Granted Patent
Utility
US 4,697,828 · App. 06/935,462
Wellhead body lockdown and method for engaging same
Inventor:
Yung-sen Chou
Patented Case
View Patent ↗
Granted: Oct 6, 1987
Filed: Nov 26, 1986
Inventor
Yung-sen Chou
Assignee (at issue)
Armco 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.