A cone-pulley with steps 1, 2, 3 and 4 is rigidly attached to (or integral with) gears 8 and 9, and they all rotate freely about shaft 5. Gears 8 and 9 are in constant engagement with gears 12 and 11 which rotate freely about intermediate shaft 14. Gear 10 rotates freely about shaft 5 and is in constant engagement with gear 13 which is keyed to shaft 14. Clutches 6 and 7 slide along square guides a and b of shafts 5 and 14. If clutch 6 is engaged to the cone-pulley and clutch 7 is disengaged, four different transmission ratios can be obtained, depending on which step, 1, 2, 3 or 4, a belt is put. Thus i₁=R/R₁, i₂=R/R₂, i₃=R/R₃ and i₄=R/R₄ where R is the radius of the driving pulley and R₁, R₂, R₃, and R₄ are the radii of pulley steps 1, 2, 3 and 4. If clutch 6 is engaged to gear 10 and clutch 7 to gear 11, four more different transmission ratios can be obtained. Thus iᵢ₅=iᵢ (z₁₁/z₉)(z₁₀/z₁₃) where i is 1, 2, 3 or 4, and z₉, z₁₀, z₁₁ and z₁₃ are the numbers of teeth of gears 9, 10, 11 and 13. Finally, if clutch 6 is engaged to gear 10 and clutch 7 to gear 12, the last four different transmission ratios can be obtained. Thus iᵢ₅=iᵢ (z₁₂/z₈)(z₁₀/z₁₃) where i is 1, 2, 3 or 4 and z₈, z₁₀, z₁₂ and z₁₃ are the numbers of teeth of gears 8, 10, 12 and 13. Thus, when the driving shaft rotates, driven shaft 5 can have any one of twelve different speeds.
$2865$CxG,SR$