Helical tension spring resists a tensile load applied by means of a suitable end form, hook or loop.
Tension helical springs, also known as extension springs, are comprised of tightly wound helical coils that are designed to operate in the direction of the tension. The spring stretches to a particular length when a force is applied to it. These springs have hooks at both its ends, and are attached to the product. When components attached to the spring are pulled apart from either sides, the spring tries to hold itself together to resist pulling, thereby causing the springing action. When no force is applied, the loops of spring are touching a hook, or loop on the other end. These springs are generally used to deliver return force to the components that are extended.