Granted Patent
Utility
US 5,688,533 · App. 08/601,074
Round ringless mold and triangular spoke sprue
Inventor:
Robert P. Berger
Patented Case
View Patent ↗
Granted: Nov 18, 1997
Filed: Feb 12, 1996
Inventor
Robert P. Berger
Assignee (at issue)
Belle de St. Claire
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.