The axis elevating means carries {HEAD ~ a support surface} which is accessible by {TAIL ~ a human operator} 
is accessible by
The axis elevating means carries { HEAD ~ a support surface } which is accessible by { TAIL ~ a human operator }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL