Granted Patent
Utility
US 4,208,752 · App. 05/956,151
Cleaning apparatus for submerged surfaces
Inventor:
Helmut Hofmann
Patented Case
View Patent ↗
Granted: Jun 24, 1980
Filed: Oct 31, 1978
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.