To this end, each of {HEAD ~ the float members} is connected to {TAIL ~ a piston head} of one of the pumping units through a linkage system 
To this end , each of { HEAD ~ the float members } is connected to { TAIL ~ a piston head } of one of the pumping units through a linkage system
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH