Granted Patent
Utility
US 4,351,077 · App. 06/217,604
Cleaning apparatus for submerged surfaces
Inventor:
Helmut Hofmann
Patented Case
View Patent ↗
Granted: Sep 28, 1982
Filed: Dec 18, 1980
Inventor
Helmut Hofmann
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.