{HEAD ~ First and second hubs} 15 and 16 are mounted on {TAIL ~ the hub support frame member} 13 for rotation about spaced generally parallel axes 17 and 18 
{ HEAD ~ First and second hubs } 15 and 16 are mounted on { TAIL ~ the hub support frame member } 13 for rotation about spaced generally parallel axes 17 and 18
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH