Lid for a beverage can

Abstract

The invention relates to a lid consisting of metal for a beverage can, which lid is designed to be permanently connected to a can body and has a lid panel in which a rivet for a grip tab is formed and in which a predetermined breaking line defining a breaking-open area is impressed, along which line an opening in the lid panel can be opened by the grip tab, wherein a rivet base, which has resulted from a formation of the rivet, is present around the rivet, within which base the metal of the lid is thinner and/or more brittle than in adjoining regions of the lid panel.

Claims

1. A lid made of metal, for a beverage can designed for permanent connection to a can body, the lid having a lid panel from which a rivet is shaped and into which a predetermined breaking line, which defines a breaking-open area, is impressed, along which an opening in the lid panel is to be opened by means of a grip tab, which is attached to the rivet and has a break-open edge pressed against a predetermined pressing point of the breaking-open area by raising a grip section of the grip tab when opening up the opening, where in the lid panel has a rivet base around the rivet, in which the metal of the lid is thinner and/or more brittle than in the regions of the lid panel adjacent to the river base, characterized in that the predetermined breaking line runs outside of the rivet base and a material-thinning embossment, which also runs outside of the rivet base and is designed in the form of an embossing recess and is associated with an embrittlement of the thinned-out material, is provided in at least one area of the lid panel situated between the rivet base and the predetermined pressing point of the breaking-open area, wherein a longitudinal section of the predetermined breaking line in this lid panel region coincides with the material-thinning embossment around the longitudinal section, wherein the embossing depth of the predetermined breaking line is greater than the embossing depth of the material-thinning embossment; wherein the predetermined breaking line is impressed in the material-thinning embossment along the longitudinal section and exists from the material-thinning embossment at the ends of the longitudinal section.

2. The lid according to claim 1, characterized in that the grip tab can be rotated around the rivet in such a way that the grip section of the grip tab can be moved beyond the opening formed by breaking open the predetermined breaking line wherein the grip section is designed for closing the opening.

3. The lid according to claim 1, characterized in that the material-thinning embossment has a greater width, measured in the direction radially to the rivet, then the predetermined breaking line.

4. The lid according to claim 1, characterized in that the material-thinning embossment has a width of 0.6 millimeter to 1 millimeter, measured radially to the rivet.

5. The lid according to claim 1, characterized in that a centerline of the material-thinning embossment is a distance of 4 millimeters from an axis of the rivet.

6. The lid according to claim 1, characterized in that the embossing depth of the material-thinning embossment is 0.03 millimeter to 4.5 millimeters from an axis of the rivet.

7. The lid according to claim 1, characterized in that the material-thinning embossment runs in a curved shape at least partially around the rivet base.

8. The lid according to claim 7, characterized in that the material-thinning embossment runs in a ring shape concentrically around the rivet.

9. The lid according to claim 1, characterized in that the material-thinning embossment runs partially around the rivet in a crescent shape.

10. The lid according to claim 1, characterized in that the material-thinning embossment runs outside of the rivet base tangentially to a circle around the rivet base.

11. The lid according to claim 1, characterized in that the longitudinal section of the predetermined breaking line with which the material-thinning embossment coincides runs in a curved shape with the concave side facing the rivet.

12. The lid according to claim 1, characterized in that the rivet is arranged on a bead, which is elevated with respect to a level of the lid panel and runs around the breaking-open area, while the predetermined breaking line and the material-thinning embossment run at the level of the lid panel.

13. The lid according to claim 1, characterized in that the material-thinning embossment forms a recess on an exterior side (customer side) of the lid facing away from the future interior of the can.

14. The lid according to claim 1, characterized in that the rivet is arranged eccentrically on the lid panel.

15. A method for producing a lid according to claim 1, characterized in that the shaping of the rivet comprises the following steps: shaping a bubble, a first rivet head shape and a second rivet head shape, wherein the material-thinning embossment is introduced into the lid panel from the exterior side of the lid during the shaping of the second rivet head, the grip tab being subsequently attached to the exterior side (customer side) and then the predetermined breaking line is impressed.

16. The method for manufacturing a lid according to claim 15, characterized in that the material-thinning embossment is created in the lid simultaneously with the predetermined breaking line, wherein the predetermined breaking line is introduced from the side of the lid into its lid panel to which the grip tab is attached subsequently (customer side) while the material thinning embossment is introduced into the lid.

Description

(1) The invention will now be explained in greater detail on the basis of exemplary embodiments with reference to the figures in the drawings.

