Granted Patent
Utility
US 6,481,931 · App. 09/665,023
Cantilever supported drilling rig
Inventor:
Walter Thomas Welsh
Patented Case
View Patent ↗
Granted: Nov 19, 2002
Filed: Sep 19, 2000
Inventor
Walter Thomas Welsh
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.