Inventor

KAWASHIMA HISAKAZU

JP3 patents

Patents

3 patents

US4630849ADec 23, 1986

Oil well pipe joint

SUMITOMO METAL IND185 citations96

US4474651AOct 2, 1984

Oil well casing and tubing joint and production of same

SUMITOMO METAL IND56 citations93

US4871194AOct 3, 1989

Oil well pipe joint and manufacturing method therefor

SUMITOMO METAL IND36 citations90