{TAIL ~ The center roller} and the first edge roller are rotatably supported on {HEAD ~ a common axis} 
{ TAIL ~ The center roller } and the first edge roller are rotatably supported on { HEAD ~ a common axis }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD