Drum B of the electric hoist is driven from shaft A to which gear 1 is keyed. Gear 1 meshes with planet gears 2 which are rigidly attached to planet gears 3. Gears 3 mesh with internal gear 4 of drum B. Planet gears 2 and 3 are connected by turning pairs to carrier 5 which is rigidly attached to gear 6. Gear 6 meshes with gears 7 which rotate about the studs of fixed member 9 and mesh with internal gear 8. Gear 8 is also rigidly attached to drum B. The speeds n₁ and n₈ of shaft A and drum B (in rpm) are related by the equation n₈=-n₁(z₁z₃z₆)/(z₂z₄z₆+z₂z₄z₈+z₁z₃z₈) where z₁, z₂, z₃, z₄, z₆ and z₈ are the numbers of teeth of gears 1, 2, 3, 4, 6 and 8. Thus, drum B and shaft A rotate in opposite directions, with the drum running at a lower speed so that it hoists the load with a large mechanical advantage.
$2953$CxG,MH$