The release member releases {HEAD ~ a force} pulling {TAIL ~ the retractable unit} when the retractable unit is moved to the closed position 
pulling
The release member releases { HEAD ~ a force } pulling { TAIL ~ the retractable unit } when the retractable unit is moved to the closed position
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH