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 211 cans in the industry.
After filling of a can body e.g. with a carbonated beverage, a respective can lid is attached 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 μm 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 μm. 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 to tilted so that the rivet provides an axis of rotation of the pull tap that has an angle of between 1° 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 precoated 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:
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.
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 mm2 to 350 mm2 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.
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
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
Can body 12 is drawn from a single piece of aluminum sheet metal, having a gauge of 242 μm. Therefore, the wall thickness in the middle of dome 24 is approximately 240 μm.
The maximum wall thickness of the can in the middle of the dome of the base is between 235 μm and 245 μm, such as 240 μm or 242 μm. 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 μm in the area of the base to about 79 μm at the middle part of side wall 18; cf. mid-side wall thickness C in
The wall thickness of the middle part of the neck is about 111 μm; cf. mid-neck thickness P in
The transition from side wall 18 to flange 20 is rounded. The radius M (cf.
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 355 ml and a height E of approximately of between 145 mm and 147 mm for a 330 ml can and a height E of between 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. to 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.
In order to improve the accessibility of handle part 42 of pull tab 38, rivet 40 may be tilted, as shown in
In the embodiment of
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
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
Number | Date | Country | Kind |
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10 2016 110 064.1 | May 2016 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/061863 | 5/17/2017 | WO | 00 |