Manufacture of variable pitch springs
Custom variable pitch springs
Variable-pitch springs are coiled springs whose spacing between coils (called pitch) varies. With a constant spring diameter and wire diameter, the more widely spaced coils require more force to deform. The coils spaced closer together therefore deform first. As the force applied increases, the coils with a higher pitch also start to deform, increasing the stiffness of the spring.
Specific features of variable pitch springs
Non-linear behaviour
Variable spacing gives the spring a progressive, and therefore non-linear, response. Variable pitch is often used to prevent the coils of a compression spring from closing completely under stress. It can also be used to compensate for the variable diameter of a tapered (conical) spring in order to recreate a linear response.
High-frequency applications
Oscillation attenuation
Another advantage of variable pitch springs is their ability to dampen oscillation. Oscillation occurs when the spring comes into resonance with the applied force. This oscillation is undesirable as it reduces the life of the spring and can even lead to immediate failure. By varying the spring pitch, spring oscillation can be reduced. This trick is often used in high-frequency applications.
CGR relies on its STRAIN advanced research laboratory to develop technical solutions to complex problems involving the calculation, sizing and manufacture of variable-pitch springs.
