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.)
Filing date
Publication date
Priority claimed from US331062Aexternal-prioritypatent/US2920761A/en
Priority claimed from US331061Aexternal-prioritypatent/US2757581A/en
Application filed by Nichols Eng & Res CorpfiledCriticalNichols Eng & Res Corp
Application grantedgrantedCritical
Publication of FI40770BpublicationCriticalpatent/FI40770B/fi