Patent ID: 7815094
Filing Date: 2010-10-19
Classification: B23K

Abstract:
1. A method of manufacturing a hollow cylindrical body, comprising the steps of: bending a plate material to have a substantially hollow cylindrical shape with end faces of the plate material opposing each other along a joining direction; bringing the end faces of the plate material into abutment against each other along the joining direction; the plate material having fingers projecting from corners along the joining direction, and pairs of said fingers form first and second protrusions projecting along the joining direction at opposite ends of the hollow cylindrical shape; gripping said protrusions by a gripping mechanism comprising first and second gripping members such that the fingers of said protrusions are maintained in abutment along said joining direction, where each of the first and second gripping members of the gripping mechanism includes a recess which surrounds and is complementary to outer edges of an associated pair of fingers of the first or second protrusion such that the fingers cannot move apart in a direction perpendicular to the joining direction; while the protrusions are gripped in place, friction-stir-welding abutting regions of the end faces of the plate material to join the end faces to each other, thereby forming a hollow cylindrical body having said protrusions; and removing said first and second protrusions; wherein said end faces of the plate material are friction-stir-welded such that said abutting region is devoid of a formation of swellings.