Link 1 turns about fixed axis B and is connected by turning pairs D and C to pawls 2 and 3 which engage ratchet wheel 6. Wheel 6 rotates about fixed axis A. When link 1 oscillates, pawls 2 and 3 alternately turn ratchet wheel 6 one tooth. Adjustable screw stops 4 and 5 limit the movement of the pawls to keep them from skipping teeth of the ratchet wheel.
$1850$LR,FD$