The ratchet wheel has {HEAD ~ an annular groove} around {TAIL ~ the periphery}, and a plurality of teeth equiangularly spaced around the annular groove 
around
The ratchet wheel has { HEAD ~ an annular groove } around { TAIL ~ the periphery } , and a plurality of teeth equiangularly spaced around the annular groove
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH