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