D. Braun, C. W. Mathews, Human Adaptable Variable Stiffness Springs, US Patent Application 18/226,204, 2023.
This patent describes variable stiffness spring mechanisms designed for human-centered applications. One design integrates a torsional spring with a self-locking mechanism and auxiliary spring, allowing stiffness to be adjusted at an energy cost independent of the spring’s stiffness or stored energy. Another design uses a compression spring with a self-adjusting mechanism that enables energy accumulation using the same maximal compression force, regardless of the energy already stored.
Why it matters: Conventional variable stiffness springs often require energy-intensive adjustments and are limited in their ability to store energy efficiently. These designs provide energy-independent stiffness modulation and scalable energy storage, offering practical solutions for wearable devices, assistive technologies, and robotics.