Granted Patent
Utility
US 4,182,603 · App. 05/890,198
Multilayer tubular extrusion die
Inventor:
Richard Knittel
Patented Case
View Patent ↗
Granted: Jan 8, 1980
Filed: Mar 27, 1978
Inventor
Richard Knittel
Assignee (at issue)
Egan Machinery 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.