a toothed arch block mounted in {HEAD ~ said box end} and operatively associated with {TAIL ~ said ratchet wheel} 
a toothed arch block mounted in { HEAD ~ said box end } and operatively associated with { TAIL ~ said ratchet wheel }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL