Granted Patent
Utility
US 6,367,565 · App. 09/049,218
Means for detecting subterranean formations and monitoring the operation of a down-hole fluid driven percussive piston
Inventor:
David R. Hall
Patented Case
View Patent ↗
Granted: Apr 9, 2002
Filed: Mar 27, 1998
Inventor
David R. Hall
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.