{HEAD ~ The support frame} 12 comprises {TAIL ~ a pair} of side rails 20 and 22 which are welded to two lateral section members 24 and 26 in a rectangular shape 
comprises
{ HEAD ~ The support frame } 12 comprises { TAIL ~ a pair } of side rails 20 and 22 which are welded to two lateral section members 24 and 26 in a rectangular shape
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH 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 OTH OTH OTH