(2) Of the figures:

(3) FIG. 1a shows a lid according to the invention, including the grip tab, in a view from above;

(4) FIG. 1b shows a cross-sectional contour of the lid according to the sectional line A-A in FIG. 1 when opening the drinking opening;

(5) FIG. 2 shows a perspective diagram of a shell for the lid from FIG. 1;

(6) FIG. 3 shows a top view of the shell from FIG. 2;

(7) FIG. 4 shows a section A-A through the shell from FIG. 3;

(8) FIG. 5 shows a detail B of the section A-A from FIG. 4 with an enlarged diagram of the material-thinning embossment and the predetermined breaking line superimposed thereon;

(9) FIGS. 6a+6b a perspective diagram as well as a top view of a blank of the shell with a preferred variant of the material-thinning embossment, such as that used with the shell from FIGS. 2 through 5;

(10) FIGS. 7a+7b show a perspective view and a top view of a blank of the shell with an alternative variant of a material-thinning embossment;

(11) FIGS. 8a+8b show a perspective diagram and a top view of a blank of the shell with an additional alternative variant of a material-thinning embossment;

(12) FIGS. 9a+9b show a perspective diagram and a top view of a blank of the shell with a third variant of a material-thinning embossment;

(13) FIG. 10a shows a top view of a shell like that in FIG. 3 in a different embodiment; and

(14) FIG. 10b shows an enlarged portion of section A-A from FIG. 10a with a sectional diagram of the predetermined breaking line and the material-thinning embossment.

(15) FIG. 1a shows a lid made of sheet metal, in particular aluminum, having a roll 12 for a subsequent connection to a can body (not shown). The lid 10 is connected to the can body by means of a double seam in the area of the roll 12.

(16) The lid 10 is in two parts and has a shell 14 and a grip tab 16. A breaking-open area 18 in the shell 14 can be broken open by means of the grip tab 16, so that a drinking opening is formed, for example.

(17) FIGS. 2 through 5 show the shell 14 of the lid 10 in detail.

(18) Like the usual lids, the lid 10 has a central panel 20 surrounded by a peripheral counter sink 22. The peripheral counter sink 22 is in turn encompassed by chuck wall 24, which develops into the roll 12. The chuck wall 24 has a peripheral protrusion 26 facing inward and serving to provide a locking hold down of a fee end of a grip section 28 of the grip tab 16, which serves as the closure for the drinking open when the tab is rotated over the resulting drinking opening after the breaking-open area 18 has been opened.

(19) Reinforcing recesses 30 and 32 and shaped in the panel 20, reinforcing the panel 20 outside of the opening system shaped into the panel.

(20) The opening system is formed by the breaking-open area 18, which is defined by a predetermined breaking line 34 and is reinforced by an annular protrusion 36 shaped into it. Furthermore, the breaking-open area 18 is surrounded by a head 38, which protrudes beyond the level of the remaining panel and serves to reinforce the edge strip of the sheet metal material surrounding the predetermined breaking line 34 as well as the periphery of the drinking opening, which is formed after breaking open the breaking-open area 18.

(21) A rivet 40 is arranged on a plateau 42 formed by the protruding bead 38 at the center of panel 20. The rivet 40 serves to fasten the grip tab 16 on the shell 14 and is arranged outside of the breaking-open area 18.

(22) FIG. 1b shows a cross-sectional contour of the lid along the sectional line A-A in FIG. 1a wherein the grip tab 16 is in a position for opening the breaking-open area 18 by lifting the grip section 28 of the grip tab. The grip tab 16 is attached pivotably to the rivet 40 by means of a fastening section, so that the opener section of the grip tab can be pivoted away together with its break-open edge 50. Therefore, the break-open edge is pressed onto a pressing point 48 of the breaking-open area 18, which is situated next to the rivet 40, so that the predetermined breaking line, which is mostly adjacent to the breaking-open area, is broken open and the breaking-open area which has now been separated is pivoted into the resulting drinking open by further lifting of the grip section.

(23) FIG. 3 shows that the panel has a so-called rivet base 47 around the rivet 40, forming a region around the rivet due to the fact that the rivet 40 has been shaped out of the shell 14 so that the sheet metal surrounding the rivet 40 has become thinner and more brittle in the rivet base 47 than the remaining sheet metal material of the shell 14. The material-thinning embossment 40 which runs concentrically around the rivet 40 in the form of an annular groove or ridge is introduced into the exterior surface of the shell 14 outside of the rivet base and at a distance therefrom, and the width of this annular groove or ridge is somewhat larger on the exterior surface than the width of the scratch forming the predetermined breaking line 34.

