An upper housing portion has {HEAD ~ an integral pressure blade} for exerting {TAIL ~ a constant downward force} on the advancing protective covering 
for exerting
An upper housing portion has { HEAD ~ an integral pressure blade } for exerting { TAIL ~ a constant downward force } on the advancing protective covering
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH