Granted Patent
Utility
US 4,386,534 · App. 06/311,858
System for obtaining exhaust samples and analyzing the same
Inventors:
Michael S. Englund, Joseph C. Hafele, Dwain C. Schulze, Jr.
Patented Case
View Patent ↗
Granted: Jun 7, 1983
Filed: Oct 16, 1981
Inventors
Michael S. Englund
Joseph C. Hafele
Dwain C. Schulze, Jr.
Assignee (at issue)
Caterpillar Tractor Co.
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.