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