Granted Patent
Utility
US 4,697,616 · App. 06/858,220
Fluid flow control apparatus
Inventor:
Andrew ASHCROFT
Patented Case
View Patent ↗
Granted: Oct 6, 1987
Filed: Apr 30, 1986
Inventor
Andrew ASHCROFT
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT 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.