The third arm 48, via its lobe section 50, permits linear movement in {HEAD ~ the directions} of {TAIL ~ the Y axis} 
of
The third arm 48 , via its lobe section 50 , permits linear movement in { HEAD ~ the directions } of { TAIL ~ the Y axis }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL