Granted Patent
Utility
US 5,025,868 · App. 07/435,953
Pneumatic ground piercing tool
Inventors:
Steven W. Wentworth, Robert F. Crane, Jon A. Haas
Patented Case
View Patent ↗
Granted: Jun 25, 1991
Filed: Nov 13, 1989
Inventors
Steven W. Wentworth
Robert F. Crane
Jon A. Haas
Assignee (at issue)
Earth Tool Company LLC
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.