Granted Patent
Utility
US 4,766,751 · App. 07/036,055
Apparatus for continuously producing tube having helical grooves in its inner surface
Inventor:
Iwao Ueda
Patented Case
View Patent ↗
Granted: Aug 30, 1988
Filed: Apr 9, 1987
Inventor
Iwao Ueda
Assignee (at issue)
Hamana Iron Works Co., Ltd.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.