Granted Patent
Utility
US 4,368,752 · App. 06/174,995
Compound check valve
Inventors:
Hideo Tamamori, Rikisaburo Nagai
Patented Case
View Patent ↗
Granted: Jan 18, 1983
Filed: Aug 4, 1980
Inventors
Hideo Tamamori
Rikisaburo Nagai
Assignee (at issue)
Nippon Air Brake Co., Ltd.
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.