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{{PatentInfo
|Inventor=David Kahn, Karl Weisser
|Assignee=David Kahn Inc
|Country=US
|ApplicationNum=320944
|ApplicationDate=1946-10-11
|PatentNum=2692580
|PatentDate=1952-11-17
|PriorityDate=1952-11-17
|Titolo=Writing instrument
|Marca=Wearever
|Descrizione=Penna a sfera
}}
==Informazioni==
Brevetto per una penna a sfera. Riferimenti a {{MentionPatent|US|1850086}}, {{MentionPatent|US|1874110}}, {{MentionPatent|US|2153488}}, {{MentionPatent|US|2449218}}, {{MentionPatent|US|2468258}}, {{MentionPatent|US|2500979}}, {{MentionPatent|US|2536923}} e {{MentionPatent|US|2580753}} ed inoltre {{MentionPatent|FR|628418}}, {{MentionPatent|IT|434348}}, {{MentionPatent|AU|128697}}, {{MentionPatent|FR|962297}}, {{MentionPatent|GB|641595}}.