Although the safety hammer is small, it can play a very important role in key moments. In the case of an accident in the vehicle, the car is in a closed state, under the strong impact, the door twist can not be opened, the use of safety hammer to break the window glass, can help passengers escape, safety hammer at this time is actually a “life-saving hammer”.
　　A life-saving hammer, also known as a safety hammer, is an auxiliary escape tool installed in an enclosed cabin. It is generally installed in closed cabins such as cars where it is easy to get away. In the event of an emergency such as a fire in an enclosed cabin such as a car or falling into water, it is easy to remove and smash the glass window doors to escape smoothly.
　　The safety hammer mainly uses the conical tip of the life-saving hammer, because the contact area of the tip is small, so when the glass is smashed with the hammer, the pressure of the contact point on the glass is quite large (which is somewhat similar to the principle of the pushpin), and the car glass is subjected to a large external force at that point and slight cracking occurs. For tempered glass, a little cracking means that the stress distribution inside the whole glass is damaged, resulting in countless spider web cracks in an instant, at this time, as long as the hammer is gently smashed a few times, the glass fragments can be removed.