Granted Patent
Utility
US 4,590,652 · App. 06/671,416
Method for fabricating an air gap pipe
Inventor:
Jon W. Harwood
Patented Case
View Patent ↗
Granted: May 27, 1986
Filed: Nov 14, 1984
Inventor
Jon W. Harwood
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.