The present invention comprises one set of drive gears and one set of {HEAD ~ driven gears} which are in {TAIL ~ a constant mesh position} 
The present invention comprises one set of drive gears and one set of { HEAD ~ driven gears } which are in { TAIL ~ a constant mesh position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL