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