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 surface a engages concave surfaces b to avoid unintentional rotation of gear 2 during its dwell periods. To each revolution of gear 1, gear 2 turns through an angle equal to ϕ=π/3. Due to the symmetrical arrangement of the teeth and locking features on gear 2 it has uniform intermittent motion when gear 1 rotates at uniform velocity.
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