angular position determining means connected to said engaging means for rotation therewith and for providing {HEAD ~ an indication} of {TAIL ~ the angular position} of said engaging means; and 
of
angular position determining means connected to said engaging means for rotation therewith and for providing { HEAD ~ an indication } of { TAIL ~ the angular position } of said engaging means ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH