Constant-diameter cam 1 rotates about fixed axis A and reciprocates follower 2 and slide 3 in fixed guides. As cam 1 rotates it first advances rack 4 into engagement with gear 5 which rotates about fixed axis C. Then slide 3, upon further rotation of cam 1, moves rack 4 crosswise, thereby turning gear 5. As cam 1 continues to rotate, it moves follower 2 in the reverse direction, disengaging rack 4 from gear 5 and advancing tooth a, rigidly attached to follower 2, into a tooth space of gear 5. This locks gear 5 against unintentional rotation during its dwell period Finally cam 1 returns slide 3 and rack 4 to the initial position.
$3323$GrC,D$