Granted Patent
Utility
US 4,815,939 · App. 06/926,152
Twisted hollow airfoil with non-twisted internal support ribs
Inventor:
Gordon S. Doble
Patented Case
View Patent ↗
Granted: Mar 28, 1989
Filed: Nov 3, 1986
Inventor
Gordon S. Doble
Assignee (at issue)
Airfoil Textron 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.