This mechanism consists of a piston that, moving in a vertical direction, drives two jaws that rotate $90.$ It is therefore a radial gripper and in order for me to size it$,$ I need to derive the expression of the torque $\text{'}\text{'}$C$\text{'}\text{'}$ as a function of the angle of rotation of the jaw. I also need to derive the static and dynamic equilibrium equations of the two bodies.