Why is the iron fence door pushed up so easy

I don't know if everyone has seen a door made of iron bars in life, commonly known as iron fence door. It is not as difficult to push away as some heavy wooden doors, but can stretch. As soon as you push it gently, the iron fence door can gather together; gently pull, the iron fence door is extended again. What is the reason why it can easily push and pull, in addition to the bottom installed, because it has a mesh structure, what is the principle?

The iron fence gate is not made from a flat iron plate, but consists of diamond -shaped (that is, parallel quadranges equal to the four edges). In the plane, the graphic composed of the first and tail of the four line segments not on the same straight line is called quadrangular. One of the major features of the quadrilateral is instability, that is, when the four -edge length of the ease of shape remains unchanged, it can slide the apex, and the shape will change.

The iron fence gate is a design created by the unstable quadrilateral instability. There are many cases in life. For example, a net pocket woven from plastic rope or wire rope can be gathered when not in use, and it can become a good tool for people to install things. Another example is a large truck that runs on the road. It consists of the front and the car. It is often the chain of the diamond -shaped structure that connects the two.

Compared with the instability of the quadrilateral shape, the stability of the triangle is compared to the triangle, that is, when the three -edge length of the triangle is determined, the shape of the triangle is also determined. There are many applications in our lives. For example, when building bridges and roofs, they often use triangles to form brackets.

In life, we can also see some changes from unstable structure to stable structure. For example, a shaking and reinforcement chair, if you nail the wooden strip along the shaking chair leg, this is basically nothing to do, and the chair will still shake. However, if the wooden strip is placed obliquely, it will form a triangle with the horizontal bar of the chair legs and seat planes. After nailing it on the intersection, the chair will not shake. This process is precisely to transform the chair structure from an unstable quadrilateral to a stable triangle.

Whether it is the instability of the quadrilateral shape or the stability of the triangle, people appropriately use different principles to make items use it and easy to use, providing convenience for our lives.

Author: Liu Kaikai

Source: Shaanxi Science and Technology News

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