Gear 1 rotates about fixed axis A and meshes with gear 4 which is rigidly attached to (or integral with) connecting rod 3. Crank 5 rotates about axis A and is connected by turning pair B to connecting rod 3 which, in turn, is connected by turning pair C to slider 2. Slider 2 moves along fixed guides a-a. When driving gear 1 rotates about axis A, slider 2 reciprocates with one forward and one back stroke to two revolutions of gear 1. Thus the transmission ratio from gear 1 to crank 5 is i₁₅=ω₁/ω₅=2 where ω₁ and ω₅ are the angular velocities of gear 1 and crank 5.
$2421$LrG,5L$