Prismatic link 1 reciprocates in fixed guide a and has bevel b at its lower end. Sliding pawl 3 moves in fixed guides d-d. It carries roller 2 and has tooth e which engages the teeth of ratchet wheel 5. Wheel 5 rotates about fixed axis A. In the down stroke of driving link 1, its bevel b actuates roller 2 pushing pawl 3 to the right. Tooth e of pawl 3 turns wheel 5 counterclockwise through an angle corresponding to one tooth. In the up stroke of link 1, spring 4 returns pawl 3 to its initial position.
$2728$RG,ML$