Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of NL21441CpublicationCriticalpatent/NL21441C/xx
Priority claimed from DET30320Dexternal-prioritypatent/DE516463C/de
Priority claimed from DET30319Dexternal-prioritypatent/DE453509C/de