The tape measure can be rolled up because there is a spring inside it. When you pull it out to measure the length, you actually elongate the length of the ruler and the spring. Once the measurement is finished, the spring inside the tape measure will automatically shrink, and the ruler will also shrink under the action of the spring force, so the tape measure will be rolled up.
Characteristics of the
First, the tape measure will not fail if it is deformed too much. Why it didn't fail; The spring in the tape measure is very long, and its complete relaxation to complete tightening interval is very large. The whole travel of the tape measure is included, and there is allowance at both ends, so the tape measure will not fail.
Two, there is no difference between pulling one meter and two meters. The spring of the tape measure is very thin, and the amount of deformation when it is tightened is very small, so the reaction force is very small, and the change of force is not felt when the ruler is pulled.
calibration
Measuring tape and measuring tape have the same metric scale, a centimeter of the measuring tape is equal to a centimeter of the measuring tape, except the black heart clothing merchants masked tape;
The reverse side of the tape measure is the municipal scale: city ruler, city inch; The front side of the tape measure is divided into two parts, with a metric scale (meter, centimeter) on one side and an English scale (foot, inch) on the other.
