Granted Patent
Utility
US 4,883,391 · App. 07/247,347
Ball end mill
Inventors:
Osamu Tsujimura, Tatsuo Arai, Masayuki Okawa
Patented Case
View Patent ↗
Granted: Nov 28, 1989
Filed: Sep 21, 1988
Inventors
Osamu Tsujimura
Tatsuo Arai
Masayuki Okawa
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.