1. Measurement function

We know that within the elastic limit, the extension (or contraction) of the spring is proportional to the external force. This property of the spring is used to make a spring balance.

2. Compression function

Observing various electrical switches, we will find that one of the two contacts of the switch must be equipped with a spring to ensure that the two contacts are in close contact and conduct well. If the contact is poor, the resistance at the contact point will increase, and the heat generated when the current passes through will increase. In severe cases, the metal at the contact point will melt. The two metal pillars of the bayonet lamp holder are equipped with springs to ensure good contact; as for the central metal sheet of the screw lamp holder and the plug-in metal sheets of all sockets, they are springs, and their function is to keep both sides in close contact to maintain good contact. In the magnetic tape, there is a phosphor bronze spring, which uses the elastic force generated by its bending deformation to make the magnetic head and the magnetic tape in close contact. In the stapler, there is a long coil spring. Its function is to tighten the staples on the one hand, and on the other hand, when the front nail is pushed out, it can send the nails behind to the front to prepare for the nails to be pushed out comfortably. In this way, the nails can be automatically pushed to the front one by one until all the nails are pushed out. Many machines automatically feed and the bullets in automatic rifles are automatically loaded by this function of springs. In addition, clips for clothes, ballpoint pens, and clips on pen covers all utilize the compression function of springs to clamp onto clothes.

3. Reset function

A spring deforms under the action of an external force, and it returns to its original state after the external force is removed. Many tools and equipment use this property of springs to reset. For example, many building door hinges are equipped with reset springs, and the doors will automatically reset after people enter and exit. People also use this function to make automatic umbrellas, automatic pencils and other items, which are very convenient. In addition, reset springs are also indispensable for various buttons and keys.

4. Driving function

Mechanical clocks and clockwork toys are driven by winding up the spring. When the spring is wound up, it bends and stores a certain amount of elastic potential energy. After being released, the elastic potential energy is converted into kinetic energy and driven to rotate through the transmission device. Toy guns, starting guns and military use also use one of the properties of the spring to work.

5. Buffering function

Springs are installed between the locomotive frame and the wheels, and the elasticity of the springs is used to reduce the bumps of the vehicle.

6. Vibration sound function

When air flows through the reed holes in a harmonica or accordion, it hits the reed, causing it to vibrate and produce sound.