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