方形罐及其双重卷边方法和装置

Original abstractA square can capable of securing high sealing performance even if a curvature radius of a seamed portion at a seamed corner portion is reduced, enabling a reduction in a countersink depth, reduced in size, having excellent sealing ability and storage efficiency and a method and an apparatus for double seaming the square can. A second seaming roll ( 55 ) is guided by a model cam for second seaming having a model cam surface for second seaming formed in such a shape that it is swelled from a model cam surface for first seaming outwards at a corner seamed portion ( 5 ). Accordingly, the seaming shape of the corner seamed portion ( 5 ) is formed in such a shape that the seaming width thereof at the center of the corner seamed portion is larger than the seaming width of a linear sealed portion ( 4 ) and is swelled outwards to absorb an increase in sheet thickness at the corner seamed portion. Also, a seaming wall ( 6 ) is formed in an obliquely inclined seamed shape so that the overlap of a cover hook ( 8 ) with a body hook ( 10 ) of a prescribed amount can be secured without allowing the cover hook ( 8 ) to fall from the body hook ( 10 ) so as to maintain excellent sealing ability.