A fastening system including a two piece swage type fastener including a pin and a collar adapted to be swaged into lock grooves in the pin and in which the lock grooves are helical and with the collar having a limited female thread which is threadably engageable with the helical lock grooves for variably...http://www.google.es/patents/US4867625?utm_source=gb-gplus-sharePatente US4867625 - Variable clamp fastener and method
