Granted Patent
Utility
US 4,653,539 · App. 06/619,933
Self-sealing check valve
Inventor:
Craig J. Bell
Patented Case
View Patent ↗
Granted: Mar 31, 1987
Filed: Jun 12, 1984
Inventor
Craig J. Bell
Assignee (at issue)
MALLINCKRODT 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.