摘要 |
A structure of a variable transmission device includes an input shaft driven by a motor to perform alternate rotation having a gear on a middle portion, an output shaft having a pair of gears secured to the upper and lower ends respectively and a speed changing shaft positioned between the input and output shaft having a pair of gears rotatably secured to two ends respectively meshed with the gears of the output shaft and a spiral outer periphery on a middle portion rotatably and slidably engaged with an inner threaded gear which meshes with the teeth of the gear of the input shaft. Thereby, the rotation of the input shaft drives the inner threaded gear to rotatably slide about the spiral outer periphery to force the gears of the speed changing shaft to rotate and in turn to drive the gears of the output shaft to rotate in concert with the input shaft.
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