Granted Patent
Utility
US 4,998,553 · App. 07/461,525
Controlling particulate material
Inventor:
Cornelius J. Schram
Patented Case
View Patent ↗
Granted: Mar 12, 1991
Filed: Jan 5, 1990
Inventor
Cornelius J. Schram
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT 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.