Granted Patent
Utility
US 4,643,439 · App. 06/783,176
Seal for relatively rotatable parts
Inventors:
Frederick S. Lewis, Robert W. Munson
Patented Case
View Patent ↗
Granted: Feb 17, 1987
Filed: Oct 2, 1985
Inventors
Frederick S. Lewis
Robert W. Munson
Assignee (at issue)
Ingersoll-Rand Company
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.