A coil spring is a helical-shaped mechanical device that is close-wound or open-wound. Coil springs store mechanical potential energy. They can be made of elastic materials or metal such as hardened steel. You can find coiled springs in many ordinary items—from farm equipment to toys, trampolines and much more.
A coil spring functions by storing energy in order to release it, absorb shock or maintain force between two surfaces. If you apply too much force, you can stretch a spring beyond its limit which will permanently distort the spring.
The coil spring has many designs and applications. The first steel coil spring was produced in 1857 for an armchair. Today, you can find coil springs in countless everyday products, including:
• Retractable pens
• Door handles
• Toys (e.g. the Slinky)
• Garage doors