Granted Patent
Utility
US 4,601,607 · App. 06/702,910
Mine shaft guide system
Inventor:
Richard P. Lehmann
Patented Case
View Patent ↗
Granted: Jul 22, 1986
Filed: Feb 19, 1985
Inventor
Richard P. Lehmann
Assignee (at issue)
Lake Shore, Inc.
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.