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.)
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Priority claimed from FR91644Aexternal-prioritypatent/FR1515194A/fr
Priority claimed from FR110496Aexternal-prioritypatent/FR92589E/fr
Application filedfiledCritical
Publication of BE708923ApublicationCriticalpatent/BE708923A/xx
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
