Granted Patent
Utility
US 4,288,215 · App. 06/153,009
Method and apparatus for preheating a rotatable fluidizable bed
Inventor:
George B. Grim
Patented Case
View Patent ↗
Granted: Sep 8, 1981
Filed: May 27, 1980
Inventor
George B. Grim
Assignee (at issue)
Caterpillar Tractor Co.
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.