Granted Patent
Utility
US 5,772,317 · App. 08/703,780
Counterflow drum mixer for making asphaltic concrete and methods of operation
Inventor:
Theodore G. Butler
Patented Case
View Patent ↗
Granted: Jun 30, 1998
Filed: Aug 27, 1996
Inventor
Theodore G. Butler
Assignee (at issue)
GENCOR INDUSTRIES, INC.
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.