The height of teeth of the toothed arch block is approximately equal to the height of {HEAD ~ teeth} on {TAIL ~ the ratchet} wheel 
on
The height of teeth of the toothed arch block is approximately equal to the height of { HEAD ~ teeth } on { TAIL ~ the ratchet } wheel
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH