Granted Patent
Utility
US 4,836,848 · App. 07/103,925
Fe-based sintered alloy for valve seats for use in internal combustion engines
Inventors:
Osamu Mayama, Yoshimi Ishikawa
Patented Case
View Patent ↗
Granted: Jun 6, 1989
Filed: Oct 2, 1987
Inventors
Osamu Mayama
Yoshimi Ishikawa
Assignee (at issue)
Mitsubishi Kinzoku Kabushiki Kaisha
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.