Granted Patent
Utility
US 4,697,301 · App. 06/814,103
Blackboard rubber made of, or including, metal
Inventor:
Jos Palmans
Patented Case
View Patent ↗
Granted: Oct 6, 1987
Filed: Dec 27, 1985
Inventor
Jos Palmans
Assignee (at issue)
Alliance Enamelsteel Corporation S.A.
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.