Granted Patent
Utility
US 4,255,135 · App. 06/117,587
Apparatus for preheating a rotatable fluidizable bed
Inventor:
George B. Grim
Patented Case
View Patent ↗
Granted: Mar 10, 1981
Filed: Nov 5, 1979
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.