{HEAD ~ Each roller gear} 86,87 comprises {TAIL ~ a rotating support plate} 90,89 respectively and two spaced rollers 92,91, respectively, rotatably mounted at diametrically opposite positions on the support plate 
comprises
{ HEAD ~ Each roller gear } 86,87 comprises { TAIL ~ a rotating support plate } 90,89 respectively and two spaced rollers 92,91 , respectively , rotatably mounted at diametrically opposite positions on the support plate
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH