Granted Patent
Utility
US 4,585,015 · App. 06/672,053
Cigarette filter
Inventor:
Donald A. Silberstein
Patented Case
View Patent ↗
Granted: Apr 29, 1986
Filed: Nov 16, 1984
Inventor
Donald A. Silberstein
Assignee (at issue)
Brown & Williamson Tobacco 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.