At least one of the arm members is designed to pivot toward and grippingly engage the receptacle when {HEAD ~ the receptacle} is positioned on {TAIL ~ the receptacle securing device} 
is positioned on
At least one of the arm members is designed to pivot toward and grippingly engage the receptacle when { HEAD ~ the receptacle } is positioned on { TAIL ~ the receptacle securing device }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL