Nippon Light Metal Company, Ltd.

Shigenori Saitoh

Keiichi Sugiyama

Mitsuo Tsuge

Shigeru Kohmura

Hisao Saitoh

The can end is formed with a circular severing score for severing the area defined thereby from the can end by pulling a manipulating tab secured within the area defined by the score at a position adjacent thereto. In order to increase the pressure resisting strength against the internal pressure caused by the content in the can, the can end is made from a thin aluminum alloy sheet having the yield strength in the range of 24-29 kgf/mm.sup.2 as well as the elongation equal to or greater than 6%, while the aperture rate defined by the ratio of the area formed within the score with respect to the total area of the can end is made at least equal to or greater than 60% so that the pressure resisting strength is kept substantially at least 5 kgf/cm.sup.2. In order to more advantageously maintain the high pressure resisting strength of the can, score is located at a position spaced from the inner periphery of the bottom of the frustoconical portion at least a distance equal to or greater than 1 mm inwardly of the area of the can end, to make the inner radius of curvature of the corner formed around the inner periphery of the bottom of the frustoconical portion equal to or less than 0.5 mm, and to make the taper angle of the frustoconical portion of the can end equal to or less than 10.degree.. An auxiliary score having a score residual smaller than that of the score for severing the area defined thereby from the can end may be formed outwardly or inwardly of the score for severing. The score residual of the can end may be preferably increased from the thinnest portion adjacent to the position where the tab is provided while a plurality of elongated ridges or grooves may be formed within the area defined by the score substantially perpendicular to the line passing through the tab and the center of the can end in order to avoid rapid severing of the area defined by the score from the can end so as to prevent spilling of the content out of the can when the can end is being opened. All these measures are effective to most advantageously enhance the pressure resisting strength of the can end.

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Shizuoka, Japan

Shigenori Saitoh