According to the present invention, the constructions and {HEAD ~ shapes} of {TAIL ~ the welded portions} are simplified 
of
According to the present invention , the constructions and { HEAD ~ shapes } of { TAIL ~ the welded portions } are simplified
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH