Granted Patent
Utility
US 4,599,893 · App. 06/598,435
Determining the level of contaminants in a hydraulic system
Inventors:
Martin Fisher, Roger A. Heron, Martin Lawrence Hughes
Patented Case
View Patent ↗
Granted: Jul 15, 1986
Filed: Apr 9, 1984
Inventors
Martin Fisher
Roger A. Heron
Martin Lawrence Hughes
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT 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.