Granted Patent
Utility
US 4,327,921 · App. 06/273,884
Pressure balanced - constant engagement force seal
Inventors:
Harold L. Reinsma, Ernest Burdell Clark, III
Patented Case
View Patent ↗
Granted: May 4, 1982
Filed: Dec 8, 1980
Inventors
Harold L. Reinsma
Ernest Burdell Clark, III
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.