Granted Patent
Utility
US 4,317,246 · App. 06/180,090
Surface cleaning machine
Inventor:
Christopher M. Knowlton
Patented Case
View Patent ↗
Granted: Mar 2, 1982
Filed: Aug 21, 1980
Inventor
Christopher M. Knowlton
Assignee (at issue)
The Scott Fetzer 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.