Compressed air, admitted through channel a, annular groove d of the piston and channel b, moves piston 1 to the left. Air from the left end of the cylinder is discharged to the atmosphere through port f. At the end of its working stroke, piston 1 closes channel b and discharge port f, and opens channel g and discharge port e. Then compressed air is admitted through channel a, annular groove d and channel g, effecting the return stroke of piston 1.
$3778$SHP,FD$