Granted Patent
Utility
US 5,427,191 · App. 08/326,975
Auger head assembly and method of drilling hard earth formations
Inventor:
Brian Rickards
Patented Case
View Patent ↗
Granted: Jun 27, 1995
Filed: Oct 21, 1994
Inventor
Brian Rickards
Assignee (at issue)
Pengo Corporation
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.