Similarly the cam surface 31 on the lever arm circles about the rod 28 and projects in {HEAD ~ one direction} on {TAIL ~ one portion} 31 of the circle and projects in the opposite direction in the opposite portion 31 of the circle 
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Similarly the cam surface 31 on the lever arm circles about the rod 28 and projects in { HEAD ~ one direction } on { TAIL ~ one portion } 31 of the circle and projects in the opposite direction in the opposite portion 31 of the circle
OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH