Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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
Application filed by Hitachi LtdfiledCriticalHitachi Ltd
Priority to JP3694975ApriorityCriticalpatent/JPS51111957A/en
Publication of JPS51111957ApublicationCriticalpatent/JPS51111957A/en
Publication of JPS553013B2publicationCriticalpatent/JPS553013B2/ja