Patent ID: 7001389

Claim:
A system for locking a fastener to a plate comprising: a) a locking fastener having a proximal end and a distal end, further comprising (i) a head having an upper region, a groove adjacent said upper region, and a lower region adjacent said groove; wherein said upper region has a first diameter at said proximal end of said locking fastener and a second diameter adjacent said groove, and wherein said lower region has a third diameter adjacent said groove and a fourth diameter at a distal end of said lower region; (ii) a shank having a proximal end and a distal end, wherein said proximal end of said shank is adjacent said lower region of said head, and wherein said distal end of said shank further comprises a shoulder; (iii) a threaded section adjacent said shank; and (iv) a locking ring having an outer diameter and an inner diameter and a leading surface and a trailing surface, wherein said leading surface further comprises a chamfer, and wherein said locking ring resides within said groove of said head; and b) a plate further comprising an anterior surface and a posterior surface, wherein said plate further comprises a through-hole through said anterior surface and said posterior surface, said through-hole having associated therewith an imaginary longitudinal axis through the centroid of said through-hole; and wherein said through-hole comprises an undercut having a proximal end and a distal end, said through-hole further comprising a first lip located proximally of said proximal end of said undercut and a second lip located distally of said distal end of said undercut.