Granted Patent
Utility
US 5,013,333 · App. 07/508,559
Unattended air cleaning system for surface maintenance machine
Inventors:
Jeffrey J. Beaufoy, Robert Aigner, Steven A. Burke
Patented Case
View Patent ↗
Granted: May 7, 1991
Filed: Apr 13, 1990
Inventors
Jeffrey J. Beaufoy
Robert Aigner
Steven A. Burke
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.