Granted Patent
Utility
US 6,257,356 · App. 09/413,111
Magnetorheological fluid apparatus, especially adapted for use in a steerable drill string, and a method of using same
Inventor:
Mark Ellsworth Wassell
Patented Case
View Patent ↗
Granted: Jul 10, 2001
Filed: Oct 6, 1999
Inventor
Mark Ellsworth Wassell
Assignee (at issue)
APS Technology, 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.