US Patent 7523688 Retention socket

A tool for torquing threaded fasteners includes a socket body having formed therein a fastener-receiving receptacle with an axis of rotation, the receptacle having a plurality of interior faces arranged in a generally polygonal configuration and substantially parallel to the axis, with each of the interior faces having projecting laterally inwardly therefrom a pair of fastener-engaging surfaces with inner and outer ends spaced apart in use substantially axially, each fastener-engaging surface being arcuate and sloping away from the axis from a closed end toward an open end of the socket.