Abstract: A 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.

Abstract: ABSTRACT A 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.

Abstract: A storage battery which can further intensify the sealing properties of the electrode rod piercing portion thereof, a technique capable of increasing the area of the sealing surface at the sealed portion of the storage battery, a technique capable of certainly preventing the missing of mounting of a rubber-based sealing material corresponding to O-ring at the sealed portion of the storage battery, and an insulating material having an excellent corrosion resistance to highly corrosive battery content and a battery container including same are provided. An electrode rod 14 is allowed to extend upward through an annular member 15, a pressing member 18 is placed on the annular member 15, and a nut 22 is then threaded on a thread portion 21. This threading job is effected until the pressing member 18 is placed on and stopped by a collar portion 23. At the time when threading ends, a neck portion 25 is somewhat compressed to exhibit sealing properties.