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