Granted Patent
Utility
US 4,249,429 · App. 05/939,751
Unlocking differential
Inventor:
Ralph E. Denning
Patented Case
View Patent ↗
Granted: Feb 10, 1981
Filed: Sep 5, 1978
Inventor
Ralph E. Denning
Assignee (at issue)
Caterpillar Tractor Co.
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.