Rocker arm 4 of four-bar linkage GBCD has collar a encircling fixed round eccentric 3. Rocker arm 4 is connected by turning pair E to connecting rod 5 which, in turn, is connected by turning pair F to piston 2. Piston 2 slides in fixed guides p-p. When crank 1 rotates about fixed axis D, piston 2 reciprocates. The stroke of piston 2 is varied by turning eccentric 3 and clamping it rigidly at the required position on axis A.
$1526$SC,6L$