Granted Patent
Utility
US 4,413,666 · App. 06/290,447
Expendable die casting sand core
Inventor:
Enno H. Page
Patented Case
View Patent ↗
Granted: Nov 8, 1983
Filed: Aug 6, 1981
Inventor
Enno H. Page
Assignee (at issue)
NL Industries, 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.