A bolt anchoring device for insertion into a bore in a concrete ceiling or the like material is provided. The bolt anchoring device comprises an anchor sleeve and a bolt. The anchor sleeve is first inserted in the bore for its provisional or temporary attachment. The bolt is then screwed into the anchor...http://www.google.com/patents/US5993129?utm_source=gb-gplus-sharePatent US5993129 - Bolt anchoring device with improved plug portion of bolt
