a second biasing means for biasing said {HEAD ~ guide member} in a direction projecting from {TAIL ~ said head} 
a second biasing means for biasing said { HEAD ~ guide member } in a direction projecting from { TAIL ~ said head }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL