Measurement is to describe the observed phenomena with data according to certain laws, that is, to describe things quantitatively. Measurement is the quantization process of non-quantized objects. In mechanical engineering, measurement refers to the experimental cognitive process of comparing the measured value with the standard quantity with the measuring unit, so as to determine the ratio between them.
Classification of commonly used measuring tools
A tool that compares the measured length with the known length to obtain the measurement result, which is called measuring tool for short. Length measuring tools include gauges, measuring tools and gauges. Traditionally, measuring tools that cannot indicate the magnitude are called gauges; A measuring tool that can represent numerical values and is used in hands is called a measuring tool; A measuring tool that can indicate size is called a meter.
Measuring tools can also be divided into mechanical, optical, pneumatic, electric and photoelectric types according to their working principles. This classification method is formed by the development history of measuring tools. However, some modern measuring tools have developed into measuring tools that combine the principles of precision machinery, optics and electricity with computer technology. Therefore, this classification method is only suitable for measuring tools with single working principle.
probe
The feeler gauge, also known as micrometer or thickness gauge, is one of the measuring instruments used to check the gap. The cross section is a right triangle with scales on the hypotenuse. The length of the short side is directly expressed on the hypotenuse by the acute angle, so that the size of the seam can be directly read.
Before using the feeler gauge, the dirt and dust on the feeler gauge and the workpiece must be removed first. When in use, one or several pieces can be overlapped and inserted into the gap, and it is appropriate to feel a slight delay. When measuring, the action should be light, and hard insertion is not allowed. It is also not allowed to measure parts with higher temperature.
When measuring the gap with a feeler gauge, select a feeler gauge with appropriate thickness and insert it into the gap to be measured, and then pull the feeler gauge while adjusting. If the resistance is too large or too small when pulling, the clearance value is less than or greater than the value marked on the feeler gauge; Tighten the lock nut until you feel a little resistance, and the value marked by the feeler gauge is the measured gap value.