Granted Patent
Utility
US 4,520,743 · App. 06/637,645
Needle thread tensioning device for a sewing machine
Inventor:
Thaddeus J. Zylbert
Patented Case
View Patent ↗
Granted: Jun 4, 1985
Filed: Aug 3, 1984
Inventor
Thaddeus J. Zylbert
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.