Granted Patent
Utility
US 4,217,839 · App. 06/064,315
Adjustable anti-spill bobbin tension spring
Inventor:
Benedict W. Barat
Patented Case
View Patent ↗
Granted: Aug 19, 1980
Filed: Aug 6, 1979
Inventor
Benedict W. Barat
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.