What is a spring finger contact?

A spring finger is an annular spring that transmits strong currents in confined spaces and can also be used as a purely mechanical connection. It places no special constraints on how it is used and works well in static and dynamic applications across medium- and high-pressure environments, including robotics, automotive, aerospace, petrochemical, medical and marine industries.

How the spring finger works

The wire coils are elliptical and inclined, similar to a canted coil. When the spring is compressed, each coil deforms independently, yet the entire spring reacts as a unit — so the load is consistent at every contact point and a nearly constant elastic force is maintained over a large deformation range. This produces a wide working range with a high permissible compression and a unique load-versus-deformation curve.

Applications and product range

Spring fingers are used wherever a compact, high-current or purely mechanical connection is required. Common products in this family include two-way coil spring fingers, single-turn spring fingers, cylindrical quick-plug self-locking connectors, connectors with equal male/female loading, electric-vehicle chargers and series connectors for high-voltage power battery packs.

If you would like to discuss a spring finger or canted coil application, our engineers can help you select or design the right contact. Contact SISE for samples, specifications and pricing.