smaller than the diameter L of the seam 41. Therefore, beverage cans can be stacked upon another, so that the stand ring of the upper can protrudes into the space within seam 41. Alternatively, the stand ring may have a larger diameter than the seam.

Can body 12 has a can body plug diameter of between 45 to 49 mm and a weight below 9.3 g for a 330 ml can, and below 9.7 g for a 355 ml can.

Can lid 14 has a can plug fitting diameter of between 45 to 49 mm, an outside diameter of between 52 to 55 mm, a central panel with a thickness of less than 0.19 mm, e.g. 0.183 mm, and a weight of less than 1.9 g. Fig. 2 is a cross-sectional view of can 10 with can lid 14 seamed to can body 12. In the cross-sectional view, chuck wall 26 and countersink 28 of can lid 14 can be seen as well as cylindrical side wall 18, neck 20, stand ring 22 and dome 24 of the can body 12.

Can diameter A is between 56 mm and 59 mm, for instance approximately 58 mm. Can diameter A corresponds to the diameter of cylindrical side wall 18. As further can be taken from Fig. 3, base 16 extends along a height F of about 5 to 10 mm. Cylindrical side wall 18 has a height G of about 120 mm. Neck 20 has a height H of about 17 mm. Can body 12 is symmetric about a longitudinal axis 46. Prior to sealing, can body 12 has an upper open end with an inner diameter B, which is called plug diameter, and which is about 46 mm.

Can body 12 is produced by a draw and wall ironing process (DWI), wherein first a cup is formed and then the side wall is formed by drawing and wall ironing. Thereafter, neck 20 is formed in a necking machine (necker) to achieve an upper can end that has a smaller diameter than the maximum can diameter. The ratio of plug diameter B to can diameter A B/A is called necking ratio. The necking ratio of can body 12 of the embodiment of Fig. 3 is a little less than 80 %.

Can body 12 is drawn from a single piece of aluminum sheet metal, having a gauge of 242 μιη. Therefore, the wall thickness in the middle of dome 24 is approximately 240 μιτι.

The maximum wall thickness of the can in the middle of the dome of the base is between 235 μιτι and 245 μιτι, such as 240 μιτι or 242 μητι. The tool for drawing and wall ironing preferably is configured to create a transitional wall thickness from the base to the side wall in two steps. The tool preferably provides a first step with an angle of 1 ° and a second step with an angle of -30'. Thus, the wall thickness of the can body is reduced from about 240 μιτι in the area of the base to about 79 μιτι at the middle part of side wall 18; cf. mid-side wall thickness C in Fig. 4.

The wall thickness of the middle part of the neck is about 1 11 μητι; cf. mid-neck thickness P in Figure 4. The neck has a flange (at its upper end) having a wall thickness N (cf. Fig. 4) in the range of between 130 μιτι and 150 μιτι, for instance 140 μιτι.

The transition from side wall 18 to flange 20 is rounded. The radius M (cf. Fig. 4) in the transition from side wall 18 to neck 20 is between 10 mm and 20 mm, for instance 15 mm. Such a transition is also called "round shoulder". The angle of the neck relative to the side wall 18 of a central longitudinal axis of can body 12 is between 25° and 35°, for instance 30°.

Beverage can 10 has a nominal volume of between 330 ml and 355ml and a height E of approximately of between 145 mm and 147 mm for a 330ml can and a height E of be- tween 156 mm and 159 mm for a 355 ml can.

A can body according to the embodiments of the Figures has a weight below 9.3 g for a can with a nominal volume of 330 ml and below 9.7 g for a can having a nominal volume of 355 ml.

The total internal volume of the seamed can is the nominal volume plus a head space. The volume of the head space is little less than 20 ml, for instance 18 ml. Thus, a can with a nominal volume of 330 ml has a total internal volume of 348 ml, and a can with a nominal volume of 355 ml has a total internal volume of 373 ml.

Figure 4 is a cross-sectional view of can lid 14 prior to seaming, illustrating the outside diameter (curl diameter) K. Figure 4 further illustrates a can lid plug diameter R that is defined by chuck wall 26 and a central panel diameter Q of central panel 30.

Figure 5 is a top-level view of a first embodiment of a can lid according to the invention. Can lid 14 as illustrated in Figure 5 has a can lid plug diameter R of 45.4 mm, and central panel diameter Q of 37.55 mm. As can be taken from Figure 5, on a central panel 30, an off centre rivet 40 is arranged that connects a rivet island 50 of pull tab 38 to central panel 30. Rivet island 50 is an integral part of pull tab 38 and forms a bendable hinge between handle part 42 of pull tab 38 and an opening part 44 of pull tab 38. An outer curl 54 of pull tab 38 provides for sufficient stiffness between handle part 42 and opening part 44, so that opening part 44 can exert strong enough a force on tear panel 32 when the handle part 42 of pull tab 38 is lifted. Tear panel 32 is defined by a score line 34 and has an area of 331 mm ² and has a shark fin design featuring a triangular extension 56 next to the rivet that improves pouring because it eases entering air in the can Can lid 14 is made from pre-coated aluminum sheet metal.

In order to improve the accessibility of handle part 42 of pull tab 38, rivet 40 may be tilted, as shown in Figure 6. The axis of rotation defined by rivet 40 is tilted with respect to a normal to a plane defined by countersink 28. Likewise, the plane defined by rivet island 50 has a tilt angle with respect to the plane defined by countersink 28. The tilt angle is between 2° and 4°, for instance 3°. A tilted rivet as shown in figure 8 is particularly useful with an embodiment as shown in figure 5. However, a tilted rivet can also be provided with an embodiment as shown in figures 6 and 7 or 9 and 10.

In the embodiment of Figure 5, pull tab 38 is already orientated in its opening position where the opening part 44 of pull tab 38 is placed above tear panel 32. Therefore, lifting handle part 42 of pull tab 38 causes opening part 44 to cause a force on tear panel 32 leading to a rupture of score line 34.

Alternatively, the can lid can have a pull tab that initially is orientated in shelf-position with respect to the tear panel. In such embodiment, the pull-tab first must be aligned with tear panel in order to allow opening of tear panel. Aligning of pull tab requires a rotation of the pull tab that can help to lift the handle part of the pull tab so that the handle part can be gripped easier.

Lifting and aligning of the handle part of pull tab can be facilitated by ramp-up beads arranged on either side of pull tab 38; see Figure 9. Ramp-up beads assist lifting the pull tab when the pull tab is rotated about an axis of rotation defined by the rivet; see the embodiments depicted in figure 7 to 10.

Figure 7 is a top-level view of a second, alternative embodiment of can lid 14'. Figure 7 depicts this second embodiment in a state, where pull tab 38' is orientated in a shelf position that is suitable for stacking cans for instance when stored in a shelf. Figure 8 depicts the same can lid with pull tab 38' in its opening position. As can be taken from Figures 7 and 8, pull tab 38' must be rotated by about 180° in order to swivel pull tab 38' from the shelf position to the opening position. Swiveling occurs around the axis of rotation defined by rivet 40'. When pull tab 38 is in its opening position, the handle part 42' extends beyond the outer diameter of central panel 30. Accordingly, handle part 42' must be lifted in order to move handle part 42' over the chime formed by double seam 41 when can lid 14' is applied to a can body such as can body 12 (see Figs. 1 and 2).

In order to facilitate lifting of handle part 42 of pull tab 38 during rotation, two ramp-up beads 56 are provided. The wedge-like shape of ramp-up beads 56 causes lifting off handle part 42 when handle part 42 slides along ramp-up bead 56 when rotated. The lifting of handle part 42 and the extension of handle part 42 over the outer periphery of central panel 30' facilitates gripping of handle part 42' with the finger of a user when opening can lid 14'. Additionally, a gap is provided between the most elevated parts of ramp-up beads 56. The gap between the two ramp-up beads 56 has a width that approximately corresponds to the width of pull tab 38. This has the effect, that pull tab 38 will slightly lock in the gap between ramp-up beads 56 and thus provides a tactile feedback when pull tab 38 has arrived in its opening position. This further facilitates handling of can lid 14' by a user.

Aligning of pull tab 38 is assisted by an tab positioning notch or recess 58 that is arranged to provide a tactile feedback if the tab 38 is swiveled in its opening position suitable for opening the tear panel. The tab positioning recess 58 is provided on the tab's side facing the central panel 30, the recess being arranged to engage with the seam 41 connecting the can lid 14 to the can body 12 when the can lid 14 is applied to a can body 12. When tab 38 is swiveled in its opening position, positioning recess 58 engages with the seam 41 as shown in the detail depicted in figure 1 1.

Figures 9 and 10 show an embodiment similar to the embodiment of figure 7 and 8 differing only in details and dimensions. The pull tab 38" of the embodiment of figure 10 has a gap or a recess 58 on the pull tab's side facing the central panel. This gap or recess 58 may engage with the double seam 41 that connects the can lid 14" with the can body 12 when the pull tab 38" is aligned in its opening position, thus providing tactile feedback to the user indicating that the pull tab is positioned for opening the can.

Figure 1 1 shows details of the orientation notch 58 on the lower side of the handle part 42 of the pull tab 38 that helps aligning the pull tab in its opening position.

Figures 12 and 13 show cross-sections of alternative embodiments of score line 34 or 34', respectively. In the embodiment shown in figure 12, an anti fracture score 60 is provided that runs in parallel to score line 34. Anti fracture score 60 has the effect to lower the tensile stress near the deepest portion of score line 34 and thus avoids an unwanted fracture of the score line prior to intended opening of tear panel 32. In the alternative embodiment shown in figure 13, a background penetration 62 is provided that runs along score line 34. Similar to the anti fracture score 60 of figure 12, background penetration 62 has the effect to lower the tensile stress near the deepest portion of score line 34 and thus avoids an unwanted fracture of the score line prior to intended opening of tear panel 32. List of reference numerals

10 Can

12 Can body

14, 14' Can lid

16 Base

18 Side wall

20 Neck

22 Stand ring

24 Dome

26 Chuck wall

28 Countersink

30 Central panel

32 Tear panel

34, 34' Score line

36 Absorption bead

38, 38" Pull Tab

40, 40' Rivet

41 Double Seam

42, 42' Handle part

44 Opening part

46 Longitudinal axis of can body

48 Panel radius

50 Rivet island

52 Bead gap

54 Pull tab curl

56 Ramp-up bead

58 Recess 60 anti fracture score

62 background penetration

A Maximum diameter

B Plug diameter

A/B Necking Ratio

C Wall thickness

D Flange wall thickness

E Can height

F Base height

G Cylindrical sidewall height

H Neck height

J Stand ring diameter

K Curl diameter

L Seam diameter

M Shoulder radius

N Flange thickness

P Neck thickness

Q Central panel diameter

R Can lid plug diameter