Article of manufacture
United States Patent 2239970

Inventors:
Osborne, Raymond G.
Publication Date:
04/29/1941
View Patent Images:
Download PDF 2239970 pdf       PDF help
Export Citation:
Click for automatic bibliography generation
Assignee:
Osborne, Raymond G.
Primary Class:
434/84
Other Classes:
446/137, 446/85, 209/213
International Classes:
G09B11/00