Pawl 2 is connected by turning pair E to rocker arm 3 of four-bar linkage ABCD. When lever 1 oscillates about fixed axis A pawl 2 turns ratchet wheel 4 intermittently about fixed axis D. The angular velocity (angle of rotation) of the ratchet wheel can be varied by adjusting slider 5 along slot a of lever 1 and clamping it in the required position.
$1817$LR,6L$