a cam surface located on an exterior portion of the tieback member in {HEAD ~ engagement} with {TAIL ~ an inner side} of the locking member 
with
a cam surface located on an exterior portion of the tieback member in { HEAD ~ engagement } with { TAIL ~ an inner side } of the locking member
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH