Ratchet wheel 4 rotates about fixed axis D. Link 3 is the rocker arm of four-bar linkage ABCD and is connected by turning pair E to pawl 5 which engages wheel 4. Spring 7 holds pawl 5 in contact with ratchet wheel 4. In one revolution of crank 1 about fixed axis A, pawl 5 turns wheel 3 intermittently clockwise through the angle α=360°/z where z is the number of teeth on ratchet wheel 4. Pawl 6 and spring 8 prevent reverse rotation of ratchet wheel 4.
$1807$LR,6L$