Granted Patent
Utility
US 4,919,422 · App. 07/376,317
Curve ball
Inventor:
Hansan Ma
Patented Case
View Patent ↗
Granted: Apr 24, 1990
Filed: Jul 6, 1989
Inventor
Hansan Ma
Assignee (at issue)
Tonka 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.