Pin rack 1 carries pins a and slides in fixed guides b-b. Reversible pawl 2 turns about fixed axis A and its operative surface e, which engages pins a, is along a circular arc drawn from centre A. Pawl 2 can be turned to the position shown by dash lines. In the first position the pawl allows rack motion only to the left; in the second position - only to the right.
$2687$RG,3L$