Gear 1 is keyed to shaft e, rotates about fixed axis A-A and has two toothed rims a and b with equal numbers of teeth. Rim a meshes with planet gear 6, and rim b with planet gear 7. Gear 6 rotates about axis B on a stud carried by brake drum 2 and meshes with internal gear 9. Gear 7 rotates about axis C on a pin of carrier 8 and meshes with internal gear 5 of brake drum 3. Internal gear 9 is keyed to carrier 8. Driven gear 4 is keyed to carrier 8 and rotates about axis A-A on shaft e. The numbers of teeth of gears 5, 6, 7 and 9 should satisfy the conditions: z₆=z₇ and z₅=z₉. The speeds n₄ and n₁ of gears 4 and 1 are related, for the case of forward rotation when a braking force is applied to drum 2, by the equation n₄=n₁z₁/(z₁+z₅). For reverse rotation, when a braking force is applied to drum 3, n₄=-n₁z₁/z₅ where z₁, z₅, z₆, z₇ and z₉ are the numbers of teeth of gears 1, 5, 6, 7 and 9.
$2879$CxG,PR$