Granted Patent
Utility
US 4,801,243 · App. 07/120,247
Adjustable diameter screw propeller
Inventor:
John A. Norton
Patented Case
View Patent ↗
Granted: Jan 31, 1989
Filed: Nov 3, 1987
Inventor
John A. Norton
Assignee (at issue)
Bird-Johnson Company
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.