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.

Constant force spring is made by winding the steel strip into a coil which exerts a nearly constant retraining force to resist uncoiling. By comparing the differences between constant force spring and traditional wire springs, the advantages will be obtain as following: To exert nearly constant force during entire extension. Short initial deflection, it means that reaching the rated load at short extension. Long extension capability. The product range from 0.03~0.75mm in thickness and 1~50mm in width.