Granted Patent
Utility
US 4,928,645 · App. 07/406,997
Ceramic composite valve for internal combustion engines and the like
Inventors:
Philip L. Berneburg, Roy W. Rice
Patented Case
View Patent ↗
Granted: May 29, 1990
Filed: Sep 14, 1989
Inventors
Philip L. Berneburg
Roy W. Rice
Assignee (at issue)
W.R. Grace & Co. Conn.
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.