Granted Patent
Utility
US 6,546,921 · App. 10/135,467
Heated PCV valve
Inventor:
Douglas Callahan
Patented Case
View Patent ↗
Granted: Apr 15, 2003
Filed: Apr 30, 2002
Inventor
Douglas Callahan
Assignee (at issue)
MINIATURE PRECISION COMPONENTS, 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.