Since {HEAD ~ annular container flange} 18 has {TAIL ~ a downwardly sloped upper annular surface} to act as a cam surface and annular lower portion 38 is resiliently hinged, passage of annular lower portion 38 thereover is facilitated without the realization of great stress in annular frangible area 28 
has
Since { HEAD ~ annular container flange } 18 has { TAIL ~ a downwardly sloped upper annular surface } to act as a cam surface and annular lower portion 38 is resiliently hinged , passage of annular lower portion 38 thereover is facilitated without the realization of great stress in annular frangible area 28
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH