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