means responsive to the reciprocable means for generating {HEAD ~ pulses} in {TAIL ~ response} to increments of movement of the reciprocable means 
in
means responsive to the reciprocable means for generating { HEAD ~ pulses } in { TAIL ~ response } to increments of movement of the reciprocable means
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH