【Haichuan Chemical: Gain New Insights】Smart bolts that use color to indicate whether they are tightened properly
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Smart bolt that tells you whether it’s tightened using color
This bolt, named “Smartbolt”, allows one to determine its tightness simply by observing the color of the sensor disc on its head – the looser the bolt, the more distinct the red color displayed there; conversely, when the bolt is tighter, no color is visible and the area appears black. It also comes with a chart showing the relationship between color intensity and tightness, enabling easy determination of the bolt’s tightness at a glance.
How does this smart bolt achieve color change based on torque? The principle is that there is an iron rod with a red tip inside the bolt, which serves as a display. When the bolt is tightened, the bolt itself is subjected to a strong compressive force; this force is transmitted to the steel rod installed inside the bolt. The steel rod is stretched longer due to this compressive force, and this change is visible at the head of the bolt, which is why a red color can be observed during operation.
When the bolt loosens, the compressive force acting on it decreases, and the iron rod inside contracts as a result; only the dark circular hole at the head of the bolt can be seen. This phenomenon can also be understood as the stretching and contracting of a spring under external forces. These bolts also have a long service life; they can be reused, and their performance does not decline even when used in different environments. The Smartbolt is a truly excellent invention.
It’s a simple decision: if torque is required, it’s better to use a torque wrench