Two piece fastener and installation tool

Abstract

A two piece pull-type fastener is disclosed herein comprising a pin and collar adapted to be swaged into locking engagement with the pin upon setting of the fastener by application of a pulling force to the pin and reaction force on the collar. The pin is provided with a minimum number of pull grooves defined by alternating crests and valleys which grooves are sufficient in strength to allow an installation tool to exert a pulling force on the pin of a magnitude required to properly set the fastener. The installation tool has a gripping structure adapted to engage the pull grooves. The gripping structure and pull grooves are complementarily shaped so as to prevent engagement of less than all of the pull grooves by the gripping structure of the tool in order to prevent stripping of the pull grooves if less than all are attempted to be engaged. Thus an installation tool nose assembly is also disclosed which nose assembly is uniquely designed for use with the present fastener. In a preferred form of the invention, the pull grooves of the fastener are provided on a pintail portion of the fastener. In a different form of the invention the pull grooves are located within an opening in the end portion of the pin.