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