In addition {HEAD ~ the last pin} can rock about a lengthwise axis and is locked in {TAIL ~ rocked position} by a wedging system  
is locked in
In addition { HEAD ~ the last pin } can rock about a lengthwise axis and is locked in { TAIL ~ rocked position } by a wedging system
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH