Cutter driver of improved lawn grass cutter

The utility model relates to a cutting knife driver of an improved lawn grass cutter, which belongs to the technical field of a power-driven revolving knife grass cutter. The utility model mainly comprises a belt pulley and a pinch roller. The utility model is characterized in that the pinch roller is connected with a curved leaf spring by a movable supporting frame, the curved leaf spring is positioned on the point of the belt pulley and is provided with a brake hoof, and the pinch roller is connected with a push rod by a steering arm. The brake hoof on the curved leaf spring is pushed to the belt wheel under the action of linkage of the curved leaf spring; thereby, the belt wheel is braked, and the safety performance of a cutting knife is guaranteed; meanwhile, a complete machine can be caused to accord with mandatory standard. The utility model has the advantages of rapid knife braking and convenient operation.