Granted Patent
Utility
US 4,809,989 · App. 07/058,938
Coil spring supported sealing element and device
Inventor:
Dickie L. Kernal
Patented Case
View Patent ↗
Granted: Mar 7, 1989
Filed: Jun 5, 1987
Inventor
Dickie L. Kernal
Assignee (at issue)
Otis Engineering Corporation
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.