A force modifying member rotatable about a fixed axis is provided and includes first and second outwardly facing {HEAD ~ surfaces} of predetermined lengths which curve about {TAIL ~ the axis} 
A force modifying member rotatable about a fixed axis is provided and includes first and second outwardly facing { HEAD ~ surfaces } of predetermined lengths which curve about { TAIL ~ the axis }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL