{HEAD ~ The pressing device} presses {TAIL ~ the retractable unit} toward the open position in which the unit is extended 
{ HEAD ~ The pressing device } presses { TAIL ~ the retractable unit } toward the open position in which the unit is extended
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH