Toggle mechanisms: Dynamics and energy dissipation

The dynamic performance of a toggle mechanism is investigated. Particular attention is given to (i) the collapse of the toggle in the presence of Coulomb friction, and (ii) the effect of a varying periodic force on the mechanism with damped elastic coupling. For case (i), a method utilizing both equations of motion and the kinetostatic analysis is outlined to solve for frictional torque and it is concluded that the performance of the mechanism under the influence of Coulomb friction depends highly upon the input energy to the system. It is shown that there is an optimum impulse speed almost equal to a defined version of the quasi-natural frequency of the system which can minimize the energy loss. For case (ii), a dimensionless grouping in terms of the forcing amplitude and the parameters of the system is found for determining the stability of the system. An approximate analytical solution for the time history of motion under the assumed condition is obtained.