Even if {HEAD ~ the stopper} becomes {TAIL ~ slack} when the cover is closed, due to the action of the biasing member, this slack portion is received within the receiving portion 
becomes
Even if { HEAD ~ the stopper } becomes { TAIL ~ slack } when the cover is closed , due to the action of the biasing member , this slack portion is received within the receiving portion
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL 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