Granted Patent
Utility
US 4,376,621 · App. 05/908,347
Method and apparatus for tube extrusion
Inventor:
William Bridge
Patented Case
View Patent ↗
Granted: Mar 15, 1983
Filed: May 22, 1978
Inventor
William Bridge
Assignee (at issue)
THE DOW CHEMICAL 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.