At {TAIL ~ the equilibrium position}, the vent and vent follower are in {HEAD ~ direct relation} to one another 
At { TAIL ~ the equilibrium position } , the vent and vent follower are in { HEAD ~ direct relation } to one another
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH