Granted Patent
Utility
US 4,781,672 · App. 06/922,079
Three stage implantable flow control valve with improved valve closure member
Inventor:
Michael D. Hooven
Patented Case
View Patent ↗
Granted: Nov 1, 1988
Filed: Oct 21, 1986
Inventor
Michael D. Hooven
Assignee (at issue)
CORDIS 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.