When the tool is applied to a fastener, a bias load is applied along the axis of the tool and {HEAD ~ the drivetrain assembly} 71 translates rearward compressing the spring and contacting {TAIL ~ the pushbutton} 
translates rearward contacting
When the tool is applied to a fastener , a bias load is applied along the axis of the tool and { HEAD ~ the drivetrain assembly } 71 translates rearward compressing the spring and contacting { TAIL ~ the pushbutton }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL