Pin wheel 1 with pins a rotates about fixed axis A and periodically meshes with teeth d of sprocket 2 which rotates about fixed axis B. Wheel 1 has concentric concave locking surface b and sprocket 2 has symmetrically located concentric convex locking surfaces c. When driving pin wheel 1 rotates continuously, driven sprocket 2 rotates intermittently with dwells. During the dwells, locking surface b engages the corresponding convex surface c to prevent unintentional rotation of sprocket 2. To each revolution of wheel 1, sprocket 2 turns through the angle ϕ₂=π/2.• The profiles of teeth d of sprocket 2 are along curves which are equidistant to a hypocycloid of a circle. The transmission ratio from wheel 1 to sprocket 2 during the rotation periods of the latter is i₁₂=r₂/r₁ where r₁ and r₂ are the pitch radii of wheel 1 and sprocket 2. Wheel 1 and sprocket 2 rotate in the same direction.
$2600$PG,D$