Rick, take another look at the spelling on that blade. I think it probably reads "GESETZLICH GESCHUTZT",(with the "U" an umlaut with the two horizontal dots above it) meaning"PROTECTED BY LAW" refering to trademark protection.
The kingdom of Prussia became the most powerful of the German States and lasted until 1918 when it became part of unified Germany, so it appears that may be a very old one. I'm not a historian, so that may not be a valid theory, but it's my SWAG (an engineering term which stands for scientific, wilda$$ed guess)
Ron