Thus, rotation of the rod 109 will pivot the levers 24 and 25 about their pivot point to change {HEAD ~ the spacing} between {TAIL ~ the roller} 8 and 7 
between
Thus , rotation of the rod 109 will pivot the levers 24 and 25 about their pivot point to change { HEAD ~ the spacing } between { TAIL ~ the roller } 8 and 7
OTH OTH OTH 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