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