Granted Patent
Utility
US 5,140,994 · App. 07/630,722
Surface vibration analysis
Inventors:
Frederick C. Campbell, Brian E. Storey
Patented Case
View Patent ↗
Granted: Aug 25, 1992
Filed: Dec 20, 1990
Inventors
Frederick C. Campbell
Brian E. Storey
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.