Pin wheel 1 rotates about fixed axis A and carries pin a which consecutively engages teeth d of wheel 2. Wheel 2 rotates about fixed axis B and has ten symmetrically located teeth d. When driving pin wheel 1 turns through the angle ψ, wheel 2 is turned through one tenth of a revolution. Unintentional rotation of wheel 2 during its idle periods is prevented by concentric surfaces b and c of pin wheel 1 which engage a tooth d of wheel 2 just before and just after its rotation period, and, in subsequent rotation, by surface b which engages two teeth d of wheel 2.
$2658$PG,FD$