A can end having a countersink bead, an inclined chuck wall and a strong seam, resists distortion from its circular profile when subjected to thermal processing or when packaging carbonated beverages. This high hoop strength affects the manner in which the can end ultimately fails when placed under extreme abuse conditions, even if buckle pressure performance is within industry specified standards. The can end of the invention has control features introduced which control the failure mode while maintaining specified buckle pressure performance. In one embodiment, the can end has a two part wall and a control feature that comprises expansion of the countersink bead to act as a trigger for local peaking, together with a groove in the chuck wall which prevents the peaking force from being concentrated at a single point which could result in leaking by the production of a pin hole.
1. A can end shell comprising:
a circular center panel;
a countersink bead having an inner wall and an outer wall joined by a generally curved bottom portion;
a flat shoulder joining the inner wall of the countersink bead to the center panel, the flat shoulder extending around a 360 degree arc;
a multipart chuck wall; and a seaming panel extending from the chuck wall.
2. The can end shell of claim 1 , wherein the flat shoulder is coined.
3. The can of claim 1 , wherein the can end shell further comprises an indentation positioned at least partially in the upper half of the chuck wall, the indentation extending either internally or externally, or a combination of these.
4. A can end shell for seaming onto a can body, the can end shell comprising:
a circular center panel;
a countersink bead having an inner wall and an outer wall joined by a generally curved bottom portion;
a flattened shoulder joining the inner wall of the countersink bead to the center panel, the flattened shoulder extending around a 360 degree arc;
a chuck wall located radially outwardly from the countersink, the chuck wall including a radially externally oriented indentation that is located at a point on the chuck wall that is proximate to a root of a seam upon seaming of the can end shell onto a can body; and
a seaming panel located radially outwardly from the chuck wall.
5. The can end shell of claim 4 , wherein the indentation is positioned at approximately a halfway point of the chuckwall.
6. The can end shell of claim 4 , wherein the externally oriented indentation is located in the upper half of the chuck wall.
7. The can end shell of claim 4 , wherein the flattened shoulder is coined.
8. The can end shell of claim 4 , wherein the indentation extends around a 360 degree arc.
9. A can end shell for seaming onto a can body, the can end shell comprising:
a circular center panel, a countersink bead having an inner wall and an outer wall joined by a generally curved bottom portion;
a flattened shoulder joining the inner wall of the countersink bead to the center panel, the flattened shoulder extending around a 360 degree arc;
a chuck wall located radially outwardly from the countersink, the chuck wall including a radially externally oriented indentation that is located at approximately a halfway point of the chuck wall; and
a seaming panel located radially outwardly from the chuck wall.
10. The can end shell of claim 9 , wherein the flattened shoulder is coined.
11. The can end shell of claim 9 , wherein the indentation extends around a 360 degree arc.
12. The can end shell of claim 1 wherein the flat shoulder extends up to the center panel without an intervening elbow.
13. The can end shell of claim 1 wherein the center panel has a center that defines a vertical axis that extends perpendicular to the center panel and the multipart chuck wall further comprises a lower portion extending at a first angle in relation to the vertical axis, and an upper portion extending at a second angle in relation to the vertical axis, the first angle being different from the second angle.
14. The can end shell of claim 4 wherein the flattened shoulder extends up to the center panel without an intervening elbow.
15. The can end shell of claim 4 wherein the center panel has a center that defines a vertical axis that extends perpendicular to the center panel and the chuck wall further comprises a lower portion extending at a first angle in relation to the vertical axis, and an upper portion extending at a second angle in relation to the vertical axis, the first angle being different from the second angle.
16. The can end shell of claim 9 wherein the flattened shoulder extends up to the center panel without an intervening elbow.
17. The can end shell of claim 9 wherein the center panel has a center that defines a vertical axis that extends perpendicular to the center panel and the chuck wall further comprises a lower portion extending at a first angle in relation to the vertical axis, and an upper portion extending at a second angle in relation to the vertical axis, the first angle being different from the second angle.