Granted Patent
Utility
US 4,243,535 · App. 05/754,811
Filter assembly with telescopic elements
Inventors:
Bertwin E. Behrends, David Diebel
Patented Case
View Patent ↗
Granted: Jan 6, 1981
Filed: Dec 27, 1976
Inventors
Bertwin E. Behrends
David Diebel
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.