When shearing thick strip or billet with hydraulic shearing machine, in order to ensure the smooth shear section of the rolled piece after shearing, the hydraulic shearing machine with blade translational motion is often used. The crank rotary lever type (also known as crank connecting rod type) hydraulic shearing machine is one of such hydraulic shearing machines. Figure 9-3 (page P301) shows the structure of the crank-connecting rod hydraulic shear. The tool holder 1 is made into a lever shape. One end of the tool holder 1 is fixed at the end of the crank shaft 2, and the other end is connected with the swing rod 3. When the crank shaft 2 (i.e. the crank) rotates, the tool holder 1 moves horizontally, and the blades fixed on the tool holder can be rolled vertically or approximately vertically. Because the blade of this kind of hydraulic shearing machine is perpendicular to the rolled piece when shearing the rolled piece, the shearing section is relatively flat. When shearing plate and strip, inclined blade can be used to reduce shearing force. The disadvantage of this kind of hydraulic shearing machine is that its structure is complex, the dynamic characteristics of the hydraulic shearing mechanism are not good, and the moving speed of the rolling piece can not be too fast. The crank-connecting rod hydraulic shearing machine used in small section mill has a rolling speed of less than 5 m/s and a thickness of 30-70 m M.