Granted Patent
Utility
US 4,655,247 · App. 06/820,544
Ball-type check valve assembly
Inventors:
Lubbert Westra, Brent J. Lirette
Patented Case
View Patent ↗
Granted: Apr 7, 1987
Filed: Jan 17, 1986
Inventors
Lubbert Westra
Brent J. Lirette
Assignee (at issue)
Chromalloy American Corp.
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.