{TAIL ~ A chain grate} 8 is driven by {HEAD ~ sprockets} 10, 12 which rotate as denoted by the curved arrows 
{ TAIL ~ A chain grate } 8 is driven by { HEAD ~ sprockets } 10 , 12 which rotate as denoted by the curved arrows
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH