Research And Production Of Flatness Gauge Of Rail Welding Joints

With the development of high-speed railway in China, rail welding quality requirements have become more sophisticated. Smoothness of welded joints is an important indicator of the quality evaluation of rail welded joints, and its value is required in 0～0.2mm. Now the smoothness of welded joints is measured with type scale, ruler and E-scale, but it takes time and hard work when the type ruler and a ruler was used to measure the rail straightness, and there is a great human error. E-scale is small, high precision and automation, easy to be used and so on. However, the most of E-scale used in china depend on the product import. It is strategically important to develop the Electronic measuring instrument systems with self-owned intellectual property rights.Based on a lot of related documents, in this article, the hard and soft system of a new style of E-Class rail foot flatness measuring instrument was designed and made. The Laser displacement sensor was mounted on the guide of mechanical device which can be fixed and remove easily. The Laser displacement sensor which was driven by a DC motor can measure the displace from rail surface of welded joints to sensor. The relative position between laser sensor and steel trail is measured by rope-type displacement sensor. Considering the designed mechanical device, the driving circuit and control circuit of DC motor which used to drive the laser displacement sensor had been developed. The measured signal of laser displacement sensor was read into the computer through RS232 serial and the measured signal of rope-type displacement sensor was read into the computer by USB of USB7360 multifunction data acquisition card. On the basis of mechanical design and control circuit design, the soft of flatness measurement was developed. The movement of DC motor was controlled by computer, and the corresponding data were collected via RS232and USB. showed through graphical, and stored and processed at the same time. According to the input standard, it can be judged that the straightness of rail meets the standards or not.Measurement of the flatness of rail hand been finished by the rail foot flatness measuring instrument, it shows that the device designed can achieve the measure of Smoothness of welded joints.