Tension springs also known as extension springs or traction springs are coil springs, normally tightly-wound, that are loaded in tension.
This type of springs is designed to bring components together and reacts to an axial force that tends to extend its length, with or without initial tension.

Tension springs are made starting from a circular cross-section wire, helically wound around an axis, with contact coils and with eyelets at the endpoints also called  loops which are attached to components. If these components are moved or pulled apart, the spring opposes this extension, exerting a force to bring them together.
Extension springs are used for several purposes:

• To indicate the amount of tension on the wire

• To act as a shock absorber

• To keep fence tension more uniform


This type of springs have a wide range of uses and are found in many applications, such as switches, levers, braking systems, trampolines, tools, garage doors. They are used in a wide range of industries from rail and agriculture to oil, gas and aerospace engineering.