Cam 1, consisting of two fingers, a and b, rotates about fixed axis A. Locking pawl 3 turns about fixed axis B and has lug e which enters the spaces between teeth d of wheel 2. Wheel 2 rotates about fixed axis C. When cam 1 rotates, its finger a turns wheel 2, one tooth at a time. Simultaneously, finger b raises pawl 3 to allow wheel 2 to turn. Pawl 3 locks wheel 2 against unintentional rotation during its dwell periods.
$3322$GrC,D$