Granted Patent
Utility
US 4,052,820 · App. 05/651,183
Portable surface treating apparatus
Inventor:
John C. Bergh
Patented Case
View Patent ↗
Granted: Oct 11, 1977
Filed: Jan 21, 1976
Inventor
John C. Bergh
Assignee (at issue)
Wheelabrator-Frye Inc.
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.