The outer edge portion 7 is mounted on {HEAD ~ the cylindrical portion} 1A of the casing 1 through {TAIL ~ bolts}  
through
The outer edge portion 7 is mounted on { HEAD ~ the cylindrical portion } 1A of the casing 1 through { TAIL ~ bolts }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH