The traditional form of the strip spring is the power spring.
The special feature of the MAXIMO power spring is that the combination of winding forward and then back increases the power density, making maximum use of the available material properties.
A spring support can be used to help guide the spring next to the outer hook.
Without a spring support, power springs have a tendency to wind up off center around the core/axis. Thin and long power springs in particular will run unevenly if the outer end is fixed only at certain points. This causes increased friction between the windings during extraction and retraction, which leads to a loss of torque during the return motion. This loss of friction can be reduced by supporting the outer coil of the spring approximately 30-60 degrees away from the outer end. Supporting the spring in this way ensures that it is as centric and encounters as little friction as possible, lowering the hysteresis value.
Power springs also benefit from this effect if the outermost coil is riveted to form a ring. The riveting then acts as a support for the power spring. For rivet, however, the spring must have a certain minimum size. An example of this would be a strip that is wide enough to take a rivet hole without weakening the strip too much. Another crucial factor is the outer diameter of the wound spring. If it is too compact, the strip material may tend to kink in the area around the rivet hole. When designing the spring, our spring specialists will carry out a detailed analysis of whether it can be produced as a rivet spring.
MAXIMO power springs, which because of their favorable stress distribution generally run with less friction than normal power springs, and therefore more evenly, can also be optimized in terms of their extraction and retraction properties if the outer spring end is supported on the inside wall of the housing.
Even in difficult installation conditions, a spring support should therefore always be considered.