A threaded fastener has a casing enclosing {HEAD ~ at least three radially inwardly biased arcuate segments} positioned to engage {TAIL ~ the threads} of a bolt or hollow threaded member 
positioned to engage
A threaded fastener has a casing enclosing { HEAD ~ at least three radially inwardly biased arcuate segments } positioned to engage { TAIL ~ the threads } of a bolt or hollow threaded member
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH