Can end and method of making same

Abstract

A can end includes a severable panel, a peripheral scoreline, an opening mechanism such as a pull tab, a rivet coupling the pull tab to the severable panel, and a rivet base scoreline in the public side of the severable panel. The rivet base scoreline includes an arcuate head portion, first and second arm portions extending from the arcuate head portion, and first and second ends. The base of the rivet has a radius of curvature forming an intersection between the stem of the rivet and the public side of the severable panel. The arcuate head portion of the rivet base scoreline is contiguous with the radius of curvature.

What is claimed is: 
     
         1 . A can end structured to be affixed to a can body, the can end comprising:
 a severable panel having a product side structured to face toward the can body when the can end is affixed to the can body, and a public side structured to face away from the can body when the can end is affixed to the can body;   a peripheral scoreline disposed on the public side of the severable panel proximate to an outer perimeter of the can end, the peripheral scoreline defining a periphery of the severable panel that is structured to be withdrawn or removed from the can end;   an opening mechanism coupled to the severable panel, the opening mechanism being actuatable to sever the peripheral scoreline;   a rivet disposed on the public side of the panel proximate to the periphery, the rivet coupling the opening mechanism to the severable panel, the rivet having a base disposed at the severable panel and a stem extending outwardly from the severable panel, the base of the rivet having a radius of curvature forming an intersection between the stem and the public side of the severable panel; and   a rivet base scoreline in the public side of the severable panel, the rivet base scoreline including an arcuate head portion,   wherein the arcuate head portion of the rivet base scoreline is within the radius of curvature of the base of the rivet.   
     
     
         2 . The can end of  claim 1  wherein the severable panel has an interior; wherein the rivet base scoreline further includes first and second arm portions extending from the arcuate head portion, and first and second ends; wherein the rivet has an inboard side facing the interior of the severable panel, and an outboard side facing the periphery of the severable panel; wherein the arcuate head portion of rivet base scoreline is disposed on the inboard side of the rivet; and wherein the first and second arm portions of the rivet base scoreline generally extend toward the outboard side of the rivet. 
     
     
         3 . The can end of  claim 2  wherein the arcuate head portion of the rivet base scoreline has a first radius of curvature; and wherein the first and second arm portions of the rivet base scoreline have a second radius of curvature. 
     
     
         4 . The can end of  claim 3  wherein the first radius of curvature of the arcuate head portion is the same as the second radius of curvature of the first and second arm portions. 
     
     
         5 . The can end of  claim 2  wherein the first and second arm portions of the rivet base scoreline extend beyond the outboard side of the rivet toward the periphery of the severable panel. 
     
     
         6 . The can end of  claim 2  wherein the first and second ends of the rivet base scoreline curve back away from the periphery of the severable panel. 
     
     
         7 . The can end of  claim 2  wherein the opening mechanism has a longitudinal axis; wherein, upon actuation of the opening mechanism, the rivet base scoreline is structured to propagate toward the peripheral scoreline of the can end, thereby defining a bend axis; wherein the bend axis extends generally perpendicularly with respect to the longitudinal axis of the opening mechanism; and wherein the bend axis is disposed proximate to the peripheral scoreline. 
     
     
         8 . The can end of  claim 2  wherein the opening mechanism is a pull tab; wherein the pull tab includes a nose and a lift portion disposed opposite and distal from the nose; wherein the stem of the rivet has a diameter and a centerline; wherein the pull tab has a dimension, X, measured by the distance between the centerline of the rivet and the nose of the pull tab, and a dimension, Y, measured by the total length of the pull tab between the nose of the pull tab and the lift portion of the pull tab; and wherein the ratio X/Y is about 0.20 or less. 
     
     
         9 . The can end of  claim 8  wherein the diameter of the stem of the rivet is about 0.1875 inch or less. 
     
     
         10 . The can end of  claim 1  wherein the opening mechanism is structured to be lifted, pivoted to a substantially inverted position, and pulled, in order to remove the severable panel; wherein, responsive to being lifted, the opening mechanism is structured to initially sever the peripheral scoreline; and wherein, responsive to being pivoted to the substantially inverted position, the opening mechanism is structured to sever at least 40 percent of the peripheral scoreline. 
     
     
         11 . The can end of  claim 1  wherein the opening mechanism is a pull tab;
 wherein the pull tab includes a nose portion and a lift portion disposed opposite the nose portion; wherein the nose portion of the pull tab overlays at least a portion of the rivet base scoreline; and wherein the nose portion of the pull tab includes a number of apertures structured to be aligned with corresponding portions of the rivet base scoreline thereunder. 
 
     
     
         12 . The can end of  claim 1  wherein the severable panel includes a number of projections protruding from the severable panel; and wherein the number of projections support the opening mechanism and resist undesired rotation of the opening mechanism relative to the rivet. 
     
     
         13 . A method of making a can end, the method comprising:
 forming a peripheral scoreline on a public side of the can end proximate to the outer perimeter of the can end to define a periphery of a severable panel portion that is structured to be withdrawn or removed from the can end, the panel portion having a product side opposite the public side,   forming a rivet on the public side of the panel proximate to the periphery, the rivet including a base disposed on the public side of the panel portion and a stem extending outwardly from the public side of the panel portion;   scoring the public side of the panel portion to form a rivet base scoreline;   forming a radius of curvature at the base of the rivet between the public side of the panel portion of the can end and the stem of the rivet; and   forming an arcuate head portion of the rivet base scoreline, the arcuate head portion being within the radius of curvature of the base of the rivet.   
     
     
         14 . The method of  claim 13 , further comprising:
 forming a pull tab including a nose portion and a lift portion disposed opposite the nose portion, the nose portion including a rivet hole and a number of apertures disposed proximate to the rivet hole,   sliding the nose portion of the pull tab over the stem of the rivet in order that the stem of the rivet is disposed in the rivet hole of the nose portion, and   aligning the number of apertures of the nose portion of the pull tab with corresponding portions of the rivet base scoreline thereunder.   
     
     
         15 . The method of  claim 14 , further comprising:
 applying a post score repair agent to the can end, and   delivering the repair agent through the number of apertures of the nose portion of the pull tab to the rivet base scoreline, in order to coat the rivet base scoreline.   
     
     
         16 . The method of  claim 14 , further comprising:
 scoring the panel portion to define a peripheral scoreline, and   staking the rivet to couple the pull tab to the panel portion,   wherein the nose portion of the pull tab is structured to sever the peripheral scoreline.   
     
     
         17 . The method of  claim 14 , further comprising:
 forming a number of protrusions protruding outwardly from the panel portion of the can end proximate to the rivet,   wherein the number of protrusions are structured to resist undesired rotation of the pull tab relative to the rivet.   
     
     
         18 . The method of  claim 13 , further comprising:
 forming the stem of the rivet to have a diameter of about 0.1875 inch or less.   
     
     
         19 . The method of  claim 13 , further comprising:
 forming first and second arm portions of the rivet base scoreline, the first and second arm portions extending from the arcuate head portion of the rivet base scoreline generally toward a periphery of the panel portion of the can end.