Ratchet wheel 4 rotates about fixed axis B. Lever 1 turns about fixed axis A and is connected by turning pairs C and D to pawls 2 and 3. When lever 1 is oscillated about axis A, pawls 2 and 3 turn ratchet wheel 4 intermittently clockwise. Pawls 2 and 3 also serve as locks preventing reverse rotation of wheel 4. In one complete oscillation of lever 1, ratchet wheel 4 turns through the angle α=720°/z, where z is the number of teeth on wheel 4.
$1790$LR,4L$