{TAIL ~ a frame} mounted to said housing for {HEAD ~ vertical movements} and located adjacent to said floor opening 
{ TAIL ~ a frame } mounted to said housing for { HEAD ~ vertical movements } and located adjacent to said floor opening
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH