Granted Patent
Utility
US 5,012,878 · App. 07/417,878
Rock boring machine drive head with up and down drilling capability
Inventor:
Llewellan Anderson
Patented Case
View Patent ↗
Granted: May 7, 1991
Filed: Oct 6, 1989
Inventor
Llewellan Anderson
Assignee (at issue)
Robbins, Inc.
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.