Granted Patent
Utility
US 4,213,411 · App. 06/062,213
Readily attachable and detachable sole plate for a sewing machine
Inventor:
Warren D. Knowles
Patented Case
View Patent ↗
Granted: Jul 22, 1980
Filed: Jul 30, 1979
Inventor
Warren D. Knowles
Assignee (at issue)
The Singer Company Limited
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.