Patent ID: 7610938
Filing Date: 2009-11-03
Classification: B21C,B21K

Abstract:
1. A cylindrical rod which is formed by bonding together a pair of opposing edges of sheet metal, wherein: each of the opposing edges has (i) convex portions each of which protrudes from the edge and includes a sub-portion whose width is larger at a side thereof more distant from the edge than at a side thereof less distant from the edge, and (ii) concave portions each of which recedes from the edge and includes a sub-portion whose width is larger at a side thereof more distant from the edge than at a side thereof less distant from the edge, the convex portions and the concave portions of one of the opposing edges are fitted into the concave portions and the convex portions of the other of the opposing edges, a periphery of each of the convex and concave portions has a linear section which forms substantially a right angle with respect to a corresponding one of the opposing edges and extends from the corresponding one of the opposing edges to a part of the respective convex or concave portion most distant from the corresponding one of the opposing edges, and a slant section which forms an acute angle with respect to the corresponding one of the opposing edges and extends from the corresponding one of the opposing edges to a part of the respective convex or concave portion most distant from the corresponding one of the opposing edges, the linear section and the slant section being on opposite sides of the each of the convex and concave portions in a direction parallel to the corresponding one of the opposing edges, and both the linear section and the slant section being adjacent to the corresponding one of the opposing edges.