Granted Patent
Utility
US 4,969,515 · App. 07/449,807
Expendable devices for well lock system
Inventor:
William W. Dollison
Patented Case
View Patent ↗
Granted: Nov 13, 1990
Filed: Dec 13, 1989
Inventor
William W. Dollison
Assignee (at issue)
Otis Engineering 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.