Granted Patent
Utility
US 4,909,320 · App. 07/258,228
Detonation assembly for explosive wellhead severing system
Inventors:
Joseph V. Hebert, Robert Schwartz
Patented Case
View Patent ↗
Granted: Mar 20, 1990
Filed: Oct 14, 1988
Inventors
Joseph V. Hebert
Robert Schwartz
Assignee (at issue)
Drilex Systems, 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.