Granted Patent
Utility
US 4,558,721 · App. 06/627,870
Double walled tubing
Inventors:
Gerald R. Trudell, Theodore F. Kraska, Dennis W. Barber
Patented Case
View Patent ↗
Granted: Dec 17, 1985
Filed: Jul 3, 1984
Inventors
Gerald R. Trudell
Theodore F. Kraska
Dennis W. Barber
Assignee (at issue)
APX Group, Inc.
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.