Granted Patent
Utility
US 4,903,916 · App. 07/301,389
Cassette reel spring having rolled edges
Inventor:
William M. Carroll
Patented Case
View Patent ↗
Granted: Feb 27, 1990
Filed: Jan 25, 1989
Inventor
William M. Carroll
Assignee (at issue)
Koller Manufacturing Corporation
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.