Generally Constant Force Springss are constructed as a rolled ribbon of spring steel. While a Constant Force Springs is applied, the amount of value deformation maintains within a certain range, and the force value remains nearly constant within this region. This is to say, when being straighten by the external force, the spring would roll up naturally and generate elasticity. Since the shifted point could go back to the designated starting point after reaching the goal, a Constant Force Springs could achieve a fixed power in an extreme space.