Granted Patent
Utility
US 4,864,293 · App. 07/188,958
Inground boring technique including real time transducer
Inventor:
Albert W. Chau
Patented Case
View Patent ↗
Granted: Sep 5, 1989
Filed: Apr 29, 1988
Inventor
Albert W. Chau
Assignee (at issue)
FlowMole 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.