Granted Patent
Utility
US 4,630,688 · App. 06/278,438
Power spinner for rotating a kelly joint
Inventors:
Martin E. True, Clarence W. Sullivan
Patented Case
View Patent ↗
Granted: Dec 23, 1986
Filed: Jun 24, 1981
Inventors
Martin E. True
Clarence W. Sullivan
Assignee (at issue)
Weatherford/Lamb, 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.