Project

Columbia Vector Technologies has developed a continuously variable transmission (CVT) that is mounted and has been tested on a bicycle. The target audience of the system is an end-user who uses their bicycle for recreational riding or commuting in city terrain. The advantages a CVT provides over a traditional derailleur system is the lack of intermittent shifting loss and a simplified shifting process for the operator. The novel CVT design proposed aims to solve this issue by eliminating the commonly accepted use of belts in CVTs, which slip at high torques, and instead utilizes a ratcheting mechanism. The gear ratio is varied by changing the moment applied to a lever arm that drives an output crank. This lever arm only engages with the output crank in the forward direction as it moves back and forth. In addition, the non-constant RPM output can be used to the advantage of pedaling, making riding bicycle a smoother experience.