Springscoil

Springscoil is a mechanical component that combines elements of a compression spring and a torsion spring into a single assembly. The goal is to store and release energy in both axial and rotational modes, enabling two degrees of freedom within a compact form factor. Designs typically use a coaxial arrangement in which an inner torsion spring operates around the same axis as an outer compression coil. End fittings, retainers, and guides keep the parts aligned and minimize lateral play. Materials commonly include high-strength steel alloys, stainless steel, or nickel-based alloys, often with surface treatments to reduce wear or corrosion. Some variants incorporate polymer bushings or ceramic coatings to increase durability.

In operation, axial compression loads the outer coil and stores energy as a linear spring, while rotation twists the inner torsion spring to store angular energy. In many geometries the two modes are largely decoupled, though certain configurations exhibit coupling between axial displacement and rotation. Stiffness and torque can be tuned by adjusting coil pitch, wire diameter, preloads, and the relative length of the two springs.

Springscoils are studied for applications requiring compact multi-axis energy storage and damping, including robotics actuators, precision instruments, vibration isolation platforms, and automotive components. Advantages include higher energy density per volume and adjustable dual stiffness; drawbacks include manufacturing complexity, cost, and potential hysteresis or wear under cyclic loading.

See also: coil spring, torsion spring, dual-axis spring, vibration damper.