{HEAD ~ This arrangement} allows {TAIL ~ crank arms} 6 to rotate along with axle 4, while crank handle 7 is kept stationary inside drum 5 
allows
{ HEAD ~ This arrangement } allows { TAIL ~ crank arms } 6 to rotate along with axle 4 , while crank handle 7 is kept stationary inside drum 5
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH