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