Granted Patent
Utility
US 4,887,629 · App. 07/364,830
Plug valve and method of assembly
Inventors:
A. Kenneth Wilson, John V. Ballun
Patented Case
View Patent ↗
Granted: Dec 19, 1989
Filed: Jun 12, 1989
Inventors
A. Kenneth Wilson
John V. Ballun
Assignee (at issue)
AMSTED 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.