Shear jack, also known as bracket jack, light and fast, is the main domestic car factories with the product, the principle is different., which is composed of an upper support rod and a lower support rod made of sheet metal.The cross section of the upper strut and the cross section of the lower strut at and near the teeth is a rectangle with an opening on one side, and the metal plates on both sides of the opening bend inward.The teeth on the upper support and lower support are made of a metal plate bent on both sides of the opening, and the teeth are wider than the metal plate.