Ratchet wheel 1 rotates clockwise about fixed axis A. Pawls 2 and 3 turn about fixed axes B and C. The lengths of the pawls and the positions of axes B and C are such that when either pawl engages a tooth of wheel 1, the other pawl is at the middle of the pitch between two adjacent teeth. The pawls prevent reverse rotation of wheel 1 by more than one half pitch. The provision of two pawls is equivalent to doubling the number of teeth on ratchet wheel 1.
$2709$RG,4L$