Hinge mechanisms ⁠

Everyone has seen how the car wind­screen wipers sweep the water away quickly But did you ever think about how they work? There is only one fixed point, it is attached to the long arm of a lever with a brush that adheres to the glass. If there is an engine that can operate this mech­a­nism, it must turn in one direc­tion, then stop suddenly and turn in the oppo­site direc­tion. But how it is actu­ally built on the wiper mech­a­nism?

If you open the hood you can see that the wiper motor always rotates in the same way, all the time when it is acti­vated. But it is a planar hinge mech­a­nism, called wind­screen trape­zoid, that rotates now in one direc­tion, now in the oppo­site one.

What is a planar hinges mech­a­nism? In short, it is made of bars of different lengths arranged on a plane and connected at their ends by nails. In prac­tice we encounter them every­where. The research on hinges mech­a­nism in math­e­matics began at the time of the inven­tion of the steam engine by James Watt and continue in our time. Math­e­mati­cians of the twenty-first century proved the “signa­ture theorem”: there is a planar hinges mech­a­nism that forges your signa­ture with any preci­sion.

In the films of the Hinges mech­a­nisms Section we will see some inter­esting facts of the history of the devel­op­ment of the hinges mech­a­nisms.