Constant Force Springs

Although there are a number of different types of Constant Force springs by far the most common are the ones, which are made from steel strip. The most familiar function of a flat strip constant force spring of course is the tape rule which everyone knows. You pull out the tape and no matter how much you pull out it doesn’t need any more effort to do it.

Constant force flat strip springs are generally manufactured from either texture rolled carbon steel or high strength stainless steel depending on the application. Sometimes people confuse them with Power Springs (commonly called Clock Springs) or Spiral Springs, which appear to have a similar construction.

Constant force springs are seen in many applications the most common of which are retractor mechanisms (as seen in car seat belts), brush springs for motors, counterbalance springs for sash windows, cable retractors and timers to name but a few.

Although not cheap to produce there functionality often out ways the unit cost. They are currently seeing resurgence in applications like childrens toys, as an environmentally friendly alternative to batteries.