Granted Patent
Utility
US 4,257,739 · App. 05/941,255
Soft inplane helicopter rotor
Inventors:
Cecil E. Covington, David Snyder, Walter Gerd Oskar Sonneborn, Wesley L. Cresap
Patented Case
View Patent ↗
Granted: Mar 24, 1981
Filed: Sep 11, 1978
Inventors
Cecil E. Covington
David Snyder
Walter Gerd Oskar Sonneborn
Wesley L. Cresap
Assignee (at issue)
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.