Driver 1 rotates about fixed axis A and carries pin a which consecutively enbgages 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 90° between the axes of adjacent slots. Driver 1 has concentric locking surface b which engages concave locking surfaces e of Geneva wheel 2 durinig its idle periods. When driver 1 rotates continuously at uniform velocity, driven Geneva wheel 2 rotates intermittently at nonuniform velocity and has four rotation periods tᵣ and four idle periods tᵢ. Locking surfaces b and e prevent unintentional rotation of Geneva wheel 2 during its idle periods. The time of one revolution of driver 1 is T=tᵣ+tᵢ. The angles of rotation of driver 1 corresponding to an idle and to a rotation period of Geneva wheel 2 equal ϕᵢ=90° and ϕᵣ=270°. The angle of rotation of Geneva wheel 2 to each revolution of driver 1 is ϕ_G=90°. The rotation and idle factors are p=tᵣ/T=0.75 and q=tᵢ/T=0.25. The working time coefficient is k=p/q=3. 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 driver 1 measured from line AB, and ω₁ and ω₂ are the angular velocities of driver 1 and Geneva wheel 2. The maximum value of the transmission ratio is i₂₁=ω₂/ω₁=0.414. Coefficient χ characterizes the angular acceleration ε₂ of Geneva wheel 2 at the instants when pin a begins and ends engagement with a slot d and equals χ=ε₂/ω₁²=1. Driver 1 and Geneva wheel 2 rotate in the same direction.
$2625$PG,GW$