Rocking back and forth of {HEAD ~ the turnable member} acts through {TAIL ~ the clutch teeth} and sprags to turn the intermediate member 
acts through
Rocking back and forth of { HEAD ~ the turnable member } acts through { TAIL ~ the clutch teeth } and sprags to turn the intermediate member
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH