Fundamentally there are two types of springs. The flat or stretched spring and the coiled spring - also known as the spiral spring.
The stretched spring
The best example of a stretched spring is the bow and arrow.
The bow itself is made of a flexible material - typically wood - and the bow-string is attached to each end of the bow.
By pulling the string back you create tension on the bow (spring) and the energy of the spring (kinetic energy or movement energy) is transferred to an arrow or similar, when you let go of the string.
Leaf springs from the time of Tutankhamun
A more advanced type of spring can be traced all the way back to the Egyptian pharaoh Tutankhamen, who used leaf springs on his carriages. The leaf springs provided a more comfortable drive and also increased the durability of the carriage.
Leonardo Da Vinci
In 1493 Leonardo Da Vinci, engineer, architect, sculptor and much more (he also painted the famous painting Mona Lisa) invented a spring for guns. The small spring made it possible to shoot with just one hand, which was revolutionary for this type of weapon.
The coil spring is probably the greatest step in the history of the spring
In 1763 R. Tradwell secured a patent for the invention of the first version of the coil spring.
This was a great step in the history of the spring, as the coil spring - in comparison to the thus far used leaf springs - did not require the same maintenance.
A leaf spring often had to be separated to be lubricated.
In 1857 the first coil spring made of steel wire was produced. This was a spring for use in an armchair.
Springs of spring wire
Since then coil springs made of spring wire have become a substantial part of the modern world. Some springs are large and visible while others are hidden in a door lock, insulin pen or are a component of a machine.
Regardless of the size, shape or purpose, the principle behind the spring is the same.