Granted Patent
Utility
US 4,193,577 · App. 05/949,844
Expanding gate valve with axially flexed spring plate
Inventor:
Willard E. Kemp
Patented Case
View Patent ↗
Granted: Mar 18, 1980
Filed: Oct 10, 1978
Inventor
Willard E. Kemp
Assignee (at issue)
ACF Industries Incorporated
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.