Spiral springs are used where a specific torque needs to be maintained within narrow limits over an extended period of time.
Due to the properties of spring steel strip and their spiral geometry, spiral springs have a rising characteristic curve that is almost linear and with minimum hysteresis, making them ideally suited as energy storage and retraction elements.
Depending on the available installation space, working distance and load type, spiral springs can achieve a service life of several million load cycles and have only a low setting loss.
Compared to power springs, spiral springs have a shorter spring length and cover applications with smaller pretension and working distances.
With the FiniteElementMethod, spring geometries can be tested with regard to their running behavior and load before the first part manufactured in series production becomes available for assessment. The method is used to calculate static and dynamic load scenarios, which have a significant influence on bending stresses on the spring and are difficult to investigate experimentally.
A typical feature of spiral springs is that they concentrate on one side. With larger rotation angles, all spring coils will then be on top of each other.
Blue marks the area with the lowest deformation, red the area with the highest deformation.
Spiral springs are also used in all areas where pointer deflection is required. Here, the spring itself is responsible for specific retraction torques that are applied or rotations in angular degrees. These springs are mostly used in mechanical measuring instruments, for example in dial gages, manometers, altimeters, in level measurement and in mechanical watches.
Depending on the choice of material, these spiral springs can also be designed to carry electric current.
For temperature-dependent actuating and control processes, spiral springs specially tailored to these applications are required. To ensure that the high demands on the deformation properties can be met, selected bimetal grades are used. Their geometries and manufacturing processes are the same as for standard flat spiral springs.
These bimetal spiral springs are used primarily in thermal fuses, fire alarms and as controllers in heating and cooling systems.
In spiral coiled springs, the strip or flat wire is bent in a helical shape, similar to compression springs or screws.
The installation situation in the measuring device determines whether a spiral coiled spring or a traditional spiral spring is used.
While the spiral spring, which lies flat, becomes too large in diameter due to its Archimedean pitch, the diameter of a spiral coiled spring remains small. By the same token, the axial length increases.