Granted Patent
Utility
US 4,613,004 · App. 06/795,574
Earth boring bit with labyrinth seal protector
Inventor:
Duane Shotwell
Patented Case
View Patent ↗
Granted: Sep 23, 1986
Filed: Nov 6, 1985
Inventor
Duane Shotwell
Assignee (at issue)
Hughes Tool Company - USA
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.