Pin wheel 1 rotates about fixed axis A and carries pin a which consecutively engages 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. Pin wheel 1 has concentric locking surface b which engages concave locking surfaces e of Geneva wheel 2 during its idle periods. When driving pin wheel 1 rotates continuously at uniform velocity, driven Geneva wheel 2 rotates intermittently at nonuniform velocity and has four rotation periods t_r and four idle periods t_i. Locking surfaces b and e prevent unintentional rotation of Geneva wheel 2 during its idle periods. The time of one revolution of pin wheel 1 is T= t_r+t_i. The angles of rotation of pin wheel 1 corresponding to an idle and to a rotation period of Geneva wheel 2 equal ϕ_t=270° and ϕ_r= 90°. The angle of rotation of Geneva wheel 2 to each revolution of pin wheel 1 is ϕ_G= 90°. The rotation and idle factors are p=(t_r)/T=0.25 and q= (t_i)/T=0.75. The working time coefficient is k=p/q=0.33. The transmission ratio from the Geneva wheel to the pin wheel 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 ipin wheel 1 measured from line AB, and ω₁ and ω₂ are the angular velocities of pin wheel 1 and Geneva wheel 2. The maximum value of the transmission ratio is i₂₁=ω₂/ω₁=2.41. Coefficient χ characterizes aningular 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. Pin wheel 1 and Geneva wheel 2 rotate in opposite directions.
$2623$PG,GW$