of opposing side walls 11 and opposing end walls 13 sometimes referred to as a basket the housing is mounted on springs 12 as shown in fig2 mounted to one of the opposing side walls 11 is a gear set including gears 14 16 and 18 the gears being in meshed relation opposing each of the gears on the opposite wall 11 is a wheel 15 shafts 21 extend through the assembly 10 and interconnect each of the gears with its opposing wheel 15 a motor 19 drives gear 14 e g via a drive belt and shiv arrangement indicated at 23 in a manner well known to the art gear 14 drives gear 16 which drives gear 18 and though connecting shafts 21 similarly drives wheels 15 mounted to each gear of gear sets 14 16 and 18 and opposing wheels 15 are weights 20 which will be more specifically described hereafter the gear wheels and attached weights are mounted on the outer sides of wall 11 as shown and a closed box 22 on the outer side of each wall 11 surrounds the gears or wheels and their weights 20 to provide lubrication of the gears and wheels a pool of low viscosity oil 24 is deposited in the box 22 at a level just below the bottom of the gears and wheels see fig2 a as indicated by the directional arrows the center gear 16 rotate opposite the side gears 18 20 the weights 20 are strategically.