Variable force spring that does not restricted to Hook's Law for compression springs that the load increases proportionally with stroke. According to your request, you can have a multi-load design. Here are some relations between load and stroke that can be used on specific occasion. The product range from 0.03~0.75mm in thickness and 1~50mm in width.

Power spring is the steel strip wound on an arbor and confined in a spring case. When a force rotates the spring, arbor will have relative motion with spring case and store rotational energy in the form of torque. When the force is removed, torque releases through the central arbor or the spring case in which it is restrained. The product range from 0.03~0.75mm in thickness and 1~50mm in width.