Patent ID: 7992849

Claim:
An actuator operatively coupled to a kinematic joint, the actuator comprising: a spring including a plurality of coils; a guiding element coupled to the spring, the guiding element divides the coils between active coils and inactive coils, wherein rotation of one of the guiding element and the spring relative to the other increases or decreases an amount of the active coils and causes the spring and guiding element to translate relative to each other; a motor, the spring and guiding element being coupled between the motor and the kinematic joint, wherein the motor rotates one of the spring and the guiding element relative to the other and to add energy to or remove energy from the kinematic joint by increasing or decreasing, respectively, energy stored in the active coils of the spring, and wherein the guiding element decouples a torque and translation relationship between the guiding element and the spring.