Granted Patent
Utility
US 4,597,147 · App. 06/654,280
Stop changer tool for in-service valve
Inventor:
Ralph E. Henry
Patented Case
View Patent ↗
Granted: Jul 1, 1986
Filed: Sep 24, 1984
Inventor
Ralph E. Henry
Assignee (at issue)
Dresser Industries, Inc.
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.