Connecting rod 4 has collar b encircling round eccentric 1 which rotates about fixed axis A. Pin C of connecting rod 4 slides along slotted link 2 which is rigidly mounted on the upright. When eccentric 1 rotates about axis A, bar 3 reciprocates in a fixed guide. The bar stroke is varied by turning slotted link 2 about point F and clamping it rigidly in the required position.
$1528$SC,6L$