Granted Patent
Utility
US 5,176,172 · App. 07/806,601
Toggle linkage check valve
Inventor:
Rand H. Ackroyd
Patented Case
View Patent ↗
Granted: Jan 5, 1993
Filed: Dec 12, 1991
Inventor
Rand H. Ackroyd
Assignee (at issue)
Watts Regulator Co.
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.