Quarter-turn fastener

Abstract

A quick action fastener suitable for fastening panels or the like in face-to-face contact, including a pierce nut adapted to be secured within one of the panels and a male stud inserted through the other panel and into a through-hole in the nut. The nut includes a central, pilot portion which is diepunched through the panel and a pair of undercut grooves on opposites sides of the pilot portion, into which edges of the panel are deformed in order to securely hold the nut on the panel. The nut includes a locking element extending across the through-hole which is received within and contacts with a spiral cam slot in the stud upon partial rotation of the stud to lock the stud in the nut and thereby securely fasten the panels together. In one embodiment, the stud is axially biased from the locking element by a spring captured between the head of the stud and one of the panels while another embodiment employs a pair of wire loops forming a spring support for the locking element. The nuts may be formed in a strip thereof and interconnected by frangible connections which are successively severed during automated die insertion of the nuts into a panel. In the strip form of the nuts, the locking element for each of the nuts is defined by a continuous frangible wire which extends along the strip and is severable at spaced between adjacent nuts during installation of the nuts into the panel.