Pin wheel 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 d are located symmetrically at angles of 60° between the axes of adjacent slots. Pins a are located opposite each other at equal distances from axis A. Pin wheel 1 has concentric locking surfaces b which engage concave locking surfaces e of Geneva wheel 2 to prevent its unintentional rotation during its idle periods. When pin wheel 1 rotates continuously at uniform velocity, Geneva wheel 2 rotates intermittently at nonuniform velocity with six rotation periods tᵣ and six idle periods tᵢ. The time of one revolution of pin wheel 1 is T=2tᵣ+2tᵢ. The angles of rotation of pin wheel 1 corresponding to an idle and a rotation period of Geneva wheel 2 are ϕᵢ=60° and ϕᵣ=120°. The angle of rotation of Geneva wheel 2 to one half revolution of pin wheel 1 is ϕ_G=60°. The rotation and idle factors are p=tᵣ/T=0.3333 and q=tᵢ/T=0.1667. The working time coefficient is k=p/q=2. The transmission ratio from the Geneva wheel to the driver is i₂₁=ω₂/ω₁=(λ(cos(ϕ₁)-λ))/(1-2λ cos(ϕ₁)+λ²) where λ=R/L, R is radius A͞D, L is centre-to-centre distance A͞B, ϕ₁ is the instantaneous angle of rotation of pin wheel 1, and ω₁ and ω₂ are the angular velocities of pin wheel 1 and Geneva wheel 2. Pin wheel 1 and Geneva wheel 2 rotate in opposite directions.
$2642$PG,GW$