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