resilient means engaging said {TAIL ~ cover member} normally urging said {HEAD ~ cover member} towards said second position 
resilient means engaging said { TAIL ~ cover member } normally urging said { HEAD ~ cover member } towards said second position
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH