Granted Patent
Utility
US 4,806,869 · App. 06/866,242
An above-ground arrangement for and method of locating a discrete in ground boring device
Inventors:
Albert W. Chau, John E. Mercer
Patented Case
View Patent ↗
Granted: Feb 21, 1989
Filed: May 22, 1986
Inventors
Albert W. Chau
John E. Mercer
Assignee (at issue)
Flow Industries, Ltd.
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.