Granted Patent
Utility
US 6,434,240 · App. 08/993,333
Sound isolation cabinet using two sound sources to generate complimentary sound waves
Inventor:
Charles J. Kulas
Patented Case
View Patent ↗
Granted: Aug 13, 2002
Filed: Dec 19, 1997
Inventor
Charles J. Kulas
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.