wherein operation of the pushbutton causes the link and cam to move, the link moving in {HEAD ~ a direction} about perpendicular to {TAIL ~ the cams direction} of motion 
about perpendicular to
wherein operation of the pushbutton causes the link and cam to move , the link moving in { HEAD ~ a direction } about perpendicular to { TAIL ~ the cams direction } of motion
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH