Measuring tape is mainly composed of eight parts: shell, ruler bar, brake, ruler hook, lift belt, ruler spring, anti-fall protective sleeve and labeling. The specific functions are as follows:

1. Shell: ABS new plastic, shiny appearance; Resistant to fall, wear and deformation.

2, ruler: the thickness of 10 wire (0.10mm) 50# grade steel strip;

3. Braking: with upper, side and bottom three-dimensional braking, hand control feeling stronger.

4, ruler hook: rivet ruler hook structure, not easy to deformation, to ensure more accurate measurement.

5, belt: rubber, nylon two kinds; High quality; Strong and durable, feel good.

6, ruler spring: generally 50# carbon steel, 65# manganese material: strong toughness, high accuracy.

7, anti fall protective cover: high quality plastic, prevent falling and collision damage, enhance durability.

After the tape measure is pulled out, the fixed tape measure can be rolled up because there is a spring in the tape measure. When you pull out the measurement length, you actually elongate the length of the ruler and the spring. Once the measurement is completed, the spring in the tape measure will automatically contract, and the ruler will also contract under the action of the spring force, so the tape measure will be rolled up.

The steel tape measure can be used as follows:
(1) When measuring with a tape measure, hang the ruler hook on the edge of the tested piece. Do not lean forward or back or side to side when using. If the diameter needs to be measured but cannot be measured directly, the diameter can be obtained by measuring the circumference of the circle.

(2) when measuring with steel tape, the tension should not be too large. The length of the ruler is based on the measured value under the condition of 20℃ and 50N tension standard. Therefore, the pulling force should be consistent with the pulling force during verification, so as to reduce the error.

(3) When steel tape measure is used in different temperature environments, the measured value should be converted into 20℃ value through the linear expansion formula.