Granted Patent
Utility
US 4,964,567 · App. 07/309,695
Expansion and check valve combination
Inventors:
Joseph H. Heffner, G. Thomas Seener, Dennis L. Hoehne
Patented Case
View Patent ↗
Granted: Oct 23, 1990
Filed: Feb 10, 1989
Inventors
Joseph H. Heffner
G. Thomas Seener
Dennis L. Hoehne
Assignee (at issue)
Sporlan Valve Company
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.