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. Due to the shape when a prestressed power spring is released, it assumes an S shape, while power spring assumes a spiral shape.
The advantages of pre-stressed power spring are as follow:
1. Pre-stressed power springs are pre-stressed to produce a flatter torque gradient than conventional power springs.
2. Pre-stressed power spring can store 25% ~ 55% greater energy than power springs.
3. Pre-stressed power spring also has higher turns than power spring when their sizes are the same.