Granted Patent
Utility
US 4,327,567 · App. 06/119,596
Tubing expander for boiler tubes or the like
Inventor:
Paul Walter Martin, III
Patented Case
View Patent ↗
Granted: May 4, 1982
Filed: Feb 7, 1980
Inventor
Paul Walter Martin, III
Assignee (at issue)
Dresser Industries, Inc.
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.