(24) The material-thinning embossment 44 is arranged and of dimensions such that the predetermined breaking line 34 runs through the bottom surface 49 (illustrated with a broken line in FIG. 5) of the material-thinning embossment 44 in its longitudinal section 46 next to the rivet 40, also running outside of the rivet base and at a distance therefrom. This ensures that the predetermined breaking line 34 will run close to the rivet 40 through the thinned and embrittled sheet metal material, which facilitates the initial breaking open of the predetermined breaking line 34 in this section. The predetermined breaking line 34 is at a distance in the range of 4 to 4.5 millimeters from the central axis of the rivet 40. As shown in FIG. 5, the material-thinning embossment has the cross-sectional contour of a flat rounded trough with an embossing depth in the range of approx. 20% of the thickness of the sheet metal material. In the area of the width of the material-thinning embossment the remaining sheet metal thickness of the sheet metal material of the lid 10 amounts to approx. 0.18 millimeter to 0.2 millimeter. However, the cross-sectional contour of the predetermined breaking line 34 has an embossing depth of 0.12 to 0.14 millimeter.

(25) The width of the material-thinning embossment (measured in the radial direction starting from the rivet) preferably amounts to between 0.6 millimeter and 1 millimeter.

(26) FIGS. 6 through 9 show various alternative embodiment variants of a material-thinning embossment according to the invention.

(27) FIGS. 6 through 9 show blanks of the shell after shaping the rivet and impressing the material-thinning embossment but before shaping the other design features of the shell and before embossing the predetermined breaking line. Therefore, only the respective rivet 40 and the material-thinning embossment 44 are shown in the region of the respective panel 20. However, the other features of the opening system are not shown.

(28) The embodiment variant in FIGS. 6a and 6b corresponds to the embodiment variant according to FIGS. 2 through 5, in which the rivet 40 is arranged so that it is offset from the center of the panel 20, and in which the material-thinning embossment 44 is in the form of a ring that is concentric with the rivet 40 and completely surrounds the rivet 40.

(29) In the embodiment variant illustrated in FIGS. 7a and 7b, the material-thinning embossment 44 is in the form of a small circular area whose midpoint is the same distance from the central axis of the rivet 40 as the center line of the ring-shaped material deepening embossment 44 in FIGS. 6a and 6b.

(30) In the embodiment variant according to FIGS. 8a and 8b, the material-thinning embossment 44 has an elongated shape along a tangent to a circle (not shown), which is concentric with the rivet 40.

(31) In the embodiment variant according to FIGS. 9a and 9b, the material-thinning embossment 44 is an arc section around the rivet 40, i.e., the concave side of the arc section faces the rivet.

(32) Other forms of material-thinning embossment are conceivable, for example, an embossment in a crescent shape resembling the arc-shaped material-thinning embossment 44.

(33) In the embodiment shown in FIG. 3, the longitudinal section 46 of the predetermined breaking line 34, along which the predetermined breaking line coincides with the material-thinning embossment 44, runs in a straight line in the direction of a tangent to the circular center line of the material-thinning embossment. However, in the embodiment in FIG. 10a, the longitudinal section 46 of the predetermined breaking line 34, which coincides with the circular material-thinning embossment 44, is designed in a curved shape with the concave side facing the rivet. The radius of curvature of the curve is somewhat greater than the radius of the circular center line of the material-thinning embossment 44. The predetermined breaking line 34 exits laterally from the material-thinning embossment at both ends of the longitudinal section 46. In comparison with the embodiment in FIG. 3, this therefore yields a greater length of the coinciding part of the predetermined breaking line 34 with the material-thinning embossment 44, so that the break in the predetermined breaking line can continue more easily to the ends of the longitudinal section 46, after the same is broken open, and can then continue into the remaining sections of the predetermined breaking line.

(34) FIG. 10 shows the trough-shaped cross-sectional contour of the material-thinning embossment 44 at the right of the rivet 40, whereas the superimposed contour 34+44 of the predetermined breaking groove and the material-thinning embossment is shown at the left of the rivet. Due to the greater width and embossing depth of the cross-sectional contour of the predetermined breaking line, the material-thinning embossment has been widened and deepened in the area of overlap by the embossing ram for the predetermined breaking line.

(35) In the embodiment in FIG. 10a, the bead and the rivet 40 are arranged at a slight offset from the center of the lid panel toward the breaking-open area 18.

LIST OF REFERENCE NUMERALS

(36) 10 Lid 12 Roll 14 Shell 16 Grip tab 18 Breaking-open area 20 Panel 22 Counter sink 24 Chuck wall 26 Peripheral protrusion 28 Grip section 30 Reinforcing recess 32 Reinforcing recess 34 Predetermined breaking line 36 Protrusion 38 Bead 40 Rivet 42 Plateau 44 Material-thinning embossment 46 Longitudinal section of the predetermined breaking line 47 Rivet base 48 Pressing point 49 Bottom surface of the material-thinning embossment 50 Break-open edge