{HEAD ~ Each pair} of {TAIL ~ ground wheels} 16 is mounted to the rear end of an arm 18 that is positioned between the legs of, and pivotally attached to, a main channel like arm 20 
of
{ HEAD ~ Each pair } of { TAIL ~ ground wheels } 16 is mounted to the rear end of an arm 18 that is positioned between the legs of , and pivotally attached to , a main channel like arm 20
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH