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