Granted Patent
Utility
US 4,285,656 · App. 06/109,696
Tubular extrusion apparatus
Inventor:
F. John Herrington
Patented Case
View Patent ↗
Granted: Aug 25, 1981
Filed: Jan 4, 1980
Inventor
F. John Herrington
Assignee (at issue)
Mobil Oil Corporation
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.