Granted Patent
Utility
US 4,809,792 · App. 07/163,584
Support system for a top driven drilling unit
Inventor:
James E. Lynch
Patented Case
View Patent ↗
Granted: Mar 7, 1989
Filed: Mar 3, 1988
Inventor
James E. Lynch
Assignee (at issue)
National Oilwell, 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.