Granted Patent
Utility
US 4,794,988 · App. 07/065,299
Surface wellhead
Inventor:
Bernard Herman Van Bilderbeek
Patented Case
View Patent ↗
Granted: Jan 3, 1989
Filed: Jun 22, 1987
Inventor
Bernard Herman Van Bilderbeek
Assignee (at issue)
Plexus Ocean Systems Ltd.
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.