Patent attributes
A fastener having a pin member and a sleeve. The pin includes a head, a pin tail portion, and a locking portion with a plurality of crests and roots. Each of the crests includes a first diameter, the first diameters sequentially increase along the locking portion towards the head, while the roots include a second diameter, the second diameters sequentially decrease towards the head. The sleeve has a head and a tubular portion which is deformed into a bulb that engages a workpiece. The tubular portion of the sleeve locks onto the crests and the pintail portion of the pin member breaks off at one of the grooves located substantially flush with the head of the sleeve.