A second base plate 51 is rotatably mounted on {HEAD ~ the first base plate} 50 having {TAIL ~ a centrally disposed pin} 52 extending into an opening 53 in the base plate 50 
having
A second base plate 51 is rotatably mounted on { HEAD ~ the first base plate } 50 having { TAIL ~ a centrally disposed pin } 52 extending into an opening 53 in the base plate 50
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH