{HEAD ~ The drive mechanism} may also include {TAIL ~ either a set} of timing gears or a spring coupling to achieve the desired intermittent rotation 
{ HEAD ~ The drive mechanism } may also include { TAIL ~ either a set } of timing gears or a spring coupling to achieve the desired intermittent rotation
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH