{HEAD ~ the pushbutton} operable to store {TAIL ~ energy} in and to withdraw energy from the spacer spring while moving the contact arm between first and second equilibrium states 
{ HEAD ~ the pushbutton } operable to store { TAIL ~ energy } in and to withdraw energy from the spacer spring while moving the contact arm between first and second equilibrium states
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH