First pivot mount 40 and second pivot mount 41 are formed on {HEAD ~ an upper surface} 50 of {TAIL ~ the support beam} 31 
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First pivot mount 40 and second pivot mount 41 are formed on { HEAD ~ an upper surface } 50 of { TAIL ~ the support beam } 31
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH