Granted Patent
Utility
US 4,936,421 · App. 07/305,133
Conical spring braking mechanism
Inventor:
Ronald L. Altnau
Patented Case
View Patent ↗
Granted: Jun 26, 1990
Filed: Feb 2, 1989
Inventor
Ronald L. Altnau
Assignee (at issue)
Speed Queen Company
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.