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