An assist mechanism aids movement of {HEAD ~ a retractable unit} reciprocally moving between {TAIL ~ an open and a closed position} and includes a pressing device, a stopper mechanism, an engagement member, a catch portion, and a release member 
reciprocally moving between
An assist mechanism aids movement of { HEAD ~ a retractable unit } reciprocally moving between { TAIL ~ an open and a closed position } and includes a pressing device , a stopper mechanism , an engagement member , a catch portion , and a release member
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL 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 OTH