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