{HEAD ~ A pair} of {TAIL ~ rollers} 4 constituting one part of a wave generator 3 and functioning as a cam are disposed to be rotatable within the flexible gear 2 
{ HEAD ~ A pair } of { TAIL ~ rollers } 4 constituting one part of a wave generator 3 and functioning as a cam are disposed to be rotatable within the flexible gear 2
HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH OTH