Lifehammer, also known as safety hammer, is an auxiliary escape tool in a closed cabin. It is usually installed in closed cabins such as automobiles where it is easily accessible. In emergencies such as fire or falling into water, it can be easily removed and broken glass windows and doors to escape smoothly.
Safety hammer is mainly used by its conical tip. Because the contact area of the tip is very small, the pressure of the contact point on the glass (not pressure, but pressure per unit area) is quite large when the glass is smashed by the hammer. This is similar to the principle of the thumbtack. The film is easily punctured and the car glass is subjected to a great deal of exterior work at that point. For tempered glass, a little cracking means that the stress distribution in the whole glass is destroyed, which causes numerous spider web cracks in an instant. At this time, only a few more strokes with a hammer can remove the glass fragments. The middle part of tempered glass is the strongest, while the corners and edges are the weakest. The best way is to hit the edges and corners of the glass with a safety hammer, especially in the middle of the upper edge of the glass. Once there is a crack in the glass, you can knock a few more times.
It is said that about 2 kilograms of pressure can break the edges of tempered glass without safety hammer, women's high heels are also a good thing, the heels are pulled up to smash the strength, the thinner the heels the better.2 Attention: If you take a long-distance bus, you'd better choose a seat closer to the safety door or the roof exit. If you like, you can look carefully at the instructions on how to open the safety door, because once an accident happens, you can't look at the instructions calmly.