Patent information:

Patent:Utility 1,631,729
Patented:June 7, 1927
Applied:February 24, 1919
Title:Ceramic Insulating Material
Description:Porcelain composition for spark plugs and insulators consisting of Sillimanite and a glassy matrix
Assigned to:Champion Porcelain Co.

Patentee Information:

JEFFERY, Joseph A. Detroit, MI
MONTGOMERY, Earle T. Detroit, MI

Class and subclass information:

Subclass:141CERAMIC COMPOSITIONS Clay containing (e.g., porcelain, earthenware, etc.);

Known specimens:

None known