Granted Patent
Utility
US 4,491,927 · App. 06/327,477
Depth monitoring system
Inventors:
Einar H. Bachmann, Kristjan Ingvarsson
Patented Case
View Patent ↗
Granted: Jan 1, 1985
Filed: Dec 4, 1981
Inventors
Einar H. Bachmann
Kristjan Ingvarsson
Assignee (at issue)
The Digger Meter 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.