Thr mechanism is called parallelogram, if you make a paralelogram with four bars and fix one of them, the opposite one keeps parallel while moving any of the adjacents. You can see the mechanism in the second and third photos.
Thr mechanism is called parallelogram, if you make a paralelogram with four bars and fix one of them, the opposite one keeps parallel while moving any of the adjacents. You can see the mechanism in the second and third photos.