| 摘要 |
PURPOSE:To obtain a blank material for ornamentation formed internally with a spiral pattern by winding a wire-shaped blank material twisted together with metallic wire rods to a circular conical shape and compressing the wound material then compressing the material from both sides to form an elliptical spiral and fixing the spiral to a frame. CONSTITUTION:Two pieces of wire rods are joined together or are folded in two and are twisted together to form a wire-shaped base material 2. Such base material is wound to a circular conical shape. The base material is then compressed from above to be flattened and is thus deformed to a circular spiral shape. The material 2 is so compressed that the parts in contact with each other are not produced in this stage. Compressive force is applied to such spiral blank material from both sides to deform the material into an elliptical shape. The elliptical blank material has therefore an extremely smooth elliptical spiral pattern as the spaces are shifted and the non-contact state are maintained in the direction perpendicular to the compressive force although the compressed parts of the material 2 contact with each other. A frame material 3 is fixed to the material 2 so as to enclose the outside circumference thereof by brazing or the like. |
