Classification and Structure of Reading Microscopes
1. Direct reading reading microscope: The scale on the line ruler is partially magnified by the objective lens and imaged on the dividing plate. If the line spacing is 1 millimeter, the magnification is equal to the distance of 100 divisions on the dividing plate, and the division value of 0.01 millimeters can be read through the eyepiece (magnification).
2. Marking mobile reading microscope: During measurement, rotate the micro motion handwheel to align the double engraved lines on the movable dividing plate with the line image of the line ruler. Read the percentile and percentile from the reading drum or other reading mechanism, and read the decile from the movable dividing plate. In order to avoid wear on the precision threads (or other micro mechanisms) on the micro motion handwheel, some microscopes make the double engraved lines on the movable dividing plate into double Archimedean spiral lines (c in the figure). The pitch of the double Archimedean spiral is equal to 1/10 of the line spacing of the ruler multiplied by the magnification of the objective lens, and there are 100 equally divided divisions engraved on its inner ring. Therefore, after aligning the line pattern, the deciles can be read from the fixed dividing plate, and the percentiles and thousandths can be read from the movable dividing plate.
3. Image mobile reading microscope: a movable optical element (such as plane parallel glass, wedge glass, or compensating lens) is added between the objective lens and the reticle. When moving such optical components, the line image of the line ruler will move. After aligning the line image with the double engraved lines on the fixed dividing plate, the values of the deciles, percentiles, and thousandths can be read from the fixed dividing plate and the movable dividing plate, respectively.
The principle of reading microscope
Firstly, perform zero adjustment and adjust the rotating nut to align the marking line with the full scale line on the X-axis. The rotating nut is divided into 50 grids, each grid is 0.01mm. The marking is on glass sheet A, and the X-axis is on glass sheet B. After the zero adjustment is completed, use a hardness tester to make an indentation on the workpiece. The force F applied by the hardness tester and the diameter D of the steel ball. Adjust the rotating nut so that the contact connected to the nut pushes the glass piece A to move in the X-axis direction, and it is tangent to the indentation twice. There is a spring connection between the glass piece A and the contact, which can expand and contract freely. The distance traveled by the marking line can be read out through a microscope, which is the diameter of the indentation. However, due to the irregular shape of the indentation, the workpiece needs to be rotated 90 ° and measured again to take the average value.
