Granted Patent
Utility
US 4,949,786 · App. 07/335,996
Emergency casing hanger
Inventors:
Lawrence A. Eckert, Graeme Johnston, Peter M. Kent
Patented Case
View Patent ↗
Granted: Aug 21, 1990
Filed: Apr 7, 1989
Inventors
Lawrence A. Eckert
Graeme Johnston
Peter M. Kent
Assignee (at issue)
Vecto Gray 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.