Abstract: This invention is a steplessly variable power transmission, comprising: an input driven planet gear, having axially disposed teeth, confined to reciprocate in straight diametrical channels in a output driving ring gear. When the teeth also move on a straight line as related to the housing, no rotary drive can be placed on the output ring gear, and the transmission is in a neutral mode. But, when the teeth are forced to curve, as related to the housing, the output gear must rotate accordingly. For example: if the input driven teeth veer away one degree, from a straight line, while the input rotates a full 360 degree rotation, then the input-output ratio is 360 to 1 underdrive. When the teeth path is a circle, the ratio is 1 to 1, but, the extreme lows, allow built-in overdrive gearing. The preferred embodiment has a stepless range from neutral to 3 to 1 overdrive. There are numerous methods to curve the path of the input driven teeth.

Abstract: The transmission has a housing enclosing an annular output gear with a drive member rotatably mounted coaxially therein. A drive gear carried by the drive member engages the output gear. A lug plate carried by the drive member interacts with a guide plate radially movable with respect to the housing to change the relative path traveled by the lugs and thereby the rotational ratio between the input and output gears. Transition between ratios is smooth and continuous over an almost infinite range of ratios.