Granted Patent
Utility
US 4,231,506 · App. 06/040,515
Method of welding metal pipe sections with explosives
Inventors:
Stephen M. Istvanffy, Vonne D. Linse
Patented Case
View Patent ↗
Granted: Nov 4, 1980
Filed: May 21, 1979
Inventors
Stephen M. Istvanffy
Vonne D. Linse
Assignee (at issue)
Canadian Industries Limited
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.