Jaw crusher is composed of frame, rotating jaw, eccentric shaft, jaw plate and plate knee, etc. The motor drives the eccentric shaft through V-belt, making the movable jaw do periodic movement according to the well timed track. The material is crushed in this process. The frame adopts whole cast steel structure or welding steel plate. Guard plates are installed on the left and right side of the frame, preventing the side frame wearing. Rotating jaw adopts moulding cast steel, which has movable jaw plate at front, the above part hang on the frame by the eccentric shaft and rotating shaft, the under part bear on the plate. Belt pulley with fly wheel and trough are installed at both side of eccentric shaft. The other side of plate knee bear on the adjust base. The plate supports the movable jaw, also it can cut off itself for safety when the load is increased, protecting the other part of the components. One spare plate is with the machine, which is used at the discharging opening. Adjust base is installed in the side trough of the frame, close to the adjust block. When the discharging opening need adjust, turn right of the screw nut with the spanner. Adjust base rise, the discharging opening becomes Small, otherwise, small instead.