When choosing a seat belt, after determining which seat belt to choose, the performance and quality of the seat belt should be checked.
(1) Check the performance of the webbing. The webbing is the most important part of the safety belt. Its properties include the tensile strength, width, width shrinkage, elongation spinning, energy absorption, weather resistance, abrasion resistance, cold resistance, heat resistance, water resistance, and Fading, etc., its main performance indicators.
Performance index of webbing
Type of webbing Tensile strength (N) Width (mm) Width shrinkage% Elongation (%) Work per unit length (N.m/m) Work ratio%
Belt 2.67×104 >48 4 >20 >550 >50
Continuous webbing 2.22×104 >30 >800 >55
Shoulder strap 1.77×104 >40 >1100 >60
Load condition 19.4N 1.11×104N 1.11×104N initial load 196N maximum load 1.11×104N
Improving the energy absorption performance of the webbing can make the occupants suffer a lower deceleration and a smaller rebound during a collision. The energy absorption of a webbing is often expressed in terms of the work absorbed per unit length of elongation or the percentage of the absorbed work to the stored work, which is called the work ratio.
The tensile strength of the webbing after the heat resistance and cold resistance test shall not be lower than 80% of that before the day test, and must be at least 1.47×104N or more. The webbing shall be subjected to the abrasion resistance and water resistance test. The tensile strength of the webbing after the weather resistance test shall not be less than 60% of that before the test.
(2) Check the buckle. The buckle should be easy and reliable to install and remove, and the surface should be smooth without sharp edges and corners. The occupant can be taken off with one hand, and it should be easily loosened by a third party in an emergency, and its release force should be less than 137N.
(3) Check the length adjustment piece. The length adjustment piece is the same as the buckle. If it is a metal piece, it must be tested for corrosion resistance; if it is a plastic piece. To conduct a heat resistance test. The adjustment power under the specified conditions should be less than 49N.
