Granted Patent
Utility
US 4,809,532 · App. 07/109,514
Method of manufacturing split ring springs for snap fasteners
Inventors:
Akira Tanaka, Kenji Hasegawa
Patented Case
View Patent ↗
Granted: Mar 7, 1989
Filed: Oct 19, 1987
Inventors
Akira Tanaka
Kenji Hasegawa
Assignee (at issue)
Yoshida Kogyo K.K.
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.