Granted Patent
Utility
US 4,442,908 · App. 06/281,334
Tool for drilling curved sections of well holes
Inventor:
Arno Steenbock
Patented Case
View Patent ↗
Granted: Apr 17, 1984
Filed: Jul 8, 1981
Inventor
Arno Steenbock
Assignee (at issue)
Preussag Aktiengesellschaft
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.