The insert is pushed forward into {TAIL ~ the open jacket} which is pushed away from the opening blade permitting {HEAD ~ closure} by gravity 
The insert is pushed forward into { TAIL ~ the open jacket } which is pushed away from the opening blade permitting { HEAD ~ closure } by gravity
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH