to output shaft 220 and rotate in unison with upper and lower constant speed drums 216 and 217 which are rigidly connected with central cylinder 228 keyed into upper and lower inner rotors 222 and 223 are upper and lower torque gears 230 and 231 which freely rotate about shaft 220 mounted for rotation between lower plate 227 and upper constant speed drum 216 are three upper planetary gears 232 similarly mounted between upper plate 226 and lower constant speed drum 217 are three lower planetary gears 233 gears 232 and 233 mesh with respective torque gears 230 and 231 and all six planetary gears 232 and 233 are engaged for rotation in the area between upper and lower plates 226 and 227 in operation a clockwise rotation introduced by the upper inner rotor 222 rotating in the upper constant speed drum 266 urges the lower inner rotor 222 in the lower constant speed drum 217 to rotate counterclockwise and visa versa the interlinking unit 214 thus uses the drums and plates which are rigidly connected to the output shaft as a pivot point therefore when a driving torque is applied on one inner rotor while the other rotor is prevented from rotating it is as if a torque of twice the value of the driving torque is applied to the output shaft the drums and rotors thus comprise torque producing means when a driving torque is applied to one inner rotor and the other inner rotor is free to rotate no torque is imparted to the output shaft 220 and the total driving.