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