The article discusses the spatial lever mechanisms attached to the speed variator. The device of the mechanism is described that has the ability to change the transmission ratio in a wide range by converting rotary motion into translational motion and having the ability of reversibility. A kinematic investigation of mechanisms was carried out, where the tasks of direct and inverse kinematics were solved and the uniformity of the output shaft rotation has been proved, as well as the main kinematic characteristics of the links were determined. In the dynamic investigation of mechanisms was used the kinetostatic analysis, where the reactions in kinematic pairs and the ratio of the input and output moments on the mechanism depending on the transmission ratio were determined. Numerical analysis has confirmed the validity and correctness of the theoretical results.