What should I do if the electric wrench suddenly fails?

The torque wrench operates by first reducing the motor's speed through a planetary gear system, which then transfers the power to the impact head. The two protruding heads on the impact head are driven by the trigger shaft, causing it to rotate and ultimately delivering the output power. This mechanism is essential for the toolâ€™s functionality during fastening tasks.

However, after prolonged use, the performance of the electric torque wrench tends to degrade over time. As usage increases, the output power gradually decreases, eventually leading to failure if not addressed. This decline in performance is often the result of internal wear and tear that accumulates with repeated use.

Through detailed disassembly and inspection, technicians discovered that all used torque wrenches exhibited significant wear on the shaft's working surface. The worn area forms a beveled edge at approximately 45 degrees relative to the original surface. This bevel causes the impact force acting on the trigger shaft during operation to be dispersed unevenly, which in turn affects the forces applied to other internal components of the wrench.

Based on these findings, it became clear that the primary cause of failure in the electric wrench is the severe wear on the shaftâ€™s working surface. To extend the lifespan of the tool, it is crucial to address this issue. Since the shaft experiences more wear than the impact head, solving the shaft wear problem is key. Once resolved, the wear on the impact head will also be significantly reduced.

To tackle this, the design was modified by replacing the solid shaft with a split-type structure. This allows the working surface of the shaft to be removed and replaced as needed, based on its condition. The replaceable working surface can be made from materials selected for their high mechanical properties, ensuring durability and performance. A high-carbon steel material was chosen, which undergoes quenching followed by medium-temperature tempering to achieve a balance of hardness and toughness. This ensures the component can withstand repeated impacts without breaking.

This modification enables mass production and long-term replacement with minimal effort. It offers a practical and cost-effective solution to the common problem of electric wrench failure. With this improvement, users can expect longer-lasting performance and fewer unexpected breakdowns during use.