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