How a torque wrench works

　　How a torque wrench works

Torque wrench, also called torque wrench, torque wrench and torque adjustable wrench, is a type of wrench and is generally divided into three categories: manual torque wrench, pneumatic torque wrench and electric torque wrench. Fixed-torque wrenches are widely used in assembly lines that have strict requirements on tightening processes, so that the torque values of each fastener of the product are consistent, and the quality of the produced products is guaranteed.

The principle of a torque wrench (torque wrench) making a clicking sound is very simple and can be understood in the following steps:

1. After the torque wrench makes a “knocking” sound, it indicates that the torque value you require has been reached;

2. The “knock” produced by the torque wrench is produced by its internal torque release structure, which is composed of three structures: a pressure spring, a torque release joint, and a torque ejector rod.

3. First set the required torque value on the torque wrench (the spring is set on the ejector rod to apply pressure on the torque release joint), lock the torque wrench, and start tightening the bolts. When the bolt reaches the torque value (when the torque used is greater than the pressure of the spring), an instantaneous disconnection effect will occur. At the moment when the disengagement effect occurs, the joints tap and the metal shell of the wrench makes a “clicking” sound. This is used to confirm the reminder function of reaching the torque value (actually, it is the same principle as when our arm joint is bent at 15 degrees and placed in an iron pipe and straightened instantly, it will hit the steel pipe).

The above are the most commonly used manual torque wrenches. In addition, there are electric torque wrenches, pneumatic torque wrenches, etc.

At present, it is divided into mechanical audio alarm type, digital display type, pointer type (dial type), and sliding type (self-sliding type). Among them, the mechanical audio alarm type uses the lever principle. When the torque reaches the set torque, a “bang” will appear. The sound of “torque wrench” mechanical collision, after which the wrench will become a dead end, equivalent to a dead wrench. If you apply more force, over-force will occur.

The digital display type and the pointer type (dial type) are similar. They both visualize the acting torque. The current digital display and pointer work on the basis of mechanical audio alarm type torque wrenches. The slipping type (self-slip type) uses Overload protection, automatic unloading mode, when the torque reaches the set torque, it will automatically unload the force (the sound of mechanical collision will also occur), and then the wrench will automatically reset. If you apply more force, it will slip again, and there will be no over-force phenomenon. This type of product is a new sentiment product that has only appeared in the past 1 or 2 years. The mechanical audio alarm type is the mainstream product in the current market, mainly reflected in its low price. The other three types are relatively expensive. However, due to various industries’ demand for The requirements in this area are getting higher and higher, and with the requirements of efficiency, the demand for digital display type, pointer type (dial type) and sliding type (self-slip type) will become higher and higher.