d) means for regulating the speed of movement of said door between the open position and closed position; comprising buffer means for retarding the speed of movement of {TAIL ~ said door}, biasing means for changing {HEAD ~ speed} of closure and reservoir means for containing viscous fluid; and 
d ) means for regulating the speed of movement of said door between the open position and closed position ; comprising buffer means for retarding the speed of movement of { TAIL ~ said door } , biasing means for changing { HEAD ~ speed } of closure and reservoir means for containing viscous fluid ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH