Seam connection and method for manufacturing the seam

Claim 1

A cylindrical sheet metal container of large volume including circumferential beads comprising a cylindrical container body having a first flange-like sheet edge; a circular cover having a second flange-like sheet edge; a seam connection between the first and second sheet edges, said seam connection including said first and second sheet edges wherein said first sheet edge is bent about an angle of more than 270* and said second sheet edge is bent about an angle of more than 360*, as seen from the beginning of curvature of the respective first and second edges, and wherein said first and second sheet edges are in a spiral shaped winding of gradually changing radii and are in metal-tometal contact throughout the entire cross-section of said seam connection; and a sealing compound exclusively in the center of said seam connection, said sealing compound completely filling said center and being under pressure.

Claim 3

A method of manufacturing a triple seam connection for a container between a cylindrical body of said container and a round cover, said body and said cover being made of sheet metal and having, respectively, first and second flanges which extend in a radial plane with respect to the axis of the container, said second flange forming the outer layer of the seam connection and having a portion which extends with respect to said first flange, said portion having an outer edge which is initially bent in the general direction of sealing before a seaming roll operation begins, comprising the steps of: a. bending said outEr edge of said second flange about 180* into a U-shaped bend with a first seaming roller having in cross-section a semi-circular groove of a very small radius, said bending being done without folding said body and without said U-shaped bend surround said first flange; b. applying a sealing compound in the U-shaped bend; c. forming the first flange in which a side-wall of said body merges into said first flange with a radius which is considerably larger than the radius of curvature at the junction of said second flange and an adjacent cylindrical portion of said cover; d. mounting said first and second flanges together; and e. rolling said first and second flanges closely into each other with a radially operating second seaming roller having, when viewed in cross-section, a semi-circular groove bottom in which said second flange is bent over more than 360* and said first flange is bent over more than 270* to form a seam connection having a closed spiral shaped cross-section.

Claim 4

A method of manufacturing a triple seam connection for a container between a cylindrical body of said container and a round cover, said body and said cover being made of sheet metal and having, respectively, first and second flanges which extend in a radial plane with respect to the axis of the container, said second flange forming the outer layer of the seam connection and having a portion which extends with respect to said first flange, said portion having an outer edge which is initially bent in the general direction of sealing before a seaming roll operation begins, comprising the steps of: a. bending said outEr edge of said second flange about 180* into a U-shaped bend with a first seaming roller having in cross-section a semi-circular groove of a very small radius, said bending being done without folding said body and without said U-shaped bend surround said first flange; b. applying a sealing compound in the U-shaped bend; c. forming the first flange in which a side-wall of said body merges into said first flange with a radius which is considerably larger than the radius of curvature at the junction of said second flange and an adjacent cylindrical portion of said cover; d. mounting said first and second flanges together; and e. rolling said first and second flanges closely into each other with a radially operating second seaming roller having, when viewed in cross-section, a semi-circular groove bottom in which said second flange is bent over more than 360* and said first flange is bent over more than 270* to form a seam connection having a closed spiral shaped cross-section.