Gear 1 rotates about fixed axis A-A and drives gear 7. Gear 3 rotates about axis A-A and drives gear 6. Carrier 4 rotates about axis A-A and drives gear 8. Gears 1 and 3 mesh with planet gears 2 and 5 which are rigidly attached together and are connected by a turning pair to carrier 4. The numbers of teeth of gears 1, 2, 3 and 5 satisfy the condition z₅=z₂+1 and z₁=z₃+1. The speeds n₆, n₇ and n₈ of gears 6, 7 and 8 (in rpm) are related by the equation n₈=n₆(z₁z₅)/(z₁z₅-z₂z₃)-n₇(z₂z₃)/(z₁z₅-z₂z₃) where z₁, z₂, z₃ and z₅ are the numbers of teeth of gears 1, 2, 3 and 5. Thus, with suitably selected numbers of teeth, the mechanism has a high transmission ratio.
$2903$CxG,DR$