{HEAD ~ A suitable control lever} 142 controls engagement/disengagement of {TAIL ~ cog wheel} 140 to transmit rotative power 
{ HEAD ~ A suitable control lever } 142 controls engagement / disengagement of { TAIL ~ cog wheel } 140 to transmit rotative power
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH