Granted Patent
Utility
US 4,665,979 · App. 06/773,396
Metal casing hanger seal with expansion slots
Inventor:
Carl F. Boehm, Jr.
Patented Case
View Patent ↗
Granted: May 19, 1987
Filed: Sep 6, 1985
Inventor
Carl F. Boehm, Jr.
Assignee (at issue)
Hughes Tool Company LLC
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.