wherein {HEAD ~ the pair} of fifth rollers sandwiches the pair of second bent parts and is mounted so as to slidably contact {TAIL ~ the pair} of second bent parts of the intermediate rail 
wherein { HEAD ~ the pair } of fifth rollers sandwiches the pair of second bent parts and is mounted so as to slidably contact { TAIL ~ the pair } of second bent parts of the intermediate rail
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH