Variable pitch springs are springs that do not have constant coil spacing. This type of coiling design offers a number of advantages, and a wide range of products depend on variable pitch springs to deliver optimal performance.
In order to understand variable pitch springs, it’s important to know two key spring parameters: pitch and rate. Spring pitch is the distance between two adjacent coils, measured from the midpoint of the spring material. Spring rate is the ratio of force required to deform a spring to the extent of deformity. In compression springs, spring rate measures how difficult it is to compress the spring; in extension springs, spring rate measures how difficult it is to extend the spring.
Variable pitch springs are employed when the manufacturer wants to control spring rate, so the two concepts are closely linked. Spring rate can also be controlled by adjusting spring diameter, but variable pitch springs can offer similar rate profiles while maintaining constant coil diameter.
