Granted Patent
Utility
US 4,474,251 · App. 06/324,251
Enhancing liquid jet erosion
Inventor:
Virgil Johnson, Jr.
Patented Case
View Patent ↗
Granted: Oct 2, 1984
Filed: Nov 25, 1981
Inventor
Virgil Johnson, Jr.
Assignee (at issue)
Hydronautics, Incorporated
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.