When the end face of the nut is in contact with the end face of the workpiece, the resistance torque rises sharply, and the rotating helical groove makes the ball move backward with the active impact block overcoming the friction force and the pressure of the working spring, so that the active impact block and the driven impact block are engaged with each other. Teeth disengage. At this time, the driven impact block does not move, while the active impact block continues to move backward. After the teeth of the driven impact block are turned, the active impact block moves forward instantaneously due to the action of the working spring, and an angular acceleration is generated along the spiral groove, the active impact block hits the driven impact block, and the two teeth collide. Then the spiral groove makes the ball and the active impact block move back and disengage. In this way, the collision occurs again and again, and the required impact torque is obtained to tighten the nut.
If the power switch is connected to the reverse position, the nut can be unscrewed. The double-insulated single-phase series-excited electric wrench is equipped with two switches on the operating handle. One is a working switch, which is used to control start and stop; the other is specially set up to change the forward and reverse rotation of the armature, and the two switches cannot be reversed.
