Patent ID: 7322091

Claim:
A working apparatus used for the working of a metal cylindrical body having a thickness which is thinner at one edge than at the other edge comprising: a base for abutting on the thinner edge surface of the cylindrical body, an outer die for enclosing the thinner edge of the cylindrical body, a pressure forming jig for pressing on the other edge of the cylindrical body, and, an inner die to be fitted to an inner circumference of the thinner edge of the cylindrical body, said inner die being provided on the abutting surface of the base, against which the thinner edge surface of the cylindrical body is abutted, wherein the outer die is of two halves and freely detachable/attachable to the base to form an opening enclosing the thinner edge of the cylindrical body at a constant interval when the outer die is attached to the base, so that the thinner edge of the cylindrical body can be shaped into the opening to have an increased thickness and an enlarged outer diameter when the pressure forming jig presses on the other edge of the cylindrical body and on the base, and the pressure forming jig is made up of a section of a circular cone, formed to have a pressure contact surface that applies pressure to the other edge surface of the cylindrical body, said circular cone having an axis passing through an apex, said axis being slanted with respect to an axis of the outer die, the inner die, and the base, wherein the pressure forming jig can turn on the apex so that the other edge of the cylindrical body can have an enlarged outer diameter by the turning motion of the pressure forming jig.