| 摘要 |
PURPOSE:To increase an impact resistance at falling time and the pressure resistance against inner and outer pressures by forming a recessed part over the whole periphery at slightly inner side from the chime rise part on the outer peripheral edge of top and bottom plates and integrally forming a mouthpiece part on the top plate. CONSTITUTION:The total height of a mouthpiece is lowered by forming a reverse trapezoidal recessed part 7 on the outer peripheral edge of the mouthpiece part 9 integrally formed on a top plate 1 and the depth H of a chime can be made shallower. The bad effect destroying the mouthpiece part 9 by an unirregular and large shaped bulging part on the top plate generated at the time of pressurizing to the inner side of a can body is prevented by forming a reverse trapezoidal recessed part 6 over the whole periphery at slightly inner side of the outer peripheral edge chime rise part 4 of the top plate 1. The bottom plate 2 subjected to pressing at the same stage as the top plate 1 as well is made shallow at its chime H similar to the top plate 1 and the expansion/deformation due to the inner pressure and the leakage of a seaming part 5 caused at falling time are prevented by forming the recessed part 6 at the outer peripheral edge.
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