Granted Patent
Utility
US 4,888,947 · App. 07/264,576
Secondary oil system
Inventor:
Douglas Thompson
Patented Case
View Patent ↗
Granted: Dec 26, 1989
Filed: Oct 31, 1988
Inventor
Douglas Thompson
Assignee (at issue)
General Motors LLC
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.