Granted Patent
Utility
US 4,202,490 · App. 05/918,640
Drill pipe identification method and system
Inventors:
Walter A. Gunkel, Robert W. Lybecker
Patented Case
View Patent ↗
Granted: May 13, 1980
Filed: Jun 23, 1978
Inventors
Walter A. Gunkel
Robert W. Lybecker
Assignee (at issue)
Hughes Tool Company 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.