{HEAD ~ The block member} moves from {TAIL ~ a first position} to a second position by contact with the slider sliding in a sliding direction to block and open the air passage 
{ HEAD ~ The block member } moves from { TAIL ~ a first position } to a second position by contact with the slider sliding in a sliding direction to block and open the air passage
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL 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 OTH