A self centering construction 19 wherein said axial movement means comprises a second liquid spring operable in tension and compression on {HEAD ~ each} of {TAIL ~ said liquid springs} 
A self centering construction 19 wherein said axial movement means comprises a second liquid spring operable in tension and compression on { HEAD ~ each } of { TAIL ~ said liquid springs }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL