POWER SPRING & Prestressed Power Spring Feature: Power Springs, also known as clock springs. Power Spring and Pre-stressed Power Springs are formed by winding a strip of material on an arbor and into a case or retaining ring to create a compact power source. When a pre-stressed power spring is released, it assumes S shape, while power spring 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. Function+Applications Power springs are mainly used in clock, spring motors for toys, timers, as well as in retractor mechanisms for electrical cords, compressor pipes, wire and seat belts. Recently medical and pharmaceutical industry empolys power spring in pen auto injector, drug delivery system.