What is the working principle of a torque wrench?

[DylanAnn]

Torque wrench working principle: The torque wrench is designed based on the bending principle of beams, the torsion principle of torsion bars, and the compression principle of helical springs, capable of measuring the torque applied to a nut. Torque wrenches can be categorized into: preset torque wrenches, digital torque wrenches, MINI torque wrenches, fixed-value torque wrenches, dial torque wrenches, sector torque wrenches, and special torque wrenches. The torque wrench first sets an upper limit for the required torque value. When the applied torque reaches the set value, the wrench will emit a clicking sound or bend slightly at the connection point, indicating that the fastener is tight and no additional force should be applied.

[FranciscoDella]

I often use a torque wrench when repairing cars, which operates based on a spring mechanism. First, you adjust the dial on the wrench to the required torque value, such as 100 Nm for the car's hub nuts. As you turn the wrench, the applied force gradually compresses the internal spring. When the force reaches the preset value, the spring suddenly releases, and the wrench makes a clear 'click' sound or the handle moves, signaling you to stop. This prevents over-tightening, which can damage the threads, or under-tightening, which may lead to accidents. Compared to a regular wrench, it allows precise control, preventing inexperienced users from overtightening, especially in car repairs, where it’s highly practical for protecting bolts and extending component lifespan. For daily use, remember to calibrate the wrench regularly to ensure accuracy, as errors can accumulate over time. I’ve seen many screws stripped due to this, leading to serious consequences. Though a small tool, it’s crucial for safety.

[LaDelaney]

When I first started learning car maintenance, I was figuring out how to operate a torque wrench. The master taught me to set the scale and then slowly twist until I felt or heard a 'click' feedback. It turns out there's a ratchet system inside that disengages when the torque reaches the set value, reminding you that the force is sufficient. Some wrenches have a digital display for easier reading. If you tighten screws randomly during repairs, they can either be over-tightened and crack or too loose and fly off at high speeds. The key is to refer to the manual for the set value and not rely on feeling. During use, I also found that the wrench head can be replaced with different sockets to fit various bolt sizes, saving the need for extra tools. Overall, the tool is simple and reliable, helping to develop good habits.

[VanAlaina]

The torque wrench utilizes the principle of leverage. Force applied to the arm generates torque, while an internal adjustable mechanism sets the critical point. As you gradually increase the applied force, the spring load reaches the preset value, triggering a release action that provides a signal. This ensures consistent torque application, preventing uneven stress on automotive components that could lead to fatigue issues. The tool clearly demonstrates the physical relationship between force and distance through its clever yet practical design. When applied to automotive fastening, it can optimize performance and reduce vibration.