Granted Patent
Utility
US 4,807,747 · App. 07/183,698
Package structure for spark plugs
Inventor:
Frederick B. Hadtke
Patented Case
View Patent ↗
Granted: Feb 28, 1989
Filed: Apr 19, 1988
Inventor
Frederick B. Hadtke
Assignee (at issue)
Champion Spark Plug 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.