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