Driver 1 rotates about fixed axis A and carries two pins a which consecutively engage straight radial slots d of Geneva wheel 2. Geneva wheel 2 rotates about fixed axis B and its slots are located symmetrically at angles of 90° between the axes of adjacent slots. Driver 1 has concentric locking surfaces b and c which engage concave locking surfaces e of Geneva wheel 2 during its idle periods. The radii of pins a are equal (A͞D=A͞E). When driver 1 rotates continuously at uniform velocity, Geneva wheel 2 rotates intermittently at nonuniform velocity and has four rotation periods and four idle periods. Locking surfaces b, c and e prevent unintentional rotation of Geneva wheel 2 during its idle periods. Geneva wheel 2 has two different idle periods. One corresponds to rotation of driver 1 through the angle ϕ₁'=ψ-90° and the other to its rotation through the angle ϕ₁''=270°-ψ, where ψ is the angle between lines AD and AE. Driver 1 and Geneva wheel 2 rotate in opposite directions.
$2627$PG,GW$