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