At least two frame engaging members of the frame support structure are moved to position {HEAD ~ the side members} of {TAIL ~ the frame} in a desired configuration 
of
At least two frame engaging members of the frame support structure are moved to position { HEAD ~ the side members } of { TAIL ~ the frame } in a desired configuration
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH