Upper point limiting accurate positioning device of plate shearing machine

The utility model discloses an accurate positioning device for limiting an upper arrival point of a plate shearing machine. The device comprises a piston rod and a cylinder body, a knife rest is arranged at one end of the piston rod, the other end of the piston rod is arranged in the cylinder body, an impact type limiting mechanism is arranged at the bottom of the cylinder body, and the impact type limiting mechanism is connected with a trigger signaling component of a numerical control system of the plate shearing machine. According to the utility model, a knife rest top end collision limiting mode adopted for upper-point signaling of the existing plate shearing machine can be effectively avoided; the system has the problems that a limiting mounting position is difficult to position, a shearing angle is large and cannot be collided upwards after limiting mounting is high, the opening height of a knife rest is insufficient due to low shearing angle, the front-back position of the kniferest is affected by adju