Drum type switch-over mechanism for a speed change device

Abstract

An improved drum type switch-over mechanism for a speed change device including a speed change pedal shaft and a speed change drum both of which are rotatably supported in axial alignment with one another on a transmission case and which are operatively connected to one another by way of an intermittent feed mechanism so as to allow the speed change drum to be rotated by a unit angle in a predetermined direction on every reciprocatable rotation of the pedal shaft by a predetermined angle. The improvement consists in that the pedal shaft is located in axial alignment with an input shaft of the intermittent feed mechanism, that a sun gear is formed on the input shaft while a plurality of planet gears are mounted on the pedal shaft for meshing engagement with the sun gear, and that a ring gear meshing with the planet gears is firmly fixed to the transmission case. This arrangement of the switch-over mechanism enables the pedal shaft, the input shaft and the speed change drum to be disposed within a limited space, realizing a very compact structure of the switch-over mechanism, a substantial reduction of its mounting space and smaller design dimensions of the speed change device.