{HEAD ~ Engagement} between {TAIL ~ the worm screw} 167 and the helical wheel 168 is maintained by the action exerted by the pinion 151 
between
{ HEAD ~ Engagement } between { TAIL ~ the worm screw } 167 and the helical wheel 168 is maintained by the action exerted by the pinion 151
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH