how would someone rig a mechanism like this? i mean the links that are driven by the teeth
Use inverse kinematics: one of the arms’ rotations is all you need to totally define the position and rotation of the half of the claw it holds, and since the halves are linked together with gears, you only need one channel to control the whole grip. Look at the attached file: only the x-rotation of one bone (“Control Arm”) controls the whole claw apparatus.
Claw IK.blend (406 KB)
Indeed. Even though “at first blush” you presume that you should animate how the device actually works … the motor “pushes” the gear which closes the arm … the best way is to do exactly the opposite: animate the final motion that you want (“the grip”), and let everything else follow it. In this case also don’t be ashamed to separately animate the magnet-pull if that’s simplest. It simply has to look right, not be right.
thanks, i will post what i do in the next days…