Patent ID: 9403199
Filing Date: 2016-08-02
CPC Classification: B21B,B21C,B21D,F16L

Claim Text:
1. A method of manufacturing a tubular member having a tube expansion portion by working a sheet-like subject matter, the method comprising: a press-cutting step of forming a plurality of slots or slits in a staggered fashion at an expandable tube portion of the sheet-like subject matter, the plurality of slots or slits including: a sheet rolling step of rolling the sheet-like subject matter press-cut by the press-cutting step into a tubular subject matter tightly connected at a butt connection portion of the tubular subject matter; and a tube expanding step of expanding the expandable tube portion of the tubular subject matter formed by the sheet rolling step such that the expandable tube portion forms a lattice configuration, the lattice configuration having quadrangular openings formed by the expanding of the plurality of slots or slits.