Blind fastening means for fastening thin materials together without crushing them. Such means comprises a blind rivet sleeve, a blind rivet pin provided with a head to engage the blind end of the sleeve, and spacing means provided intermediate the blind end of the sleeve and the head thereof. As the...http://www.google.es/patents/US4170920?utm_source=gb-gplus-sharePatente US4170920 - Blind spacer fastener
