Granted Patent
Utility
US 5,940,928 · App. 09/007,669
Surface maintenance machine with computer controlled operational and maintenance systems
Inventor:
Robert Erko
Patented Case
View Patent ↗
Granted: Aug 24, 1999
Filed: Jan 15, 1998
Inventor
Robert Erko
Assignee (at issue)
TENNANT COMPANY
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.