A sprocket 64 having a plurality of {HEAD ~ teeth} 66 is fixedly attached to an outer surface of the first plate 56 , the sprocket 64 having a diameter smaller than {TAIL ~ a diameter} of the first plate 56 
A sprocket 64 having a plurality of { HEAD ~ teeth } 66 is fixedly attached to an outer surface of the first plate 56 , the sprocket 64 having a diameter smaller than { TAIL ~ a diameter } of the first plate 56
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH