Granted Patent
Utility
US 5,316,092 · App. 07/838,791
Method and apparatus for drilling a tunnel
Inventor:
Valto Ilomaki
Patented Case
View Patent ↗
Granted: May 31, 1994
Filed: Mar 17, 1992
Inventor
Valto Ilomaki
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.