Granted Patent
Utility
US 4,133,068 · App. 05/827,185
Cleaning apparatus for submerged surfaces
Inventor:
Helmut Hofmann
Patented Case
View Patent ↗
Granted: Jan 9, 1979
Filed: Aug 23, 1977
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.