Granted Patent
Utility
US 4,843,945 · App. 07/023,385
Apparatus for making and breaking threaded well pipe connections
Inventor:
Michael C. Dinsdale
Patented Case
View Patent ↗
Granted: Jul 4, 1989
Filed: Mar 9, 1987
Inventor
Michael C. Dinsdale
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.