Patent ID: 8668617

Claim:
A transmission system, comprising: rotation input means for delivering an input rotation into the transmission system, the rotation input means having a first input gear fixedly mounted thereon such that the first input gear rotates with, and at the same speed as, the rotation input means; a first ring gear adapted to engage with the first input gear on a first side of the first ring gear such that rotation of the rotation input means causes rotation of the first ring gear; a first output planet gear located coaxially with the first ring gear on a second side of the first ring gear; a second ring gear in engagement with the first output planet gear; a first sun gear mounted on a first end of a first transmission shaft and engaging the first output planet gear; a third ring gear mounted coaxially with the second ring gear for corresponding rotation; a second output gear engaging with the third ring gear and mounted on a first end of a second transmission shaft; a second input gear mounted on a second end of the second transmission shaft; a fourth ring gear mounted coaxially with the first transmission shaft and engaging the second input gear; a fifth ring gear mounted coaxially with the first transmission shaft; rotation output means for delivering an output rotation from the transmission system; a second planet gear engaging with the fifth ring gear and also with a second sun gear, the second sun gear located on a second end of the first transmission shaft; and rotatable modulation means for engaging at least one of the first transmission shaft or the second transmission shaft wherein a rotational velocity of the rotatable modulation means can be selectively varied to control a speed and/or direction of the output rotation relative to a speed and/or direction of the input rotation.