Gears 1 and 2 rotate about fixed axes A and B. When driving gear 1 rotates continuously clockwise, driven gear 2 rotates intermittently with dwells. Concentric locking surfaces a engage concave surfaces b to avoid unintentional rotation of gear 2 during its dwell periods. Due to the different numbers of teeth at various parts of gear 1 and different lengths of the various concentric surfaces a, as well as of the corresponding tooth spaces and concave surfaces b on gear 2, the latter has nonuniform intermittent motion when gear 1 rotates at uniform velocity.
$2379$SG,D$