Granted Patent
Utility
US 4,483,660 · App. 06/378,303
Submersible pump impeller locking method
Inventor:
Leo L. Roberts
Patented Case
View Patent ↗
Granted: Nov 20, 1984
Filed: May 14, 1982
Inventor
Leo L. Roberts
Assignee (at issue)
Hughes Tool Company LLC
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.